Materials and Methods

I ’ is a new nonsteroidal drug with anti-inflammatory, analge-sic, and immunomodulatory properties in various laboratory animals2 ( 1). It is a result of analysis of structure-activity rela-tionships in a series of aryloxoalkanoic acids (2). It has been assumed (3) that the anti-inflammatory activity is probably con-nected with an active metabolite, II (fig. 1) with the same pharmacological properties as I itself, exhibiting extremely long-lasting action. The aim of the present study was to investigate pharmacoki-netics and biotransformation of I in the rat using noncompart-mental methods, to support toxicology with sufficient data for risk estimation during first administration of I to humans, and to compare its pharmacokinetics with that of structurally related fenbufen (3)