Drug activity can be classified as:-
(a) Structurally non-specific activity.
(b) Structurally specific activity.
1- Structurally non-specific activity
** It is depend on the physical properties of the drug like solubility partition coefficients and vapor pressure and not on the presence or absence of some chemical group.
** It is depend on the physical properties of the drug like solubility partition coefficients and vapor pressure and not on the presence or absence of some chemical group.
** Substances such as alkanes, alkenes, alkynes, alcohols, amides, ethers, ketones and chlorinated hydrocarbons exhibit narcotic activity and potency of each substance is related to its partition coefficient.
** Structurally non-specific action results from accumulation of a drug in some vital part of a cell with lipid characteristics.
** The structurally non-specific drugs include general anesthetics, hypnotics together with a few bactericidal compounds and insecticides.
2- Structurally specific activity
It is depend upon some factors such as the presence or absence of certain functional groups, intramolecular distance, and shape of the
molecules.
molecules.
** Activity is not easily co-related with any physical property and small changes in structure often lead to changes in activity.
** Structurally specific activity is dependent upon the interaction of the drug with a cellular receptor.