DRUG DELIVERY, vol.14, no.3, pp.139-145, 2007 (SCI-Expanded)
The aim of our study was to formulate a stable multiple emulsions containing two nitromidazole derivates, metronidazole (MT) and ornidazole (OR), for vaginal therapy. MT and OR were located internal and external phases of multiple emulsion, respectively, and the in vitro release studies were realized in phosphate (pH 7) and lactate buffer (pH 4.5) solutions to investigate better the effect of pH and location of active substance on the release. The imaging studies were realized in rabbits following labeling NIT and OR with Technethium-99m (Tc-99m) to evaluate the in vivo absorption characteristics. The percentage of MT and OR released from the multiple emulsions in alkaline media were 3.2- and 2.8-fold greater than that observed in acidic media, respectively, when they were introduced in the internal phase of the multiple emulsions. The absorption rate of NIT from vaginal epithelium was faster than OR. We observed that especially in alkaline medium a high release was found that was convenient for the vaginal infections seen in the alkaline pH. We concluded that W/O/W multiple emulsions were locally effective in vagina and they could be introduced as a new drug carrier system. for vaginal delivery.