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The purpose of this study is to fabricate the polyethylene glycol matrix tablet by mold technique. Indomethacin and hydroxypropylmethylcellulose were used as model drug and polymer, respectively, in PEG matrix system. The physical and drug release characteristics of developed matrix tablet were studied. This inert carrier system comprising 7:3 polyethylene glycol 4000: polyethylene glycol 400 could effectively enhance the solubility of indomethacin and an addition of hydroxypropylmethylcellulose could sustain the drug release. Scanning electron microscope photomicrograph indicated the drug diffusion outward through the porous network of this developed matrix tablet into the dissolution fluid. Least square fitting the experimental dissolution data to the mathematical expressions (power law, first-order, Higuchi's and zero-order) indicated the drug release kinetics primarily as Fickian diffusion. Both the enhancement of drug dissolution and the prolongation of the drug release could be achieved for aqueous insoluble drug such as, indomethacin, by using polyethylene glycol-hydroxypropylmethylcellulose matrix system prepared with melting and mold technique.

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The purpose of this study was to use polyethylene glycol as a carrier to improve the solubility of an aqueous insoluble drug by melting and molding method. The release of dissolved drug was designed to be subsequently sustained with an addition of xanthan gum. The release of indomethacin from the developed system into phosphate buffer pH 6.2 was conducted using the dissolution apparatus. This carrier system could effectively enhance the solubility of indomethacin and an addition of xanthan gum could sustain the drug release. Eudragit L100 film coating could protect the carrier not to be disturbed with HCl buffer pH 1.2 and could dissolve in phosphate buffer pH 6.2, therefore, the drug release from coated tablet was initially very low but subsequently gradually released and prolonged in phosphate buffer pH 6.2. Differential scanning calorimetry study indicated the amorphous state of drug in polyethylene glycol carrier. Scanning electron microscopy photomicrograph indicated the drug diffusion outward through the porous network of matrix tablets into the dissolution fluid and curve fitting signified that the drug release kinetic was Fickian diffusion.

Chitosan possess many attractive properties for applying as biomaterials. For some application, biomaterial devices have to be sterilized using high temperature, e.g. stream sterilizing process. However, thermal degradation behavior of chitosan has been reported previously. Many researchers have attempted to improve thermal degradation behavior of chitosan by synthesize chitosan derivatives or blending chitosan with other polymers or additives. However, chitosan derivatives found to be less thermal stability than chitosan itself. On the contrary, adding some lipid additive could improve thermal stability of chitosan. In this study, protecting effect of aluminum monostearate (Alst) on thermal stability of chitosan was investigated employing thermal analysis techniques, e.g. thermogravimetry (TG), differential scanning calorimetry (DSC) and hot-stage microscope. Lactic acid solution (2% w/v) was used as solvent for dissolving chitosan. Chitosan solution, named as chtiosan-lactate (CL) and chitosan solution contained 2.5% w/w Alst (CLAlst) were prepared and fabricated into sponges using freeze drying technique. Degradation temperature of CLAlst system investigated from TG was shifted to the higher temperature comparing that of CL which indicated that Alst could improve thermal stability of chitosan after processed as biomaterial. From DSC result, small endothermic peak was observed around 60-70°C for CLAlst whereas that of CL did not exhibit any peak. Melting behavior of the sponges observed under hot-stage microscope was demonstrated that chitosan was decomposed whereas Alst dispersed in chitosan backbone was gradually melted.