Formulation and pharmacokinetic study of ranitidine hydrochloride suppositories

The present work is an extension of previous effect of certain excipients on the bioavailability of ranitidine hydrochloride. It was concluded that sodium sulphate ranitidine hydrochloride mixture in ratio 1:1 in both physical and coground mixtures are the excipient of choice for overcoming the hygroscopic nature of ranitidine. Also, statistical analysis of the pharmacokinetic data revealed that coground mixture gave more relative bioavailability than the physical mixture. Influence of the hydrophobicity of different fatty suppository bases on the dissolution profile of ranitidine hydrochloride coground mixture was studied. Witepsol W[25], W[3], and W[35] either single base or blends in [1:1] w/w ratio were used as hydrophobic suppository bases. Weight variation, content uniformity, hardness and melting range tests were conducted on the formulations. In vitro release was carried out according to USP basket method. Shelf storage of bases showing the highest drug release namely Witepsol W[25], W[25]+W[35], W[25]+W[31], showed no significant change in the drug release. Witepsol W[25] was subjected to in-vivo availability study as representative of the most promising formula according to the in vitro release data. The in-vivo availability and pharmacokinetic studies of the selected formula as well as on the oral administration of commercial product and coground mixture to act as reference product revealed that for practical use the dose of suppositories should be 60% of the oral dose of coground mixture according to AUC[0-6] values

Enhancement of dissolution properties of repaglinide using liquisolid compacts

The potential of liquisolid systems to improve the dissolution properties of water insoluble drugs was investigated using repaglinide as the model medication. The new formulation technique of liquisolid compacts was used to convert liquid medications such as solution or suspension of repaglinide in polysorbate 80, a non-volatile liquid vehicle, into acceptably flowing and compressible powders by blending with selective powder excipients. Several liquisolid tablet formulations were prepared using a new mathematical model to calculate the appropriate quantities of powder and liquid ingredients required to produce acceptably flowing and compressible admixtures. Due to their increased wetting properties and surface of drug available for dissolution. liquisolid compacts demonstrated significantly higher drug release rate than that of commercial products. Differential thermal analysis [DTA] was used for evaluation of physicochemical properties of repaglinide in liquisolid formula. It was shown that Avicel PH101 had more liquid retention potential in comparison with starch, and the formulations containing polysorbate 80 as a liquid medication, Avicel PH101 as a carrier and calcium silicate as a coat. showed higher dissolution rate at excipients ratio 5