Friday, August 15, 2014

PLA-PEG-PLA optimized micelle for drug delivery determined by computer simulation and confirmed by laboratory results

PolySciTech (www.polyscitech.com) provides a wide array of biodegradable block copolymers including PLA-PEG-PLA triblock copolymers at a variety of MW’s and chiral characteristics. Recent research utilizing Dissipative Particle Dynamic simulations back by laboratory experimental results have honed in on the optimal PEG to PLA ratio for forming a micelle for drug delivery. Read more: Chansuna, Mantana, and Nuttaporn Pimpha. "Mesoscale simulation and experimental studies of self-assembly behavior of a PLA-PEG-PLA triblock copolymer micelle for sustained drug delivery." Journal of Polymer Research 21, no. 6 (2014): 1-9. http://link.springer.com/article/10.1007/s10965-014-0452-1

“Abstract: Dissipative Particle Dynamic simulation (DPD) was employed to investigate PLA-PEG-PLA copolymer micelles to gain more understanding at the molecular level in addition to experimental studies. Critical micelle concentration (cmc), micelle size and small molecule encapsulation of these triblock copolymer micelles with different hydrophobic/hydrophilic (LA/EG) block ratios (2.56, 4.88 and 7.25 with fixed PEG length = 23 monomer units) were determined. Only the appropriated LA/EG block ratio (4.88 and 7.25) can induce the formation of spherical micelle in a dilute solution. The cmc and micelle size were decreased and increased, respectively, as a function of the LA/EG block ratio. Upon adding small solubilizate molecules, a larger micelle size was formed. Then, PLA-PEG-PLA with the same LA/EG block ratios as DPD simulation were synthesized and the micelle solution was prepared. Pyrene was used as the molecular probe to find the cmc by fluorescence spectroscopy. Light scattering was applied to determine the hydrodynamic radius (R H ) of these micelles. The cmc and RH were decreased and increased, respectively, with LA/EG ratio, qualitatively similar to the trends as simulation results. The behavior of these copolymer micelles to encapsulate the small solubilizate molecules was also studied by fluorescence technique. The partition coefficients of pyrene between the water phase and the micelle core were increased with a higher LA/EG block ratio similar to results from the simulation. Keywords: Triblock copolymer, Micelle, Mesoscale simulation, Drug delivery”
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