ADME	absorption, distribution, metabolism, excretion
AS	allometric scaling
AUC0-inf	area under the concentration-time curve from zero to infinity
BDDCS	biopharmaceutics drug disposition classification system
BW	brain weight
CB	drug concentration in blood
CL	clearance
CLH	hepatic clearance
CLint	intrinsic clearance
CLint, H	hepatic intrinsic clearance
CLint,H, human	human hepatic intrinsic clearance
CLint,H, pred	predicted hepatic intrinsic clearance
CLint,in vitro	in vitro intrinsic clearance
CLint,met	intrinsic metabolic clearance
CLint,sec	intrinsic secretory clearance
CLmet	metabolic clearance
cLogP	partition coefficient
clogP	calculated logP
CLorg	organ clearance
CP	drug concentration in plasma
CR	concentration in VR
CRBC	drug concentration in red blood cells
Cu	unbound drug concentration at distribution equilibrium
DMPK	drug metabolism and pharmacokinetic
DN	dispersion number
ECM	extended clearance model
ER	extraction ratio
ERH	hepatic extraction ratio
ERH, obs	observed hepatic extraction ratio
ERH, pred	predicted hepatic extraction ratio
F	fraction of absorption
${\mathrm{f}}_{\mathrm{IW}}^{\mathrm{i}}$	unbound fraction in the intracellular water of ionized compound
${\mathrm{f}}_{\mathrm{IW}}^{\mathrm{n}}$	unbound fraction in the intracellular water of neutral compound
${\mathrm{f}}_{\mathrm{p}}^{\mathrm{i}}$	unbound fraction in the plasma of ionized compound
${\mathrm{f}}_{\mathrm{p}}^{\mathrm{n}}$	unbound fraction in the plasma of neutral compound
Fa	fraction of absorption
fb	unbound fraction in blood
FCIM	fraction unbound intercept correction method
FH	hepatic availability
FI	ionization factor
fnH	fractional contribution of hepatic elimination
fnmet	fractional contribution of metabolic elimination
fnsec	fractional contribution of biliary elimination
fp	unbound fraction in plasma
FPO	oral bioavailability
fu, mic	non-specific binding factor to microsomes
fu,liver	unbound fraction into the liver
Ha	number of hydrogen-bond acceptors
HBD	number of hydrogen-bond donor
Hct	hematocrit
HLM	human liver microsomes
IIV	inter-individual variability
ISEF	inter-system extrapolation factor
ISTD	internal standard
IVIVE	in vitro-in vivo extrapolation
IW	intracellular water
ka	absorption rate constant
ka,eq	equilibrium solution for ka
ki	the rate constant of intestinal transit
Km	Michaelis constant
L	length of perfusion segment
MA	multiexponential allometric scaling
MLBF	monkey liver blood flow
MLP	maximum life-span potential
MPPGL	microsomal protein per gram of liver
MPR	microsomal protein recovery
MRT	mean residence time
MW	molecular weight
NCA	non-compartmental analysis
Peff	effective permeability
PK	pharmacokinetic
PLR	plasma to whole liver concentration ratio
Pm	drug permeability across intestinal mucosa
PSA	polar surface area
PSbile	biliary clearance
PSefflux, total	apparent sinusoidal total efflux clearance from the intracellular side of hepatocytes back into blood
PSinf, act	sinusoidal efflux from hepatocytes back into blood
PSuptake,total	total apparent uptake clearance
QH	hepatic liver flow
QSAR	quantitative structure activity relationship
R	radius of human jejunum
RAF	relative activity factor
RB/P	blood to plasma ratio
RE/I	ratio of distributed albumin in the extravascular space to that in the intravascular space
Rfu	unbound fraction in plasma ratio between rats and humans
rhCYP	recombinant human CYP system
RN	efficiency number
ROE	rule of exponent
S	absorptive surface area
t1/2	half-life
V	volume of distribution
Varea, Vβ	volume of distribution by area
Vc	volume of distribution of central compartment
VE	extracellular space volume minus the plasma volume
Vmax	maximal rate of the reaction
Vmet	metabolic rate
Vplasma	plasma volume
VR	physical volume into which the drug distributes minus the extracellular space
Vss	volume of distribution at steady state
W	body weight
ε2	variance for each sinusoid in the whole liver