I have to find the effect of a particular drug combination is synergistic, antagonistic or additive through Isobologram. How to calculate isobologram and combination index using origin software?
you can check this article
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAAahUKEwi8mZidltPHAhVWBI4KHeSrDUE&url=http%3A%2F%2Fwww.researchgate.net%2Fpost%2FCan_anyone_help_to_calculate_isobologram_and_combination_index_CI_analysis_using_Origin_software&ei=mjTkVbzkDNaIuATk17aIBA&usg=AFQjCNH25awhAUXWgxxafybbZHfn3WH9QA
Do you have to use Origin software? I did this kind of calculations in excel...
It's easy to do, you just need to have the IC 20, 50, 80 of each drug alone and of the combinations.
Thanks Ela... Can you please give some ideas to do isobologram and combination index in Excel...
It's complicated to explain in words, if you want I can send you an excel file with my calculations as template.
To do the calculation you first need to do a proliferation experiment with your drugs, in a series of concentrations (I usually do a range from 0.01nM to 10,000nM)
1. each drug alone
2. drug 1 in a series of concentrations + drug 2 in a set concentration
3. drug 2 in a series of concentrations + drug 1 in a set concentration
Choosing the set concentration for each drug can sometimes be tricky. It should be such that it gives about 10-20% inhibition by itself. Sometimes the effect varies a bit between experiments so that can be a pain :). You can first try different concentrations for each drug to see what works best.
I will be very thankful if you send me your template for my calculation.
Hi Ela,
Thank you for sharing the xlsx file
I would like to know how you plotted the graph with the data. which are the data points and which is the source of the data of your excel graph
Thank you
Ela - thank you. We were really struggling with the analysis of drug interactions. Your excel sheet was highly useful for checking our analysis we were on the right track. Up to now our analysis had used only IC50 conditions and it was useful to see analysis at IC70 and IC30. We are using rough semi-log plots for IC50 determination. is there some direct software (preferably) no cost for such determinations?
@ Ela Markovsky, I have looked at the excel file you sent Yahima F. Herrera.
Please explain to me how you calculated the CI (combination index). Thanks
Can we make isobologram by MIC values of two antimicrobial drugs and their FICI in combination?
Ela Markovsky Kevin G Chen Khatereh Khorsandi Richard K Owusu-Apenten :My CIs for IC30 and IC50 is above 1.However, the CI for IC70 is below 1. What should I deduce from this result? Are both my drugs interacting antagonistically or synergistically? Any help would be great!
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