Skin penetration and dermal pharmacokinetics (IVPT) on intact and damaged human skin, aligned with OECD TG 428

In vitro permeation testing on real human skin. Static Franz-type diffusion cells, temperature-controlled to 32 °C at the skin surface. Ex vivo human skin — full-thickness, dermatomed or heat-separated epidermis — ethically sourced. Thickness measured on every disc and barrier integrity verified by TEWL before dosing; discs outside acceptance criteria are rejected.

What we report

•    Cumulative amount permeated, maximum flux (Jmax), lag time, permeability coefficient (Kp)

•    Full mass balance: surface wash and swabs · tape stripping (stratum corneum) · epidermis · dermis · receptor fluid · cell wash

•    Finite or infinite dose; vehicle and formulation comparisons

Damaged skin — our speciality. Barrier disruption by tape stripping, abrasion, microneedling or SDS, always against the intact control from the same donor. Our damaged-skin models are characterised in a peer-reviewed paper: Barthe M. et al., Frontiers in Medicine 2024;11:1481645.

Barrier assessment. TEWL, TEER, and Lucifer Yellow penetration imaged and quantified on skin sections by fluorescence microscopy and image analysis.

Regulatory context. Studies are designed against OECD TG 428 and Guidance Document 28, OECD No. 156 (2nd edition, 2022), the SCCS criteria for cosmetic ingredients, the FDA draft guidance on IVPT for topical products in ANDAs, and EFSA guidance for plant protection products.

Quantification. LC-MS/MS at qualified partner laboratories, or liquid scintillation counting for radiolabelled test items.

We would like to meet companies developing topical or transdermal products, microneedle and patch developers, and formulation teams who need human skin data rather than animal data.