SOLID DISPERSION: AN APPROACH TO ENHANCE ORAL BIOAVAILABILITY OF POORLY WATER SOLUBLE DRUGS

Improving oral bioavailability of drugs those used as solid dosage forms remains a challenge for the formulation scientists due to solubility problems associated with it.  The dissolution rate could be the rate-limiting process in the absorption of a drug from a solid dosage form of relatively insoluble drugs. Solid dispersion techniques have attracted the considerable interest in improving the dissolution rate of highly lipophilic drugs, thereby improving their bioavailability by micronization, improving wettability and use of a surface active agent. The term solid dispersion refers to a cluster of solid products consisting of at least two different components, generally a hydrophilic inert carrier or matrix and a hydrophobic drug. This article reviews the historical background of solid dispersion technology, limitations, classification, and various preparation techniques with its advantages and disadvantages. This review also discusses the recent advances in the field of solid dispersion technology. The experience with solid dispersions over the last 10-15 years indicates that this is a very fruitful approach in improving the release rate and oral bioavailability of poorly water-soluble drugs. Hence, this approach is expected to form a basis for the development of many poorly water-soluble and water-insoluble drugs in their solid-dispersion formulations in the future.