Background: Carbamazepine (CBZ) has complex pharmacokinetic properties leading to
fluctuation in plasma level, which requires routine therapeutic drug monitoring (TDM) to ensure its
efficacy and prevent adverse effects. The objective of this study is directed towards developing and
validating a simple, precise, rapid and highly sensitive liquid chromatography-mass spectrometry
(LC/MS) technique for measuring CBZ concentration in human plasma of epileptic patients in routine
Methods: The blood samples of 103 epileptic patients were collected for therapeutic monitoring of CBZ
with validated LC/MS assay. The analytes from plasma were extracted with methanol by simple protein
precipitation method. The Agilent 1100 LC/MS system was used. The ammonium acetate 5mM: methanol
(40: 60 v/v) and diamonsil C18 (150mm×4.6mm, 5µm) were used as mobile phase and analytical
column for the separation of analyte, respectively. The temperature of column was 25°C and the rate of
flow was set at 0.8 mL/minute. International Conference on Harmonisation (ICH) guidelines were used
for the validation of the method.
Results: The stated LC/MS assay displayed good linearity in the range of 5-1000ng/ml and linearity
equation of calibration curve was y= 2.44516x +0.00348175 with a correlation coefficient (R2) of
0.99881. The lower limit of quantitation (LLOQ) of the stated technique was observed at concentration
of 5ng/ml. The linearity, recovery, accuracy and precision, specificity and stability results were within
the acceptance limits of ICH guidelines.
Conclusion: The simple, precise, rapid and highly sensitive LC/MS technique was developed and validated
and successfully applied in TDM of 103 epileptic patients who were using CBZ. Besides TDM,
the stated method can also be applied in bioequivalence, pharmacokinetics and pharmacovigilance studies.