Associating Copolymer Gels As Drug Delivery Systems

Xinyin Liu, Steve Krier, Anthony Lowman
Drexel University
3141 Chestnut Street
Philadelphia, PA, 19104
xl24@drexel.edu
(215) 895-5820

In this work, we have prepared associating copolymer hydrogels of poly (vinyl alcohol) (PVA) and poly (vinyl pyrrolidone) (PVP) for use in drug delivery applications. The copolymer gels are prepared by casting copolymer solutions followed by drying under vacuum at ambient temperatures. Upon hydrating of the copolymers, the ensuing gels are insoluble due to the presence of physical crosslinks consisting of PVA crystallites and hydrogen bonds between the PVA and PVP. This type of gel preparation also allows for loading of drugs, including sensitive protein and peptide drugs, during the preparation step.  In this work, we have prepared gels of varying copolymer composition and polymer molecular weight.  Additionally, we have incorporated a protein, myoglobin, into the gels. The properties of the gels were evaluated using equilibrium swelling, rubber elasticity analysis and differential scanning calorimetry.  Based on these data, we were able to evaluate the effects of copolymer composition on the structure of these networks.  Additionally, we investigated the release characteristics of the model drugs from hydrogels of varying composition.