Synthesis and Characterization of Isosorbide-Based Polyurethanes Exhibiting Low Cytotoxicity Towards HaCaT Human Skin Cells.

The synthesis of four samples of new polyurethanes was evaluated by changing the ratio of the diol monomers used, poly(propylene glycol) (PPG) and D-isosorbide, in the presence of aliphatic isocyanates such as the isophorone diisocyanate (IPDI) and 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI). The thermal properties of the four polymers obtained were determined by DSC, exhibiting Tg values in the range 55⁻70 °C, and their molecular structure characterized by FTIR, ¹H, and 13C NMR spectroscopies. The diffusion coefficients of these polymers in solution were measured by the Pulse Gradient Spin Echo (PGSE) NMR method, enabling the calculation of the corresponding hydrodynamic radii in diluted solution (1.62⁻2.65 nm). The molecular weights were determined by GPC/SEC and compared with the values determined by a quantitative 13C NMR analysis. Finally, the biocompatibility of the polyurethanes was assessed using the HaCaT keratinocyte cell line by the MTT reduction assay method showing values superior to 70% cell viability.

New Polyurethane Nail Lacquers for the Delivery of Terbinafine: Formulation and Antifungal Activity Evaluation.

Onychomycosis is a fungal nail infection. The development of new topical antifungal agents for the treatment of onychomycosis has focused on formulation enhancements that optimize the pharmacological characteristics required for its effective treatment. Polyurethanes (PUs) have never been used in therapeutic nail lacquers. The aim of this work has been the development of new PU-based nail lacquers with antifungal activity containing 1.0% (wt/wt) of terbinafine hydrochloride. The biocompatibility, wettability, and the prediction of the free volume in the polymeric matrix were assessed using a human keratinocytes cell line, contact angle, and Positron Annihilation Lifetime Spectroscopy determinations, respectively. The morphology of the films obtained was confirmed by scanning electron microscopy, while the nail lacquers' bioadhesion to nails was determined by mechanical tests. Viscosity, in vitro release profiles, and antifungal activity were also assessed. This study demonstrated that PU-terbinafine-based nail lacquers have good keratinocyte compatibility, good wettability properties, and adequate free volume. They formed a homogenous film after application, with suitable adhesion to the nail plate. Furthermore, the antifungal test results demonstrated that the terbinafine released from the nail lacquer Formulation A PU 19 showed activity against dermatophytes, namely Trichophyton rubrum.