Esflurbiprofen

DescriptionMarketed by Taisho Pharmaceutical Holdings Co., Ltd., and Teijin Pharma Ltd., the (S)-enantiomer of flurbiprofen (named Esflurbiprofen) was approved as a new drug by the PMDA of Japan in 2015. (S)- Flurbiprofen, a cyclooxygenase (COX)-inhibiting nonsteroidal anti-inflammatory (NSAID) drug, is formulated with mentha oil and administered by way of a patch as a treatment for osteoarthritis in the current invention. Interestingly, the (R)- enantiomer is responsible for minimal COX inhibition but has been implicated as a possible treatment for a variety of other diseases. Synthetic approaches to racemic flurbiprofen have been reported in the chemical literature as early as the 1960s, and the mixture was approved as a drug in the United States by the FDA in 1988, marketed by Pharmacia and Upjohn. Toward this end, the current patent estate defines the utility of the active S-enantiomer, and synthetic approaches therein apply to this enantiomer only.

Description(S)-Flurbiprofen is the COX-active enantiomer of the non-selective COX inhibitor flurbiprofen with IC50 values of 0.48 and 0.47 μM for COX-1 and COX-2, respectively, in guinea pig whole blood. It inhibits the release of 6-keto prostaglandin F1α (6-keto-PGF1α; ) and thromboxane B2 (TXB2; ) from rat whole blood, gastric mucosa, lung, and jejunal tissue ex vivo in a dose-dependent manner. (S)-Flurbiprofen (1 nM) inhibits basal and bradykinin-, serotonin-, and histamine-stimulated prostaglandin E2 (PGE2) release from isolated skin flaps of rat lower hind paws. It also inhibits release of the neuroinflammatory marker calcitonin gene-related peptide (CGRP; Item Nos. 24405 | 24725 | 24728) when used at a concentration of 1 μM. In vivo, (S)-flurbiprofen reduces the number of flinches per minute in the formalin test in rats, indicating antinociceptive activity.