Résumé
Solid dispersions (SDs) are resulted by dispersion of drug in biologically inert matrix. They can be used to increase the solubility of a drug with low aqueous solubility, thereby improving its oral bioavailability. Higher drug dissolution rates from a SD can be facilitated by optimizing the wetting characteristics of the compound surface, as well as increasing the interfacial area available for drug dissolution. Although the latter can be easily accomplished by, for example: decreasing the particle size of the drug powder but micronized powders may result in further complications as they occasionally tend to agglomerate. A more preferable solution would be to introduce the drug in the form of a molecular dispersion. The aim of present study was to enhance the dissolution rate of diclofenac a practically less water-soluble drug. The same was done by preparation of solid dispersions of the drug employing different ratios of established polymers. This was done by using polymers namely; hydrophilic polymer β-cyclodextrins, PVP and PEG. The kneading method was used to prepare solid dispersions in various ratios with polymer. The dissolution data was studied for all the three formulations. The data obtained was compared with that of physical mixtures containing drug, polymer and lactose in the same ratio as that of solid dispersions. The dissolution data showed that best release was obtained in formulation f1 containing beta –cyclodextrins, PVP and PEG as polymer. The comparative data showed 98% release at approximately 4 hours with polymer β –cyclodextrins, whereas, 90% and 88% release were obtained using PEG and PVP respectively in the same time frame.