Preparation of multi-membrane alginate aerogels used for drug delivery

A significant amount of investigation has already taken place into alginate spherical hydrogels' attractiveness for application as drug delivery carriers. One of their weaknesses is, however, their short lives within dry air conditions. In this study we used a multi-step sol-gel process for generating dry and stable complex alginate aerogels with multi-membranes. Firstly, the formation was performed of spherical hydrogels within a CaCl2 solution. These cores were further immersed in alginate solution, filtered through a sieve, and dropped into the salt solution again. Different multi-membrane hydrogels were obtained by repeating the above process. They were further converted into aerogels by supercritical drying. The effect of the membranes' numbers was investigated regarding the model drug nicotinic acid's loading and release. The drug loading increased and the drug release was prolonged by adding more membranes around the core. By increasing the amount of drug inside the multi-membrane spheres, the burst drug release was even further inhibited compared to the lower drug-loaded samples. (C) 2013 Elsevier B.V. All rights reserved.