Correlation between gel structural properties and drug release pattern in scleroglucan matrices.

The drug delivery behavior of scleroglucan hydrogels was correlated with the structural features found by means of steady-state fluorescence studies. Theophylline at 0.4% in weight was used as the model drug and its release was measured using a Franz cell device. The results were fitted with a semi-empirical power law equation, finding significant differences between the 0.5% and higher than 0.8% scleroglucan concentrations (w/w). Four molecular fluorescent probes were used to test microenvironmental properties of the gel cavities, which will play a key role on the release of the pharmaceutical drugs. The results found by the fluorescence analysis are in good agreement with the ones obtained by release kinetics.