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

Tingting Xu ^1,2, Wei Zuo ^1,2, Zhuo Sun ^1,2

⁰Department of Pharmacy, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

Biomedical Chromatography : Bmc +

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June 14, 2025

View abstract on PubMed

Summary

A new LC-MS/MS method accurately quantifies nusinersen in Chinese spinal muscular atrophy (SMA) patients. This reliable quantification in plasma and cerebrospinal fluid supports future pharmacokinetic studies for this ASO drug.

Area Of Science

Pharmacology
Analytical Chemistry
Biochemistry

Background

Nusinersen is the first antisense oligonucleotide (ASO) approved for spinal muscular atrophy (SMA) in China.
Pharmacokinetic data for nusinersen in Chinese SMA patients is currently lacking.

Purpose Of The Study

To develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.
To quantify nusinersen in human plasma and cerebrospinal fluid (CSF) samples.

Main Methods

Sample preparation involved protein precipitation.
Separation was achieved using a C18 column with a gradient elution.
Detection was performed using a QTRAP6500+ mass spectrometer in negative ion MRM mode with ESI.

Main Results

The validated LC-MS/MS method demonstrated reliable quantification of nusinersen.
Quantification ranges were 5.00–1000 ng/mL for plasma and 2.00–400 ng/mL for CSF.
This is the first report of nusinersen quantification in human plasma and CSF using LC-MS/MS.

Conclusions

A reliable LC-MS/MS methodology for nusinersen quantification in human plasma and CSF has been established.
This validated method is suitable for pharmacokinetic studies in Chinese SMA patients.
The developed method will facilitate a deeper understanding of nusinersen's behavior in this population.

Keywords:

IP‐RP‐LC/MS/MS antisense oligonucleotide nusinersen spinal muscular atrophy