Tyloxapol Niosomes as Prospective Drug Delivery Module for Antiretroviral Drug Nevirapine

With the aim of assuring more patient compliant pharmacotherapy for acquired immuno deficiency syndrome, a formulation of the first line anti-retroviral drug, nevirapine (NVP), has been developed by encapsulating it within niosomes. Biocompatible niosomes were fabricated using a biological surfactant, tyloxapol, with variable cholesterol concentrations. Formulation with surfactant/cholesterol molar ratio 1:0.1 exhibits maximum stability and optimum hydrophobicity. Thus, it is most suitable for the entrapment of NVP and has high entrapment efficiency of 94.3%. FTIR and DSC results indicate that NVP has sufficient compatibility with the excipients of the formulation. Photoluminescence quenching measurements were employed to elucidate the position of drug molecules in niosome bilayer along with the partition coefficient. Dissolution results indicate that the efflux of drug is sustained which creates a depot effect and decreases the fluctuations in drug release. Such a versatile and improved formulation of NVP is expected to increase its therapeutic index and alleviate toxic systemic side effects while improving the quality of life and duration of survival of the patients.