In this study, different ratios of mucin-grafted polyethylene-glycol-based microparticles
were prepared and evaluated both in vitro and in vivo as carriers for the oral delivery of insulin.
Characterization measurements showed that the insulin-loaded microparticles display irregular
porosity and shape. The encapsulation efficiency and loading capacity of insulin were >82%
and 18%, respectively. The release of insulin varied between 68% and 92% depending on the
microparticle formulation. In particular, orally administered insulin-loaded microparticles resulted in
a significant fall of blood glucose levels, as compared to insulin solution. Subcutaneous administration
showed a faster, albeit not sustained, glucose fall within a short time as compared to the polymeric
microparticle-based formulations. These results indicate the possible oral delivery of insulin using
this combination of polymers.
