Background: Carbamazepine has been used in the treatment of bipolar disorder,
both in acute mania and maintenance therapy, particularly in developing countries. Not only
its interaction with various drugs and auto-inducer nature, but the narrow therapeutic
range of carbamazepine also makes monitoring necessary to guarantee the adequacy of its
safety and therapeutic concentration. To date, the most common biological specimen used
for therapeutic drug monitoring (TDM) purposes is still plasma, but saliva can become an
alternative biological matrix since its level in saliva strongly correlates with carbamazepine
Objective: This study validated the bioanalytical method parameters used for carbamazepine
in spiked-saliva in accordance with the Food and Drug Administration (FDA) criteria
in the Guidance for Industry Bioanalytical Method Validation.
Methods: HPLC-UV detector was employed at 285 nm λ with methanol: water: glacial
acetic acid (65:34:1) as the mobile phase and C8 as the stationary phase (4.6x150 mm; 5 μm).
Results: The linearity test in a range of 0.0 - 5 μg/mL carbamazepine concentration resulted
in a correlation coefficient of 0.999 with 0.20 μg/mL LoD, 0.30 μg/mL LLoQ, and 0.61
μg/mL LoQ. The coefficient of variation and %diff in the selectivity, accuracy, and precision
parameters remained below 20%, indicating fulfillment of the criteria for a bioanalytical
method, while the average % recovery was more than 90%.
Conclusion: The currently-developed bioanalytical method has fulfilled the stipulated validation
criteria to be used for determining carbamazepine concentration in spiked-saliva as
an alternative method for relative bioequivalence studies or TDM application in a clinical