抄録
New hydrogels containing pentoxifylline were prepared by adding NaOH solution to Eudragit L, S, Eudispert hv, mv and lv (acrylic resins) at various concentrations. The in vitro release rate of pentoxifylline from hydrogels was much the same as that found for Witepsol S-55 suppository and could he controlled by modifying the milliequivalent (mEq) of NaOH per unit weight of the polymer materials and the percentages of the polymer materials added to the hydrogels. Furthermore, the xerogel newly prepared by freeze-drying 10% Eudispert by hydrogel added 5 mEq of NaOH resulted in the slowest release of pentoxifylline. In in vivo evaluation using rabbits, it was found that 15% Eudispert by hydrogel and xerogel prepared from 10% Eudispert by hydrogel adding 5 mEq of NaOH were useful as rectal controlled release preparations of pentoxifylline. The relative bioavailability of Eudispert by hydrogels and xerogels increased to 1.3-1.5 fold compared with Witepsol S-55 suppository. From the results of the statistical moment analysis for Eudispert hv hydrogels and xerogels, it became clear that there were statistically significant correlations between the in vitro mean dissolution time (MDTin vitro) and the in vivo mean residence time (MRT).
