RESUMO
Nanostructured lipid carriers (NLC) are aqueous dispersions of nanoparticles formed by solid and liquid lipids. In this study, NLC containing an organic UV filter, bemotrizinol, were developed for sunscreen formulation using carnauba wax and caprylic/capric triglycerides through ultrasonication technique. A Box-Behnken design was used to evaluate the influence of three variables on the particle size with the purpose of choosing the best system for further characterization. The particle size decreased as the surfactant concentration increased, reaching an average size of 122.4 ± 0.3 nm at 30 days of storage. Scanning electron microscopy showed intact and spherical particles. Thermal analysis and Fourier-transform infrared spectroscopy suggest that bemotrizinol was incorporated into the NLC. The X-ray diffraction showed a reduction in the crystallinity of the NLC. In vitro analysis indicated an improvement in the photoprotective activity of bemotrizinol when incorporated into NLC. These findings suggest a promising, stable, and biocompatible system.
Assuntos
Portadores de Fármacos/química , Lipídeos/química , Nanoestruturas/química , Fenóis/química , Protetores Solares/química , Triazinas/química , Ceras/química , Microscopia Eletrônica de Varredura , Difração de Raios XRESUMO
Vascular thrombosis is a potentially fatal disease. Thrombolysis represents an efficient therapeutic option, although it still presents intrinsic bleeding risks. In order to minimize this problem, intra-thrombus injections, alone or associated with some kind of mechanical thrombectomy, have been used. In this work, a new approach to thrombolysis is presented, where the preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam are reported. Foams were prepared by mixing albumin solution with CO2 at different volume ratios. Foam stability and apparent viscosity were the parameters used to characterize the foams. The volume ratio between CO2 and albumin solution that yielded the samples with the best properties was used to prepare the thrombolytic foams, where streptokinase was used as the thrombolytic agent. The thrombolytic effect of this foam was assessed in vitro by delivering it intra-thrombus and the results were compared with those of the foam without streptokinase as well as those of a regular streptokinase solution. Both foam stability and viscosity increased as the ratio of CO2:albumin solution increased and the 3:1 ratio was used to incorporate streptokinase. The in vitro thrombolytic activity study revealed that the streptokinase foam caused a 46.6 % of thrombus lysis after 30 min of experiment against 21 and 31 % of those of the foam without streptokinase and the regular streptokinase liquid solution, respectively. Thus, the use of CO2:albumin foam enhanced the in vitro thrombolytic effect of streptokinase, which indicates its potential as a novel vehicle for carrying and delivering streptokinase to targeted thrombi.