Barrier model selection alters apparent diclofenac permeation parameters: a controlled

Introduction: Synthetic membranes and keratinocyte-based constructs are both used as accessible alternatives to Methods: Permeation studies were performed using Franz diffusion cells in an internally controlled experimental design. Both formulations were tested in triplicate under identical conditions, including receptor medium, temperature, sampling protocol, and analytical method. Steady-state flux (Jss), permeability coefficient (Kp), lag time ( Results: Barrier model selection affected the apparent permeation behavior of diclofenac. Strat-M® detected a statistically significant difference in steady-state flux between Voltaren® and Olfen®, whereas no statistically significant between-formulation difference was detected with the HaCaT construct under the same experimental conditions. Lag time was the parameter most strongly influenced by barrier selection and was consistently shorter with the HaCaT construct than with Strat-M®. Discussion: Under identical IVPT conditions, Strat-M® and the HaCaT-based epidermal construct generated different apparent permeation profiles and yielded different comparative assessments of Voltaren® and Olfen®. This model-dependent divergence underscores the need to justify barrier selection explicitly and to consider its limitations when interpreting comparative IVPT data.