IN-VIVO AND IN-VITRO EVALUATIONS OF WATER-ABSORPTION PROPERTIES OF VARIOUS OINTMENTS

The water-absorption properties of various vehicles were evaluated in rats whose stratum corneum had been stripped off over the application site. Polyethylene glycol (PEG) applied to the site effectively absorb ed the exudate, but other applied ointments absorbed little exudate or water. By the PEG ointment, the exudate was absorbed,continuously and extensively, and a linear relationship was obtained between the amoun t of water absorbed and the square root of time. To establish an accep table alternative in vitro method for the design of a suitable ointmen t for treating skin ulcers with exudate, in vitro evaluations were per formed by three methods: the Franz cell method, the cellulose membrane diffusion method and the spontaneous water uptake method. The membran e diffusion method, and the spontaneous water uptake method appeared t o be acceptable alternatives to the in vivo method in evaluating the w ater absorption of ointments. It is a simple and useful method for pre liminary formulation studies of ointments for the treatment of skin ul cers with exudate.