ABSTRACT
OBJECTIVE: To research and regulate the crystal quality of alanylglutamine for improving their stability and pharmacodynamics as well as vacuum freeze-drying efficiency. METHODS: Scanning electron microscopy (SEM), X-ray powder diffractometer (XRD), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TG) as well as lyophilized experiments were used to investigate the effect of pre-freeze method on crystallinity and uniformity of particle size of alanylglutamine. RESULTS: The result of SEM revealed that the lyophilized alanylglutamine with accelerated pre-freeze method is small-size particle with low crystallinity. Then the lyophilized alanylglutamine with multi-step annealing pre-freeze method become uniformly large particle with high crystallinity. The RESULTS of XRD and DSC indicted that, comparing with the lyophilized alanylglutamine with accelerated pre-freeze method, the lyophilized sample with multi-step annealing pre-freeze method is easier to form the crystal medicine with uniform particle size, less crystal defects, high crystallinity. And the former has lower stability than the later. CONCLUSION: The final lyophilized experiment give us a CONCLUSION that using the multi-step annealing pre-freeze method can improve the freeze-drying efficiency and crystal quality of alanylglutamine, which to achieve the ultimate goal of cost and energy saving.