RESUMO
In the present work, we propose the development of a novel carrier that does not need organic solvents for its preparation and with the potential for the intravenous delivery of lipophilic and hydrophilic drugs. Named lipomics, this is a mixed colloid of micelles incorporated within a liposome. This system was designed through ternary diagrams and characterized by physicochemical techniques to determine the particle size, zeta potential, shape, morphology, and stability properties. The lipomics were subjected to electron microscopy (SEM, TEM, and STEM) to evaluate their physical size and morphology. Finally, pharmacokinetic studies were performed by radiolabeling the lipomics with Technetium-99m chelated with BMEDA to evaluate the in vivo biodistribution through techniques of molecular imaging (microSPECT/CT) in rats. Radiolabeling efficiency was used to compare the encapsulation efficiency of the hydrophilic and lipophilic molecules in lipomics and liposomes. According to the results, lipomics are potentially carriers of lipophilic and hydrophilic drugs.
RESUMO
In the present work, we show that we obtained nanometric structures made of water, 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), cholesterol (Chol), and a mixture of ethoxylated and non-ethoxylated sorbitan fatty acid esters (Tween 20, Span 20, Tween 80, and Span 80) by mixing all of them near the cloud point temperature (cp) of the ethoxylated surfactant. The influence that the constituents had on the size of the particle was determined by a pseudo-ternary phase diagram of water/Tween-Span/DPPC-Chol; the colloidal particles obtained were studied by differential scanning calorimetry, confocal fluorescence microscopy, scanning electron microscopy, and atomic force microscopy. These studies were made for all the systems with at least 23 d of colloidal stability. The most stable system was obtained with the Tween 80-Span 80 pair, behaving as a typical suspension for 48 d; this system was made of water, Tween 80-Span 80 (80:20), DPPC-Chol (95:5) in a corresponding molar ratio of 48:37:100:10. The colloidal particles obtained were a kind of emulsion and liposome structures. The second stable system was obtained with the same mixture, but in a molar ratio of 8:6:9:0, its structure was also a kind of emulsion particles. In both systems and in other less stable ones, the "emulsion particle" was completely new, it structurally corresponds to a nucleus of mixed micelles surrounded by at least one bilayer of DPPC.
