Development and Validation of an Improved HPLC-MS/MS Method for Quantifying Total and Unbound Lenalidomide in Human...

Area of Science:

• Analytical Chemistry
• Pharmacokinetics
• Bioanalysis

Background:

• Lenalidomide is a crucial drug for multiple myeloma treatment.
• Accurate quantification of total and unbound lenalidomide is essential for therapeutic drug monitoring and understanding its pharmacokinetics.

Purpose of the Study:

• To develop and fully validate a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method.
• To quantify both total and unbound lenalidomide concentrations in human plasma samples.

Main Methods:

• Ultrafiltration was used to prepare plasma ultrafiltrate for unbound drug measurement.
• Liquid-liquid extraction was employed for sample preparation, followed by HPLC separation on a Halo C18 column.
• Detection and quantification were performed using tandem mass spectrometry in positive ion mode with multiple reaction monitoring.

Main Results:

• The method demonstrated excellent linearity over a concentration range of 5-1000 ng/mL (r² > 0.996) for both total and unbound lenalidomide.
• High precision and accuracy were achieved for total lenalidomide (CVs 1.70-7.65%, accuracy 94.45-101.10%) and unbound lenalidomide (CVs 1.98-10.55%, accuracy 93.95-98.48%).

Conclusions:

• A sensitive, reproducible, and efficient bioanalytical method was successfully developed and validated.
• The method requires a small plasma volume (50 μL) and has a short run time (2.5 min).
• The validated method was effectively applied to measure lenalidomide concentrations in multiple myeloma patients with renal impairment.