Development and validation of a bioanalytical method to quantify povorcitinib in human skin with clinical application

Quantification of drug concentrations in human skin is essential for understanding mechanisms of action in dermatologic therapeutics but remains analytically challenging. The study aimed to develop and validate a standardized tissue homogenization and liquid chromatography - tandem mass spectrometry workflow for quantifying povorcitinib in human skin biopsies.

Key skin homogenization parameters, including solvent composition, processing volume, and homogenate density, were systematically evaluated. Wet and dry homogenization approaches were compared. Following protein precipitation, samples were analyzed using liquid chromatography - tandem mass spectrometry.

Eighteen solvent systems and various processing volumes were evaluated, with three solvent mixtures producing homogeneous preparations. Limiting homogenization volumes to less than half tube capacity and using 20 mg/mL improved sample consistency. Povorcitinib stability under acidic and thermal conditions was confirmed. Comparable performance was observed between wet and dry homogenization methods, and a dry workflow was validated.

This study provides the first systemic evaluation of human skin homogenization parameters and a direct comparison of wet and dry approaches. The validated dry homogenization method enabled accurate and reproducible quantification of povorcitinib in skin biopsies from a phase I clinical study and offers a robust framework for quantifying a broad range of analytes in human skin tissues.Clinical trial registration: https://www.clinicaltrials.gov/study/NCT06505265 [clinicaltrials.gov] identifier is NCT06505265.