Kinetics of Elimination – First-Order and Zero-Order Kinetics

This presentation provides a comprehensive overview of drug elimination kinetics, focusing on first-order and zero-order kinetics. It covers key concepts, graphical representations, mathematical expressions, and clinical implications. The slides include detailed comparisons, relevant equations, and easy-to-understand visuals to enhance learning.

Topics covered:
✔ Introduction to drug elimination kinetics
✔ First-order kinetics: definition, characteristics, and graph
✔ Zero-order kinetics: definition, characteristics, and graph
✔ Mathematical expressions for both kinetics
✔ Key differences and clinical significance

This is a must-read for pharmacology students, researchers, and healthcare professionals looking to understand drug metabolism and elimination processes.

1. Kinetics of Elimination – First-Order and Zero-Order Kinetics An overview of drug elimination kinetics Understanding first-order and zero-order kinetics

2. Introduction Definition of drug elimination kinetics Importance in pharmacokinetics Overview of first-order and zero-order kinetics

3. First-Order Kinetics A constant fraction of drug is eliminated per unit time Exponential decline in drug concentration Half-life remains constant Rate depends on drug concentration Example : Most drugs follow first-order kinetics

4. Graph of First-Order Kinetics • Logarithmic decline curve • Illustrates exponential drug elimination

5. Mathematical Expression of First-Order Kinetics Formula : dC/dt = -kC C = drug concentration k = rate constant t = time Half-life formula: t1/2 = 0.693/k

6. Zero-Order Kinetics A constant amount of drug is eliminated per unit time Linear decline in drug concentration No fixed half-life Rate is independent of drug concentration Example : Ethanol, phenytoin, aspirin (at high doses)

7. Graph of Zero-Order Kinetics Linear decline curve Illustrates constant rate of elimination

8. Mathematical Expression of Zero-Order Kinetics Formula : dC/dt = -k C = drug concentration k = rate constant t = time Half-life changes with concentration

9. Comparison of First-Order and Zero-Order Kinetics First-Order : Rate proportional to concentration Zero-Order : Constant amount eliminated First-Order : Constant half-life Zero-Order : Varies with dose First-Order : Most drugs Zero-Order : Ethanol, phenytoin

10. Clinical Implications Risk of drug accumulation in zero-order kinetics Dosing adjustments in different kinetic models Importance in therapeutic drug monitoring

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