AVMA Journals Style Pharmacologic Pharmacokinetics Terminology

The following list represents the Journals's preferred format for commonly encountered pharmacologic and pharmacokinetics terms.

Term* Standard expansion† Additional information Typical
units‡
α Alpha Rate constant for the distribution portion of the plasma concentration-versus-time curve, as in: C(t) = A•e–α•t + B•e–β•t h–1
β Beta Rate constant for the elimination portion of the plasma concentration-versus-time curve, as in: C(t) = A•e–α•t + B•e–β•t h–1
λz Terminal rate constant Also: terminal slope of the concentration- versus-time curve h–1
AUC Area under the concentration- versus-time curve   μg•h/mL
AUC0–last Area under the concentration- versus-time curve from time 0 to the last measured concentration   μg•h/mL
AUC0–∞ Area under the concentration-versus-time curve from time 0 to infinity   μg•h/mL
AUMC Area under the first moment curve   μg•h2/mL
Cl Clearance Also: systemic clearance mL/kg/h
Cl/F Clearance corrected for bioavailability Used for a non-IV dose (also: clearance per fraction absorbed) mL/kg/h
C Concentration   μg/mL
C0 Concentration at time 0 Used for an IV dose μg/mL
Cmax Maximum observed concentration Also: maximum serum concentration, maximum plasma concentration, or peak concentration μg/mL
Cmin Minimum observed concentration Also: minimum serum concentration or minimum plasma concentration μg/mL
Css Concentration at steady state Also: plasma concentration at steady state or serum concentration at steady state μg/mL
F Bioavailability Also: extent of absorption or fraction of the dose absorbed No units (expressed as a fraction) or % (F X 100)
k Rate constant   h–1
k01 Rate constant for absorption into the central compartment Used for a non-IV dose h–1
k10 Rate constant for drug elimination from the central compartment   h–1
k12 Rate constant for drug movement from the central to the peripheral compartment Also: rate constant for drug movement from compartment 1 to compartment 2 h–1
k21 Rate constant for drug movement from the peripheral to the central compartment Also: rate constant for drug movement from compartment 2 to compartment 1 h–1
ke or kel Elimination rate constant   h–1
ka or kabs Absorption rate constant Used for a non-IV dose h–1
MIC Minimum inhibitory concentration   μg/mL
MIC50 Minimum inhibitory concentration for 50% of isolates   μg/mL
MIC90 Minimum inhibitory concentration for 90% of isolates   μg/mL
MRT Mean residence time   min
t1/2 Half-life Also: apparent elimination half-life min
t1/2α Distribution half-life Corresponds to ln2/α min
t1/2β Elimination half-life Corresponds to ln2/β min
t1/2λ Terminal half-life Corresponds to ln2/λ min
t1/2 kel Half-life for drug elimination Also: t1/2 ke min
t1/2 ka Half-life for drug absorption Used for a non-IV dose (Also: t1/2 kabs) min
tlag Time delay between drug
administration and first observed concentration
Also: lag time min
tmax Time to maximum concentration   min
VdC Volume of distribution of the central compartment Used for an IV dose (equivalent to V1) L/kg
Vd Volume of distribution   L/kg
Vdarea Volume of distribution calculated using the AUC method Used for an IV dose (equivalent to VZ) L/kg
Vd/F Volume of distribution corrected for bioavailability Also: volume of distribution per fraction absorbed L/kg
Vdss Volume of distribution at steady state Used for an IV dose L/kg
Vdss/F Volume of distribution at steady state corrected for bioavailability Also: volume of distribution at steady state per fraction absorbed L/kg

 

*The MRT can include a subscript to indicate the data used for calculations (eg, MRT0–obs).
†For C and related parameters, the text should indicate the sample type for which concentrations were evaluated (these may not always be measured in serum or plasma). The variable that the rate constant k pertains to should also be mentioned in the text.
‡Units that are equivalent when conversions are applied are also acceptable (eg, L/kg/h or mL/kg/min for Cl or Cl/F; ng/mL or mg/L for C and related parameters; min–1 for k and related parameters; h for t and t1/2 related parameters; mg/L for MIC data; mL/kg for Vd and related parameters). Units of mL/kg/h are equivalent to mL•h–1•kg–1; the former term is preferred because of its simplicity.

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