Tenosal is a new compound obtained by esterifying salicylic acid with 2-thiophene-carboxylic acid and displays anti-inflammatory, analgesic and antipyretic properties. Extraction recovery measured is on average 95.75% for Tenosal, 98.71% for salicylic acid (SA) and 91.11% for TA. In the whole analysis of Tenosal extracted from plasma, the inter-assay coefficient of variation (C.V.) ranges from 1.00 to 5.86% and the intra assay C.V. is 5.01%. The administration of Tenosal allows a higher bioavailability of SA to be achieved than after dosing with ASA.