Plasma Stability

This assay is used to determine the stability of a test article in plasma from human, rat, mouse, dog, or monkey.

Required from Sponsor

  • Either a minimum of 100 µL of test article at 10 mM in DMSO or 2 mg of powder
  • The exact molecular mass of test article and its salt form
  • MSDS or handling and storage information, e.g., light-sensitive, store at -20°C, etc.


  • A table of percent remaining of test article at each time point
  • Half-life, as applicable


  • Test article at 1 µM dissolved in plasma collected with K2EDTA as the anticoagulant

Assay System

  • Plasma from a species specified by the sponsor
    • Human: mixed-gender, ≥ 3 donors pooled
    • Rat: male Sprague-Dawley, ≥ 3 donors pooled
    • Mouse: male CD-1, ≥ 3 donors pooled
    • Dog: male Beagle, ≥ 3 donors pooled
    • Monkey: male Cynomolgus, ≥ 3 donors pooled

Assay Conditions

  •  Adjust pH of  plasma to 7.4 prior to initiation of the experiment
  • Single incubation of test article (n=1) in plasma at 37°C
  • Sample a single replicate (n=1) at 0, 15, 30, 60, and 120 minutes
  •  Use LC-MS/MS to determine the peak area response ratio (peak area corresponding to test article divided by that of an analytical internal standard) without running a calibration curve


  1. The results from this assay will be provided to the sponsor in the ExpressPlus report format, which may include graphical representations of data and comparison with historical data for reference articles.
  2. This assay is often run to develop sample handling protocols for in vivo PK studies.
  3. To distinguish effects of pH and ionic strength on test article stability from the effects of the biological matrix, it is recommended that stability also be checked in phosphate-buffered saline.


  1. The sponsor must specify: the species —mouse, rat, dog, monkey or human