Preliminary clinical pharmacokinetic evaluation of bemotrizinol - A new sunscreen active ingredient being considered for inclusion under FDA's over-the-counter (OTC) sunscreen monograph

Abstract

Protection against sunburn, skin damage and the carcinogenic effects of ultraviolet light are the primary health benefits associated with UV filters used in topical sunscreen drug products. Countries such as Europe have 30+ UV filters approved for sunscreen products while the US has about 10, greatly reducing the options to provide diverse, effective sun protection products. Bemotrizinol (BEMT) is the first new sunscreen active ingredient to be evaluated for inclusion in the Over-The-Counter (OTC) sunscreen monograph using FDA's new Generally Recognized as Safe and Effective (GRASE) testing guidelines. An in vitro skin permeation test (IVPT) and clinical pilot pharmacokinetic Maximum Usage Trial (MUsT) were completed to support the GRASE determination for 6% BEMT. IVPT results indicated an oil +10% ethanol as the model sunscreen intervention for the pilot MUsT. The open-label trial revealed: BEMT concentrations rarely exceeded FDA's defined threshold (0.5 ng/mL) in plasma; no evidence for BEMT accumulation or steady-state concentrations above threshold; only one moderate and few mild treatment emergent adverse events (TEAEs). Therefore, maximal topical applications of 6% BEMT in a model sunscreen formulation did not contribute to meaningful systemic exposure. These results support the safety of BEMT 6% for human sunscreen use.

Keywords: Bemotrizinol; FDA GRASE Determination; In vitro permeation test (IVPT); Maximum usage trial (MUsT); OTC Sunscreen monograph; Skin cancer; Sunscreen; Systemic absorption; UV filter.