Abstract:

 Observe the appearance and the collapse of the freezedried products and measure the collapse temperatures (Tc) in the multiple component system containing sucrose, amino acid and／or Pluronic F68. Further determine the factors relating to Tc.The collapse of sucrose solution was observed using freezedrying microscope. Tc was measured for different freeze-drying formulations: (1) sucrose solutions at the concentration of 2.5％, 5％ and 7.5％.(2)Binary systems containing 2.5％, 5％ or 7.5％ sucrose and 10 mmol/L sodium phosphate buffer. (3)Ternary systems composed of 5％ sucrose and 0.15％ amino acid (Arg, Asp, Glu or Tyr). (4) Quaternary system containing 5％ sucrose, Pluronic F68 and 0.15％ amino acid.  The results obtained as follows: (1) Tc of sucrose solution increased with the sucrose concentration; (2) Introduction of low concentration of sodium phosphate did not lead to change in Tc (P>0.05); (3) The presence of Tyr caused Tc increase by 7℃ (P<0.05); (4) Addition of Pluronic F68 resulted in a decrease in the Tc values, especially in the system with Tyr (6.0℃) (P>0.05). Tc is dependent on the composition of formulation. Introduction of low concentration of sodium phosphate does not lead to the change in Tc. The presence of Tyr results in significant increase in Tc.

Key words: freeze-drying; formulation; collapse temperature