Any dissolution test method involves immersing the dosage form in a suitable dissolution medium, which is kept in motion at a constant speed and requires determining the rate at which the drug substance is released from the dosage form and […]
Systems of solids in liquids include the most frequently encountered and probably the most important type of pharmaceutical solutions. Many important drugs belong to the class of weak acids and bases. They react with strong acids and bases and, within […]
Effect of Ionic Dissociation and Molecular Association on Partition: The solute can exist partly or wholly as associated molecules in one of the phases or it may dissociate into ions in either of the liquid phases. The distribution law applies […]
Combined Effect of pH and Solvents: Stockton and Johnson and Higuchi studied the effect of an increase of alcohol concentration on the dissociation constant of sulfathiazole, and Edmonson and Goyan investigated the effect of alcohol on the solubility of phenobarbital. […]
ELECTRICAL PROPERTIES OF INTERFACES: The existence of difference in electrical potential across a solid–liquid interface is demonstrated by the following phenomena: Electrophoresis: Movement of dispersed particles through a liquid medium under the influence of an electric field. Electro-osmosis: Movement of […]
SOLUBILIZATION: It can be defined as the preparation of a thermodynamically stable isotropic solution of a substance normally insoluble or very slightly soluble in a given solvent by the addition of component or by any suitable methods. SOLUBILITY: The maximum […]
Hydrophilic–Lipophilic Balance Concept: The HLB concept was introduced by Griffin in 1947 to classify nonionic surfactants but has since been applied to ionic surfactants as well. In this system, each surfactant is assigned a number between 1 and 20, representing […]