Development and evaluation of liposomal formulation containing nimodipine on anxiolytic activity in mice.

Nimodipine has been investigated in the treatment of anxiety. Its administration, however, presents a number of limitations, particularly by low bioavailability, low aqueous solubility and photosensitivity. These difficulties can be resolved by the use of nanometer-scale pharmaceutical carriers. The goal of the present study was thus to develop a liposomal formulation containing nimodipine (NMD-Lipo) and evaluate anxiolytic activity using models of anxiety (open-field, light and dark and elevated plus-maze test). The results suggest that administration of NMD-Lipo has no sedative or muscle relaxant effect in animals, since there was no reduction in the number of crossings, grooming and rearings. The increased residence time of the animals treated with NMD-Lipo in the bright field is a reflection of the anxiolytic-like activity of the formulation. Furthermore, the reduction in residence time of rodents treated with the combination of flumazenil and NMD-Lipo in the illuminated box suggests that NMD-Lipo acts on benzodiazepine receptors. The increase in the number of entries and length of stay in the open arms of mice treated with NMD-Lipo suggests that anxiolytic activity of formulation and reduction in number of entries and length of stay in open arms of rodents treated with a combination of flumazenil and NMD-Lipo suggest that NMD-Lipo act on benzodiazepine receptors.