Encapsulation and Controlled Release of rHu-Erythropoietin from Chitosan Biopolymer Nanoparticles

The objective of this research project was to develop a drug delivery system for recombinant human erythropoietin (rHu-EPO), a glycoprotein hormone used in the treatment of renal anaemia and chemotherapy induced anaemia, using the biopolymer chitosan as the base component. Two types of chitosan nanoparticles were produced through ionotropic gelation using flush mixing with either tripolyphosphate (TPP) or carrageenan polymer. Chitosan-TPP and chitosan-carrageenan nanoparticles were generated under a variety of conditions to evaluate the effects of chitosan concentration, chitosan to anion mass ratio and solution pH on the nanoparticle characteristics of particle diameter, surface charge and particle size distribution. A statistical method of experimentation design, known as response surface modeling, was applied to allow for accurate manipulation of nanoparticle characteristics and to create nanoparticles with optimized characteristics. The encapsulation and controlled release of rHu-EPO from chitosan nanoparticles was evaluated with chitosan-TPP nanoparticles demonstrating an encapsulation efficiency of 43.45±0.84% and ~68% drug release within two weeks, while chitosan-carrageenan nanoparticles had an encapsulation efficiency of 47.97±4.10% and ~50% drug release within two weeks. Both types of chitosan nanoparticles exhibited improved encapsulation and release of rHu-EPO compared to previous results. Also, the molecular weight of the chitosan used and the surface charge of the nanoparticles were shown to have an effect on the encapsulation and release of rHu-EPO