Hybrid Self‐Assembled Gel Beads for Tuneable pH‐Controlled Rosuvastatin Delivery

This article describes the fabrication of new pH‐responsive hybrid gel beads combining the polymer gelator calcium alginate with two different low‐molecular‐weight gelators (LMWGs) based on 1,3 : 2,4‐dibenzylidene‐d‐sorbitol: pH‐responsive DBS‐COOH and thermally responsive DBS‐CONHNH(2), thus clearly demonstrating that different classes of LMWG can be fabricated into gel beads by using this approach. We also demonstrate that self‐assembled multicomponent gel beads can be formed by using different combinations of these gelators. The different gel bead formulations exhibit different responsiveness – the DBS‐COOH network can disassemble within those beads in which it is present upon raising the pH. To exemplify preliminary data for a potential application for these hybrid gel beads, we explored aspects of the delivery of the lipid‐lowering active pharmaceutical ingredient (API) rosuvastatin. The release profile of this statin from the hybrid gel beads is pH‐dependent, with greater release at pH 7.4 than at pH 4.0 – primary control of this process results from the pK (a) of the API. The extent of pH‐mediated API release is also significantly further modified according to gel bead composition. The DBS‐COOH/alginate beads show rapid, highly effective drug release at pH 7.4, whereas the three‐component DBS‐COOH/DBS‐CONHNH(2)/alginate system shows controlled slow release of the API under the same conditions. These initial results indicate that such gel beads constitute a promising, versatile and easily tuned platform suitable for further development for controlled drug‐delivery applications.