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 μm and EPS II = 7 μm) 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 (∼30%) with hexadecane, and negligible in the presence of olive oil-in-water emulsions.