Kinetics of drug M Pharmacy .pptx

Drug Kinetics

1. Presented by Neha Srivastava Pharmacy Punjab College of Technical Education Ludhiana Stability Kinetics

2. Introduction Shelf Life Long term Stability studies Accelerated Stability Studies

3. Theoratical Consideration Order of Reaction Zero order reaction Independent of concentration When solid in solution

4. Theoratical Consideration

5. Theoratical Consideration Pseudo zero order Reaction Drug react with moisture and behave as suspension Excess of drug is available so, first order behave as pseudo zero order K = K’

6. Theoratical Consideration First Order Reaction Reaction rate depend on concentration of only one reactant

7. Theoratical Consideration

8. Theoratical Consideration

9. Theoratical Consideration When time is t Half Life

10. Theoratical Consideration Pseudo First order Reaction Basically second order but behave as first order When concentration of one drug is in excess

11. Influence of pH H + ions catalyzes in Acidic pH OH - ions catalyzes in basic pH

12. Influence of temperature

13. Influence of temperature

14. Influence of temperature Limitation to Arrhenius Theory

15. Stability Prediction

16. Stability Prediction

17. General acid base catalysis of reaction Buffer salts catalyzes the reaction

18. Influence of ionic strength Drug is positively charge undergoing H + catalysis, in rate of reaction Drug is positively charge undergoing OH - catalysis, in rate of reaction

19. Degradative pathways Hydrolysis Ester Hydrolysis Rapture of covalent linkage between C and O Supported by catalyst Alkaline catalyzed reaction is irreversible Acid catalyzed reaction is reversible

20. Degradative pathways Hydrolysis Ester Hydrolysis Rapture of covalent linkage between C and O Supported by catalyst Alkaline catalyzed reaction is irreversible Acid catalyzed reaction is reversible

21. Degradative pathways Hydrolysis Ester Hydrolysis Rapture of covalent linkage between C and O Supported by catalyst Alkaline catalyzed reaction is irreversible Acid catalyzed reaction is reversible

22. Degradative pathways Factor affecting ester hydrolysis pH Type of solvents Complexation Surfactants Modification of chemical structures Salt and esters

23. Degradative pathways Amide hydrohylsis

24. Degradative pathways Amide hydrohylsis

25. Degradative pathways Ring alteration

26. Degradative pathways Ring alteration

27. Degradative pathways Oxidation Reduction Removal of electrons Addition of oxygen and removal of Hydrogen Autoxidation – Reaction with molecular oxygen

28. Degradative pathways

29. Degradative pathways Heavy metal act as catalyst To overcome: Antioxidants Chelating agents pH Solvent system

30. Degradative pathways Photolysis Racemization