The retention time of Itopride HCl in HPLC can shift due to changes in mobile phase composition, flow rate, column temperature, column condition, and sample matrix effects. These factors influence the interactions between the analyte and the stationary phase, affecting retention behavior.

With same method different day different retention time (significant change) is possible?

The retention time of Itopride HCl in HPLC can change because of things like differences in the mobile phase (the mix of chemicals used), the temperature of the column, the condition of the column (if it’s dirty or worn out), the speed of the flow, or other substances in the sample interfering. Even small changes in pH or how the analyte interacts with the column can cause shifts, so keeping everything consistent and the equipment clean helps prevent these issues.

Best,

Ahmed

You will need to give way more details to do meaningful troubleshooting: The concentration of each component, pH, instrument component and settings; do you prepare the mobile phase fresh everyday or reuse a bottle over several days, do you have any sparging, how stable is the room temperature, how big of a shift are you seeing, how new/old is your column, has your HPLC been serviced regularly, do you have system suitability runs, do you see retention time shift in system suitability samples, what is your matrix, sample prep method, etc. etc.