Development and Validation of an LC-MS/MS Assay for Quantitative Analysis of Nusinersen in Human CSF and Plasma

Area of Science:

• Pharmacology
• Analytical Chemistry
• Biochemistry

Background:

• Nusinersen is a key treatment for spinal muscular atrophy (SMA).
• Pharmacokinetic data for nusinersen in Chinese SMA patients is currently unavailable.
• Accurate quantification methods are essential for therapeutic drug monitoring.

Purpose of the Study:

• To develop and validate a sensitive LC-MS/MS method for nusinersen quantification.
• To enable pharmacokinetic studies in Chinese SMA patient populations.
• To establish a reliable analytical tool for therapeutic drug monitoring.

Main Methods:

• Protein precipitation for sample preparation.
• Reversed-phase liquid chromatography (LC) using a C18 column.
• Tandem mass spectrometry (MS/MS) detection in negative ion MRM mode.

Main Results:

• The LC-MS/MS method was successfully validated for human plasma and cerebrospinal fluid (CSF).
• Quantification ranges were established: 5.00–1000 ng/mL for plasma and 2.00–400 ng/mL for CSF.
• This is the first reported LC-MS/MS quantification of nusinersen in human plasma and CSF.

Conclusions:

• A reliable and validated LC-MS/MS method for nusinersen quantification has been developed.
• This methodology will facilitate crucial pharmacokinetic studies in Chinese SMA patients.
• The method supports the clinical application of nusinersen in this population.