Improving the development of modified release matrix systems strictly depends on selecting an appropriate agent capable of controlling the drug's release. In this study, Adenanthera pavonina galactomannan was investigated as a potential basis for developing a controlled release of rutin. This galactomannan was extracted, purified and characterized by GPC, NMR and FT-IR spectroscopy. The mannose/galactose ratio (M/G) of 1.46 was calculated by the relative area from signals of the anomeric region of 1H-NMR spectrum. The main chain of this galactomannan consists of β(1®4)-D-mannose and α(1®6)-D-galactose linked units (1H-decoupled 13C NMR, 13C DEPT 135º NMR and HSQC spectra). The sustained-release tablets containing rutin and galactomannan were compared with the extensively investigated hydrophilic matrix HPMC. Drug release analysis revealed similar release mechanism for both matrices. A new formulation for controlled drug delivery from water-swellable matrix systems is proposed.

This work describes the development and characterization of triglyceride-based magnetic nanocomposites for application in magnetic hyperthermia and controlled drug delivery. The magnetic solid lipid nanocomposites (MSLN) constituted by mixtures of trilaurin-tricaprylin and trilaurin-tricaprin have been successfully obtained by emulsification-solvent evaporation method. The developed MSLNs were subjected to an external oscillating magnetic field and showed significant hyperthermia. The samples were exposed to frequencies of 688 and 869 kHz causing, respectively, a temperature increase of 15.5 and 22.7 °C (trilaurin-tricaprylin) and 17.3 and 26.1 °C (trilaurin-tricaprin). Also, in vitro assays in the absence of magnetic field showed that the triglyceride-based formulations were able first to encapsulate and then to sustained release an antitumoural hydrophobic drug. After 72 h of assay trilaurin-tricaprylin and trilaurin-tricaprin released 73 and 55% of their cargo, respectively. In addition, MSLN exhibited low in vitro cytotoxic activity against human neutrophils.

Alkyl polyglycosides (APGs) are new biodegradable surfactants, non-toxic, synthesized from abundant renewable sources, potentially more appropriate than anionic surfactants. A range of glycosides denoted APG-Cy was synthesized by the Köenig-Knorr reaction using C10, C16 and C18 alcohols and derived from the degradation of amylose from English potato. The molecular structures of the glycosides were characterized by Nuclear Magnetic Resonance (1H and 13C NMR) together with Infrared Spectroscopy (FTIR) and Gel Permeation Chromatography (GPC). The study by NMR allowed the junctions between hydrophilic head groups and hydrophobic tail-groups to be characterized in detail. Conformation of the glycosidic units is 4C1 type with a b anomeric configuration. The formation of glycosides with five glucose rings linked to the alkyl chain was confirmed by 1H NMR and GPC. Liquid crystals identified by the presence of double melting points were observed by Differential Scanning Calorimetry (DSC) showing thermotropic properties. The surface tension (γ) and critical micelle concentration (cmc) were determined by du Noüy method, noting that increasing the length of alkyl chain led to the expected reduction in the cmc. The energies of adsorption and micellization processes calculated from isotherms γ versus ln c (g.dm-3) indicate cooperativeness of hydrophilic and hydrophobic groups.