ABSTRACT:
Bioavailability is one of the important parameter to achieve desired concentration of drug in systemic circulation. A drug with poor bioavailability is one with poor aqueous solubility, slow dissolution rate in biological fluids, poor stability of dissolved drug at physiological pH, poor permeation through bio membrane, extensive presystemic metabolism. Drugs having low bioavailability require to be administered at a higher dose as only a small fraction of the administered dose is absorbed in the systemic circulation and reach the target site. A various approaches are used for bioavailability enhancement of the orally administered drugs. Insinuation of the novel lipid based nanocarriers and nanomaterials like dendrimers and carbon nanotubes as a delivery system can effectively enhance the oral bioavailability of drugs by breaching the barriers, and resolve all critics related to solubility and bioavailability. Dendrimers have successfully proved themselves as useful additives in different routes of drug administration because they can render drugs greater water solubility, bioavailability, and biocompatibility. These features make it attractive candidates as drug carriers for controlled release or targeted delivery. This review covers the points of synthesis, types, properties, applications, characterisation etc. Poly (amidoamine) (PAMAM) dendrimers with particular reference to oral delivery systems have been evaluated for the influcnce tmanipulate of surface functionality and size on the epithelial barrier of the gut with the goal of identifying safe carriers.