Solubility Enhancement of Lipophilic Drugs - Solid Self Micro-Emulsifying Drug Delivery System

Approximately more than 50%of new chemical entities exhibit poor aqueous solubility and present a major challenge to modern drug delivery system, because of their low bioavailability. The bioavailability of these drugs (BCS class II) is rate-limited by its dissolution, so that even a small increase in dissolution rate sometimes results in a large increase in bioavailability. The rate and extent of absorption of class II compounds is highly dependent on the performance of the formulated product. Self-microemulsifying drug delivery systems (SMEDDS) are usually used to improve the bioavailability of hydrophobic drugs. Conventional SMEDDS, however, are mostly prepared in a liquid form, which can produce some disadvantages. Accordingly, solid SMEDDS (S-SMEDDS), prepared by solidification of liquid/semisolid self-emulsifying (SE) ingredients into powders, have gained popularity. This article presents an account on types of self-emulsifying formulations with emphasis on formulation of solid dosage forms, characterization and in-vitro analysis.