Sclerotium rolfsii scleroglucan:: The promising behavior of a natural polysaccharide as a drug delivery vehicle, suspension stabilizer and emulsifier

Gel matrices of scleroglucans from Sclerotium rolfsii ATCC 201126 (EPS I and EPS II, from 48-h and 72-h fermentations, respectively) were evaluated on their release kinetics of theophylline (Th). Equivalent polymer (2%, w/w) and Th (0.2%, w/w) concentrations showed almost coincident drug release patterns, independently of polymer molecular weight or the microstructural properties of gel matrices. Dynamic rheological studies of scleroglucan hydrogel structures (storage, G', and loss, G '', moduli) indicated a solid-like behavior. Differences on pore size dimensions (EPS I = 20 mu m and EPS II = 7 mu m) were in accordance to the differences in G' (EPS I = 113 Pa and EPS II = 161 Pa), a fact likely related to variations in the cross-linking density of polymer networks. Compared to already known biopolymers, EPS I and EPS II at 0.5 g/L showed a good dispersing ability against particulate suspensions of activated charcoal, bentonite, CaCO3, celite and quartz powder. Emulsifying ability of both EPSs at 2 g/L was high (E = 56-60%) when tested with kerosene, moderate (similar to 30%) with hexadecane, and negligible in the presence of olive oil-in-water emulsions. (c) 2007 Elsevier B.V. All rights reserved.