The document discusses the rate of dissolution, defined as the amount of drug that dissolves per unit time under specific conditions. It highlights the mechanisms of drug dissolution, including the diffusion layer model, and explains the concepts of solubility and saturation in the context of forming solutions. Additionally, it notes the application of these principles to formulations like enteric-coated and extended-release drugs.

1. Dr Sarad Pawar Naik B

3. • Rate of dissolution is the amount of drug that goes in
solution per unit time under standardized conditions of
liquid/solid interface, temperature & solvent composition.

4. Mechanism/Theories of Drug Dissolution

10. Assumption:
Solid surface area
remains constant during
dissolution
(draw back).

17. Diffusion Layer Model

19.  In the process of dissolution, an internal energy change often, but not always, occurs
as heat is absorbed or evolved.
 An increase in disorder always results when a solution forms.
 Dissolution is the process where a solute in gaseous, liquid, or solid phase
dissolves in a solvent to form a solution.
 Solubility is the maximum concentration of a solute that can dissolve in a solvent at
a given temperature.
 At the maximum concentration of solute, the solution is said to be saturated.

44. (Chewable tablets)
• Used for solutions requiring pH/buffer changes like
enteric-coated/extended-release drugs.