Pharmaceutical R&D, Baxter Healthcare, 927 S. Curry Pike, Bloomington, Indiana, 47403, USA.
Present Address: IMA Life, Inc., Tonawanda, New York, 14150, USA.
AAPS PharmSciTech. 2021 Jan 19;22(1):53. doi: 10.1208/s12249-021-01921-2.
The objective of this investigation was to evaluate two methods for measuring the maximum sublimation rate that a freeze-dryer will support-the minimum controllable pressure method and the choke point method. Both methods gave equivalent results, but the minimum controllable pressure method is preferred, since it is easier, faster, and less subjective. The ratio of chamber pressure to condenser pressure corresponding to the onset of choked flow was considerably higher in this investigation (up to about 20:1) than in previously published reports. This ratio was not affected by the location of the pressure gauge on the condenser; that is, on the foreline of the vacuum pump versus on the body of the condenser itself. The total water loss due to sublimation as measured by tunable diode laser absorption spectroscopy was consistently within 5% of gravimetrically determined weight loss, regardless of whether the measurement took place during choked versus non-choked process conditions.
本研究旨在评估两种测量冻干机制冷升华最大速率的方法——最小可控压力法和阻塞点法。两种方法得出的结果相当，但最小可控压力法更优，因为它更简单、更快、更客观。在本研究中，与阻塞流起始相对应的腔室压力与冷凝器压力之比（高达约 20:1）显著高于以前的报道。该比值不受冷凝器上压力表位置的影响，即，在真空泵的前级线还是在冷凝器本体上。无论测量是在阻塞过程条件下还是非阻塞过程条件下进行，通过可调谐二极管激光吸收光谱法测量的升华总水分损失始终与重量法测定的重量损失相差 5%以内。
