My experiment was to determine the xanthine oxidase resistance activity of a sample. I want to determine the IC50 value from % inhibition.
Image "data": is the raw data.
Image "formula": is the formula to calculate the% inhibition.
I only performed the experiment once (this time, each treatment I measured OD 4 times to calculate the mean - could it be called: repeat one time a quadruplicate experiment?).
But the problem I encountered is, when I input data into Prism to calculate IC50, I need to have the % inhibition data repeated at least 3 times, or the mean and SD/SEM. But in my case, there is only 1.
So, I must conduct this experiment 2 times more, or are there any valid ways to determine the IC50 value?
Hi Bùi LẬP Duy ,
If you wish to use prism for IC50 determination.
Try using the following link with helping guide:
https://www.graphpad.com/guides/prism/7/curve-fitting/reg_dr_inhibit.htm
Thank you,
Good luck
IC50 determination, besides including technical replicates in the cytotoxic/cytostatic assays, should contemplate two other biological replicates.
If you get a cell line, expand it and cryopreserve it. Ideally, you should thaw one of the cryopreserved aliquots, grow them, and make the corresponding assays (three technical replications for every treatment dose/concentration) and obtain de the IC50 value. This could correspond (in this particular context) to a single biological replicate. To have a robust IC50 value you should repeat this process at least two other times.
In graphpad prism, you will need to input the raw data, log2 transform it, normalize it using your positive and negative controls and then obtain the IC50 with the included fitting model for this particular case.
If you can't obtain more data and the info that you show is all you have, you could use your four different measurements of OD as technical replicates to obtain mean, SD and confidence intervals to build the curve and obtain a IC50 value. HOWEVER, this information will be almost useless and making statistical assumptions with these values will be almost irrelevant. At most, it could only be used as a reference for further experiments in your specific context.
- Badges
- Science topic
- Similar topics
- Chemistry
- Pharmacology