Evaluation of the Permeability Profile of Coegin Pharma’s BMP-6-Derived Cosmetic Peptide NPP-4 Using In Vitro Permeability Testing (IVPT)

Sammanfattning

This study aimed to evaluate the permeation-enhancing properties of Coegin Pharma’s gel serum formulation on NPP-4, a peptide of interest for melanogenesis stimulation. A full-thickness reconstructed human skin model (MatTek EpiDermFT), comprising epidermis and dermis, was used to evaluate NPP-4 distribution in the gel serum vs a H2O reference vehicle. In parallel, methylene blue was used as a model permeant using Franz diffusion cells with Strat-M synthetic membranes and porcine skin to evaluate their suitability as in vitro permeation models for future studies on NPP-4. NPP-4 was applied to MatTek EpiDermFT inserts (n = 3) at 0.025 g (25 µL) in gel serum (0.5%) and H2O (1%). After 24 hours, the epidermis and dermis were separated, homogenized, and analyzed alongside the receptor medium by reversed-phase, high-performance liquid chromatography. NPP-4 permeated the full thickness model under both vehicles, with significantly higher dermal than epidermal accumulation (p < 0.05). The gel serum significantly enhanced dermal accumulation vs H2O (p < 0.05), likely due to its lipid-based, water-free composition, demonstrating its ability to deliver NPP-4 to melanocytes at the dermal-epidermal junction. Methylene blue was applied to Strat-M and porcine membranes (n = 4) at 100,00 10,00 and 1,00 µg/g in placebo, and at 100,000 µg/g in H2O. After 24 hours, receptor fluid samples were analyzed by ultraviolet-visible spectrophotometry at 660 nm. Methylene blue failed to produce quantifiable receptor fluid concentrations across both models, with no statistically significant differences detected between vehicles (p > 0.05), suggesting the dye was retained within the membrane rather than permeating through. This finding highlighted the importance of permeant physicochemical properties, adequate sample size, and membrane reproducibility in IVPT.