Self Microemulsifying Drug Delivery System: a Lipid Based Drug Delivery System

Administration of drug by oral route is the most effective and acceptable route as it has better therapeutic efficacy, low cost and good patient compliance. More than 40% of new drugs are poorly water soluble. These drugs present development challenges and also have poor bioavailability. Although many formulation approaches like solid dispersions, complexation, pH modification exist, novel lipid based drug delivery system is best approach to design formulation with increased therapeutic benefit for poorly water soluble drug. This review provides recent updates on lipid based drug delivery system with main focus on self micro-emulsifying drug delivery system. Selfmicroemulsifying formulations are evident to improve the oral bioavailability of hydrophobic drugs due to their efficiency in presenting the hydrophobic drug in solubilized form whereby dissolution process can be circumvented. Oil, surfactant and cosurfactant also contribute to the overall improvement in oral bioavailability via promoting the lymphatic transport; thereby hepatic first pass metabolism can be surmounted. INTRODUCTION: Today, one of the major problems to drug formulation development is poor water solubility of new drug. More than 40% of all new drugs are poorly water soluble. 1 Poor solubility and ultimately low dissolution rate of these drugs in the gastro-intestinal fluids cause poor bioavailability. For BCS class II drugs, the bioavailability may be enhanced by increasing the solubility and dissolution rate of these drugs in the gastro-intestinal fluids. QUICK RESPONSE CODE DOI: 10.13040/IJPSR.0975-8232.7(2).443-52 Article can be accessed online on: www.ijpsr.com DOI link: http://dx.doi.org/10.13040/IJPSR.0975-8232.7 (2).443-52 The efficacy of these can be improved by increasing its gastrointestinal solubilization with modification of pharmacokinetic profiles. 2 Oral route is the preferred route as it is non invasive, economic, and does not give pain at site of injection. 3 It is the most convenient method for chronic treatment. Oral route is limited by problems related to physicochemical properties of the drug, including poor solubility, low permeability, instability, and rapid metabolism, all of which decrease oral bioavailability. 4 Lipid-based drug delivery systems play an important role in the delivery of hydrophobic drugs with low bioavailability by using lipids as carriers. 5 Lipid-based drug delivery systems have gained considerable interest after the commercial success of Sandimmune Neoral, Novartis Pvt. Ltd. and