Self emulsifying drug delivery systems for solubility and bioavailability enhancement of poorly water soluble drugs
Oral delivery of lipophilic drugs having low aqueou s solubility presents a major challenge in pharmace utical product development because these drugs have limite d solubility in gastrointestinal fluids and hence h ave poor absorption and bioavailability. Various pharmaceuti cal techniques involving chemical modification (e.g pro drug, salt formation etc. or formulation modification (e .g. size reduction, solid dispersion, lipid based d rug delivery systems etc. are available for solubility enhancem ent of poorly aqueous soluble drugs. The formulatio n approach is better option than chemical modification approach w ich may lead to the change in chemical structure w hich in turn may influence pharmacological activity of drug Out of various formulation approaches Lipid based drug delivery systems have taken much attention due to t heir excellent ability to improve the solubility an d bioavailability of poorly water soluble drugs and higher degree of bi compatibility. Lipid based drug delivery systems ay include emulsions (self emulsifying drug delivery systems) vesicular systems (Liposomes, Neosomes) and partic ul te system (solid lipid particle) Self emulsifying drug deliv ery systems are isotropic mixture of natural or syn thetic oils, surfactants and/or one or more hydrophilic co surfa ctants which upon mild agitation followed by diluti on in aqueous media, such as GI fluids, can form fine oil in water (o/w) emulsions or microemulsions. Self e mulsifying drug delivery systems are gaining popularity in pha rm ceutical research and development because of man y advantages like reduction in intra subject and inte r subject variability and food effect, capability t o deliver peptides that are prone to enzymatic hydrolysis in GIT, suit able for formulating both liquid and solid dosage f orm and ease of manufacture and scale up.