UPLC-Tandem Mass Spectrometry Method for Simultaneous Determination of Fluoxetine, Risperidone, and Its Active Metabolite 9-Hydroxyrisperidone in Plasma: Application to Pharmacokinetics Study in Rats

A UPLC-MS/MS Assay for Simultaneous Determination of Two Antipsychotics and Two Antidepressants in Human Plasma and Its Application in Clinic

BACKGROUND

Antidepressants and antipsychotics are widely prescribed drugs for the treatment of mental diseases. Therapeutic drug monitoring (TDM) is recommended for patients taking these drugs to ensure pharmaceutical efficacy, medication compliance and prevent toxicity.

OBJECTIVE

An ultra-high performance liquid chromatography/tandem-mass spectrometry (UPLC-MS/ MS) method was developed for simultaneous determination of two Antidepressants-Fluoxetine (FLU) and Escitalopram (ESC), and two antipsychotics-risperidone (RIS) and aripiprazole (ARI), in human plasma.

METHODS

The sample was processed by simple protein precipitation and the targeted analytes were separated on a C18 column by gradient elution with a mobile phase containing 0.1% formic acid (v/v) and acetonitrile. All the analytes were qualitative and quantitative measured by electrospray ionization source with Multiple Reaction Monitoring (MRM) in positive ion mode. A total of 56 plasma samples were obtained from out- or in-patients who were taking the cited four drugs for further analysis.

RESULTS

The calibration curves for FLU, ESC, RIS and ARI were linear in the range of 45-1800, 4-320, 2-200 and 50-1800 ng/mL, respectively. The entire analytical time for the analytes was 7.0 min for each run and the extraction efficiency was more than 90%. The sample was stable within various storage conditions. The trough concentrations in patients were measured with the validated method.

CONCLUSION

The developed method was successfully used for simultaneous determination of FLU, ESC, RIS and ARI in the plasma of the patients, which provides effective technical support for routine TDM of these four drugs and is of great clinic value for individual therapy.

LC-MS/MS Method for Simultaneous Quantification of Dexmedetomidine, Dezocine, and Midazolam in Rat Plasma and Its Application to Their Pharmacokinetic Study

A simple, sensitive, and accurate LC-MS/MS method was established and validated for the simultaneous quantification of dexmedetomidine, dezocine, and midazolam in rat plasma. Chromatographic separation was achieved on a C18 column (50 mm × 2.1 mm, 3 µm) using a mobile phase composed of water (containing 0.1% formic acid) and acetonitrile. The lower limits of quantification were 0.1, 0.1, and 0.2 ng/mL for dexmedetomidine, dezocine, and midazolam in rat plasma, respectively. The analytes were determined with selected reaction monitoring under positive ionization mode. The intra- and interday precision and accuracy were all within acceptable limits during the entire validation, and the stability of analytes was acceptable under various storage conditions. The validated method was successfully applied in pharmacokinetic studies of dexmedetomidine, dezocine, and midazolam following intravenous injection.