New biomimetic barrier Permeapad™ for efficient investigation of passive permeability of drugs.

In this work the suitability of a newly invented physical patch comprising a biomimetic barrier (named Permeapad™) for drug permeability tests has been investigated. Exemplars of Permeapad™ were adapted to Franz diffusion cells and apparent permeability (Papp) of a series of drugs were measured and compared with calculated partition coefficients (logPcal) of the investigated drugs as well as literature reference values obtained from Parallel Artificial Membrane Permeation Assay (PAMPA) and the cellular based method Caco-2. Moreover, tightness of the barrier to hydrophilic marker's permeation, resistance of these barriers to proton permeation (pH changes) and shelf-life functionality were also investigated. Comparison with the published data indicated a good correlation between the permeability values measured and partition coefficients (logPcal). Moreover, a good correlation between the permeabilities measured with the new barrier and well-established in vitro permeability methods (PAMPA and Caco-2 respectively) was found for both highly absorbed and poorly permeable compounds. Permeapad™ also proved to maintain high integrity over time and in different pH environments. In conclusion, Permeapad™ as an innovative barrier appears to be a promising tool for fast, cost effective and reliable screening of drugs and chemical entities' passive permeability.