Abstract
Hydrogels of poly(methacrylic acid-co-N-vinyl pyrrolidone) were synthesized and evaluated for their use as carriers for oral protein delivery. Insulin loading efficiencies were determined to be near 90% for carriers crosslinked with ethylene glycol dimethacrylate with corresponding weight incorporation levels near 12%. Although no insulin was released in gastric conditions, as desired, near instantaneous release occurred when the pH was raised to values typical of the intestinal area. Cytocompatibility studies with Caco-2 and Caco-2/HT29-MTX cultures demonstrated that microparticles did not elicit toxic effects at concentrations up to 5.0 mg/mL. Insulin transport studies revealed that the carriers did not disrupt the cell layer and thus did not change the insulin permeability in the apical-to-basolateral direction. Therefore, microparticles of this system were best suited for oral delivery of therapeutic agents that do not require transport facilitation.