Pharmacy 303: Pharmacokinetics Overview

Drug Development and Testing

• Medicinal chemists synthesize new drugs for potential therapeutic applications.
• New drugs developed target HDL cholesterol through enzyme inhibition.

In Vitro Testing Results

• Drugs tested for enzyme inhibition measured using two indices:
  • IC50 (nM): Drug 1 (0.01), Drug 2 (0.05), Drug 3 (1)
  • Emax (%): All drugs achieve 100% efficacy.
• Drug 1 is expected to be the most potent in humans based on in vitro IC50 values.

Efficacy vs. Potency

• Efficacy refers to the maximum effect a drug can produce (Emax).
• Potency is described by the IC50 value; lower IC50 indicates higher potency.
• After administration, differences in drug effectiveness projected (iv vs oral) suggest variance in relative effect measurements.

Pharmacology Definitions

• Pharmacology: Study of drugs (derived from "pharmac-" meaning drugs, and "-ology" meaning study).
• Pharmacodynamics: Examines physiological drug effects at various concentrations.
• Pharmacokinetics: Investigates drug movement and disposition within the body.

Interaction of Pharmacodynamics and Pharmacokinetics

• Pharmacodynamics describes the impact of the drug on the body (e.g., drug-receptor interactions leading to physiological changes).
• Pharmacokinetics reveals how the body affects a drug throughout its lifecycle—administration to clearance.

Time-Concentration Relationship

• Pharmacokinetics depicted through concentration vs. effect relationships.
• Example of drug mexiletine shows serum concentration correlations over time.
• An increase in drug concentration typically improves physiological effect until a saturation point is reached.

Amiodarone Case Study

• Amiodarone illustrates the pharmacodynamic response relative to its interaction at drug action sites.
• Integrating pharmacokinetics and dynamics is essential for understanding the overall drug response in clinical settings.