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The rate and extent of dissolution of the active ingredient from any solid dosage form determines the rate and extent of absorption of the drug. Potential bioavailability problems are prevalent with extremely hydrophobic drugs due to erratic or incomplete absorption from gastro intestinal tract. Clinically, HMG Coenzyme reductase inhibitors are the most frequently prescribed drugs for cholesterol reduction. Simvastatin, potent inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase which catalyzes the conversion of 3-hydroxy-3-methyl-glutaryl-coenzyme A to mevalonate, which is an early and rate-limiting step in the biosynthesis of cholesterol. Simvastatin is a poorly absorbed from the gastrointestinal tract because of it solubility. According to the Biopharmaceutical Classification System it is under class II (Low Solubility and High Permeability) thus, dissolution is a rate-limiting step for its absorption. In the light of above fact, the present study has been undertaken with objectives of improve the dissolution of simvastatin by preparing inclusion complex with cyclodextrin derivatives and solid dispersion with hydrophilic polymers.

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