Separation, characterization and cytotoxicity of unknown forced degradation impurity of selpercatinib using Prep-LC,...

Area of Science:

• Pharmaceutical Chemistry
• Drug Discovery
• Analytical Chemistry

Background:

• Selpercatinib is an oral selective RET inhibitor for RET-positive cancers.
• Quality control of pharmaceuticals requires identification of impurities.
• Forced degradation studies are crucial for understanding drug stability.

Purpose of the Study:

• To isolate and characterize an unknown acid forced degradation impurity of selpercatinib.
• To evaluate the antitumor activity of the identified impurity.
• To contribute to the quality control of selpercatinib and explore new drug candidates.

Main Methods:

• Isolation and purification using semi-preparative liquid chromatography (semi-Prep-LC).
• Purity assessment by high-performance liquid chromatography (HPLC).
• Structural elucidation using high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR).
• In vitro antitumor activity evaluation using MTT assays.

Main Results:

• An unknown impurity, designated sel-1, was isolated with 99.1% purity.
• The molecular structure of sel-1 was elucidated as 6-(2-hydroxy-2-methylpropoxy)-4-(6-(6-((6-oxo-1,6-dihydropyridin-3-yl)methyl)-3,6-diazabicyclo[3.1.1]heptan-3-yl)pyridin-3-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile.
• Sel-1 exhibited significant in vitro antitumor activity against HepaRG and MKN-1 cell lines, surpassing selpercatinib's inhibitory effects.

Conclusions:

• The study successfully identified and characterized a key degradation impurity of selpercatinib.
• The impurity, sel-1, possesses notable antitumor properties, indicating its potential as a novel therapeutic agent.
• This research enhances selpercatinib quality control standards and opens avenues for sel-1 drug development.