The Effect of Freeze/Thaw Cycles on the Stability of Compounds in
DMSO

Author(s): Barbara A. Kozikowski ; Thomas M. Burt ; Debra A. Tirey ; Lisa E. Williams ; Barbara R. Kuzmak ; David T. Stanton ; Kenneth L. Morand ; Sandra L. Nelson
Source: Journal of Biomolecular Screening Volume: 8 Number: 2 Page: 210 -- 215

Abstract: A diverse set of 320 compounds from the Procter & Gamble
Pharmaceuticals organic compound repository was prepared as 20-mM DMSO
solutions and stored at 4°C under argon in pressurized canisters to simulate
a low-humidity environment. The plates were subjected to 25 freeze/thaw
cycles while being exposed to ambient atmospheric conditions after each thaw
to simulate the time and manner by which compound plates are exposed to the
atmosphere during typical liquid-handling and high-throughput screening
processes. High-performance liquid chromatography-mass spectrometry with
evaporative light-scattering detection was used to quantitate the amount of
compound remaining after every 5th freeze/thaw cycle. Control plates were
stored either at room temperature under argon or at 4°C under argon without
freeze/thaw cycling and were evaluated at the midpoint and the endpoint of
the study. The study was conducted over a short time period (i.e., 7 weeks)
to minimize the effect of compound degradation over time due to the exposure
of the compounds to DMSO. The results from this study will be used to
determine the maximum number of freeze/thaw cycles that can be achieved
while maintaining acceptable compound integrity.