Artificial membranes in combination with selected natural oils for in vitro drug passive diffusion screening in Ussing type chamber apparatus applied to gastro-retentive systems.

This study aimed at developing an effective in vitro technique for the screening of drug passive diffusion utilising artificial membranes in combination with three selected oils (i.e. cognac, emu, and olive oil). Artificial membranes of varying chemical composition and characteristics have been investigated individually and in combination with the selected oils in terms of the passive diffusion of a fluorescent probe (i.e. Rhodamine 6G or R6G), in a diffusion apparatus as compared to excised pig intestinal tissues. In general, the permeation results showed that the rate and extent of R6G permeation were dependent on the membrane composition as well as the type of oil used. The apparent permeability coefficient (Papp) value for R6G across the cellulose nitrate membrane (0.197 × 10-7 ± 0.069 cm/s) was the closest to the Papp of R6G across the excised pig intestinal tissue (0.210 × 10-7 ± 0.080 cm/s). The cellulose acetate-nitrate mixture membrane impregnated with emu oil also produced a Papp value (0.191 × 10-7 ± 0.010 cm/s) that was relatively close to that of R6G across the excised pig intestinal tissue. The delivery of R6G from gastro-retentive matrix type tablets correlated with the release of R6G from the gastro-retentive tablets.

Utilization of ionotropic gelation technique for bioavailability enhancement of cinnarizine: in-vitro optimization and in-vivo performance in human.

Gastro retentive drug delivery system techniques were adopted to deliver drugs having narrow absorption window from a particular site in the GIT. Therefore, gastro retentive dosage forms were retained in the stomach, thus improving absorption and bioavailability would be improved consequently. In this study, cinnarizine (CNZ) was employed as the model drug. CNZ is a poorly soluble basic drug, suffering from low and erratic bioavailability. This is attributed to its pH-dependant solubility (highly soluble at pH < 4). CNZ is characterized by short half-life (3-6 h). Accordingly, floating CNZ emulsion gel calcium pectinate beads were developed. A mixture design was employed to study the effect of the percent of LM pectin (A), the percent of GMO (B) and the percent of Labrafac Lipophile (C) simultaneously on the percent of drug released and loaded. The optimized floating CNZ emulsion gel calcium pectinate beads and Stugeron® (the marketed reference product) were compared through a pharmacokinetic study carried on healthy human volunteers. Fortunately, simple floating CNZ emulsion gel calcium pectinate beads were prepared with zero-order release profile for 12 h. A promising in-vivo CNZ controlled release dosage form with higher bioavailability, when compared to once daily administration of Stugeron® tablets was achieved.