Determination of temozolomide in serum and brain tumor with micellar electrokinetic capillary chromatography

Micellar electrokinetic capillary chromatographic (MEKC) with photodiode-array detection was applied to determine temozolomide (TMZ) in human serum and brain tumor. The limit of quantitation (LOQ) was 0.096 μg/mL using 325 nm as detection wavelength. The method made possible that the TMZ could be detected in in vivo serum samples without sample pretreatment. In order to detect TMZ at lower concentration, an extraction with ethyl acetate was applied to preconcentrate the analyte. Small amount of brain tumor tissues (less than 1 g) were lyophilized and pretreated using extraction as a clean up and concentrating step. After removing the organic solvent a final sample volume of only 10 μL was analyzed. The obtained peak concentrations (8.2–10.1 μg/mL) and Tmax (44–65 min) of TMZ in serum were similar to the data reported by others, the in vivo TMZ concentrations found in brain tumor ranged between 0.061 and 0.117 μg/g.