ACTA Pharmaceutica Sciencia 2021 , Vol 59 , Num 1
Determination of Phenytoin in Human Plasma by a Validated HPLC Method: Application to Therapeutic Drug Monitoring Study
Emrah Dural 1 Aslı Bolayır 2 Burhanettin Çiğdem 2
1 Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Sivas Cumhuriyet University, Sivas, Turkey
2 Department of Neurology, Faculty of Medicine, Sivas Cumhuriyet University, Sivas, Turkey
DOI : 10.23893/1307-2080.APS.05909 The aim of this study was to develop a simple and reliable HPLC method for the determination of phenytoin (PHT) in human plasma. Accuracy (RE%) were determined between (-0.93%) to 2.49% and precision (RSD%) values was ?7.94. The quantitation limit was 3.54 µg/mL and recovery was found between 82.15% and 101.06%. The method was applied to real plasma samples (n = 7). Plasma-PHT levels were found between 1.12 and 18.76 µg/mL (9.52 ± 7.78, mean±SD). Both the plasma and dose-rated plasma results of PHT showed so high RSD% which were between 81.74% and 89.61%. In addition plasma-PHT levels were outside the recommended treatment range in 4 of the 7 patients (57.14%) examined, and also surprisingly PHT could not be detected in a patient"s plasma. This procedure is relatively simple, precise, and applicable for routine therapeutic drug monitorization of PHT in neurology clinics or toxicological analyses in reference laboratories. Keywords : Phenytoin, Human plasma, Therapeutic drug monitoring, Method validation, HPLC-UV

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