The intrinsic dissolution rate is defined as the rate of dissolution of a pure pharmaceutical active ingredient when the surface area, stirring speed, pH and ionic strength of the dissolution medium is kept constant. I.e. the surface area of the compound is well defined in contrast to in a dissolution rate measurement.

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.