Loxoprofen-Na (sodium 2-[4-(2-oxocyclopentylmethyl)phenyl]propionate dihydrate) is a potent analgesic drug. We developed loxoprofen-Na plasters to extend duration time of analgesic activity and to reduce side effect on gastrointestinal tract. Analgesic effect of Loxoprofen-Na plasters was investigated. Loxoprofen-Na plaster had good analgesic effect in rat paw pressure test, Tail-flick latency test and acetic acid-induced writhing test. Also, it had anti-inflammatory effect on carrageenan-induced rat hind paw edema. In pharmacokinetic study of Loxoprofen-Na, plasters dosage form showed that plasma drug concentration was prolonged up to 14 hours. So, we can conclude that loxoprofen-Na plasters, when applied on skin, will he a new type of drug for controlling the various local pain or inflammation.