Question:
I recently read your information about accelerated stability testing using the Arrhenius equation.
I am soon to conduct a stability test on some biological material containing malaria antigen (recombinant HRP2 proetin) which will be used for controls for a rapid diagnostic malaria test.
I have only limited incubators and time to perform this study. Pilot studies show that the samples will become negative for malaria antigen after 24 hours at 60C, 35 days at 45C days, 40 days at 40C and 60 days at 35c. During this pilot wide time interval were chosen (i.e 10 days for all temperatures except for 60C (4 hourly). Also the decrese in the malaria antigen was only measured using a positive/negative test. For the upcoming study an ELISA test will be used to quantify the % chnage from the 4C sample.
The controls will be used in developing countries and in some areas are likely to be exposed to temperatures of 35C and 50C.
My two questions are:
- You mention testing at three elevated temperatures, what temperatures would you recommend.
- How important is it to test at three elevated temperatures? Will two suffice? We were thinking 50C and 35C??
Resolution:
The choice of temperature is affected by the expected deterioration time. My guess is that you'll want to define stable as 80% or so of the original values so 60 degrees would be inappropriate - degradation is much too fast. As far as temperatures go, I might suggest 55, 45, 35 - at least 3 is important for the quality of your final regression analysis. Don't forget that it will not take as long to degrade to 80% as opposed to completely negative.
Good luck!
