Development and validation of a sensitive LC-MS/MS method for the estimation of scopolamine in human serum

•A bioanalytical method for accurate and precise quantification of scopolamine in human serum was developed and validated.•This solid-phase extraction and liquid chromatography – mass spectrometry based assay requires only 0.5 mL of serum.•It can quantify a broad range of concentration between 5–5000 pg/mL. Lower limit of quantification was 5 pg/mL.•The total assay precision and accuracy was 6.3% and 96%, respectively.•The assay was applied in clinical studies to measure scopolamine in serum after administering it as IV bolus and TDS. Scopolamine is an anticholinergic alkaloid that is widely used in the form of a transdermal system to manage nausea associated with motion sickness. Currently available methods to quantify scopolamine require large sample volumes and involve cumbersome sample preparation. In this work, a simple method for the rapid separation and sensitive quantification of scopolamine in human serum was developed. Scopolamine was extracted from 0.5 mL of human serum using solid-phase extraction. The extracted samples were injected onto Zorbax XDB-C18 column (4.6 × 50 mm, 1.8 μm, and 600 bar) on an Agilent 1200 series HPLC. The chromatographic separation involved gradient elution with water and acetonitrile containing 0.1% v/v formic acid as a mobile phase. The samples were quantified in positive ion mode using a TSQ Quantum triple quadrupole mass spectrometer. The assay was validated and found to be linear over a concentration range of 5–5000 pg/mL. The total assay precision and accuracy was 6.3% and 96%, respectively. The lower limit of quantification (LLOQ) of the assay was 5 pg/mL. The assay was used in a human pharmacokinetic study to measure the concentration of scopolamine in serum after an administering scopolamine as transdermal delivery system or as an intravenous bolus dose.