Beagle study finds skin drug penetration factors vary by body site

A new exploratory study in the American Journal of Veterinary Research found that skin structures in Beagles differ meaningfully by body site in ways that could affect how well drugs penetrate through the skin. Researchers Fusako Takeo, Nobuo Murayama, and Junichi Kamiie collected skin samples from six Beagles at the dorsum, lateral trunk, and ventral abdomen between November 2024 and March 2025, then compared epidermal thickness, stratum corneum layers, and dermal vessel density. The paper adds species- and site-specific evidence to a long-standing principle in transdermal medicine: where a drug is applied can change how much gets through the skin and how predictably it does so. (sciencedirect.com)

Why it matters: For veterinarians, the study is a reminder that transdermal and topical prescribing in dogs isn't just about the molecule or vehicle. Regional differences in skin thickness, barrier layers, hair, and blood supply can influence absorption, efficacy, and adverse effects, and prior veterinary and comparative literature has warned that extrapolating across species, patients, or body sites can be unreliable. That has practical implications for compounded transdermal products, site selection in clinical protocols, and client instructions for pet parents applying topical therapies at home. (sciencedirect.com)

What to watch: The next step is whether follow-on work links these histologic differences to measured drug absorption at each site, which would make the findings more actionable for formulation and prescribing decisions. (sciencedirect.com)