Improvement of the Pharmacutica Properties of Certain Drugs in Liquid and Solid Dosage Forms

It is well known that poorly water soluble drugs suffering from many difficulties in their gastrointestinal absorption. For any substance to be absorbed it must go into solution at first to be available for absorption. The bioavailability of such kind of drugs is dissolution rate limited. Improving the aqueous solubility and dissolution rate of poorly water soluble drugs have taken a great attention, in order to enhance their total bioavailability.So, the aim of the work in this thesis is to improve the aqueous solubility and to enhance the rate of dissolution of two poorly water soluble drugs namely Clonazepam and Nimesulide .The work in this thesis is divided into three parts: Part One Enhancement of the Solubility and Dissolution Rate of Clonazepam The purpose of the study in this part was to improve the dissolution of Clonazepam (CZP) for enhancing its bioavailability and therapeutic efficacy. The work in this part includes two chapters:- Chapter I: Formulation and Characterization of Clonazepam Solid Dispersions Physical mixtures (PMs) and solid dispersions (SDs) of CZP with each of PEG 4000, PEG 6000, Polyvinyl pyrrolidone (PVP) and Urea (UR) as drug carriers were prepared by solvent evaporation method in ratios 1:1