Incorporation of Pneumococcal Surface Protein, Pspa, in Cross-Linked Poly (vinyl alcohol) Hydrogel Membranes

Polyvinyl Alcohol (PVA) membranes are prolonged-released micro-matrices which can be useful in therapeutic applications. Research has shown that Pneumococcal surface proteins that are important in pathogenesis demonstrate potential as vaccine components and targets for new classes of therapeutic agents.  Pneumococcal surface protein A, PspA, has been shown to provide protective immunity in mice against pneumococcal infection.  As a part of a development of a drug release system, this study investigates the effect of structural changes on protein release from this polymeric network.  The studied parameters include: cross-linking agent (glutaraldehyde, GA) concentration, PVA content of the films, Psp A percentage and the overall effect on swelling of the hydrogels, protein release efficiency, diffusion and release characteristics of Psp A from PVA films.  In this method, different percentages of glutaraldehyde and PspA are added with a catalyst to a PVA solution during membrane preparation.  Transport studies have indicated that higher GA content results in slower diffusion rates than the lower GA content.  Although drug release systems have been studied, our objective is to investigate the mechanism of release and how accurate amounts of a potential vaccine can be released from a membrane. The open mesh of the hydrogels results in advantageously high diffusivity that can be controlled by variations in the degree of crosslinking of the polymer matrix. Preliminary results indicate that the protein drug was successfully incorporated and a lower degree of crosslinking will permit the development of the most efficient membranes.