title: Kinetics of in vitro release of a model nucleoside deoxyuridine from crosslinked insoluble collagen and collagen-gelatin microspheres.
abstract: The objective of this research is to investigate the effect of highly crosslinked insoluble collagen and collagen-gelatin hybrid matrices as platforms for controlled release of a highly water soluble model nucleoside, deoxyuridine as well as a high molecular weight model compound fluoroscienisothoicyanate (FITC)-dextran. Collagen and gelatin can be considered as biodegradable proteinous materials. Microspheres of deoxyuridine and FITC-dextran were prepared by emulsification solvent evaporation technique using collagen alone and collagen-gelatin combination. The microencapsulation efficiency, particle size and in vitro release profiles were compared. Microencapsulation efficiency of approximately 10% was obtained with collagen while 20% encapsulation efficiency was obtained when collagen was used in combination with gelatin. Particle size range became wider when only collagen was used as compared to collagen-gelatin combination. A slower release profile was observed for crosslinked as compared to noncrosslinked microspheres. This study demonstrated diffusion controlled release of both compounds from the two polymers used. A good correlation was obtained between theoretically predicted and experimentally obtained in vitro release rates for both deoxyuridine and FITC-dextran using Higuchi's square root model.
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, Kansas City, MO 64110-2499, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Chowdhury
authors.forename: A K
authors.initials: AK
authors.lastname: Mitra
mesh_terms: D003094:Collagen / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003692:Delayed-Action Preparations; D003857:Deoxyuridine / Q000493:pharmacokinetics*; D003911:Dextrans / Q000493:pharmacokinetics*; D004058:Diffusion; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005780:Gelatin / Q000737:chemistry*; D066298:In Vitro Techniques; D008863:Microspheres; D008962:Models, Theoretical; D010316:Particle Size; D012995:Solubility; D013997:Time Factors
chemical_list: D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D003911:Dextrans; C015219:fluorescein isothiocyanate dextran; D005780:Gelatin; D003094:Collagen; D016650:Fluorescein-5-isothiocyanate; D003857:Deoxyuridine