Desenvolvimento de um método inovador de formação de nanoemulsões para liberação modificada de praziquantel através da diluição de cristais líquidos

摘要

Liquid crystalline mesophase (LC) have an organized molecular arrangement and combining properties of liquid and solid state as the flow of liquids and the ordered and crystalline structure of solids. High- and low energy techniques were used to produce LC. N-methylpyrrolidone (NMP) and sodium oleate interactions with the system were investigated. LC fabricated by high-energy method were characterized by polarizing light microscopy (PLM), rheology and droplet size. PLM showed structures that indicated lamellar phases. Surface tension no important difference between the samples was observed. Rheology showed a zero shear viscosity in flow curves with a shear-thinning behavior in oscillatory tests, which with increasing of NMP, there was a decrease in degree of structure. Novel method to obtain lipid based drug delivery system (LBDDS) were developed through LC dilution and drug-loading was tested. LC fabricated with low-energy method was diluted with water and NMP 10% aqueous solution, at 25 °C and 70 °C, which droplet size and drug loading were evaluated. The systems diluted with water showed lower range size (165.22 nm- 381.26 nm) and higher drug-loading (40.96 mg/mL - 43.44 mg/mL) when compared with systems diluted by NMP solution. NMP aqueous solution did not contribute to form smaller particle size and higher praziquantel-loading. An increment in the apparent solubility of Praziquantel was achieved from incorporation in dilution of LC with water, increasing the soluble drug fraction approximately 200-fold when compared with water solubility. Small angle X-ray scattering (SAXS) measurements and PLM comproved the transition from lamellar mesophase to worm-like micelle systems confirming the success of new techinique for obtain LBDDS from LC dilution.