Comparison of mouse plasma and brain tissue homogenate sample pretreatment methods prior to high-performance liquid chromatography for a new 1,2,4-triazole derivative with anticonvulsant activity

Simultaneous quantification of thalidomide, lenalidomide and pomadomide in plasma by LC-MS/MS

OBJECTIVE

To develop a new method for quantitatively analyzing three immunomodulators (thalidomide, lenalidomide and pomadomide) by liquid chromatography tandem mass spectrometry (LC-MS/MS).

METHODS

Using thalidomide-d4 as internal standard, the three analytes were separated on Agilent Zorbax SB-C18(2.1 mm × 100 mm, 3.5 μm, Agilent, USA) column and monitored in multiple reactions monitoring mode in Agilent G6460A triple quadrupole mass spectrometer operating in positive ionization mode. The sample was pretreated by protein precipitation using methanol at 3-fold volume to sample. The mobile phase was comprised of 0.1% formic acid in water (phase A) and acetonitrile (phase B) and was delivered in gradient elution program. The flow rate was 0.3 mL/min, and the injection volume was 5 μL.

RESULTS

The accuracy and stability of the method are within ±15.0%, and the precision is not >15.0%. The recoveries were 85.04% ∼ 119.07%, and the matrix effect was 73.68% ∼ 116.75%. Specificity, linearity, LLOQ, carry-over and dilution were all in line with the requirements of pharmacopeia and guidelines. The peak concentrations of thalidomide, lenalidomide shows huge inter-individual differences.

CONCLUSIONS

This newly developed method was sensitive, simple, and robust and can be used in therapeutic drug monitoring of three immunomodulators in multiple myeloma patients.

LC-MS/MS Method for Determination of Hydroxychloroquine and Metabolites: Application in a Pharmacokinetic Study

Hydroxychloroquine (HCQ) was originally used as an antimalarial and immunomodulation drug. We developed and validated a simple and sensitive ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous quantitation of HCQ and its three metabolites in rat blood, and reported their pharmacokinetic parameters. The chromatographic separation and detection of analytes were achieved within 4 min on ZORBAX SB-C₈ (3.5 μm, 2.1 × 150 mm) column with gradient elution, and the flow rate was 0.25 mL/min. Simple protein precipitation was successfully applied for sample pretreatment. The HCQ displays a good linearity in the range of 2.0-5000.0 ng/mL, and the three metabolites also show good linearity ranging from 1.0 to 2500.0 ng/mL, with all correlation coefficients (R ²) better than 0.98. In conclusion, this rapid, sensitive method was successfully developed, validated, and then applied to a pharmacokinetic study of HCQ in rat model in high dose. The results of the pharmacokinetic study presented an average half-life time 21.14 ± 10.31 h (mean ± SD) of HCQ, which is much shorter in human compared to that in mice. For the three metabolites, longer half-life times (approximately 100 h) were shown in rat.