The main objective of this work was to develop a nanoemulsion based on linseed oil and betulinic acid, stabilized with Pluronic F127 and polyglycerol polyricinoleate, for anticancer applications. The nanoemulsions were synthesized by ultrasound and evaluated for in vitro cytotoxicity, particle size, polydispersity index, zeta potential, morphology, encapsulation efficiency, storage stability, rheology and in vitro release kinetics. In vitro cytotoxicity assays were performed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (72 h) against HCT-116 (colorectal carcinoma), SNB-19 (glioblastoma), NCI-H460 (lung carcinoma) and L-929 (normal fibroblasts) cells. The determination of 50% inhibitory concentration (IC50) showed an increased selectivity for the emulsified betulinic acid when compared to its free form for the HCT-116 cells. The IC50 values for the synthesized nanoemulsions showed a range from 3.2 to 3.7 µM (HCT-116), 5.6 and 11.5 µM (NCI-H460), 5.8 and 7.3 µM (SNB-19) and > 16.5 µM for normal fibroblasts. In the 48 h in vitro release assays, it presented controlled release explained by the Korsmeyer-Peppas model, releasing 572.25 and 619.95 µg of betulinic acid in a controlled way, generating promising perspectives for the prolonged release of betulinic acid in anticancer applications.

Non-doped (Hap) and doped hydroxyapatites with Cu2+ and Fe2+ were synthesized and used to study the adsorption of furan (Fur), pyrrole (Pyr), and thiophene (Thi) in single and ternary component systems. Spectroscopic data and N2 isotherms indicated there were no structural alterations in Hap with the incorporation of Cu2+ and Fe2+. For both single and ternary components, the incorporation of the metal ions resulted in an adsorption increment consistent with the hard-soft acid-base concept. When comparing the systems, there is an inversion with Thi (5.41 mg g-1) and Fur (5.51 mg g-1) being the most adsorbed species in the single and ternary components, respectively. Monte Carlo simulations helped explain the observed experimental trends. While the electrostatic effect seems to prevail in the single system, in the ternary one the mass transport phenomenon is also operative implying greater availability of Fur on surface leading to its higher adsorption efficiency.