Surfactant vesicles for enhanced antitoxoplasmic effect of norfloxacin: In vitro and in vivo evaluations

The goal was to scrutinize niosomes as potential carriers for enhanced efficacy of norfloxacin against Toxoplasma gondii RH strain. This was assessed in vitro and in vivo. Standard niosomes of Span 60 and cholesterol were prepared. Gelucire 48/16 or Tween 80 was incorporated as hydrophilic fluidizer. The prepared vesicles were characterized for shape, size, viscosity and norfloxacin release. The in vitro anti-Toxoplasma was assessed by monitoring tachyzoites viability after incubation with niosomes. In vivo efficacy of niosomes encapsulated norfloxacin was evaluated on infected mice. Transmission electron micrographs showed nano-sized spherical vesicles. Norfloxacin release varied with niosomal composition to show faster liberation in presence of fluidizing agent. The half maximum effective concentration of norfloxacin against tachyzoites (EC50) was significantly reduced after niosomal encapsulation compared with simple drug solution with no significant difference between vesicular formulations. Tachyzoite count in the peritoneal fluid of infected mice was reduced by 45.2, 90.8, 88.3 and 84% after treatment with simple drug dispersion, standard niosomes, Gelucire containing and Tween containing vesicles, respectively compared to infected untreated mice. These results correlate with the in vitro data and reflects the efficacy of niosomes. The study introduced surfactant vesicles as a tool for enhanced efficacy of norfloxacin against toxoplasma.