Formação de sistema híbrido carreador de citrato de tamoxifeno associado ao argilomineral laponita

Abstract

Breast cancer is the most prevalent type and the second that most kills women worldwide. It has several subtypes but the most common is the luminal, characteristic for being estrogen receptor positive (RE+) and the treatment for this type of breast cancer is based on the use of drugs such as tamoxifen citrate (CTMX), a highly liposoluble drug with low solubility in water and that has harmful adverse effects, making it necessary the use of alternativities to improve the bioavailability of CTMX. Drug delivery systems are viable strategies, as is the case of adsorption in clay minerals such as laponite (LAP), a solid biocompatible with high drug adsorption capacity, formulating nanoparticulate hybrid systems (SHN). The aim of this study was to evaluate the formation of SHN between the CTMX and the LAP. The concentration, time and temperature conditions of the CTMX adsorption process in the LAP were evaluated through mathematical models of Langmuir, Freundlich and Temkin isotherms, for analysis of the influence of the initial concentration of CTMX, kinetics of pseudo-first order, pseudo- second order and Elovich for analysis of the contact time. The physicochemical characteristics of three SHN (TL-1, TL-2 and TL-3) were analyzed using techniques such as x-ray diffraction (DRX), Fourier transform infrared (FTIR) and thermal analyzes such as thermogavimetry ( TG) and differential thermal analysis (DTA). The analysis of the adsorption profile showed that the adsorption process is dependent on the initial concentration of CTMX, with ideal conditions for adsorption being 2350 mg L-1, agitation time 60 minutes, pH 5.5 and temperature of 25 °C, adsorbing to the maximum 339.37 (±11.52) mg g-1 under these conditions. The mathematical adsorption model that best suited the process was that of Langmuir (r² = 0.99772), indicating that the process is carried out in a monolayer where one molecule of CTMX adsorbs at each site on the surface of the LAP, in two stages, with rapid interaction reaching the maximum adsorption in 60 minutes followed by a decay step in adsorption, the process is spontaneous and occurs at 25 °C. According to the DRX analyses, the basal space increases with the increase in the initial concentration of CTMX, being greater in the SHN TL-1 and the FTIR confirmed the interaction between the CTMX and the LAP that was able to increase the thermal stability of the CTMX. With this, it was possible to adsorb CTMX in LAP and produce SHN, characterizing them as promising drug delivery systems, requiring further analyzes to prove the improvement of the bioavailability profile of CTMX in this system.