pH-responsive polymeric micelles of poly(ethylene glycol)-b-poly(alkyl(meth)acrylate-co-methacrylic acid): Influence of the copolymer composition on self-assembling properties and release of candesartan cilexetil
| Autor: | P.M Satturwar, François Ravenelle, Mohamad Nasser Eddine, Jean-Christophe Leroux |
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| Rok vydání: | 2007 |
| Předmět: |
Time Factors
Light Chemistry Pharmaceutical Drug Compounding Tetrazoles Pharmaceutical Science Microscopy Atomic Force Methacrylate Micelle Polyethylene Glycols chemistry.chemical_compound Polymethacrylic Acids Polymer chemistry Scattering Radiation Technology Pharmaceutical Organic chemistry Particle Size Micelles Drug Carriers Acrylate Gastric Juice Calorimetry Differential Scanning Molecular Structure Chemistry Atom-transfer radical-polymerization Hydrolysis Biphenyl Compounds Temperature Water General Medicine Hydrogen-Ion Concentration Molecular Weight Solubility Polymerization Methacrylic acid Methacrylates Benzimidazoles Drug carrier Angiotensin II Type 1 Receptor Blockers Ethylene glycol Biotechnology |
| Zdroj: | European Journal of Pharmaceutics and Biopharmaceutics. 65:379-387 |
| ISSN: | 0939-6411 |
| DOI: | 10.1016/j.ejpb.2006.09.012 |
| Popis: | The objective of the present study was to investigate the influence of chemical structure and molecular weight of pH-sensitive block copolymers on their self-assembling properties, the loading and the release of candesartan cilexetil (CDN). Block copolymers of poly(ethylene glycol) and t-butyl methacrylate, iso-butyl acrylate, n-butyl acrylate or propyl methacrylate were synthesized by atom transfer radical polymerization. pH-sensitivity was obtained by hydrolysis of t-butyl groups. The poorly water-soluble drug CDN was incorporated in the micelles and the in vitro drug release was evaluated as a function of pH. The critical aggregation concentration of hydrolyzed copolymers (pK(a)=6.2-6.6) was higher compared to the unhydrolyzed ones. Dynamic light scattering studies and atomic force microscopy images revealed uniform size micelles with aggregation numbers ranging from 60 to 160. The entrapment efficiency of CDN was generally found to be above 90%, with drug loading levels reaching approximately 20% (w/w). Differential scanning calorimetry studies showed the amorphous nature of entrapped CDN. The release of CDN from pH-sensitive micelles was triggered upon an increase in pH from 1.2 to 7.2. These findings suggest that the PEG-b-poly(alkyl(meth)acrylate-co-methacrylic acid)s can self-assemble to form micelles which exhibit high loading capacities for CDN and release the drug in a pH-dependent fashion. |
| Databáze: | OpenAIRE |
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