Pharmacokinetics & Drug ionization

These flashcards cover essential vocabulary related to pharmacokinetics, including processes of drug absorption, ionization, and the impact of pKa and pH on drug effectiveness.

Pharmacokinetics

Quantitative study of drug movement through the body

Absorption

The transfer of a drug from its site of administration to the bloodstream.

Passive diffusion

A process where drug molecules move across a membrane down their concentration gradient without using energy.

Active transport

Movement of drug molecules across a membrane against their concentration gradient, requiring energy (ATP).

pKa

The pH at which 50% of a drug is ionized and 50% is unionized.

Ionization

The process by which a drug molecule gains or loses an electrical charge, affecting its ability to cross cell membranes.

Bioavailability

The degree and rate at which a drug or active ingredient is absorbed and becomes available at the site of action.

Henderson-Hasselbalch equation

A mathematical formula used to calculate the pH of a solution based on the concentration ratio of protonated and unprotonated forms of a weak acid or base.

Weak acid

A type of acid that only partially ionizes in solution.

Weak base

A type of base that only partially ionizes in solution.

AUC (Area Under the Curve)

A measure of the total exposure of the body to a drug over time.

Volume of distribution (Vd)

A calculated value that helps to understand how a drug is distributed in the body.

Plasma protein binding

The degree to which drugs attach to proteins in the blood, affecting their distribution and effects.

Lipid-soluble drugs

Drugs that can easily pass through cell membranes due to their ability to dissolve in lipids.

Water-soluble drugs

Drugs that have an electrical charge and generally cannot cross cell membranes easily.

pH

A measure of the acidity or basicity of a solution, significantly influencing drug ionization.

Acidic drug

A drug that releases protons (H+) in solution, tending to remain non-ionized in acidic environments.

Basic drug

A drug that accepts protons (H+) in solution, tending to remain non-ionized in basic environments.

in order to reach their site of action

a drug has to pass through several membranes

transport against concentration gradient

active transport