PHARMACEUTICAL SOLID DISPERSION TECHNOLOGY: A PROMISING TOOL TO ENHANCE ORAL BIOAVAILABILITY

Abstract

The solubility behavior of drugs remains one of the most challenging aspects in formulation development with the advent of combinatorial chemistry & high throughput screening, The number of poorly water soluble compounds has dramatically increased. Therefore a drug with poor aqueous solubility will typically exhibit permeation rate limited absorption. Although solid solutions have tremendous potential for improving drug solubility, 40years of research have resulted in only a few marketed product using this approach. Thus a greater understanding of dissolution & absorption behavior of drug with low aqueous solubility is required to successfully formulate them into more soluble & hence bioavailable drug product in case of poorly water soluble drug. Dissolution may be the rate limiting step in the process of drug absorption. Drug with poor water solubility have been shown to be unpredictably & slowly absorbed compared with drugs of higher solubility. Therefore a better oral, parentral or topical formulation can be developed by increasing the water solubility of the drugs. The various techniques are available for enhancement of solubility. Solid dispersion is one of the most promising approach for solubility enhancement. Solid dispersion refers to a group of solid products consisting of at least two different components, generally hydrophilic matrix & a hydrophobic drug. The matrix can be either crystalline or amorphous. This article gives an overview of sold dispersion systems, preparation methods, characterization & applications of solid dispersions.