Synthesis, Characterization, Properties, and Drug Release of Poly(alkyl methacrylate-b-isobutylene-b-alkyl methacrylate)
| Autor: | Jae Cheol Cho, Rudolf Faust, Robert E. Richard, Dingsong Feng, Ken Chan, Mark Boden, Marlene Schwarz, Guanglou Cheng |
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| Rok vydání: | 2006 |
| Předmět: |
Drug Carriers
Magnetic Resonance Spectroscopy Calorimetry Differential Scanning Polymers and Plastics Polymers technology industry and agriculture Cationic polymerization Bioengineering Polyenes Microscopy Atomic Force Methacrylate Styrene Biomaterials chemistry.chemical_compound Anionic addition polymerization chemistry Polymerization Polymer ratio Polymer chemistry Microscopy Electron Scanning Materials Chemistry Copolymer Spectrophotometry Ultraviolet Stents Drug carrier |
| Zdroj: | Biomacromolecules. 7:2997-3007 |
| ISSN: | 1526-4602 1525-7797 |
| Popis: | Polyisobutylene (PIB)-based block copolymers have attracted significant interest as biomaterials. Poly(styrene-b-isobutylene-b-styrene) (SIBS) has been shown to be vascularly compatible and, when loaded with paclitaxel (PTx) and coated on a coronary stent, has the ability to deliver the drug directly to arterial walls. Modulation of drug release from this polymer has been achieved by varying the drug/polymer ratio, by blending SIBS with other polymers, and by derivatizing the styrene end blocks to vary the hydrophilicity of the copolymer. In this paper, results are reported on the synthesis, physical properties, and drug elution profile of PIB-based block copolymers containing methacrylate end blocks. The preparation of PIB-poly(alkyl methacrylate) block copolymers has been accomplished by a new synthetic methodology using living cationic and anionic polymerization techniques. 1,1-Diphenylethylene end-functionalized PIB was prepared from the reaction of living PIB and 1,4-bis(1-phenylethenyl)benzene, followed by the methylation of the resulting diphenyl carbenium ion with dimethylzinc (Zn(CH(3))(2)). PIB-DPE was quantitatively metalated with n-butyllithium in tetrahydrofuran, and the resulting macroinitiator could initiate the polymerization of methacrylate monomers, yielding block copolymers with high blocking efficiency. Poly(methyl methacrylate-b-isobutylene-b-methyl methacrylate) (PMMA-b-PIB-b-PMMA) and poly(hydroxyethyl methacrylate-b-isobutylene-b-hydroxyethyl methacrylate) (PHEMA-b-PIB-b-PHEMA) triblock copolymers were synthesized and used as drug delivery matrixes for coatings on coronary stents. The PMMA-b-PIB-b-PMMA/PTx system displayed zero-order drug release, while stents coated with PHEMA-b-PIB-b-PHEMA/PTx formulations exhibited a significant initial burst release of PTx. Physical characterization using atomic force microscopy and differential scanning calorimetry of the formulated PMMA-b-PIB-b-PMMA coating matrix indicated the partial miscibility of PTx with the PMMA microphase of the matrix. |
| Databáze: | OpenAIRE |
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