PHARMACOLOGY

 DISSOLUTION -RATE AND ABSORPTION OF DRUG ::

Drugs are given in the solution or solid form The first requirement for absorption is the soluble state of the drug Thus if the drug is given in the solid form (e.g.tablet capsule powder Suspension etc ) it has to be distintegrated and dissolved before its absorption The dissolution rate depends on many factors High temperature intense agitation low viscosity of the solvent saturation of the solution smaller particle size and high solubility of the drug are the factors that increase the dissolution rate Esterification can also increase the dissolution rate 

in -vitro or in-vivo conditions following oral administration ::

In addition to above mentioned factors tablet formulation factors like filters binders lubricants and compression pressure etc also affect absorption of the drug A large tablet disintegrates more quickly as compared to highly compressed small tablet Dissolution rate can also be influenced by gastric motility lower pH increases dissolution rate of weak bases but decreases that of weak acids