I am finding a difficulty in developing an HPLC method for the compound. But I am not getting a linear response.
Retention time is stable but areas are going here and there.
Yati Chugh Ph. Your problem appears to be that of pH. C18 may not be ok. Some suggestions is possible if you give more chemistry of your compound. I Had similar problem with one of my compound. When I deleted DMSO as injection solvent or peek fittings from HPLC system the problem was solved.