SOLID DISPERSION: A FRUITFUL APPROACH FOR IMPROVING THE SOLUBILITY AND DISSOLUTION RATE OF POORLY SOLUBLE DRUGS

Abstract

In recent years, the formulation of poorly soluble compounds presented interesting challenges for formulation scientists in the pharmaceutical industry. Up to 40% of new chemical entities discovered by the pharmaceutical industry are poorly soluble or lipophilic compounds, which lead to poor oral bioavailability, high intra and inter subject variability and lack of dose proportionality. This frequently results in potentially important products not reaching the market or not achieving their full potential. Poorly water-soluble drugs often require high doses in order to reach therapeutic plasma concentrations after oral administration. Improvement in the extent and rate of dissolution is highly desirable for such compounds, as this can lead to an increased and more reproducible oral bioavailability and subsequently to clinically relevant dose reduction and more reliable therapy. The enhancement of dissolution rate and oral bioavailability is one of the greatest challenges in the development of poorly water soluble drugs. Experience with solid dispersions over the last 20-30 years indicates that this is a very fruitful approach to improving the solubility, dissolution rates and consequently the bioavailability of poorly soluble drugs. Solid dispersion is used to produce a homogeneous distribution of a small amount of drug in solid state.  This article summarize some of the practical aspects for the preparation of solid dispersion like selection of carrier ,method of physicochemical characterization, their advantages, limitations and applications along with an insight into the molecular arrangement of drug in solid dispersion. Solid dispersion technique is a very useful method for pharmaceutical point of view because of its capability to solve the solubility problems by using solid dispersion method.

Key words: Solid dispersion, solubility, dissolution, selection of carriers