We observe three regions with two distinct transition points, T g,β and T g,α for both the PLGA 50:50 and PLGA 75:25 microspheres (Figure ). For the PLGA 50:50 formulation, the high exendin-4 loaded microspheres have a significantly higher T g,β = 219 K, than the blank and low polypeptide loaded microspheres (T g,β = 167 K, and T g,β = 168 K, respectively).