First- and zero-order kinetics of porogen release from the cross-linked cores of diblock nanospheres

作者：Liu GJ^*; Zhou JY

来源：Macromolecules, 2003, 36(14): 5279-5284.

DOI：10.1021/ma0300140

The porogen poly(2-hydrocinnamoyloxyethyl methacrylate) containing some adenine groups P(hCEMA-r-A) was prepared and separated into five fractions. The porogen and diblock copolymer poly-{(2-cinnamoyloxyethyl methacrylate)-random-(2-hydrocinnamoyloxyethyl methacrylate)-random-[2-(1-thyminylacetoxyethyl methacrylate)]}-block-poly(tert-butyl acrylate), P(CEMA-r-hCEMA-r-T)-b-PtBA, formed micelles with PtBA coronas and P(CEMA-r-hCEMA-r-T)/P(hCEMA-r-A) cores in chloroform/cyclohexane. The cores of the micelles were cross-linked due to photodimerization of the CEAM units. Dispersion of the nanospheres in deuterated N,N-dimethylformamide (DMF-d(7)) triggered porogen release, and the kinetics were followed by NMR spectroscopy. While the release of the low-molar-mass fractions followed approximately the first-order rate law, zero-order kinetics was observed for the release of the fraction with the highest molar mass. The rationale for the first- to zero-order kinetic transition was given. Also justified is the scaling relation observed between the diffusion coefficient and molar mass of the porogens. This zero-order release kinetics may find applications in controlled drug delivery.

• 出版日期2003-7-15