Pharmaceutical and Pharmacological Evaluations of “Indometacin M Ointment” as a Pharmacy Preparation

Pharmacy preparations have been playing an important role in self-medication which is now being actively promoted. However, most pharmacy preparations lack objective data as evidence of their quality and efficacy. In view of this, we conducted pharmaceutical and pharmacological testing to obtain such data on the pharmacy preparation Indometacin M Ointment, an analgesic salve containing 0.75% indometacin that is often sold at pharmacies. In our study we conducted chronological testing of the physical properties of softness and spreadability, of stability under various storage conditions and absorption of indometacin by the skin, and compared its pain-relieving effect with similar commercial drug preparations by the Randall-Selitto method. We found that Indometacin M ointment retained its softness and spreadability when stored at 27-29℃ for 56 days, but it became too hard to use when kept at 6-8℃ for the same period. However, under the former conditions the indometacin content decreased to 92.6% but remained stable under the latter conditions. The pain-relieving threshold increased rapidly one hour after the application (p＜0.01) and was found to be equal to that of commercial products containing 1% indometacin. Further, since Indometacin M ointment contains no additives which can induce dermatitis, it may have fewer adverse effects than commercial preparations and therefore be more appropriate for people with sensitive skins. The essential data we obtained will help pharmacists advise patients on the use of Indometacin M Ointment in self-medication for pain relief.