Avaliação do potencial de carreadores lipídicos nanoestruturados funcionalizados com ácido fólico para veiculação de doxorrubicina no tratamento do câncer de mama

Abstract

Breast cancer (CM) is the second most common type of cancer diagnosed among women. Among the risk factors are age, genetic factors, exposure to X-rays and hormonal replacements. Treatment is directly related to the stage the disease is in, and early discovery provides a greater chance of cure. Doxorubicin (DOX), an anthracycline class antibiotic, is commonly used in treatment, but has a short half-life, low degree of stability and is a non-specific compound leading to side effects such as pain, nausea and vomiting, diarrhea, in addition to cardiotoxicity. Nanostructured lipid carriers (CLN) present imperfectly organized matrices, composed of a surfactant that allows the incorporation of high concentrations of chemotherapeutic substances, in addition to having high cellular uptake due to its characteristics. In addition, a strategy to improve the targeting of the CLN to the CM cells is its functionalization with folic acid, since folate receptors are around 60% in breast tumors. In this context, the objective of the work consists in the development and characterization of nanostructured lipid carriers functionalized with folic acid containing doxorubicin for application in breast cancer. The CLN were obtained by the fusion-emulsification technique, using a modified polymer (pluronic-folic acid) synthesized and characterized by Fourier transform infrared spectroscopy (FTIR). Furthermore, CLN with and without cetrimony bromide were developed to verify the influence of cationic or anionic charge. The developed CLNs were characterized by the technique of dynamic light scattering (DLS), scanning electron microscopy (SEM), encapsulation efficiency (EE), in vitro release and in vitro cell cytotoxicity. The FTIR technique revealed that the synthesis of the functionalized polymer was carried out properly by means of the characteristic ester group in 1703 cm-1. Macroscopically, the CLNs were homogeneous and stable for more than 180 days. The DLS showed CLNs with size between 124 and 180 nm and polydispersity <0.3. The zeta potential between 22 and 13.2 for CLN + and -12.2 and -17 for CLN-. Through SEM, spherical morphology and absence of clusters were observed. The EE was 79% and 102% for the CLN + and CLN- tested, respectively. The release profile reached ~ 100% after the 10h time and the commercial DOX released 100% in 30 min. Cell viability was tested in an MCF-7 model and demonstrates that CLN- showed greater cytotoxicity (87%) compared to commercial DOX (54%), both of which had the same concentration (46 µM), probably due to the higher cellular uptake that, is proven for any assets incorporated in nanosystems. CLN + with or without DOX showed greater cytotoxicity (~ 90%), a fact associated with high concentrations of cetrimony bromide (1150 µm). Therefore, it is possible to conclude that the developed systems have characteristics that point them as potential candidates for pre-clinical studies in vivo aiming at elucidating toxicity and antitumor activity.