Drug Release from a pH-Sensitive Multiblock Co-Polymer Thermogel
SCIE
SCOPUS
- Title
- Drug Release from a pH-Sensitive Multiblock Co-Polymer Thermogel
- Authors
- Garripelli, VK; Namgung, R; Kim, WJ; Jo, S
- Date Issued
- 2012-05
- Publisher
- PubMed
- Abstract
- A Pluronic (R)-based pH-sensitive multiblock co-polymer thermogel has been proposed for sustained release of therapeutic agents. Hydrophobic small-molecule drugs (paclitaxel and camptothecin) and model hydrophilic macromolecules (fluorescein-labeled dextrans of molecular mass 10, 20, 40, 150 and 250 kDa) were successfully loaded into and released from the thermogels. Drug-loaded polymer solutions were characterized for gelation behavior and micelle size. Drug loading increased the size of the multiblock co-polymer micelles from 20 to 100 nm. The co-polymer improved paclitaxel and camptothecin loading in an aqueous solution by 6900- and 1050-fold, respectively, compared to their solubility in water. The thermogels released loaded drugs in a pH-dependent fashion, regardless of their properties. At pH 5.0 and 6.5, paclitaxel and camptothecin completely released in 4 and 15 days, respectively, by a combined mechanism of diffusion and erosion. At neutral pH, diffusion predominated gel erosion to sustain the drug release up to 40 days. Fluorescein-labeled dextran release from the thermogels showed a similar pH-dependent trend as the hydrophobic small molecule drugs. However, dextran release at neutral pH was entirely dependent on the molecular mass of the dextran. Low-molecular-mass (10 and 20 kDa) dextrans were completely released in 12 and 21 days, respectively, while high-molecular-mass (>= 40 kDa) dextrans being continuously released over 36 days, indicating that the threshold of molecular weight necessary for sustained release of a hydrophilic macromolecule from this thermogel (e. g., enzymes, monoclonal antibodies and immunotoxins) is 40 kDa. Taken together, the MBCP thermogel showed potential as a controlled drug-delivery system that showed sustained release of both hydrophilic and lipophilic molecules. (C) Koninklijke Brill NV, Leiden, 2011
- Keywords
- Pluronic (R); thermosensitive; pH-dependent; thermogel; hydrophilic drug; macromolecule; lipophilic drug; sustained release; AQUEOUS-SOLUTIONS; BLOCK-COPOLYMERS; DISSOLUTION PROFILES; TRIBLOCK COPOLYMERS; EXTRACELLULAR PH; HYDROGELS; DELIVERY; PROTEINS; SOL; GEL
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/15865
- DOI
- 10.1163/092050611X584414
- ISSN
- 0920-5063
- Article Type
- Article
- Citation
- JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION, vol. 23, no. 12, page. 1505 - 1519, 2012-05
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