i have done drug excipient compatibility study under isothermal stress condition (50 degree celsius for 1 month), HPLC assay showed 65%, 40%, 78%, 85 with different excipient. on the basis of above results we can say drug is compatible or not. how?
Hi Faraat,
I guess the data is not enough to predict the compatibility of the drug with the excipients. This information seems more like you are calculating the purity of the compound. In a formulation, the drug concentration will never go to 85% as there are excipients present in the preparation. There might be a chance that the drug is not compatible with the excipients and the formulation breaks and when you took the sample for the testing, you might have taken the sample with a high amount of drug/ excipient side. I suggest you perform some additional experiments such as FTIR and LCMS to confirm the results. The peak from HPLC can be confirmed by comparing the retention time of the individual excipients and the drug with the final preparation, or by using MS of the LCMS.
For LCMS, If you are getting the same mass of the drug in the formulation and in the blank, or the retention time is the same with the blank (drug only) and the drug in the formulation, then you can say that the drug is compatible with the excipients.
To verify your results, you can perform the HPLC experiments on the sample over a period (2 months) performing the HPLC every two weeks and notice the change in the intensity of the drug peak. If the variation is not that significant, then the drug is compatible with the excipients.
I hope this information might be helpful to you.
Hi, in addition of the nice comments above, at first we did generally for studying drugs excipient compatibility studies, we used DSC. I attach our published work a long time ago, Best regards.
DSC is an effective and easy method to study the compatibility of excipients and Active drugs.
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