Main Article Content
Methyl salicylate (MS) is an active pharmaceutical ingredient of NSAIDS group, often used in topical dosage forms such as ointments, gels, patches, etc. to treat and relieve muscle and joint diseases. Microemulsion is a potential drug delivery system thanks to its various advantages: oil droplet size of only several nanometres, good appearance, transparence, simple methods of preparation and simple application in manufacturing. This study aims to formulate a phase diagram to identify the area of methylsalicylate microemulsion formation and formulate MS microemulsion 1% and 5%. The water titration method was used to build the phase diagram. MS microemulsions were evaluated for their appearance, thermodynamic stability, particle size and stability after storage. The study results show that the using of isopropyl mirystate as the oil phase, Tween 80 as a surfactant and Transcutol P auxiliary surfactant resulted in a larger microemulsion formation area than the using of coconut oil as the oil phase and polyethylene glycol 200 as an auxiliary surfactant. MS microemulsion 5% and 1% had a droplet size of about 20 nm and thermodynamical stability. As MS microemulsion 5% was stable by particle size, its change was not statistically significant after a three-week storage.
Methyl salicylate, microemulsion, phase diagram.
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