AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Comparison of Release Profiles of Drug-Loaded PLGA Polymer Particles in Well-Mixed and Encapsulated Forms
JENNIFER HEAD, Da-Ren Chen, Washington University in St. Louis
Abstract Number: 696 Working Group: Nanoparticles and Materials Synthesis
Abstract The release profiles of nano-sized, drug-loaded PLGA particles produced in well-mixed form and in encapsulated form by electrospray (ES) were compared to determine the optimal particle structure design for nanomedicine as well as the effect of solute diffusion during the particle formation. A single-capillary ES system was utilized to produce nanoparticles in the well-mixed form. In this case, poly(lactic-co-glycolic acid) (PLGA) 85:15 and Paclitaxel (PTX), a commercially available drug often used in cancer treatment, were both dissolved in the same solution containing 1:1 dimethyl sulfxoxide (DMSO): acetonitrile (ACN). A dual-capillary ES system with compound jets was used to produce encapsulated particles at high encapsulation efficiency. Separate solutions of 1:1 DMSO: ACN containing PLGA and PTX were fed through the outer and inner ES capillaries, respectively. The overall size of as-prepared PLGA nanoparticles and the percent PTX in final particles were held constant at 100 nm and 20%. Particles containing PTX only were also produced by single-capillary ES system as the reference.
The concentration of solutes in an evaporating sphere was modeled for the well-mixed case. As solvents evaporated during the particle formation, the solutes became more concentrated in the particle sphere. Solutes with higher diffusion coefficients (i.e., PTX) were able to travel more rapidly to the center of the particle, while slow moving ones (i..e, PLGA polymer) concentrated near the particle’s border. As a result, well mixed cases whose solutes had widely different diffusion coefficients had release profiles more similar to those produced from the encapsulated form. Tests were repeated using PLGA 50:50 as the polymer to further examine the effect of relative diffusion coefficients on release profiles. The details of this study will be presented in a poster at the AAAR conference.