title: Preparation and characterization of cross-linked microspheres C(Dex-g-PSSS) and their drug-carrying and colon-specific drug delivery properties.
abstract: The graft polymer Dex-g-PSSS was obtained through poly(sodium 4-styrene sulfonate) (PSSS) grafted on dextran(Dex) by using the cerium salt-hydroxyl group redox initiation system. The cross-linked microspheres C(Dex-g-PSSS) were synthesized by suspension polymerization with epichlorohydrin as the cross-linking agent. The chemical structure and physicochemical characteristics of C(Dex-g-PSSS) microspheres were represented by infrared spectroscopy (FTIR), optical microscope, and zeta potential analysis. The aim of the study is to constitute a colon-specific drug delivery system via molecular design, using C(Dex-g-PSSS) microspheres as the drug-carrying material and taking 5-fluorouracil (5-FU) as the model drug. The drug-carrying ability and mechanism of the cross-linked microspheres C(Dex-g-PSSS) for 5-FU were investigated. Finally, in vitro release tests for the drug-carrying microspheres were conducted. The experimental results show that in the medium with pH 2, the cross-linked microspheres C(Dex-g-PSSS) exhibit a strong adsorption ability for 5-FU because of strong electrostatic interactions and have an adsorption capacity of 154 ± 7.5 mg/g, displaying high drug-carrying efficiency. The in vitro release behavior of the drug-carrying microspheres is highly dependent on pH and dextranase. In the medium with pH 2, the drug-carrying microspheres do not release the drug and in the medium with pH 1, they release a little, whereas in the medium with pH 7.4, a sudden delivery phenomenon of the drug will occur, and in the presence of dextranase, a more sudden delivery phenomenon of the drug will occur, displaying an excellent colon-specific drug delivery behavior.
authors.affiliation: a Department of Chemical Engineering , North University of China , Taiyuan 030051 , P.R. China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Jianping
authors.forename: Guo
authors.initials: G
authors.lastname: Jianfeng
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yao
authors.forename: Yang
authors.initials: Y
authors.lastname: Jiao
mesh_terms: D000327:Adsorption; D000963:Antimetabolites / Q000008:administration & dosage / Q000493:pharmacokinetics; D002563:Cerium / Q000737:chemistry; D003106:Colon; D003910:Dextranase / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D004811:Epichlorohydrin / Q000737:chemistry; D005472:Fluorouracil / Q000008:administration & dosage / Q000493:pharmacokinetics; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D011108:Polymers / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D055672:Static Electricity; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D000963:Antimetabolites; D003911:Dextrans; D004337:Drug Carriers; D011108:Polymers; D013451:Sulfonic Acids; D004811:Epichlorohydrin; D002563:Cerium; D003910:Dextranase; D005472:Fluorouracil; C077114:styrenesulfonic acid polymer
keywords: 5-fluorouracil; colon-specific drug delivery; cross-linked microspheres; dependence of pH and dextranase; dextran; sodium 4-styrene sulfonate