(625e) Phase Separation During Non-Isothermal Cooling of Polymer- Drug Dispersion

Biopolymer can improve the solubility of the poor-soluble drugs. This work focus on how polyethylene glycol 3350 (PEG3350), a polymer widely applied in drug delivery, combines with Ibuprofen (IBU) by hot melt in region I and region II of a eutectic mixture. The experiments demonstrate that the amorphous IBU separates from PEG and locates at the boundary of PEG crystals for mixture in region I while in region II some amorphous IBU is in the PEG crystal the other concentrate at PEG crystals' boundary. Phase diagram of PEG3350-IBU as well as a model is built to integrate the process of phase separation during solidification. Phase contrast optical microscopy technique is applied to analyze the mechanism of non-isothermal solidification of PEG3350-IBU mixture. It was found that the homogeneous nucleation crystallization occurs in region I mixture crystallization while both homogenous and heterogeneous nucleation crystallization appear in the solidification of mixture in region II. Proposed solution of Stephan-type problem of phase separation due to crystallization process is in good agreement with experimental data.