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 (P_app) value for R6G across the cellulose nitrate membrane (0.197 × 10^-7 ± 0.069 cm/s) was the closest to the P_app 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 P_app 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.