Document Detail

Novel pH-sensitive hydrogels for colon-specific drug delivery.
MedLine Citation:
PMID:  20141506     Owner:  NLM     Status:  MEDLINE    
The purpose of this study is to develop novel intestinal specific drug delivery systems with pH-sensitive swelling and drug release properties. Acryloyl ester of 5-[4-(hydroxy phenyl) azo] salicylic acid (HPAS) as an azo derivative of 5-amino salicylic acid (5-ASA) was prepared under mild conditions. The HPAS was covalently linked with acryloyl chloride, abbreviated as APAS. Cubane-1,4-dicarboxylic acid (CDA), linked to two 2-hydroxyethyl methacrylate (HEMA) groups, was the cross-linking agent (CA). Methacrylic-type polymeric prodrugs were synthesized by free radical copolymerization of methacrylic acid, poly(ethyleneglycol monomethyl ether methacrylate), and APAS in the presence of cubane cross-linking agent. The effect of copolymer composition on the swelling behavior and hydrolytic degradation were studied in simulated gastric (SGF, pH 1) and intestinal fluids (SIF, pH 7.4). The composition of the cross-linked three-dimensional polymers was determined by FTIR spectroscopy. The hydrolysis of drug-polymer conjugates was carried out in cellophane membrane dialysis bags containing aqueous buffer solutions (pH 1 and pH 7.4) at 37 degrees C. Detection of the hydrolysis product by UV spectroscopy shows that the azo prodrug (HPAS) was released by hydrolysis of the ester bond located between the HPAS and the polymer chain. Drug release studies showed that the increasing content of MAA in the copolymer enhances hydrolysis in SIF. These results suggest that pH-sensitive systems could be useful for preparation of a muccoadhesive system and controlled release of HPAS as an azo derivative of 5-amino salicylic acid (5-ASA).
Mehrdad Mahkam
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Drug delivery     Volume:  17     ISSN:  1521-0464     ISO Abbreviation:  Drug Deliv     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-03-17     Completed Date:  2010-06-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9417471     Medline TA:  Drug Deliv     Country:  England    
Other Details:
Languages:  eng     Pagination:  158-63     Citation Subset:  IM    
Chemistry Department, Azarbaijan University of Tarbiat Moallem, Tabriz, Iran.
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MeSH Terms
Body Fluids / chemistry
Colon / metabolism*
Cross-Linking Reagents
Drug Delivery Systems*
Hydrogels / chemistry*
Hydrogen-Ion Concentration
Magnetic Resonance Spectroscopy
Materials Testing
Mesalamine / administration & dosage,  chemistry
Methacrylates / chemistry
Polyethylene Glycols
Spectrophotometry, Ultraviolet
Spectroscopy, Fourier Transform Infrared
Reg. No./Substance:
0/Cross-Linking Reagents; 0/Excipients; 0/Hydrogels; 0/Methacrylates; 0/Polyethylene Glycols; 0/Prodrugs; 79-41-4/methacrylic acid; 868-77-9/hydroxyethyl methacrylate; 89-57-6/Mesalamine

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

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