• 1.

    Hernandez JA, Garbarino EJ, Shearer JK, et al. Comparison of the calving-to-conception interval in dairy cows with different degrees of lameness during the prebreeding postpartum period. J Am Vet Med Assoc 2005;227:12841291.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2.

    Melendez P, Bartolome J, Archbald LF, et al. The association between lameness, ovarian cysts, and fertility in lactating dairy cows. Theriogenology 2003;59:927937.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3.

    Garbarino EJ, Hernandez JA, Sweeper JK, et al. Effect of lameness on ovarian activity in postpartum holstein cows. J Dairy Sci 2004;87:41234131.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4.

    Sogstad AM, Osteras O, Fjeldaas T. Bovine claw and limb disorders related to reproductive performance and production diseases. J Dairy Sci 2006;89:25192528.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Hernandez JA, Garbarino EJ, Shearer JK, et al. Comparison of milk yield in dairy cows with different degrees of lameness. J Am Vet Med Assoc 2005;227:12921296.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6.

    Green LE, Hedges VJ, Schukken YH, et al. The impact of clinical lameness on the milk yield of dairy cows. J Dairy Sci 2002;85:22502256.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7.

    Booth CJ, Warnick LD, Grohn YT, et al. Effect of lameness on culling in dairy cows. J Dairy Sci 2004;87:41154122.

  • 8.

    Whay HR. Pain in the lame cow. Cattle Pract 1997;5:113118.

  • 9.

    Singh GR, Amarpal, Aithal HP, et al. Lameness in cattle—a review. Indian J Anim Sci 2005;75:723740.

  • 10.

    Trent AM, Plumb D. Treatment of infectious arthritis and osteomyelitis. Vet Clin North Am Food Anim Pract 1991;7:747778.

  • 11.

    Orsini JA. Strategies for treatment of bone and joint infections in large animals. J Am Vet Med Assoc 1984;185:11901193.

  • 12.

    Jackson PGG, Strachan WD, Tucker AW, et al. Treatment of septic arthritis in calves by joint lavage: a study of 20 cases. Ir Vet J 1999;52:563569.

    • Search Google Scholar
    • Export Citation
  • 13.

    Tulleners EP. Management of bovine orthopedic problems. Part ii. Coxofemoral luxations, soft tissue problems, sepsis, and miscellaneous skull problems. Compend Contin Educ Pract Vet 1986;8:S117S125.

    • Search Google Scholar
    • Export Citation
  • 14.

    Smith JA, Williams RJ, Knight AP. Drug therapy for arthritis in food-producing animals. Compend Contin Educ Pract Vet 1989;11:8793.

  • 15.

    Lazzarini L, Lipsky BA, Mader JT. Antibiotic treatment of osteomyelitis: what have we learned from 30 years of clinical trials? Int J Infect Dis 2005;9:127138.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16.

    Lazzarini L, Mader JT, Calhoun JH. Osteomyelitis in long bones. J Bone Joint Surg Am 2004;86:23052318.

  • 17.

    Goodrich LR, Nixon AJ. Treatment options for osteomyelitis. Equine Vet Educ 2004;16:267280.

  • 18.

    Guard C. Strategies for managing septic arthritis of the digit in cattle, in Proceedings. 33rd Annu Conf Am Assoc Bov Pract 2000;2123.

    • Search Google Scholar
    • Export Citation
  • 19.

    Hau T, Nishikawa RA, Phuangsab A. The effect of bacterial trapping by fibrin on the efficacy of systemic antibiotics in experimental peritonitis. Surg Gynecol Obstet 1983;157:252256.

    • Search Google Scholar
    • Export Citation
  • 20.

    Johnson KA. Osteomyelitis in dogs and cats. J Am Vet Med Assoc 1994;205:18821887.

  • 21.

    Henry SL, Galloway KP. Local antimicrobial therapy for the management of orthopedic infections. Clin Pharmacokinet 1995;29:3645.

  • 22.

    Rochat MC. Preventing and treating osteomyelitis. Vet Med (Praha) 2001;96:678685.

  • 23.

    Whitehair KJ, Adams SB, Parker JE, et al. Regional limb perfusion with antibiotics in three horses. Vet Surg 1992;21:286292.

  • 24.

    Whitehair KJ, Bowerstock TL, Blevins WE, et al. Regional limb perfusion for antibiotic treatment of experimentally induced septic arthritis. Vet Surg 1992;21:367373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25.

    Murphey ED, Santschi EM, Papich MG. Regional intravenous perfusion of the distal limb of horses with amikacin sulfate. J Vet Pharmacol Ther 1999;22:6871.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26.

    Werner LA, Hardy J, Bertone AL. Bone gentamicin concentration after intra-articular or regional intravenous perfusion in the horse. Vet Surg 2003;32:559565.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27.

    Pille F, Baere SD, Ceelen L, et al. Synovial fluid and plasma concentrations of ceftiofur after regional intravenous perfusion in the horse. Vet Surg 2005;34:610617.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28.

    Rubio-Martinez LM, Lopez-Sanroman J, Cruz AM, et al. Evaluation of safety and pharmacokinetics of vancomycin after intravenous regional limb perfusion in horses. Am J Vet Res 2005;66:21072113.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29.

    Parra-Sanchez A, Lugo J, Boothe DM, et al. Pharmacokinetics and pharmacodynamics of enrofloxacin and a low dose of amikacin administered via regional intravenous limb perfusion in standing horses. Am J Vet Res 2006;67:16871695.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30.

    Gehring R, Haskell SR, Payne MA, et al. Aminoglycoside residues in food of animal origin. J Am Vet Med Assoc 2005;227:6366.

  • 31.

    FARAD. Prohibited Drug List. Available at: www.farad.org/prohibit.html. Accessed Mar 15, 2007.

    • Crossref
    • Export Citation
  • 32.

    Gagnon H, Ferguson JG, Papich MG, et al. Single-dose pharmacokinetics of cefazolin in bovine synovial fluid after intravenous regional injection. J Vet Pharmacol Ther 1994;17:3137.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33.

    Navarre CB, Zhang L, Sunkara G, et al. Ceftiofur distribution in plasma and joint fluid following regional limb injection in cattle. J Vet Pharmacol Ther 1999;22:1319.

    • Search Google Scholar
    • Export Citation
  • 34.

    Dietz O, Gangel H, Woborill J. Intravenous local antibiotic treatment for infectious diseases of the hoof and claw in cattle. Monatsh Veterinarmed 1980;35:729734.

    • Search Google Scholar
    • Export Citation
  • 35.

    Steiner A, Ossent P, Mathis GA. Intravenous regional anaesthesia and antibiotic therapy applied to the limbs of cattle: indications, techniques and complications. Schweiz Arch Tierheilkd 1990;132:227237.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 36.

    Rubio-Martinez L, Cruz AM. Antimicrobial regional limb perfusion in horses. J Am Vet Med Assoc 2006;228:706712.

  • 37.

    Fajt VR, Apley MD. Antimicrobial issues in bovine lameness. Vet Clin North Am Food Anim Pract 2001;17:159173.

  • 38.

    deHaas V, Bonnier M, Gicquel M, et al. Florfenicol: a time-or concentration-dependent antibiotic. XXII World Buiatrics Congress 2002;1725.

    • Search Google Scholar
    • Export Citation
  • 39.

    Nuflor Injectable Solution product information. Available at: www.nuflor.com/_pdfs/productdisclosure.pdf. Accessed Mar 15, 2007.

    • Crossref
    • Export Citation
  • 40.

    deCraene BA, Deprez P, D'Haese E, et al. Pharmacokinetics of florfenicol in cerebrospinal fluid and plasma of calves. Antimicrob Agents Chemother 1997;41:19911995.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 41.

    Bretzlaff KN, Neff-Davis CA, Ott RS, et al. Florfenicol in nonlactating dairy cows: pharmacokinetics, binding to plasma proteins, and effects on phagocytosis by blood neutrophils. J Vet Pharmacol Ther 1987;10:233240.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 42.

    Soback S, Paape MJ, Filep R, et al. Florfenicol pharmacokinetics in lactating cows after intravenous, intramuscular and intramammary administration. J Vet Pharmacol Ther 1995;18:413417.

    • Search Google Scholar
    • Export Citation
  • 43.

    Adams PE, Varma KJ, Powers TE, et al. Tissue concentrations and pharmacokinetics of florfenicol in male veal calves given repeated doses. Am J Vet Res 1987;48:17251732.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 44.

    Varma KJ, Adams PE, Powers TE, et al. Pharmacokinetics of florfenicol in veal calves. J Vet Pharmacol Ther 1986;9:412425.

  • 45.

    Lobell RD, Varma KJ, Johnson JC, et al. Pharmacokinetics of florfenicol following intravenous and intramuscular doses to cattle. J Vet Pharmacol Ther 1994;17:253258.

    • Search Google Scholar
    • Export Citation
  • 46.

    The United States Pharmacopeia. Rockville, Md: US Pharmacopeial Convention, 2006.

  • 47.

    Gibaldi M, Perrier B. Pharmacokinetics. 2nd ed. New York: Marcel-Dekker, 1982.

  • 48.

    Gabrielsson J, Weiner D. Pharmacokinetic and pharmacodynamic data analysis, concepts and applications. 3rd ed. Stockholm: Swedish Pharmaceutical Press, 2001.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 49.

    Hurley JD, Wilson SD, Worman LM, et al. Chronic osteomyelitis. Treatment by regional perfusion with antibiotics. Arch Surg 1966;92:548553.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 50.

    Finsterbush A, Weinberg H. Venous perfusion of the limb with antibiotics for osteomyelitis and other chronic infections. J Bone Joint Surg Am 1972;54:12271234.

    • Search Google Scholar
    • Export Citation
  • 51.

    Nuflor Injectable Solution Environmental Assessment. Available at: www.fda.gov/cvm/FOI/141-063EA.pdf. Accessed Jun 1, 2007.

    • Crossref
    • Export Citation
  • 52.

    El-Aty AM, Goudah A, El-Sooud KA, et al. Pharmacokinetics and bioavailability of florfenicol following intravenous, intramuscular and oral administrations in rabbits. Vet Res Commun 2004;28:515524.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 53.

    Park BK, Lim JH, Kim MS, et al. Pharmacokinetics of florfenicol and its major metabolite, florfenicol amine, in rabbits. J Vet Pharmacol Ther 2007;30:3236.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 54.

    Senoh H, Aiso S, Arito H, et al. Carcinogenicity and chronic toxicity after inhalation exposure of rats and mice to N,N-dimethylformamide. J Occup Health 2004;46:429439.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 55.

    Fail PA, George JD, Grizzle TB, et al. Formamide and dimethylformamide: reproductive assessment by continuous breeding in mice. Reprod Toxicol 1998;12:317332.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 56.

    Kowalski P, Konieczna L, Chmielewska A, et al. Comparative evaluation between capillary electrophoresis and high-performance liquid chromatography for the analysis of florfenicol in plasma. J Pharm Biomed Anal 2005;39:983989.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 57.

    Nagaraja TG, Narayanan SK, Stewart GC, et al. Fusobacterium necrophorum infections in animals: pathogenesis and pathogenic mechanisms. Anaerobe 2005;11:239246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 58.

    Verschooten F, Vermeiren D, Devriese L. Bone infection in the bovine appendicular skeleton: a clinical, radiographic, and experimental study. Vet Radiol Ultrasound 2000;41:250260.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 59.

    Freedom of Information Summary. NADA 141–063, Nuflor Injectable Solution, 1999, Available at: www.fda.gov/ohrms/dockets/98fr/141063Fi.pdf. Accessed Jun 1, 2007.

    • Crossref
    • Export Citation
  • 60.

    Yoshimura H, Kojima A, Ishimaru M. Antimicrobial susceptibility of Arcanobacterium pyogenes isolated from cattle and pigs. J Vet Med B Infect Dis Vet Public Health 2000;47:139143.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 61.

    Chirino-Trejo M, Woodbury MR, Huang F. Antibiotic sensitivity and biochemical characterization of Fusobacterium spp. and Arcanobacterium pyogenes isolated from farmed white-tailed deer (Odocoileus virginianus) with necrobacillosis. J Zoo Wildl Med 2003;34:262268.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 62.

    Gagea MI, Bateman KG, Shanahan RA, et al. Naturally occurring Mycoplasma bovis-associated pneumonia and polyarthritis in feedlot beef calves. J Vet Diagn Invest 2006;18:2940.

    • Search Google Scholar
    • Export Citation
  • 63.

    Ayling RD, Baker SE, Peek ML, et al. Comparison of in vitro activity of danofloxacin, florfenicol, oxytetracycline, spectinomycin and tilmicosin and recent field isolates of Mycoplasma bovis. Vet Rec 2000;146:745747.

    • Search Google Scholar
    • Export Citation

Advertisement

Pharmacokinetics of florfenicol in serum and synovial fluid after regional intravenous perfusion in the distal portion of the hind limb of adult cows

John N. GilliamDepartment of Clinical Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078.

Search for other papers by John N. Gilliam in
Current site
Google Scholar
PubMed
Close
 DVM, MS
,
Robert N. StreeterDepartment of Clinical Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078.

Search for other papers by Robert N. Streeter in
Current site
Google Scholar
PubMed
Close
 DVM, MS
,
Mark G. PapichDepartment of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Chapel Hill, NC 27599.

Search for other papers by Mark G. Papich in
Current site
Google Scholar
PubMed
Close
 DVM, MS
,
Kevin E. WashburnDepartment of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843.

Search for other papers by Kevin E. Washburn in
Current site
Google Scholar
PubMed
Close
 DVM
, and
Mark E. PaytonDepartment of Statistics, College of Arts and Sciences, Oklahoma State University, Stillwater, OK 74078.

Search for other papers by Mark E. Payton in
Current site
Google Scholar
PubMed
Close
 PhD

Abstract

Objective—To define the pharmacokinetics of florfenicol in synovial fluid (SYNF) and serum from central venous (CV) and digital venous (DV) blood samples following regional IV perfusion (RIVP) of the distal portion of the hind limb in cows.

Animals—6 healthy adult cows.

Procedures—In each cow, IV catheters were placed in the dorsal common digital vein (DCDV) and the plantar vein of the lateral digit, and an indwelling catheter was placed in the metatarsophalangeal joint of the left hind limb. A pneumatic tourniquet was applied to the midmetatarsal region. Florfenicol (2.2 mg/kg) was administered into the DCDV. Samples of DV blood, SYNF, and CV (jugular) blood were collected after 0.25, 0.50, and 0.75 hours, and the tourniquet was removed; additional samples were collected at intervals for 24 hours after infusion. Florfenicol analysis was performed via high-performance liquid chromatography.

Results—In DV blood, CV blood, and SYNF, mean ± SD maximum florfenicol concentration was 714.79 ± 301.93 μg/mL, 5.90 ± 1.37 μg/mL, and 39.19 ± 29.42 μg/mL, respectively; area under the concentration versus time curve was 488.14 ± 272.53 h•μg•mL−1, 23.10 ± 6.91 h•μg•mL−1, and 113.82 ± 54.71 h•μg•mL−1, respectively; and half-life was 4.09 ± 1.93 hours, 4.77 ± 0.67 hours, and 3.81 ± 0.81 hours, respectively.

Conclusions and Clinical Relevance—Following RIVP, high florfenicol concentrations were achieved in DV blood and SYNF, whereas the CV blood concentration remained low. In cattle, RIVP of florfenicol may be useful in the treatment of infectious processes involving the distal portion of limbs.

Abstract

Objective—To define the pharmacokinetics of florfenicol in synovial fluid (SYNF) and serum from central venous (CV) and digital venous (DV) blood samples following regional IV perfusion (RIVP) of the distal portion of the hind limb in cows.

Animals—6 healthy adult cows.

Procedures—In each cow, IV catheters were placed in the dorsal common digital vein (DCDV) and the plantar vein of the lateral digit, and an indwelling catheter was placed in the metatarsophalangeal joint of the left hind limb. A pneumatic tourniquet was applied to the midmetatarsal region. Florfenicol (2.2 mg/kg) was administered into the DCDV. Samples of DV blood, SYNF, and CV (jugular) blood were collected after 0.25, 0.50, and 0.75 hours, and the tourniquet was removed; additional samples were collected at intervals for 24 hours after infusion. Florfenicol analysis was performed via high-performance liquid chromatography.

Results—In DV blood, CV blood, and SYNF, mean ± SD maximum florfenicol concentration was 714.79 ± 301.93 μg/mL, 5.90 ± 1.37 μg/mL, and 39.19 ± 29.42 μg/mL, respectively; area under the concentration versus time curve was 488.14 ± 272.53 h•μg•mL−1, 23.10 ± 6.91 h•μg•mL−1, and 113.82 ± 54.71 h•μg•mL−1, respectively; and half-life was 4.09 ± 1.93 hours, 4.77 ± 0.67 hours, and 3.81 ± 0.81 hours, respectively.

Conclusions and Clinical Relevance—Following RIVP, high florfenicol concentrations were achieved in DV blood and SYNF, whereas the CV blood concentration remained low. In cattle, RIVP of florfenicol may be useful in the treatment of infectious processes involving the distal portion of limbs.

Lameness is a major concern for the cattle industry, resulting in economic loss through decreased reproductive performance,1–4 decreased milk production,5,6 and premature culling.7 In addition to the economic loss, lameness is also an important animal welfare concern.8 Most lameness in bovids originates in the foot.9 If not treated properly, common causes of lameness, such as interdigital necrobacillosis and sole ulcers, can progress to involve deeper structures of the foot9 and result in osteomyelitis, septic arthritis, and septic tenosynovitis, which are collectively known as deep digital sepsis. These conditions are among the most debilitating causes of lameness, often resulting in substantial loss of function or destruction of the animal.10

Treatment of deep digital sepsis generally requires surgical interventions (eg, debridement, drainage, and lavage) and stabilization of the affected tissues10–12 along with antimicrobial treatments. Antimicrobials may have to be administered for as long as 6 weeks in some instances.10,13–16 The expenses and labor associated with long-term antimicrobial administration may be impractical in many situations. In addition, systemic administration of antimicrobials may have limited efficacy because of the presence of necrotic material or inflammatory mediators, poor vascular perfusion, entrapment of bacteria in fibrin, and the presence of biofilm or glycocalyx surrounding foreign material or surgical implants.17–20

Regional IV perfusion of antimicrobials in the distal portion of a limb may offer several advantages over systemic administration of those drugs in the treatment of deep digital sepsis. The advantages include development of high concentrations of the antimicrobial at the site of infection and, because of the more localized effects, low systemic drug exposure.20–22 Other potential advantages include decreased duration of antimicrobial treatment and reduced drug costs.

The successful use of RIVP in the treatment of orthopedic infections in horses has been reported.23,24 The dispositions of amikacin,25 gentamicin,26 ceftiofur,27 vancomycin,28 and enrofloxacin29 in horses following RIVP have been described. The concern regarding extended withdrawal periods for aminoglycosides limits the use of those drugs in food animals.30 Federal law prevents the extralabel use of enrofloxacin and vancomycin in food animals.31 However, the pharmacokinetics of cefazolin32 and ceftiofur33 delivered via RIVP in cattle have been described, and the RIVP of benzylpenicillin in cattle has been described in the European veterinary literature.34,35 Both of those reports refer to clinical studies and do not include assessments of the pharmacokinetics of the antimicrobials.

Although concentration-dependent antimicrobials are ideally suited for RIVP, time-dependent antimicrobials may be effective as well.36 The concentration-dependent antimicrobials that are presently available to food animal practitioners include aminoglycosides and fluoroquinolones, but the use of such drugs in food animals is severely limited. Ceftiofur, a time-dependent antimicrobial, has been evaluated for use via RIVP in cattle.33 On the basis of the findings of that study, therapeutic ceftiofur concentrations are short-lived after tourniquet removal; consequently, an 8-hour dosing interval is required for maximum effectiveness of that drug.37 However, administration of RIVP every 8 hours is not practical in most clinical settings.

Florfenicol is a phenolic antimicrobial that inhibits the 50S subunit of the bacterial ribosome.38 Florfenicol is approved for use in the treatment of bovine respiratory disease complex and interdigital necrobacillosis in cattle.39 Although labeled for IM or SC administration, florfenicol can be safely administered IV.40–44 Pharmacodynamic properties of florfenicol are not as well-known as those of other classes of antimicrobials, but recent research38 has revealed that the drug has concentration-dependent bactericidal activity. In the report of that study, florfenicol was described as a time-dependent antimicrobial with notable concentration dependency against several major pathogens in veterinary medicine38; the pathogens of concern for cattle included Mannheimia haemolytica, Pasteurella multocida, and Haemophilus (Histophilus) somnus. Although the concentration-dependent activity detected was not as marked as that associated with typical concentration-dependent antimicrobials, even limited concentration dependency may be beneficial in the application of florfenicol via RIVP in food animals.

The purpose of the study reported here was to define the pharmacokinetics of florfenicol in SYNF and serum from CV and DV blood samples following RIVP of the distal portion of the hind limb in cows. We hypothesized that RIVP of florfenicol would result in concentrations of florfenicol in SYNF and in serum from DV blood samples that would meet or exceed therapeutic targets for the antimicrobial.

Materials and Methods

Animals—Six adult mixed-breed beef cows were included in the study. The cows' ages ranged from 6 to 10 years; weights ranged from 445 to 688 kg. The cows were each identified with an ear tag labeled with a single letter (A, D, E, F, G, or K). No clinical signs of lameness were evident at the beginning of the study. The cattle were owned by the veterinary teaching hospital for at least a year prior to this study and had not been treated with florfenicol during that time. Throughout the study, the cows were housed in stalls in the hospital and provided with free-choice grass hay and water ad libitum. The cows were evaluated for evidence of lameness by the principle investigator during the sampling period and daily for 1 week following completion of sample collections. The study was approved by the Institutional Animal Care and Use Committee of Oklahoma State University.

Catheter placement—The cows were sedated via IV administration of 25 mg of xylazine hydrochloridea and restrained in lateral recumbency in a hydraulic tilt chute. The distal aspect of the left hind limb, beginning at the midmetatarsal region, was clipped and cleaned with chlorhexidine scrub solution. A rubber tourniquet was placed tightly around the midmetatarsal region. Anesthesia of the distal portion of the limb was accomplished by use of ring block anesthesia (2% lidocaineb) applied around the midmetatarsal area. The digits were covered with a sterile glove, and the skin over the distal portion of the limb was prepared in sterile manner.

Venipuncture of the DCDV was performed by use of an 18-gauge, 2.5-cm needle. A sterile guide wire was placed through the needle into the vein, and the needle was removed. A stab incision was then made over the vein with a No. 15 scalpel blade while the wire was used as a guide. An 18-gauge, 4.8-cm catheterc was then passed over the wire and into the vein. The wire was removed, and a T-portd with injection cape was then placed on the catheter. The catheter and T-port were sutured into place by use of 2-0 nylon suture. The same procedure was repeated for the PVLD of the left hind limb. The tourniquet was removed after venous catheterizations were completed.

The metatarsophalangeal joint was catheterized with a 20-gauge epidural infusion catheter.f Arthrocentesis was performed over the craniolateral aspect of the joint by use of an 18-gauge, 3.8-cm needle. An injection cap was placed on the needle, and 30 to 50 mL of sterile saline (0.9% NaCl) solution was infused into the joint space through a 19-gauge butterfly catheterg that was placed in the injection cap. As the joint capsule was distended, the caudolateral aspect of the joint region was palpated to identify the joint pouch. A 0.5-cm stab incision was made over the joint pouch with a No. 15 blade, and a 19-gauge, 9-cm Tuohy needle was placed in the caudolateral joint pouch. This needle was placed in the stab incision and held at an angle of approximately 30° lateral to the median plane of the limb and 15° caudal to the dorsal plane of the limb. The needle was advanced until it entered the distended joint space. A curved 16-gauge, 10-cm needle was placed through the skin approximately 4 cm proximal to the stab incision, advanced under the skin, and allowed to exit through the stab incision. The purpose of this needle was to create a subcutaneous tunnel through which the catheter tubing could be placed. The catheter tubing was passed approximately 1.5 cm into the joint through the Tuohy needle. The Tuohy needle was removed, and the catheter tubing was shortened to the desired length. The free end of the tubing was passed through the 16-gauge needle, and the needle was removed. The tubing was pulled through the subcutaneous tunnel until it was no longer exposed at the stab incision. An injection cap was placed on the catheter tubing, and the catheter was secured to the skin by use of 2-0 nylon suture in a Chinese finger-cuff pattern. A light bandage was placed over the catheters for protection. Sedation was reversed when needed via IV administration of tolazolineh (1 mg/kg). All catheters were placed at least 24 hours prior to beginning the study.

Dosage calculation—The dose of 2.2 mg of florfenicol/kg used in the study was determined by weighing the distal portion of a hind limb (distal half of metatarsus and foot) of a cow that had been euthanized for nonmusculoskeletal disease and calculating a dose for that weight (12-kg limb specimen obtained from a 545-kg cow) on the basis of 40 mg of florfenicol/kg. The dose of 2.2 mg/kg of whole body weight was chosen because it provided 2 to 3 times the upper limit of the label dose (40 mg/kg) for the weight of the distal portion of the limb. At that dose, the volume of florfenicol delivered was small.

Florfenicol administration and sample collection—Each cow was sedated via IV administration of xylazine (25 mg) and restrained in lateral recumbency on the hydraulic tilt chute. A pneumatic tourniqueti was placed around the limb at the midmetatarsal level. A 3-mL blood sample was collected from the PVLD, and both IV catheters were flushed with 3 mL of saline solution containing heparin. A 3-mL CV blood sample was also collected from the left jugular vein via venipuncture. A 0.5-mL sample of SYNF was collected from the metatarsophalangeal joint via the indwelling catheter. These first samples served as the baseline (time 0 hour) samples. The tourniquet was inflated to 300 mm Hg. Florfenicolj (2.2 mg/kg) was administered into the DCDV (time 0). The catheter was not flushed after florfenicol administration; because the catheter was not flushed, an additional 0.6 mL of florfenicol was added to the dose to account for the volume of the catheter. The volume of florfenicol administered ranged from 3.9 to 5.6 mL. Digital venous and CV blood samples (3 mL) were collected from the PVLD and jugular vein, respectively, and an SYNF sample (0.3 to 0.5 mL) was collected at 0.25, 0.50, and 0.75 hours after florfenicol administration. The tourniquet was removed, and the cow was allowed to stand. Sample collection was repeated at 1, 1.5, 2, 4, 8, 12, 18, and 24 hours after florfenicol administration. Prior to each sample collection, 3 mL of blood and 0.2 mL of SYNF were collected and discarded. Blood samples were collected in plain glass tubes, and SYNF samples were placed in 0.5-mL plain plastic cryotubes.k Synovial fluid samples were labeled and placed on ice immediately after collection. Blood samples were allowed to clot at room temperature (approx 26.5°C), and serum was harvested via centrifugation. Serum was placed in 1.5-mL plain plastic cryotubes.l Samples that could not be centrifuged within 2 hours of collection were refrigerated. All sera were harvested within 18 hours of collection. Synovial fluid samples that were contaminated with blood were centrifuged, and the supernatant was collected.32,33 Synovial fluid samples with visible blood contamination were from cow A only. Serum and synovial fluid samples were frozen at 20°C until analysis could be performed.40

Sample analysis—The serum and synovial fluid samples were assayed for florfenicol via reverse-phase high-pressure liquid chromatography with UV detection. The laboratory used other published references42–45 as a guide but added some modifications to the procedure to generate an assay adapted for the fluids collected from the cows in this study. The high-pressure liquid chromatography system consisted of a quaternary pump and degasser,m an automated sampler,n and a UV detector.o Plasma extraction was accomplished with solid-phase hydrophilic-lipophilic balanced extraction cartridgesp that were conditioned with 1 mL of methanol followed by 1 mL of distilled water. After addition of 200 μL of a serum sample to the cartridge, it was washed with 1.0 mL of distilled water and methanol (95:5 mixture). The eluent was discarded. The final elution was achieved via addition of 1.0 mL of methanol into a clean glass tube. The eluate was evaporated in a hot water bath (45°C) for 20 to 25 minutes and reconstituted with 200 μL of mobile phase.

A reverse-phase, stable-bond C-8 columnq (4.6 mm × 15 cm) was heated to 40°C to achieve separation. The mobile phase consisted of 70% distilled water and 30% acetonitrile. The UV detector was set to a wavelength of 223 nm. The volume for each injection was 20 μL. Retention time for florfenicol was 4.5 to 5.0 minutes. Chromatograms were integrated with computer software.r We were not aware of any active metabolites to be detected.

A stock solution of florfenicol was prepared by dissolving a pure analytical reference standard of florfenicols in acetonitrile at a concentration of 1 mg/mL; the stock solution was stored in a refrigerator. The analytical reference standard solution was used to make calibration standards and fortify quality-control samples. The 1 mg/mL stock solution was further diluted serially with distilled water to concentrations ranging from 1,000 to 3.91 μg/mL. Standard curves for serum analysis were prepared by fortifying 200 μL of pooled bovine serum with 20 μL of the diluted stock solutions to make 11 calibration standards (including zero concentration) of florfenicol. Concentrations in the calibration curve incorporated the range of 100 to 0.195 μg/mL. Unfortified cattle serum was used as a blank sample to verify that the assay contained no interfering compounds and to determine the background noise for the assay. The fortified calibration samples were processed and prepared exactly as described for the collected experimental samples. For each day's assay run, fresh sets of calibration and blank samples were prepared. Calibration curves of peak height versus concentration were calculated by use of linear regression analysis. All calibration curves were linear with a value of R2 ≥ 0.99. Limit of quantification for florfenicol in bovine serum was 0.195 μg/mL, which was determined from the lowest point on a linear calibration curve that was accompanied by an acceptable signal-to-noise ratio. The laboratory used guidelines published by the United States Pharmacopeia (2006).46

The SYNF samples were prepared in the same manner as that of the serum samples, except for slight modification. Because SYNF is highly viscous, processing is difficult in extraction cartridges. Therefore, prior to processing, hyaluronidase (10 μL) was added to each sample followed by vortexing. The SYNF samples were then processed in the same manner as the sera. For the calibration samples, SYNF was collected from bovids that were examined by the college's necropsy service for reasons other than musculoskeletal disease. According to each animal's record, these cattle had not been treated with florfenicol. To prepare calibration samples, the collected SYNF was fortified with florfenicol in the same manner as the study serum samples. The calibration range was the same as that for the serum samples.

Pharmacokinetic analysis—Serum and SYNF concentrations of florfenicol after the injection into the DCDV were analyzed by use of a computer program.t A noncompartmental analysis that does not assume any compartmental structure was used for the analysis because this was considered a locally (rather than systemically) administered injection and because calculation of compartmental parameters would have been subject to error. Calculation methods were derived from published methods.47,48

For the noncompartmental analysis, the AUC(0–Ct) for serum or SYNF (defined by the limit of quantification) was calculated by use of the log-linear trapezoidal method. The AUC(0–∞) was calculated by addition of the terminal portion of the curve (estimated from the relationship of CtZ, where λZ is the terminal rate constant of the curve, and Ct is the last measured concentration) to the AUC0–Ct. The AUC%extrap (extrapolated by use of the trapezoidal rule) was calculated by use of the following equation:

div1

Values for Cmax and Tmax were taken directly from the data. Half-lives were calculated from the terminal slope as follows: t½ = ln 2.0/(terminal rate constant), where ln 2.0 is the natural logarithm of 2.0. Traditional pharmacokinetic parameters, such as apparent volume of distribution and systemic clearance, were not calculated because the study involved regional administration of a drug and because those parameters describe whole-body effects.

Statistical analysis—Data were analyzed by use of computer software.u The experimental design was a randomized complete-block design with repeated measures. The cow was considered the blocking variable, and location was considered the main unit factor. Time was the repeated-measures factor. Because of normality and heterogeneity of variance problems associated with the response variable, a natural logarithm(x+1) transformation was used to stabilize and normalize the data. Analysis of variance and an autoregressive period-1 covariance structure were used to model the intralocation covariances across time. If the test of simple effects yielded a significant result, pairwise t tests were used to separate the means. A value of P ≤ 0.05 was considered significant.

Results

Among the 6 cows, no lameness or other adverse effects were observed throughout the study period. A sample could not be collected from the PVLD for 1 cow at the 4-hour time point (cow D) and from another cow at the 18-hour time point (cow K; loss of catheter). The 24-hour DV blood sample for cow K was collected via venipuncture of the PVLD. Also, SYNF samples were not collected from 1 cow (cow A) at the 0.75- and 1-hour sample collection times because of difficulties with catheter function. Florfenicol was not detected in any of the samples collected at 0 hours or in the serum and synovial fluid samples used for calibration of the assay.

The concentration versus time profiles of florfenicol in DV blood, SYNF, and CV blood samples were calculated. Mean ± SD peak florfenicol concentrations in DV blood, SYNF, and CV blood samples were 714.8 ± 301.9 μg/mL, 39.2 ± 29.4 μg/mL, and 5.9 ± 1.4 μg/mL, respectively. At 0.25 hours after infusion, florfenicol concentration in DV blood samples was significantly higher than that in either SYNF or CV blood samples (Table 1). At 0.5 and 0.75 hours after infusion, concentrations in all sample types were significantly different. At 8 hours after infusion, no significant differences in florfenicol concentration were detected among sample types.

Table 1—

Mean ± SE florfenicol concentration (μg/mL) in samples of serum derived from DV blood, SYNF, and serum derived from CV blood following RIVP of florfenicol (2.2 mg/kg) in the distal portion of a hind limb in 6 adult cows. Florfenicol was administered into the DCDV. Samples were collected for analysis after 0.25, 0.50, and 0.75 hours, and the tourniquet was removed; additional samples were collected at intervals for 24 hours after infusion.

Time (h)DV bloodSYNFCV blood
0.25706.15 ± 120.84a8.58 ± 2.87b4.18 ± 1.20b
0.50568.43 ± 145.17a21.03 ± 4.81b4.22 ± 1.29c
0.75508.65 ± 167.59a24.33 ± 7.28b3.75 ± 1.0c
1.0017.41 ± 5.51a42.58 ± 13.83a4.87 ± 0.46b
1.509.30 ± 2.39b27.54 ± 6.38a3.57 ± 0.27b
2.005.69 ± 0.96b21.59 ± 4.98a2.95 ± 0.28b
4.003.26 ± 0.58a,b8.83 ± 2.37a1.90 ± 0.21b
8.001.49 ± 0.38a2.71 ± 0.70a0.83 ± 0.12a
12.001.07 ± 0.67a1.01 ± 0.32a0.40 ± 0.07a
18.000.38 ± 0.20a0.42 ± 0.10a0.19 ± 0.04a
24.000.49 ± 0.25a0.25 ± 0.07a0.09 ± 0.02a

Fora given time point, values with different superscript letters are significantly (P ≤ 0.05) different.

The mean pharmacokinetic parameters of florfenicol in DV blood, SYNF, and CV blood samples were calculated (Table 2). Values of pharmacokinetic parameters derived from DV blood, SYNF, and CV blood samples for individual cows varied considerably. For example, 2 of the cows (cows A and F) had lower values for Cmax, AUC(0–Ct), and AUC(0–∞) in DV blood and SYNF relative to findings in other cows.

Table 2—

Mean ± SD pharmacokinetic parameters for florfenicol in samples of serum derived from DV blood, SYNF, and serum derived from CV blood following RIVP of florfenicol (2.2 mg/kg) in the distal portion of a hind limb in 6 adult cows.

Time (h)DV bloodSYNFCV blood
Elimination rate(1/h)0.22 ± 0.150.19 ± 0.040.15 ± 0.02
t1/2 (h)4.09 ± 1.933.81 ± 0.814.77 ± 0.67
Tmax(h)0.29 ± 0.100.88 ± 0.380.63 ± 0.31
Cmax (μg/mL)714.79 ± 301.9339.19 ± 29.425.9 ± 1.37
AUC0–Ct(h•μg•mL−1)485.47 ± 270.17112.97 ± 54.7622.57 ± 6.72
AUC0–∞(h·μg·mL−1)488.14 ± 272.53113.82 ± 54.7123.1 ± 6.91
AUC%extrap(%)0.46 ± 0.411.01 ± 0.882.55 ± 0.62

Discussion

Regional limb perfusion with antimicrobial agents for the treatment of chronic osteomyelitis in humans was reported in the late 1950s and early 1960s.49 Regional IV perfusion is easily performed on the distal portion of a limb by placing a tourniquet on the limb and infusing the antimicrobial distal to the tourniquet. Affected areas that are more proximal on the limb may be isolated by placing tourniquets proximal and distal to the area to be infused. Tourniquet application occludes venous drainage from the limb, resulting in an increase in intravascular pressure; the increased intravascular pressure and the concentration gradient created by infusion of the antimicrobial promote diffusion of the drug into the surrounding tissues.50 The antimicrobial agent may be infused into any accessible vein in the target area—the DCDV is the most easily accessible and commonly used vein for RIVP in the distal portion of the limbs of cattle.

In the present study, the metatarsophalangeal joint was catheterized to facilitate the collection of multiple SYNF samples over a period of time. During the placement of these catheters, the joint space was distended with sterile saline solution to facilitate identification of the caudolateral joint pouch and ensure correct placement of the catheter. Catheter placement was performed in an aseptic manner to minimize the risk of infection. Distention of the joint capsule could potentially result in inflammatory changes in the synovial membrane if the distention continued for a long period of time. Also, the acidic pH of physiologic saline solution could result in changes in the synovial membrane if it is not removed from the joint space. In the cows of our study, the distention was immediately relieved once the catheter was in place and was unlikely to result in notable changes in the joint. All catheters, including venous catheters, were placed at least 24 hours prior to the beginning of the study.

In horses, antimicrobials delivered via RIVP are often diluted to a volume of 60 mL.36 It is thought that a larger infusion volume results in increased intravascular pressure and better diffusion of the antimicrobial into the tissues.36 In the present study, florfenicol was not diluted because of the drug's poor solubility in water and we chose not to infuse high volumes of an organic solvent diluent into these tissues. In aqueous solution, the solubility of florfenicol is reported to be 2 mg/mL.51 The doses administered in our study would have had to be diluted in several liters of fluid to achieve solubilization, which is not practical for RIVP.

Because of the poor solubility of florfenicol in water, flushing a catheter with saline solution that contains heparin following florfenicol administration will result in precipitation of the florfenicol and obstruction of the catheter. In the authors' clinical experience, injection of 1 mL of the patient's own serum before and after the administration of florfenicol is an effective means of ensuring drug delivery through the catheter. Dilution of florfenicol with sterile water combined with a solubilizing agent, dimethyl formamide, has been described.52,53 However, that compound is a carcinogen54 and causes birth defects55; therefore, it cannot be used in food animals.

Florfenicol is stable in physiologic fluids, which reduces the potential effects of sample handling on drug concentrations. Florfenicol recovery rates > 99% have been achieved in plasma and CSF that were stored at room temperature for 24 hours.40 In plasma samples that underwent 3 freeze-thaw cycles at −20°C over a 2-month period, florfenicol remained stable.56

In the present study, administration of florfenicol via RIVP of the distal portion of the limb of cows resulted in high drug concentrations in DV blood and in SYNF collected from the metatarsophalangeal joint. There were some differences in drug concentrations in the 3 sample types among the study cows. In 2 cows, florfenicol concentrations in DV blood and SYNF samples were lower and the concentration in CV blood was higher than findings in corresponding samples collected from the other 4 cows. These data suggest that the tourniquet may not have provided enough venous occlusion in the limbs of those 2 cows, thereby allowing more of the administered dose to reach the systemic circulation prior to tourniquet removal. As a result, the comparatively lower concentrations of florfenicol in the vasculature distal to the tourniquet lead to a lower concentration gradient for drug diffusion into the joint.

The tourniquet pressure of 300 mm Hg was chosen for use in our study on the basis of the pressure that has been reported to be effective in horses27; however, the pressure that we used was lower than that reported in 1 study32 involving mature cattle. Although the present study was not intended to evaluate the effects of various tourniquet pressures, we chose the lower pressure because it was effective in horses and theoretically less likely to cause adverse effects. Although none of the regionally perfused drug should reach the systemic circulation prior to tourniquet removal, some leakage does occasionally occur. In a previous study25 by one of the authors, amikacin was detectable systemically prior to tourniquet removal in 1 of 3 horses in which the drug was administered via RIVP. Another difference between the study reported here and other published studies is that most other studies are performed in anesthetized horses, whereas the cows of the present study were restrained but conscious. Struggling against restraint could potentially affect the performance of the tourniquet. We cannot speculate on the potential effect of higher tourniquet pressures in our study without additional data.

Regional IV administration of florfenicol into the DCDV resulted in high drug concentrations in the serum derived from DV blood samples. The concentration remained high until the tourniquet was removed, at which time the concentration decreased rapidly. Although the concentration of florfenicol decreased after tourniquet removal, the concentration remained > 1 μg/mL for 12 hours. Following administration of a single dose of 22 mg of florfenicol/kg in the jugular vein of veal calves, an initial drug concentration of 65.68 μg/mL has been reported.44 In another study,45 an initial florfenicol concentration of 39.7 μg/mL was detected following administration of a 20 mg/kg dose to feeder calves. Both of those studies investigated whole-body pharmacokinetics and did not involve regional drug administration or sample collection. In the present study, the initial florfenicol concentration in DV blood was 706.15 μg/mL following administration of a much smaller dose of the drug into the DCDV; this indicates that RIVP has the ability to attain much higher drug concentrations in the digital circulation, compared with peripheral concentrations achieved via central IV administration, even though lower doses (on a mg/kg basis) are administered.

In the study reported here, administration of florfenicol via RIVP in the distal portion of the hind limbs of cows resulted in high concentrations of florfenicol in the metatarsophalangeal joint. The mean peak SYNF concentration was 39.19 μg/mL, and Tmax was 0.88 hours. This peak concentration occurred after removal of the tourniquet, which indicated that diffusion of florfenicol into the joint continued to occur after tourniquet removal. Florfenicol concentration in SYNF remained > 1 μg/mL for 12 hours and was 0.25 μg/mL at 24 hours after administration.

As expected, the peak florfenicol concentration in the DV blood samples was detected in the first sample collected after drug administration. The concentration slowly decreased from that time point until the tourniquet was removed, after which the concentration decreased rapidly. This decrease was expected because florfenicol diffuses from the vascular space into the surrounding tissues. The rapid decrease in DV blood concentration after tourniquet removal was expected and attributable to the release of the sequestered DV blood into the systemic circulation. Also, the florfenicol concentration in SYNF samples increased slowly from the time of administration until tourniquet removal. This increase was expected because florfenicol diffuses into the digital tissues as a result of the concentration gradient generated by the high concentrations of florfenicol in the vascular space. However, peak SYNF concentration was detected after removal of the tourniquet, a finding that was unexpected. It is possible that florfenicol in the periarticular tissues continued to diffuse into the SYNF after tourniquet removal.

The concentrations of florfenicol detected in the CV blood samples remained low throughout the study. Initial concentrations were higher than anticipated; those concentrations were probably caused by leakage of the drug beyond the region confined by the tourniquet location.

The terminal t½ for florfenicol determined in our study was slightly longer than values in other reports in the literature. Reported mean t½ values for florfenicol following IV administration include 2.87,44 3.0,42 and 2.6545 hours. In the present study, the t½ of florfenicol in DV blood, SYNF, and CV blood samples was 4.09, 3.81, and 4.77 hours, respectively. Following IM administration, the t½ of florfenicol ranges from 12.542 to 18.345 hours. Because this is an extralabel use of florfenicol, a scientifically derived meat withdrawal time should be applied to IV administration of the drug. Following IM administration at a dose of 20 mg/kg, florfenicol has a meat withdrawal time of 28 days. Administration of florfenicol via RIVP as described in this report involved a lower systemic dose, compared with the label dose; furthermore, IV administration did not prolong the terminal t½, compared with that achieved with an IM injection. Therefore, on the basis of established label recommendations, we propose that such extralabel IV administration of florfenicol is unlikely to result in violative tissue residues.

Most digital infections in cattle involve a mixed bacterial population, including Arcanobacterium pyogenes and Fusobacterium necrophorum.18,57 A study58 involving 445 bovids with infections of portions of the appendicular skeletal revealed that A pyogenes was the most common bacterial agent. Florfenicol is active against both of these organisms. A New Animal Drug Application for florfenicol (NADA-141-063)59 reports an MIC90 for F necrophorum of 0.25 μg/mL. In a study60 of 49 A pyogenes isolates from cattle and pigs, the MIC90 for florfenicol was 1.56 μg/mL. In another investigation61 of 16 A pyogenes isolates from white-tailed deer, the MIC90 for florfenicol was 0.5 μg/mL. In the present study, the florfenicol concentrations from the DV blood samples remained greater than the florfenicol MIC90 for A pyogenes for a minimum of 8 hours and greater than the florfenicol MIC90 for F necrophorum for a minimum of 18 hours. In the SYNF samples, the drug concentration remained greater than the florfenicol MIC90 for A pyogenes for a minimum of 8 hours and greater than the florfenicol MIC90 for F necrophorum during the entire 24-hour study period.

Mycoplasma bovis is a common cause of infectious arthritis in calves, especially following an episode of respiratory disease.62 The florfenicol MIC90 against M bovis is 16 μg/mL, and the minimum mycoplasmacidal concentrations of florfenicol at which 50% and 90% of organisms are inhibited are 16 and 32 μg/mL, respectively.63 Only danofloxacin is more active than florfenicol against M bovis.58 In our study, RIVP of florfenicol resulted in SYNF concentrations that exceeded the minimum mycoplasmacidal concentrations of florfenicol at which 50% and 90% of M bovis are inhibited for 2 hours and 1 hour, respectively.

Although it is thought that concentration-dependent antimicrobial agents are best suited for use in RIVP, both time- and concentration-dependent antimicrobials have been used.36 Pharmacokinetics of antimicrobials that have both time- and concentration-dependent pharmacodynamic characteristics have been investigated, but the efficacies of these 2 types of antimicrobial agents have not been compared in a controlled study, to our knowledge. Florfenicol pharmacodynamic properties are not understood as well as those of agents in other antimicrobial classes. However, recent research has revealed that florfenicol has concentration-dependent bactericidal activity.38 Unfortunately, the organisms investigated in that study were respiratory tract pathogens and did not include F necrophorum or A pyogenes.

Results of the present study indicated that RIVP of florfenicol administered at a dose of 2.2 mg/kg resulted in high drug concentrations in both serum and SYNF samples collected from the distal portion of the limb in cattle; however, that method of administration resulted in low drug concentration in CV blood. The most likely pathogens encountered in cases of deep digital sepsis include F necrophorum and A pyogenes,18 and the concentrations of florfenicol achieved in the distal portion of the limbs in our study exceed the published MIC90 of these pathogens by several-fold. In addition, the concentration of florfenicol in SYNF exceeded the MIC90 of F necrophorum for at least 24 hours. In cattle, RIVP of florfenicol is worth investigating as a potential treatment of deep digital sepsis.

ABBREVIATIONS

AUC

Area under the concentration versus time curve

AUC(0–Ct)

Area under the concentration versus time curve from time 0 to the last measured time point

AUC(0–∞)

Area under the concentration versus time curve extrapolated to infinity

AUC%extrap

Value (%) of ([AUC − AUC0 − Ct])/AUC) × 100

Cmax

Maximum serum or synovial fluid concentration

CV

Central venous

DCDV

Dorsal common digital vein

DV

Digital venous

MIC90

Minimum inhibitory concentration at which 90% of organisms are inhibited

PVLD

Plantar vein of the lateral digit

RIVP

Regional IV perfusion

SYNF

Synovial fluid

t½

Half-life

Tmax

Time to maximum serum or synovial fluid concentration

a.

Xylazine 20 injection (20 mg/mL), The Butler Co, Dublin, Ohio.

b.

Lidocaine 2% injectable solution, The Butler Co, Dublin, Ohio.

c.

Intravenous catheter (1.3 × 48 mm), BD Insyte, Franklin Lakes, NJ.

d.

Non-DEHP T connector, Medex, Dublin, Ohio.

e.

Prepierced reseal male adapter plug-short, Hospira, Forest Lake, Ill.

f.

Periflex continuous epidural anesthesia set, B. Braun Medical, Bethlehem, Pa.

g.

Surflo winged infusion set, 19-gauge, 0.75-inch thin-walled needle with 12-inch tubing, Terumo Medical, Somerset, NJ.

h.

Tolazoline injectable solution (100 mg/mL), Lloyd Laboratories, Shenandoah, Iowa.

i.

Portable tourniquet system, Delfi Medical Innovations Inc, Vancouver, BC, Canada.

j.

Florfenicol injectable solution (300 mg/mL), Schering-Plough Animal Health, Omaha, Neb.

k.

Microcentrifuge tube (0.5 mL), SCI Dynamics, Adelphia, NJ.

l.

Microcentrifuge tubes (1.5 mL), SCI Dynamics, Adelphia, NJ.

m.

Agilent 1000 series solvent delivery system, Agilent Technologies, Wilmington, Del.

n.

Agilent 1000 series autosampler, Agilent Technologies, Wilmington, Del.

o.

Agilent 1000 series variable wavelength detector (VWD), Agilent Technologies, Wilmington, Del.

p.

Oasis HLB solid phase extraction cartridges, Waters Corp, Milford, Mass.

q.

Zorbax Eclipse XDB-C8 4.6 mm × 15 cm column, Agilent Technologies, Wilmington, Del.

r.

Agilent 1100 series Chemstation software, Agilent Technologies, Wilmington, Del.

s.

Donated by Schering-Plough Corp, Summit, NJ.

t.

WinNonLin, version 5.0.1, Pharsight Corp, Mountain View, Calif.

u.

SAS, version 9.2, SAS Institute Inc, Cary, NC.

References

  • 1.

    Hernandez JA, Garbarino EJ, Shearer JK, et al. Comparison of the calving-to-conception interval in dairy cows with different degrees of lameness during the prebreeding postpartum period. J Am Vet Med Assoc 2005;227:12841291.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2.

    Melendez P, Bartolome J, Archbald LF, et al. The association between lameness, ovarian cysts, and fertility in lactating dairy cows. Theriogenology 2003;59:927937.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3.

    Garbarino EJ, Hernandez JA, Sweeper JK, et al. Effect of lameness on ovarian activity in postpartum holstein cows. J Dairy Sci 2004;87:41234131.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4.

    Sogstad AM, Osteras O, Fjeldaas T. Bovine claw and limb disorders related to reproductive performance and production diseases. J Dairy Sci 2006;89:25192528.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Hernandez JA, Garbarino EJ, Shearer JK, et al. Comparison of milk yield in dairy cows with different degrees of lameness. J Am Vet Med Assoc 2005;227:12921296.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6.

    Green LE, Hedges VJ, Schukken YH, et al. The impact of clinical lameness on the milk yield of dairy cows. J Dairy Sci 2002;85:22502256.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7.

    Booth CJ, Warnick LD, Grohn YT, et al. Effect of lameness on culling in dairy cows. J Dairy Sci 2004;87:41154122.

  • 8.

    Whay HR. Pain in the lame cow. Cattle Pract 1997;5:113118.

  • 9.

    Singh GR, Amarpal, Aithal HP, et al. Lameness in cattle—a review. Indian J Anim Sci 2005;75:723740.

  • 10.

    Trent AM, Plumb D. Treatment of infectious arthritis and osteomyelitis. Vet Clin North Am Food Anim Pract 1991;7:747778.

  • 11.

    Orsini JA. Strategies for treatment of bone and joint infections in large animals. J Am Vet Med Assoc 1984;185:11901193.

  • 12.

    Jackson PGG, Strachan WD, Tucker AW, et al. Treatment of septic arthritis in calves by joint lavage: a study of 20 cases. Ir Vet J 1999;52:563569.

    • Search Google Scholar
    • Export Citation
  • 13.

    Tulleners EP. Management of bovine orthopedic problems. Part ii. Coxofemoral luxations, soft tissue problems, sepsis, and miscellaneous skull problems. Compend Contin Educ Pract Vet 1986;8:S117S125.

    • Search Google Scholar
    • Export Citation
  • 14.

    Smith JA, Williams RJ, Knight AP. Drug therapy for arthritis in food-producing animals. Compend Contin Educ Pract Vet 1989;11:8793.

  • 15.

    Lazzarini L, Lipsky BA, Mader JT. Antibiotic treatment of osteomyelitis: what have we learned from 30 years of clinical trials? Int J Infect Dis 2005;9:127138.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16.

    Lazzarini L, Mader JT, Calhoun JH. Osteomyelitis in long bones. J Bone Joint Surg Am 2004;86:23052318.

  • 17.

    Goodrich LR, Nixon AJ. Treatment options for osteomyelitis. Equine Vet Educ 2004;16:267280.

  • 18.

    Guard C. Strategies for managing septic arthritis of the digit in cattle, in Proceedings. 33rd Annu Conf Am Assoc Bov Pract 2000;2123.

    • Search Google Scholar
    • Export Citation
  • 19.

    Hau T, Nishikawa RA, Phuangsab A. The effect of bacterial trapping by fibrin on the efficacy of systemic antibiotics in experimental peritonitis. Surg Gynecol Obstet 1983;157:252256.

    • Search Google Scholar
    • Export Citation
  • 20.

    Johnson KA. Osteomyelitis in dogs and cats. J Am Vet Med Assoc 1994;205:18821887.

  • 21.

    Henry SL, Galloway KP. Local antimicrobial therapy for the management of orthopedic infections. Clin Pharmacokinet 1995;29:3645.

  • 22.

    Rochat MC. Preventing and treating osteomyelitis. Vet Med (Praha) 2001;96:678685.

  • 23.

    Whitehair KJ, Adams SB, Parker JE, et al. Regional limb perfusion with antibiotics in three horses. Vet Surg 1992;21:286292.

  • 24.

    Whitehair KJ, Bowerstock TL, Blevins WE, et al. Regional limb perfusion for antibiotic treatment of experimentally induced septic arthritis. Vet Surg 1992;21:367373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25.

    Murphey ED, Santschi EM, Papich MG. Regional intravenous perfusion of the distal limb of horses with amikacin sulfate. J Vet Pharmacol Ther 1999;22:6871.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26.

    Werner LA, Hardy J, Bertone AL. Bone gentamicin concentration after intra-articular or regional intravenous perfusion in the horse. Vet Surg 2003;32:559565.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27.

    Pille F, Baere SD, Ceelen L, et al. Synovial fluid and plasma concentrations of ceftiofur after regional intravenous perfusion in the horse. Vet Surg 2005;34:610617.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28.

    Rubio-Martinez LM, Lopez-Sanroman J, Cruz AM, et al. Evaluation of safety and pharmacokinetics of vancomycin after intravenous regional limb perfusion in horses. Am J Vet Res 2005;66:21072113.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29.

    Parra-Sanchez A, Lugo J, Boothe DM, et al. Pharmacokinetics and pharmacodynamics of enrofloxacin and a low dose of amikacin administered via regional intravenous limb perfusion in standing horses. Am J Vet Res 2006;67:16871695.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30.

    Gehring R, Haskell SR, Payne MA, et al. Aminoglycoside residues in food of animal origin. J Am Vet Med Assoc 2005;227:6366.

  • 31.

    FARAD. Prohibited Drug List. Available at: www.farad.org/prohibit.html. Accessed Mar 15, 2007.

  • 32.

    Gagnon H, Ferguson JG, Papich MG, et al. Single-dose pharmacokinetics of cefazolin in bovine synovial fluid after intravenous regional injection. J Vet Pharmacol Ther 1994;17:3137.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33.

    Navarre CB, Zhang L, Sunkara G, et al. Ceftiofur distribution in plasma and joint fluid following regional limb injection in cattle. J Vet Pharmacol Ther 1999;22:1319.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 34.

    Dietz O, Gangel H, Woborill J. Intravenous local antibiotic treatment for infectious diseases of the hoof and claw in cattle. Monatsh Veterinarmed 1980;35:729734.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 35.

    Steiner A, Ossent P, Mathis GA. Intravenous regional anaesthesia and antibiotic therapy applied to the limbs of cattle: indications, techniques and complications. Schweiz Arch Tierheilkd 1990;132:227237.

    • Search Google Scholar
    • Export Citation
  • 36.

    Rubio-Martinez L, Cruz AM. Antimicrobial regional limb perfusion in horses. J Am Vet Med Assoc 2006;228:706712.

  • 37.

    Fajt VR, Apley MD. Antimicrobial issues in bovine lameness. Vet Clin North Am Food Anim Pract 2001;17:159173.

  • 38.

    deHaas V, Bonnier M, Gicquel M, et al. Florfenicol: a time-or concentration-dependent antibiotic. XXII World Buiatrics Congress 2002;1725.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 39.

    Nuflor Injectable Solution product information. Available at: www.nuflor.com/_pdfs/productdisclosure.pdf. Accessed Mar 15, 2007.

    • Crossref
    • Export Citation
  • 40.

    deCraene BA, Deprez P, D'Haese E, et al. Pharmacokinetics of florfenicol in cerebrospinal fluid and plasma of calves. Antimicrob Agents Chemother 1997;41:19911995.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 41.

    Bretzlaff KN, Neff-Davis CA, Ott RS, et al. Florfenicol in nonlactating dairy cows: pharmacokinetics, binding to plasma proteins, and effects on phagocytosis by blood neutrophils. J Vet Pharmacol Ther 1987;10:233240.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 42.

    Soback S, Paape MJ, Filep R, et al. Florfenicol pharmacokinetics in lactating cows after intravenous, intramuscular and intramammary administration. J Vet Pharmacol Ther 1995;18:413417.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 43.

    Adams PE, Varma KJ, Powers TE, et al. Tissue concentrations and pharmacokinetics of florfenicol in male veal calves given repeated doses. Am J Vet Res 1987;48:17251732.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 44.

    Varma KJ, Adams PE, Powers TE, et al. Pharmacokinetics of florfenicol in veal calves. J Vet Pharmacol Ther 1986;9:412425.

  • 45.

    Lobell RD, Varma KJ, Johnson JC, et al. Pharmacokinetics of florfenicol following intravenous and intramuscular doses to cattle. J Vet Pharmacol Ther 1994;17:253258.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 46.

    The United States Pharmacopeia. Rockville, Md: US Pharmacopeial Convention, 2006.

  • 47.

    Gibaldi M, Perrier B. Pharmacokinetics. 2nd ed. New York: Marcel-Dekker, 1982.

  • 48.

    Gabrielsson J, Weiner D. Pharmacokinetic and pharmacodynamic data analysis, concepts and applications. 3rd ed. Stockholm: Swedish Pharmaceutical Press, 2001.

    • Search Google Scholar
    • Export Citation
  • 49.

    Hurley JD, Wilson SD, Worman LM, et al. Chronic osteomyelitis. Treatment by regional perfusion with antibiotics. Arch Surg 1966;92:548553.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 50.

    Finsterbush A, Weinberg H. Venous perfusion of the limb with antibiotics for osteomyelitis and other chronic infections. J Bone Joint Surg Am 1972;54:12271234.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 51.

    Nuflor Injectable Solution Environmental Assessment. Available at: www.fda.gov/cvm/FOI/141-063EA.pdf. Accessed Jun 1, 2007.

  • 52.

    El-Aty AM, Goudah A, El-Sooud KA, et al. Pharmacokinetics and bioavailability of florfenicol following intravenous, intramuscular and oral administrations in rabbits. Vet Res Commun 2004;28:515524.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 53.

    Park BK, Lim JH, Kim MS, et al. Pharmacokinetics of florfenicol and its major metabolite, florfenicol amine, in rabbits. J Vet Pharmacol Ther 2007;30:3236.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 54.

    Senoh H, Aiso S, Arito H, et al. Carcinogenicity and chronic toxicity after inhalation exposure of rats and mice to N,N-dimethylformamide. J Occup Health 2004;46:429439.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 55.

    Fail PA, George JD, Grizzle TB, et al. Formamide and dimethylformamide: reproductive assessment by continuous breeding in mice. Reprod Toxicol 1998;12:317332.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 56.

    Kowalski P, Konieczna L, Chmielewska A, et al. Comparative evaluation between capillary electrophoresis and high-performance liquid chromatography for the analysis of florfenicol in plasma. J Pharm Biomed Anal 2005;39:983989.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 57.

    Nagaraja TG, Narayanan SK, Stewart GC, et al. Fusobacterium necrophorum infections in animals: pathogenesis and pathogenic mechanisms. Anaerobe 2005;11:239246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 58.

    Verschooten F, Vermeiren D, Devriese L. Bone infection in the bovine appendicular skeleton: a clinical, radiographic, and experimental study. Vet Radiol Ultrasound 2000;41:250260.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 59.

    Freedom of Information Summary. NADA 141–063, Nuflor Injectable Solution, 1999, Available at: www.fda.gov/ohrms/dockets/98fr/141063Fi.pdf. Accessed Jun 1, 2007.

    • Crossref
    • Export Citation
  • 60.

    Yoshimura H, Kojima A, Ishimaru M. Antimicrobial susceptibility of Arcanobacterium pyogenes isolated from cattle and pigs. J Vet Med B Infect Dis Vet Public Health 2000;47:139143.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 61.

    Chirino-Trejo M, Woodbury MR, Huang F. Antibiotic sensitivity and biochemical characterization of Fusobacterium spp. and Arcanobacterium pyogenes isolated from farmed white-tailed deer (Odocoileus virginianus) with necrobacillosis. J Zoo Wildl Med 2003;34:262268.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 62.

    Gagea MI, Bateman KG, Shanahan RA, et al. Naturally occurring Mycoplasma bovis-associated pneumonia and polyarthritis in feedlot beef calves. J Vet Diagn Invest 2006;18:2940.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 63.

    Ayling RD, Baker SE, Peek ML, et al. Comparison of in vitro activity of danofloxacin, florfenicol, oxytetracycline, spectinomycin and tilmicosin and recent field isolates of Mycoplasma bovis. Vet Rec 2000;146:745747.

    • Crossref
    • Search Google Scholar
    • Export Citation

Contributor Notes

Supported by the Research Advisory Council, Oklahoma State University and Schering-Plough Animal Health. One of the authors (MGP) has been a consultant for the manufacturer of florfenicol, Schering-Plough Corporation and has also received research support funding from Schering-Plough Corporation.

Presented in abstract format at the American College of Veterinary Internal Medicine Forum, Seattle, June 2007.

The authors thank Delta Dise for technical assistance.

Address correspondence to Dr. Gilliam.