Antiinflammatory activity and bioavailability of percutaneous piroxicam

Both the topical and the percutaneous antiinflammatory potencies of a topical formulation of piroxicam were investigated using as reference standards nonsteroid and steroid antiinflammatory drugs having the same excipient base (indometacin and hydrocortisone acetate) or as topical formulations available in commerce (ketoprofen and oxyphenbutazone). In regard to the topical activity, piroxicam antagonized significantly both the croton oil edema and the UV-erythema; against the latter experiment also ketoprofen exerted intense inhibition, whilst oxyphenbutazone proved inactive. In the case of percutaneous application (carrageenin edema), piroxicam was appreciably more effective than reference compounds. In the latter experimental model piroxicam applied to the "inflamed" hind paw exerted 64% of the potency of oral piroxicam, but 2.3-2.5 times the percutaneous potency of piroxicam applied to other regions of the skin. These findings combined with the results of the bioavailability tests suggest that the percutaneous application of piroxicam may be exploited to advantage in clinical practice.