Month: March 2019

Amphiphilic hyaluronic acid derivatives toward the design of micelles for the sustained delivery of hydrophobic drugs

The idea of this study was to combine hyaluronic acid (HA) viscosupplementation and a local/controlled delivery of a hydrophobic anti-inflammatory drug. To this aim, we investigated the ability of an octenyl succinic anhydride (OSA) modified HA (OSA-HA), to act as a solubility enhancer and as a platform for slow release of hydrophobic drug(s). This novel HA derivative could act as a viscosupplementation agent and, for this reason, a rheological study was conducted along with calorimetric analysis. Differential scanning calorimetry (DSC) results revealed that the ability of HA to sequester water is enhanced by the introduction of lipophilic functions within HA molecules, resulting in a decrease of the fraction of free water able to freeze compared to the unmodified HA. Moreover, OSA-HA solutions appear to be an appropriate tool to be used in viscosupplementation therapy owing to their suitable viscoelastic features. Our results indicate that OSA-HA is able to self-assemble into micelles, load a hydrophobic drug and release the active molecule with controlled kinetics. In particular, the analysis of release profiles showed that, in all cases, drug diffusion into the gel is faster compared to gel/drug dissolution, being the dissolution contribution more relevant as the OSA-HA concentration increases.(Carbohydr Polym. 2014 Feb 15;102:110-6)

Preparation and characterization of octenyl succinic anhydride modified agarose derivative

Agarose was successfully modified with octenyl succinic anhydride (OSA) and the factors affecting OSA modifying process were studied. The degree of substitution (DS) could be regulated from 0.02 to 0.21 by changing the reaction condition, simultaneously the molecular weight of the OSA-agarose (OSAG) varied from 342 kD to 483 kD. FT-IR spectrum of the OSAG at 1734 cm-1 and 1576 cm-1 revealed characteristic absorption peaks of the ester carbonyl groups (CO) and the carboxylate (RCOO-), respectively. NMR spectrum of the OSAG suggested the main substitution occurred at the C-2 in the d-galactopyranose. The SEM image of agarose showed the porous network structure became dense and the fiber became thin after OSA modification. Compared with original agarose, the prepared OSAG showed novel physical properties including low gelling and melting temperature and high transparency. The remaining gelation ability and newly introduced amphiphilic character anticipate potential application as functional polysaccharide materials in foods. (Food Chem. 2019 May 1;279:30-39.)