Background: Indomethacin is a potential nonsteroidal anti-inflammatory drugs (NSIDs), but it can cause gastrointestinal irritation if it is given orally. The delivery system of indomethacin through skin can avoid the side effect, but the skin has a major barrier that is stratum corneum which causes low drug penetration. Therefore, nanoemulsion preparation is made to enhance drug penetration and to avoid the side effects.
Purpose: The purpose of this study was to prepare indomethacin nanoemulsion preparation and to determine the analgesic and anti-inflammatory effect in rats.
Method: The nanoemulsion preparations containing 1 % indomethacin was prepared with menthol as an enhancer, Tween 80 as a surfactant, and sorbitol as co-surfactant by spontaneous emulsification method. The particle size of nanoemulsion was measured by using Particle Size Analyzer. In vitro penetration study was determined with diffusion cell using rabbit's skin. Analgesic effect was measured by using plantar test infrared method in mice and anti-inflammatory effects by using paw edema method in mice.
Results: The average particle size of indomethacin nanoemulsion without menthol was 313.16 nm and nanoemulsion containing 4% menthol was 816.71 nm. The surface tension of indomethacin nanoemulsion and indomethacin nanoemulsion containing 4% menthol were 47.70 and 46.2 dyne/cm, respectively. The addition of menthol increased the penetration of indomethacin and the analgesic and anti-inflammatory effects. The penetration of indomethacin and analgesic and anti-inflammatory effects of Indomethacin nanoemulsion containing 4 % menthol were higher compared to commercial 1% indomethacin gel.
Conclusion: From the results of the study it can be concluded that the indomethacin can be formulated into nanoemulsion preparation with menthol as an enhancer. Indomethacin nanoemulsion with the addition of mentol gives the higher penetration and the analgesic and anti-inflammatory effects.