Poly(PEGDMA‐MAA) copolymeric micro and nanoparticles for oral insulin delivery

Poly(ethylene glycol) dimethacrylate (PEGDMA) and methacrylic acid (MAA) based micro and nanoparticles were prepared and evaluated as a carrier for oral delivery of insulin. PEGDMA was synthesized by esterification reaction of the PEG4000 with MAA in the presence of an acid catalyst. Particles of different size were prepared by emulsion polymerization reaction using different concentration of sodium lauryl sulphate (SLS) as an emulsifying agent. Synthesized copolymeric particle were characterized by attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR), scanning electron microscopy, and acid value. The mean particle diameter of the polymeric micro and nanoparticles at various physiologically relevant pH values was measured using dynamic light scattering. Insulin loading efficiency of the particles was found to be directly proportional to the particle size and inversely proportional to the acid value of the particles. In vitro insulin release studies from various insulin loaded particles were performed by simulating the gastrointestinal tract conditions using HPLC. At pH 2.5, the release of insulin from polymeric particles was observed in the range of 5–8% while a significant higher release (20–35%) was observed at pH 7.4 during first 15 min of in vitro release. Largest size copolymeric particles of 8.3 µm also showed the highest efficiency to reduce the blood glucose level in diabetic rabbits. Copyright © 2010 John Wiley & Sons, Ltd.