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

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.(Journal of Biomolecular Screening 2003:210-215)

In Silico Estimation of DMSO Solubility of Organic Compounds for Bioscreening

“…Thus, the problem of chemical degradation of compounds dissolved in DMSO has been addressed in a series of recent works. [10][11][12] For instance, the effect of temperature cycling (the impact of repeated freeze-thaw cycles) on dissolved samples from the large chemical repositories was studied. 10 Water absorption by DMSO, as another factor pertaining to compound instability, was also investigated.…”

“…[10][11][12] For instance, the effect of temperature cycling (the impact of repeated freeze-thaw cycles) on dissolved samples from the large chemical repositories was studied. 10 Water absorption by DMSO, as another factor pertaining to compound instability, was also investigated. 11,12 The materials used to produce the storage vials and microplate seals have changed significantly over the past 2 to 3 years for improving compound handling and data quality.…”

“…This assumption is supported by regular random reexamination of samples after the described dissolution procedure, as well as by the reported data on the stability of dissolved samples in DMSO. [10][11][12] It should be noted that the described estimation method does not provide the exact value of DMSO solubility, as opposed to the conventional solubility measurements. The latter techniques typically require the samples of known purity as well as precise methods of determining the precipitation point, such as light-scattering measurements.…”

Compound Precipitation in High-Concentration DMSO Solutions

“…10 Although several reports have described the stability of compounds in DMSO solutions 4,8 and the effect of freeze-thaw cycling on DMSO solutions, 13 to our knowledge, there are no data reported with regard to the extent of precipitation caused by freeze-thawing versus initial insolubility. We set out to determine what proportion of precipitation is caused by freeze-thaw cycles versus intrinsic insolubility of compounds in DMSO at given concentrations.…”

NanoStore: A Concept for Logistical Improvements of Compound Handling in High-Throughput Screening

“…In addition, the generation of multiple screening plates from a single compound master plate reduces repeated freeze/thaw cycles of compound solutions, a process that is known to adversely affect the integrity of many compounds in solution. 3,4 Finally, the applied dry-down procedure entirely removes the DMSO in which the test compounds are usually dissolved, therefore, in turn, eliminating any DMSO sensitivities certain assays exhibit.…”