Agarose as a tunable platform for oral drug delivery: Controlled release of a highly soluble drug, theophylline, within a sequentially-changing-pH medium

Abstract

The purpose of this study was to expand the use of freeze-dried agarose-based systems for the oral controlled release of highly water-soluble drugs. Three additives (Eudragit S-100 and RL-PO and Labrafac) were included within these systems together with Theophylline. The release of this drug from the rehydrated systems was evaluated in deionized water and in a sequentially-changing-pH medium that simulated the conditions under oral administration. Considering the results obtained in the preliminary release test in water, only the Eudragit-containing compositions were further characterized. The theophylline release in a sequentially-changing-pH medium showed two different patterns that mainly depend on the additive nature: those systems containing Eudragit S-100 showed a similar behaviour to that observed in the absence of additives while the presence of Eudragit RL-PO yields a progressive and pH-independent release. Agarose-based systems were capable of accommodating additives that allows tailoring a controlled release of theophylline, a highly soluble drug.