Novel lyophilized hydrogel patches for convenient and effective administration of microneedle-mediated insulin delivery.

A lyophilized hydrogel patch system was developed for microneedle-mediated insulin delivery. The matrix of Cross-linked poly(acrylamide-co-acrylic acid) were synthesized by precipitation polymerization. Recombinant human Insulin was loaded into the lyophilized polymer matrix, which can be rehydrated by water. After the hydrated patch was applied to the abdominal skin of diabetic rats after microneedle pretreatment, pharmacodynamics and pharmacokinetics evaluation was performed. The blood samples were collected to monitor blood glucose and serum insulin levels for 12 h. Blood glucose was lowered in proportion to the concentration of insulin loaded in lyophilized hydrogel patches (R(2)=0.99), with a longer duration of action compared to subcutaneous injection. Stability study confirmed more than 90% of insulin activity was retained in lyophilized hydrogel after 6 months of storage at 4 °C. In conclusion, hydrogel patches were demonstrated to be appropriate drug reservoir for sustained release of insulin with microneedle mediated transdermal delivery.