IMPROVING SOLUBILITY OF BCS CLASS II DRUGS USING SOLID DISPERSION: A REVIEW

Biopharmaceutics Classification System is important for determining the bioavailability of the drugs. Drug development tool that allows estimation of the 3 major factors that affect oral drug absorption from immediate release solid oral dosage form is Dissolution, Solubility and Intestinal permeability. The bioavailability issue can be due to insufficient solubility of permeability. Most compounds face the solubility problems. The dissolution rate of drug from its dosage form is considered as an important parameter in the absorption. Dissolution is the rate-limiting step in the absorption of drugs from 1 solid dosage form especially when the drug is poorly water soluble. Poor wettability of drugs leads to the decrease in their bioavailability. Presently only 8% of new drug candidates have both high solubility and permeability and more than 60% of the products have poor water solubility. As a result the potentially important drugs do not reach the market and are not achieving their full potential. Hence, with the advancement of chemical science, the need of development of pharmaceutical technologies is also increasing. Solid dispersions have attracted considerable interest as an efficient means of improving the dissolution rate and hence the bioavailability of many drugs belonging to BCS class II. Solid dispersion has been used over last 20 to 30 years and has been known to give fruitful result in improving the release rate and oral bioavailability of poorly water soluble drugs. Solid dispersion with different polymers and at different ratios is carried out and is known to show good release when compared to the drug alone and the physical mixture. Improvement in dissolution of drug was observed in all the solid dispersions as compared to pure drug. Keywords: Solid dispersion,eutectic mixtures,isothermal titration calorimetry,kneading metho