Vonoprazan Fumarate Impurity 82
[CAS 2127152-98-9]

Identification

• Classification: Organic raw materials >> Organic fluorine compound
• Name: Vonoprazan Fumarate Impurity 82
• Synonyms: 1-[5-(2-fluorophenyl)-1-pyridin-3-ylsulfonylpyrrol-3-yl]-N-methylmethanimine
• Molecular Formula: C₁₇H₁₄FN₃O₂S
• Molecular Weight: 343.38
• CAS Registry Number: 2127152-98-9
• SMILES: CN=CC1=CN(C(=C1)C2=CC=CC=C2F)S(=O)(=O)C3=CN=CC=C3

Properties

• Density: 1.3 g/cm³ Calc.^*
• Boiling point: 564.5 °C 760 mmHg (Calc.)^*
• Flash point: 295.2 °C (Calc.)^*
• Index of refraction: 1.622323 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P280-P305+P351+P338

chemBlink Chemical Story

Why would a pharmaceutical laboratory deliberately buy an impurity? Because proving what should not be in a medicine is part of proving what is in it. CAS 2127152-98-9, sold as Vonoprazan Fumarate Impurity 8, is a structurally related reference compound used in analytical and process-control work around vonoprazan manufacture.

Public reference-standard sources identify CAS 2127152-98-9 as 1-(5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl)-N-methylmethanimine. It retains the fluorophenyl-pyrrole-pyridylsulfonyl framework associated with vonoprazan chemistry but differs in the side-chain functionality. That makes it useful as a marker for a possible process-related or transformation product rather than as an active pharmaceutical ingredient.

Vonoprazan itself belongs to the potassium-competitive acid blocker, or P-CAB, class. Unlike proton-pump inhibitors that require acid activation and covalent modification of the gastric H⁺/K⁺-ATPase, vonoprazan accumulates in the acidic secretory canaliculi and reversibly suppresses the proton pump through potassium-competitive binding. Its rapid and sustained acid suppression has made it an important therapy in acid-related disease. But the clinical story of the active drug is only half of pharmaceutical chemistry. The other half is controlling every plausible related substance made along the route or formed during storage.

Impurity standards allow analysts to answer concrete questions. Does a chromatographic peak correspond to this specific compound? At what concentration can it be detected and quantified? Does a process change increase or decrease its formation? Does it grow during heat, light, humidity, or oxidative stress? A characterized impurity standard gives retention-time, spectral, and quantitative reference points so a manufacturer does not have to identify every unexpected peak from scratch.

This is also why the word "impurity" should not be interpreted as a casual synonym for contamination. Pharmaceutical impurities can arise from starting materials, intermediates, side reactions, reagents, degradation, or even alternative crystal and salt behavior. Regulatory control requires that significant related substances be understood and kept within justified limits. Reference compounds such as CAS 2127152-98-9 are tools for that discipline.

The memorable lesson is almost paradoxical: making a pure drug requires studying impure chemistry in great detail. Vonoprazan Fumarate Impurity 8 is valuable not because anyone wants it in the tablet, but because a known unwanted molecule is much easier to control than an unknown one.

References:
1. Pharmaceutical reference-standard listings for CAS 2127152-98-9: 1-(5-(2-Fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl)-N-methylmethanimine.
2. ICH Q3A(R2), Impurities in New Drug Substances.
3. ICH Q3B(R2), Impurities in New Drug Products.
4. Reviews of vonoprazan and potassium-competitive acid blockers in acid-related disease.

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