Modified β-cyclodextrin/amlodipine inclusion complexes: Preparation and application in aqueous systems

Abstract

Cyclodextrins (CDs) are cyclic oligosaccharides obtained from starch. They present a hydrophobic outer and a hydrophobic cavity and they can complex hydrophobic molecules. In addition to the conventional forms of CDs, there are its derivatives, which can bring characteristics relevant to the molecule. In this context the objective of this work was the modification of the β-cyclodextrin (β-CD) with hexanoic anhydride (β-CDM) and to perform the complexation of the drug amlodipine (AMLO) in β-CD or modified β-CD (β-CDM). The complexation occurred by suspension with subsequent lyophilization, by kneading and by simple physical mixture. The product of the modification was characterized by 1H NMR, HMBC and TGA being confirmed the esterification of the β-CD in hydroxyls C2 and C6. The complexes were analyzed by 1H NMR which indicated complexation by the presence of characteristic signals of the drug and of β-CD or β-CDM. In vitro drug release assays have shown that complex media with β-CDM had a faster release in aqueous media than dissolution of the drug in natural. This is interesting because amlodipine has a very prolonged action causing an accumulation of this substance in the organism.