SITE SPECIFIC DRUG DELIVERY

摘要

Why site specific drug delivery is necessary ? No drug designed or developed so far is free from Undesirable side effects, which mainly arise due to binding of the drug, with sites other than the target sites. This problem can be overcome by selectively directing the drug to the target sites by appropriate carriers. But drug delivery by different carriers also suffers from their early recognition by the cells of reticuloendothelial system (RES). This initial problem could be avoided by : [i] creating recitulo-endothelial blockage (e.g. dextran sulphate or dummy liposomes) or [ii] designing delivery systems in such a way that they can bypass liver and spleen (e.g. peggylated or stealth liposomes). In order to avoid other related problems the targeting of drug encapsulated liposomes or other delivery vesicles are thought of. Targeting primarily could be of two types, e.g. [i] passive targeting, and [ii] active targeting.