Heretofore, anti-inflammatory analgesics for external use, which are supplemented with a non-steroidal anti-inflammatory agent such as a salicylic acid-based compound (e.g., methyl salicylate), indomethacin, diclofenac, or ketoprofen, and with l-menthol as a cooling agent, have been frequently used, irrespective of patches substantially free from moisture in an adhesive or poultices containing moisture in an adhesive. However, adhesive preparations containing methyl salicylate have room for improvement in terms of analgesic effects, even though they are very frequently used.
Non-Patent Documents 1 and 2 have reported that the plasma concentration of methyl salicylate was measured, when an adhesive preparation supplemented with methyl salicylate was applied to a human. Of these documents, Non-Patent Document 1 discloses that the plasma concentration of methyl salicylate hardly rose, when two pieces of adhesive preparation supplemented with 74.88 mg/piece of methyl salicylate were applied to a human, and that a plasma concentration of methyl salicylate of approximately 30 ng/mL was obtained, when eight pieces of such adhesive preparation were applied to a human.
Non-Patent Document 1: Journal of Clin Pharmacol 2004; 44: 1151-1157
Non-Patent Document 2: Journal of chromatography. B, Biomedical sciences and applications, Jun. 11, 1999; 729 (1-2): 163-71