Physical characteristics, pharmacological properties and clinical efficacy of the ketoprofen patch: a new patch formulation.
The mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs), to which ketoprofen belongs, is based on their cyclo-oxigenase (COX) inhibiting action, concerning both subtype COX-1 constitutive isoform and COX-2 inducible isoform. Ketoprofen administration may be carried out by oral and parenteral routes as well as by topical application, which includes transdermic patch use. Following a synthetic description of the results obtained by several investigators on ketoprofen use, the Authors present a new formulation of the ketoprofen patch obtained by the so called DermaLight Technology. According to such a technique, the active principle is dissolved in oil components and dispersed inside an anhydrous polymeric matrix made up of styrene-isoprene-styrene (SIS), which is an elastic and flexible material that provides a gentle adhesion to the skin, maintains an elevated ketoprofen concentration and induces a strong thrust that favours the crossing of the skin by the drug; in addition, the patch is fit to be applied to the various areas of the body, including the joints. Patch adhesiveness reduces skin irritation due to multiple applications and to long-term use, as the DermaLight Technology minimises keratinocytes exfoliation. In pharmacokinetic studies carried out on pigs ketoprofen has been demonstrated to reach deep tissues, where the drug was detected in much higher concentrations, with respect to plasma levels, 12 hours following its application. Experimental studies carried out on rats have shown that ketoprofen patch significantly reduces the edema induced by chronic inflammation. The ulcerogenic effect of ketoprofen patch is then compared with that shown by oral administration of the drug. UD50 values of ketoprofen patch were 49.9 mg/kg and 48.9 mg/kg for the stomach and the small intestine, respectively, whereas UD50 values of oral ketoprofen were 3.6 mg/kg and 3.7 mg/kg, respectively. The Authors conclude by stating that ketoprofen patch is both a good alternative and a safe modality of administration, with special reference to patients who are prone to gastrointestinal disorders.