Influence of a pore-forming agent on swelling, network parameters, and permeability of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels: Application in transdermal delivery systems

We characterized hydrogels, prepared from aqueous blends of poly(methyl vinyl ether‐co‐maleic acid) (PMVE/MA) and poly(ethylene glycol) (PEG 10,000 Daltons) containing a pore‐forming agent (sodium bicarbonate, NaHCO3). Increase in NaHCO3 content increased the equilibrium water content (EWC) and average molecular weight between crosslinks (Mc) of hydrogels. For example, the %EWC was 731, 860, 1109, and 7536% and the Mc was 8.26, 31.64, 30.04, and 3010.00 × 105 g/mol for hydrogels prepared from aqueous blends containing 0, 1, 2, and 5% w/w of NaHCO3, respectively. Increase in NaHCO3 content also resulted in increased permeation of insulin. After 24 h, percentage permeation was 0.94, 3.68, and 25.71% across hydrogel membranes prepared from aqueous blends containing 0, 2, and 5% w/w of NaHCO3, respectively. Hydrogels containing the pore‐forming agent were fabricated into microneedles (MNs) for transdermal drug delivery applications by integrating the MNs with insulin‐loaded patches. It was observed that the mean amount of insulin permeating across neonatal porcine skin in vitro was 20.62% and 52.48% from hydrogel MNs prepared from aqueous blends containing 0 and 5% w/w of NaHCO3. We believe that these pore‐forming hydrogels are likely to prove extremely useful for applications in transdermal drug delivery of biomolecules. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012