A comparative study of the in vitro dermal absorption of radiolabeled benzophenone through human skin

Sadaff Ejaz; Clive Roper; Zoe Finlayson; Kyle S Saitta; Timothy McCarthy; Frank Sun; Michael D Southall

doi:10.1016/j.tiv.2024.105835

A comparative study of the in vitro dermal absorption of radiolabeled benzophenone through human skin

Toxicol In Vitro. 2024 Apr 26:98:105835. doi: 10.1016/j.tiv.2024.105835. Online ahead of print.

Authors

Sadaff Ejaz¹, Clive Roper², Zoe Finlayson³, Kyle S Saitta⁴, Timothy McCarthy⁴, Frank Sun⁴, Michael D Southall⁴

Affiliations

¹ Kenvue Inc., 199 Grandview Rd, Skillman, NJ 08558, USA. Electronic address: SEjaz1@kenvue.com.
² Roper Toxicology Consulting Limited, 6 St Colme Street, Edinburgh EH3 6AD, UK.
³ Charles River Laboratories, Tranent, Edinburgh EH33 2NE, UK.
⁴ Kenvue Inc., 199 Grandview Rd, Skillman, NJ 08558, USA.

PMID: 38679218
DOI: 10.1016/j.tiv.2024.105835

Abstract

Octocrylene is a common sun filter ingredient used to protect the skin from damaging UV rays. Benzophenone is an impurity found in formulations containing octocrylene. [¹⁴C]-Benzophenone was spiked (0.1 g/L) into 2 commercial sunscreen formulations; Neutrogena® Beach Defense Sunscreen Spray Broad Spectrum SPF 70 Aerosol, Neutrogena® Ultra Sheer Body Mist Sunscreen Broad Spectrum SPF 30 Aerosol, and an acetone vehicle. The formulations were applied (ca 2 μL/cm²) to dermatomed human skin mounted in static diffusion cells in vitro. Receptor fluid was collected up to 24 h post dose. All samples were analyzed by liquid scintillation counting. The dermal delivery of [¹⁴C]-Benzophenone was 10.02, 9.04 and 5.19% for the 3 formulations. However, the [¹⁴C]-Benzophenone mass balances were low; 81.5, 85.3 and 8.02%, respectively. A volatility test was performed replacing skin with aluminum foil for the sunscreen formulations only. The [¹⁴C]-Benzophenone mass balance at dosing was 99% but fell to 56.9 and 60.6% at 24 h post dose, confirming the losses were due to [¹⁴C]-Benzophenone volatility. A conservative dermal absorption value of 12.42% was proposed to cover [¹⁴C]-Benzophenone containing formulations.

Keywords: Benzophenone; Commercial sunscreen formulas; Dermal absorption; Human skin; Monkey skin; Volatility.