SELF MICROEMULSIFYING DRUG DELIVERY SYSTEM: A METHOD FOR ENHANCEMENT OF BIOAVAILABILITY

Oral route is the easiest and most convenient route of drug administration, being non invasive and cost effective, thereby leading worldwide drug delivery market. But major problem encountered in oral formulations (as estimated more than 50 % of oral formulations are found to be poorly aqueous soluble), is low bioavailability, giving rise to further problems like, high inter and intra subject variability, lack of dose uniformity and finally leading to therapeutic failure. The challenging task is to increase the bioavailability of drugs. Number of technological strategies are investigated and reported in literature for improving bioavailability like solid dispersions, cyclodextrins, micronization etc. But Self-microemulsifying Drug Delivery System (SMEDDS) have gained exposure for their ability to increase solubility and bioavailability of poorly aqueous soluble drugs with reduction in dose and also drugs are protected from hostile environment in gut. SMEDDS are isotropic mixture of oil, surfactant, drug and sometimes containing co-surfactant and administered orally which on mild agitation with GI fluids forms o/w microemulsion. This review gives complete overview of SMEDDS but special attention has been paid to formulation design, evaluation and little emphasis on application of SMEDDS.