title: Biodegradable hydrophobic-hydrophilic hybrid hydrogels: swelling behavior and controlled drug release.
abstract: The objective of this work was to investigate a new family of hydrophobic-hydrophilic biodegradable hybrid hydrogels as drug carriers. A series of hydrophobic-hydrophilic biodegradable hybrid hydrogels was formulated via photo means from hydrophobic three-arm poly (epsilon-caprolactone) maleic acid (PGCL-Ma) and hydrophilic dextran maleic acid (Dex-Ma) precursors over a wide range of the two precursors' feed ratio (PGCL-Ma/Dex-Ma at 100:0, 70:30, 50:50, 30:70 and 0:100). A low-molecular-weight and hydrophilic drug, the alpha-7 agonist cocaine methiodide, was used as the model drug for the release study from the hybrid hydrogels in pH 7.4 phosphate buffer solution at 37 degrees C. The swelling data of these hybrid hydrogels depended on the hydrophobic to hydrophilic precursors' feed ratio, and there were several-fold differences in swelling ratios between a pure hydrophilic Dex-Ma and a pure hydrophobic PGCL-Ma hydrogels. The presence of the hydrophobic PGCL-Ma component significantly reduced the initial burst swelling of the hybrid hydrogels. Depending on the two precursors' feed ratios, the swelling data during the early period obeyed either Fickian diffusion (for 50:50 PGCL-Ma/Dex-Ma hydrogel), non-Fickian or anomalous transport (for 70:30 and 100:0 PGCL-Ma/Dex-Ma), or relaxation-controlled (for 30:70 and 0:100 PGCL-Ma/Dex-Ma). A wide range of cocaine methiodide release profiles was achieved by controlling hydrophobic to hydrophilic precursors' feed ratios. Initial drug burst release was significantly reduced as the concentration of the hydrophobic PGCL-Ma component increased in the hybrid hydrogels. The bulk of cocaine methiodide released during the 160-h period was via diffusion-controlled mechanism, while degradation-controlled mechanism dominated thereafter.
authors.affiliation: Department of Fiber Science and Apparel Design & Biomedical Engineering Program, Cornell University, Ithaca, NY 14853-4401, USA.
authors.forename: Da-Qing
authors.initials: DQ
authors.lastname: Wu
authors.forename: Chih-Chang
authors.initials: CC
authors.lastname: Chu
mesh_terms: D003042:Cocaine / Q000031:analogs & derivatives / Q000378:metabolism; D003692:Delayed-Action Preparations / Q000737:chemistry* / Q000378:metabolism*; D003911:Dextrans / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry* / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008301:Maleimides / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D003911:Dextrans; D004337:Drug Carriers; D008301:Maleimides; D011091:Polyesters; D014867:Water; C016240:polycaprolactone; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C056477:dextran-maleimide; C076070:cocaine methiodide; D003042:Cocaine