Polycaprolactone triol-based polyurethane nanocapsules: high-efficiency encapsulation and sustained release of piperine with enhanced compatibility

Nanocapsules are advanced encapsulation systems designed to protect bioactive compounds and ensure sustained release, enhancing their stability and efficacy. In this context, this study proposes a new encapsulation system, using polyurethane as a polymeric matrix, based on polycaprolactone triol, a biodegradable polymer, for the sustained release of piperine, a compound with promising bioactive properties. The polyurethane synthesis was performed using 1,6-hexamethylene diisocyanate, a monomeric compound, chosen for its high reactivity and low toxicity, ensuring safety in biomedical applications. Polyurethane nanocapsules (NPUs) were prepared using a simple emulsion method, with three distinct piperine loading formulations: 45 mg (NPU45), 67.5 mg (NPU67), and 90 mg (NPU90). Dynamic light scattering confirmed the system's homogeneity, while cryo-transmission electron microscopy and atomic force microscopy (AFM) revealed nanocapsules with spherical morphology and confirmed average particle sizes between 570 and 740 nm. Fourier transform infrared spectroscopy, and atomic force microscopy infrared spectroscopy (AFM-IR) validated the chemical structure of the material. The nanocapsules exhibited high encapsulation efficiency for the NPU67 formulation (89.24%). The release profile, modeled by the Higuchi equation, highlights the nanocapsules potential for sustained release. Cytotoxicity assays indicated high biocompatibility, suggesting NPUs’ potential for the safe and effective delivery of bioactive compounds.