Document Detail


Tailored drug release from biodegradable stent coatings based on hybrid polyurethanes.
MedLine Citation:
PMID:  19376173     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Highly adjustable and precisely controllable drug release from a biodegradable stent coating was achieved using a unique family of nanostructured hybrid polyurethanes. These polyurethanes are polyhedral oligosilsesquioxane thermoplastic polyurethanes (POSS TPUs) featuring alternating multiblock structures formed by nanostructured hard segments of POSS and biodegradable soft segments of a polylactide/caprolactone copolymer (P(DLLA-co-CL)) incorporating polyethylene glycol (PEG) covalently. POSS aggregated to form crystals serving as physical crosslinks on the nanometer scale, while the soft segments were designed carefully to modulate the drug release rate from the POSS TPU stent coatings in PBS buffer solution, with 90% of the drug releasing from within half a day to about 90 days. In order to interpret the underlying drug release mechanisms, an approximation model capable of describing the entire drug release process was developed. This model is based on Fickian diffusional transport, but also takes into account the polymer degradation and/or swelling of the coating, depending on the dominance of the degradation/swelling behavior compared to that of the diffusion characteristics. A general methodology was utilized for statistically fitting the drug release curves from the POSS TPU stent coatings using the model. We observed that the fitted initial drug release diffusion coefficient covered more than three orders of magnitude, depending on the polymer glass transition temperature (T(g)), according to a modified Williams-Landel-Ferry (WLF) equation. In addition, two additional rate constants describing the impact of degradation and swelling on drug elution were determined and found to be consistent with independent measurements. Our results clearly show that the studied hybrid polyurethane family allows a drug release rate that is effectively manipulated through variation in polymer T(g), degradation rate, and thickness increment rate.
Authors:
Qiongyu Guo; Pamela T Knight; Patrick T Mather
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-04-17
Journal Detail:
Title:  Journal of controlled release : official journal of the Controlled Release Society     Volume:  137     ISSN:  1873-4995     ISO Abbreviation:  J Control Release     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-06-29     Completed Date:  2009-10-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8607908     Medline TA:  J Control Release     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  224-33     Citation Subset:  IM    
Affiliation:
Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, United States.
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MeSH Terms
Descriptor/Qualifier:
Antineoplastic Agents, Phytogenic / administration & dosage*,  chemistry
Coated Materials, Biocompatible / chemical synthesis,  chemistry*
Computer Simulation
Diffusion
Drug Carriers / chemical synthesis,  chemistry
Models, Chemical
Organosilicon Compounds / chemical synthesis,  chemistry*
Paclitaxel / administration & dosage*,  chemistry
Polyurethanes / chemical synthesis,  chemistry*
Solubility
Stents*
Transition Temperature
Chemical
Reg. No./Substance:
0/Antineoplastic Agents, Phytogenic; 0/Coated Materials, Biocompatible; 0/Drug Carriers; 0/Organosilicon Compounds; 0/Polyurethanes; 0/polyhedraloligosilsesquioxane; 33069-62-4/Paclitaxel

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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