Glass transition temperature of poly(lactic-co-glycolic acid) particles

Poly(lactic-co-glycolic acid) (PLGA), is a commonly used biodegradable biomaterial used to make many different biomedical products including drug delivery particles. The glass transition temperature (T_g) of a polymer particle can have a profound effect on its behavior in vivo such as aggregation behavior and drug release profile. Bulk PLGA has a T_g of approximately 40°C. Since normal body temperature is 37°C, it is assumed that PLGA particles will remain in their solid, glassy state during in vivo experiments. However, many factors can affect the T_g of a particle, such as thermal history. The method used to produce the PLGA particle will therefore affect its T_g. Most experiments are done with polymer samples in the bulk form that have been annealed to erase thermal history. In this work, PLGA particles are made by nanoemulsion, nanoprecipitation, and electrohydrodynamic jetting and the T_g of the particles is measured using the first heating scan of a modulated differential scanning calorimetry run to determine the role of processing conditions on the T_g of PLGA particles.