Métodos de preparação e caracterização de sistemas fármaco-HPßCD-lipossomas furtivos

Abstract

Researchers from around the world have been studying controlled drug delivery systems as they offer many advantages over conventional free drug delivery systems. Liposomes as well as cyclodextrins are one of the best carrier and drug delivery systems as they are biocompatible, improve the bioavailability of the drug, limit toxic side effects and also promote greater absorption than the corresponding free actives enhancing drug action. 2-hydroxypropyl-b-cyclodextrin (HP-β-CD) is one of the drug carriers belonging to the class of cyclic oligosaccharides. In turn, these compounds have a hydrophobic internal cavity and its hydrophilic exterior, in aqueous medium as well as, encapsulate in its inner cavity hydrophobic molecules. Furtive Liposomes (LF) are vesicles formed by phospholipids, forming structures with an aqueous compartment and lipid bilayer. Also used as carriers of lipophilic and hydrophobic drugs. However, the drugs incorporated into the liposomes can still be released which ultimately limits the use of the system. Encapsulation of the Drug / HP-β-CD complex in LF can bypass the disadvantages of each system individually in order to obtain the best possible controlled drug delivery system. In this way, the present work aims to test methods of preparation of binary systems (Drug / HP-β-CD): freeze-drying; preparation of the complex in aqueous phase and co-evaporation in terms of complexation efficiency and association constant. Three methods for the preparation of the ternary complex (F / HP-β-CD in LF) will also be used, being: dehydration-rehydration; method of preparation by injection of ethanol and method by hydration of the lipid film, then quantify both complexes in terms of complexation efficiency using UV and Vis (UV-Vis) spectrophotometry.