A Review on Solid Dispersion as a Technique for Enhancement of Bioavailability of Poorly Water Soluble Drugs

The enhancements of oral bioavailability of poorly water soluble drugs often show poor bioavailability because of low and erratic levels of absorption. Drugs that undergo dissolution rate limited gastrointestinal absorption generally show improved dissolution and bio availability as a result of reduction in particle size. Oral bioavailability of drugs depends on its solubility and/or dissolution rate, therefore major problems associated with these drugs was its very low solubility in biological fluids, which results into poor bioavailability after oral administration. Solid dispersions have achieved considerable interest as an efficient means of improving the dissolution rate and hence the bioavailability of a range of poorly water soluble drugs. The term solid dispersion refers to a group of solid products consisting of at least two different components, generally a hydrophilic inert carrier or matrix and a hydrophobic drug. Improving oral bioavailability of drugs which are given as solid dosage forms remains a challenge for the formulation scientists due to solubility problems. The dissolution rate for such drugs can be the rate-limiting process in the absorption. Solid dispersions of poorly water-soluble drugs with water soluble carriers have been reduced the incidence of these problems and enhanced dissolution. This article summarizes on solid dispersion technology, limitations of solid dispersion, classification of solid dispersion techniques, and advantages and disadvantages of solid dispersion techniques.