pH-Sensitive Polymer Nanospheres for Use as a Potential Drug Delivery Vehicle

Research Center for Biomolecular Nanotechnology, Department of Life Science, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju, Republic of Korea.
Biomacromolecules (Impact Factor: 5.75). 12/2007; 8(11):3401-7. DOI: 10.1021/bm700517z
Source: PubMed


We report the development and characterization of pH-sensitive poly(2-tetrahydropyranyl methacrylate) [poly(THPMA)] nanospheres and demonstrate their feasibility as an effective drug delivery vehicle. Poly(THPMA) nanospheres were prepared using either the double emulsion or single emulsion method for the encapsulation of, respectively, water soluble (rhodamine B) or organic soluble (paclitaxel) payloads. The resulting nanospheres showed pH-dependent dissolution behavior, resulting in significant morphologic changes and loss of nanoparticle mass under mild acidic conditions (pH 5.1) with a half-life of 3.3 days, as compared to physiologic condition (pH 7.4) with a half-life of 6.2 days. The in vitro drug release profile of the paclitaxel-loaded poly(THPMA) nanospheres revealed that the rate of drug release in pH 5.1 acetate buffer was relatively faster than that in pH 7.4 HEPES buffer. Furthermore, poly(THPMA) nanospheres showed lower cytotoxicity and higher cellular uptake as compared to the FDA-approved PLGA-based nanospheres currently in clinical practice.

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    • "Based upon physicochemical characteristics of these nanomicelles, we contemplate that these nanostructures can release the loaded drugs in the endosomal compartments in a pH-dependent manner. Similarly, pH-sensitive poly(2-tetrahydropyranyl methacrylate) [poly(THPMA)] nanospheres have recently been developed and shown higher cellular uptake potential with a pH-dependent release of the loaded drug (PTX) [37]. Micellar formulation of PTX using cholesterol-grafted poly(N-isopropylacrylamide-co-N, N-dimethylacrylamide-co-undecenoic acid) was reported to provide nanomicelles (~220 nm) with low CMC (~ 20 mg/L) and fast liberation of drug at pH 5.0 [38]. "
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