Sistema lipossomal modificado com ácido hialurônico: preparação e caracterização

Abstract

Lipids are biochemical compounds that have followed human evolution for thousands of years and are essential for various functions of living organisms. They are amphoteric compounds and some of them when in contact with water form nanovesicles, self-assembled bilayers named liposomes. Liposomes were discovered in the mid-1960s and since then they have been applied to various segments of nanotechnology. One of the main characteristics of liposomes is that they are excellent nanocarriers, capable of delivering drugs more effectively against diseases. In the research of drug delivery improvement, scientists began to modify the surface of liposomes through chemical syntheses. Liposome’s functionalization is a strategy created from these modifications that has an advantage of recognizing target cells. One of the most recent functionalization techniques is bioconjugation, where a molecule is connected to a biomolecule through a spacer. That said, this work aimed to chemically modify a lipid, cholesterol, and bioconjugate it to hyaluronic acid in the formulation of a functionalized liposome. This was proposed because hyaluronic acid is a polysaccharide that is present on the surfaces of endothelial cells and, according to some publications, has an affinity for erythrocytes infected by malaria parasite. For this, a cholesterol derivative was prepared through five steps in order to have an amino terminal group and a spacer based on triethyleneglycol. They were characterized by nuclear magnetic resonance spectroscopy (NMR), infrared and monitored by the chromatographic method. In the end, it was possible to observe a successful cholesterol-hyaluronic acid molecule, which was later used in lipid formulations to encapsulate a bioactive substance developed to combat malaria, 10 - ((4,5- dihydrothiazole-2 -yl) thio) decan-1-ol. By the encapsulation efficiency test, it was possible to notice that the drug carried in the liposomal formulation with hyaluronic acid showed better results than the drug carried in the conventional liposome, which indicated a better efficiency in superficially modified liposomes.