Biopharmaceutical Characteristics of Indomethacin Gel Ointment

The characteristics of insomethacin (ID) gel ointment were compared with those of conventional types of ointments. 1) The percutaneous abserption of ID from a 50% alcoholic solution occurred by a simple diffusion process, sincc the percentage of absorbed ID did not depend on the concentration of ID. 2) The in vitro release of ID from the gel ointment was greater than that from conventional ointments. 3) The gel ointment had greater volatility and the concentration of ID in the gel base doubled in 4 hours under the conditions of 75% relative humidity at 25°C. 4) Reflecting the results of in vitro studies, the absorption of ID from the gelointment into rat skin and muscle was greater than that from conventional types of ointments. 5) From the time course of muscle ID levels, little lag time of ID transfer through the skin was apparent.