DEVELOPMENT OF ORAL NIFEDIPINE-LOADED POLYMERIC NANOCAPSULES: PHYSICOCHEMICAL CHARACTERISATION, PHOTOSTABILITY STUDIES, IN VITRO AND IN VIVO EVALUATION

In this study, nifedipine (NFP)-loaded polymeric nanocapsules were prepared and characterised with a view to protect the drug from degradation. Nanocapsule suspensions were prepared using two different surfactants (pluronic F68 and polyvinyl alcohol). Physicochemical stability and in vivo antihypertensive effect were evaluated. The particle size, zeta potential and entrapment efficiency remained constant during a period of 28 days of exposure under light irradiation. A smaller particle size and a higher zeta potential were obtained for the nanocapsules prepared with Pluronic F68 as surfactant. The solid drug and the nanocapsules were submitted to light exposure for 28 days. After this period of time, the percentage of drug remaining in the PF68NFP and PVANFP nanocapsules was 28.1% and 21.3%, respectively. In contrast, the solid drug was completely degraded after 4 days, suggesting that the nanocapsule suspensions promoted significant protection of the drug against light exposure. In addition, in vivo studies were carried out, which demonstrated that the formulations with polyvinyl alcohol exhibited a very rapid onset of action after oral administration in rats and led to faster drug release. The nanoparticles developed can be considered as an alternative for improving NFP stability in liquid formulations.