Affection of freezing store on the determination of phenytoin and carbamazepine in human plasma

Objective: To study the HPLC chromatogram and the concentrations of phenytoin and carbamazepine in human plasma after freezing store (–20℃) for different time. Methods: The HPLC chromatogram was recorded and the concentrations of phenytoin and carbamazepine in human plasma after freezing store for different time were calculated. Whether there was notable difference between the 5 determined concentrations of each plasma was determined. Results: The HPLC chromatogram were almost the same and there were no notable difference between the 5 determined concentrations of phenytoin and carbamazepine in human plasma after freezing store for different time. Conclusion: Freezing store does not affect the determination of phenytoin and carbamazepine in human plasma.