PT  - JOURNAL ARTICLE
AU  - Williams, N. Adeyinka
AU  - Schwinke, David L.
TI  - Low Temperature Properties of Lyophilized Solutions and Their Influence on Lyophilization Cycle Design: Pentamidine Isethionate
DP  - 1994 May 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 135--139
VI  - 48
IP  - 3
4099  - http://journal.pda.org/content/48/3/135.short
4100  - http://journal.pda.org/content/48/3/135.full
SO  - PDA J Pharm Sci Technol1994 May 01; 48
AB  - Pentamidine isethionate is a lyophilized antiprotozoal drug. Its solutions, when lyophilized, have been found to exhibit a range of properties that depend on its concentration and the manner in which it is allowed to freeze. These properties were examined by Differential Scanning Calorimetry (DSC), freeze-drying microscopy and X-ray powder diffraction. In DSC studies, the drug exhibited eutectic behavior with a eutectic temperature of –2.8°C. Freeze-drying microscopic examination of a sample of solution after cooling at about 1°C/min showed that the sample dried with retention up to –4°C, where melting was observed. By using the appropriate drug concentration and manipulating the freezing stage, crystallization of the drug from solution could be induced during cooling to yield a crystalline end-product.