Affiliations: Department of Bioengineering, School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA | Department of Chemical and Petroleum Engineering, School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA | School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA | Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
Note: [] Address for correspondence: Eric J. Beckman, PhD, Department of Chemical and Petroleum Engineering, 1249 Benedum Hall, University of Pittsburgh, Pittsburgh, PA 15261, USA. Tel.: +1 412 624 9641; Fax: +1 412 624 9739; E-mail: beckman@engr.pitt.edu.
Abstract: Naphthalene analogs with differing hydroxyl and amine functionality were incorporated into degradable polyurethane foams synthesized from lysine diisocyanate and glycerol to determine if chemical structure can be used in controlled release systems. Excitation and emission spectra of the various naphthalene analogs in aqueous solution were collected to ensure they were capable of being quantitatively detected in aqueous solution at low concentrations. The fluorescence stability of the compounds was assessed over a 2-week period at 70°C; the analogs were all found to exhibit signal decay to varying degrees. Polyurethane foam materials containing the naphthalene analogs were synthesized and examined via scanning electron microscopy; incorporating naphthalene ligands did not grossly alter the polyurethane morphology. The analog distribution was then assessed via fluorescence microscopy, and the naphthalene analogs were found evenly dispersed throughout the polyurethane materials. Foam samples containing various analogs were then incubated in PBS buffer solution (pH 7.4) at 4, 22, 37 and 70°C for 11-weeks. Temperature dependent release of naphthalene analogs from the polyurethane foams was found to depend upon the functional groups present on the naphthalene analog. These results suggest that the chemical structure of a drug plays a unique role in controlling release from hydrolytically degradable drug delivery systems.
Keywords: Drug delivery, controlled release, naphthalene, polyurethane, lysine diisocyanate
