Protein adsorption on biodegradable polyanhydride microparticles

The in vitro adsorption of plasma proteins on polyanhydride microparticles based on sebacic acid (SA), 1,6-bis(p-carboxyphenoxy)hexane (CPH), and 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane (CPTEG) was studied. Three model proteins from bovine serum (albumin (BSA), immunoglobulin G (IgG), and fibrinogen (Fg)) were used. The adsorption was studied using X-Ray Photoelectron Spectroscopy and gel electrophoresis. 2D electrophoresis was used to study the adsorption of plasma proteins from bovine serum. Differences in the amount of protein adsorbed were detected as a function of the following: (i) copolymer composition and (ii) specific protein studied. A direct correlation between polymer hydrophobicity and protein adsorbed was observed and higher quantities of Fg and IgG were absorbed. In vitro release studies were performed with ovalbumin-encapsulated microparticles that were incubated with Fg; these studies showed a reduction in the amount of ovalbumin released from the microparticles when Fg is adsorbed on the surface. An understanding of protein adsorption patterns on parenteral delivery devices is valuable in optimizing their in vivo performance.