-  -KeC (the elimination rate)

-the rate of elimination is proportional to the concentration of the drug

-1st order kinetics

-C(t)=C₀^-ket

C₀= concentration at time 0

-Relates the concentration of drug in the compartment(plasma) to the amount introduced

-V_d=dose/C₀

-if you know the V_dthen you can predict what the concentration change of the drug in the plasma will be after a bolus injection of the drug

-normalized to body weight l/kg

**not an actual volume, it is the volume needed to account for all drug introduced into the system at a given plasma concentration

-relates the rate of elimination to plasma concentration

Elimination rate=CL*C

unitls of ml/min/kg

CL-->amount per drug per unit time

Ke-->change in concentration per unit time (mg/ml)/hour

Non-instaneous Delivery

official definition of V_d

-We can still get the elimination rate constant from the late decay phase, but we can't extrapoalate to t=0 to get C₀ and thus V_d

_-so we use the official definition of V_d

-V_d=dose/(k_eAUC)

-The delivery rate must equal the elimination rate

-Dosing rate-CL*C_ss

-generally takes 4-5 half lives to reach steady state

-plasma-liver-kidney

-if drug is added instantaneously to central compartment, it will take some time before it is evenly distrubuted throughout the body

-this is the distribution phase and the drug concentration will fall more rapidly than during the later elimination phase

-each bolus of drug raises the plasma concentration (ΔC) by

-ΔC=dose/V_d

-convert drug to more polar metabolite (thus increasing its water solubility

-add a polar functional group (-OH, -NH2. -SH

-always change the pharmacologic activity of the drug

-polar substances or polar functional groups acquired during phase I are conjugated to endogenous polar substrates such as glucuronic acid, sulfuric acid, acetic acid, or glycine

-almost all conjugated products are completely inactive