الفهرس | Only 14 pages are availabe for public view |
Abstract Mefenamic acid is an anthranilic acid derivative with an antiinflammatory properties. It is characterized by its low solubility, which ffects its dissolution rate, bioavailability, and consequently its onset of action. The objective of chapter I was to prepare fast release microspheres of inefenamic acid salt by emulsion congealing method using polyethylene glycols of moderate molecular weights because of their low toxicity and lack of absorption from the gastrointestinal tract. Moreover, it has been reported that PEGs can be used to enhance the aqueous solubility or dissolution characteristics of poorly water-soluble compounds. Variable processing factors have been investigated, namely, the type of polymer used as a matrix, (Formulae B, C, E, F & L), drug to polymer ratio Forinulae K, F & V), surfactant concentration (Formulae R, F& 0) , oil type of the external phase (Formulae F & G), volume of the oil phase (Formulae A, F& N), stirring rate (Formulae Q, P& F) and finally effect of particle size on the % drug released (all formulae). The effect of these variables were studied on three different particle size ranges (400-500, 500- 630 and 63 0-800 jim) of the prepared microspheres. The ammonium salt of the drug which yielded spherical, free-flowing microspheres was used, since the acid form of mefenamic failed to produce microspheres, where only a soft mass was obtained. |