Superporous Hydrogel Composites of Acrylamide Using Starch-silicone Dioxide Coprecipitate as Composite Agent

Aim: Present study includes the development and evaluation of superporous hydrogel composites of acrylamide using starch silicone dioxide coprecipitate (SSC) as composite agent.
Methodology: Gas blowing method was used for synthesis of superporous hydrogels. Different ingredients were mixed in specified amount in test tube and foaming agent was added at last. Simultaneous foaming and gelation lead to formation of porous hydrogel networks. Effect of different treatments (acetone dehydration and simulated gastric fluid (SGF) treatment) and drying conditions on the porous structure was evaluated. The prepared superporous hydrogels were evaluated for density, porosity, equilibrium swelling ratio, equilibrium swelling time, mechanical strength, scanning electron microscopy studies. The pure drug (Verapamil Hydrochloride) mixed with Carbopol 934 (1:0.5 and 1:1 ratio) was loaded into the selected batches of SPHC using in situ method of drug loading (drug added directly into the reaction mixture). The in vitro drug release was carried out using USP II dissolution apparatus.
Results: Acetone dehydrated superporous hydrogel composites were observed as better floating devices due to least density and maximum porosity values. Maximum swelling ratio was found in case of oven dried conventional superporous hydrogel and superporous hydrogel composites with equilibrium swelling time of more than 25 min. On the other hand, acetone dehydrated SPH showed less equilibrium swelling ratio with equilibrium swelling time of 5-10 min. Minimum swelling ratio was observed in case of SGF treated hydrogels with equilibrium swelling time of 15-19 min. Mechanical strength was improved by addition of starch silicone dioxide coprecipitate as composite agent. SGF treatment also leads to enhanced mechanical strengthbut compromised swelling characteristics. SEM images showed uniformity in pore structure in case of acetone dehydrated hydrogels. Acetone dehydrated SPHC showed sustained drug release behavior with 71.14% and 57.84% of verapamil released in 12 h in the batches with Drug: Carbopol 934ratio of (1:0.5 and 1:1) respectively.
Conclusion: Acetone dehydrated SPHC were found to be promising formulations with sufficient swelling and mechanical properties for achieving sustained drug delivery.