Salicylic acid (SA), a well-known anti-inflammatory drug, can reduce insulin resistance and doses of recommended medication for diabetes patients. SA-based poly(anhydride-esters) have been researched over the past decade as novel drug delivery systems, with research suggesting that these polymers can facilitate bone regeneration in diabetics. In these research, various ratios of SA-based poly(anhydride-esters) have been physically cross-linked with poly(acrylic acid) to develop pH-sensitive cross-linked hydrogel systems. These hydrogels were characterized by Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry to understand physical interaction between these compounds. Furthermore, pore size, swelling and mucoadhesion behavior of these hydrogels were evaluated. Pore size, swelling and mucoadhesion behavior was depending on poly(acrylic acid) ratios; increasing poly(acrylic acid) increased mucoadhesion behavior and swelling value. Moreover, insulin was physically incorporated into hydrogels and ~50% insulin was able to incorporate into the networks. Insulin and SA release was evaluated in pH 1.2 and in pH 6.8 to simulate stomach and intestine conditions, respectively. Insulin release was minimum (~4-8%) in stomach-stimulating conditions (pH 1.2) over 2 h. In intestine-simulating conditions (pH 6.8), 90% of the insulin and 70% of SA were released within 24 h from the hydrogel system. Furthermore, insulin stability was confirmed by size exclusion chromatography and imaged capillary isoelectric focusing. These results suggest that hydrogels can protect insulin in stomach-stimulating conditions and can possible be used for oral insulin and salicylic acid delivery to benefit diabetes patients.

Salicylic acid-based, pH-sensitive hydrogels as potential oral insulin delivery system

251st National Meeting (2016)

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