# Facile Access to Solifenacin Impurity K: One-Step Synthesis and an HPLC-MS Method for Its Determination

## TL;DR

This paper presents a simple method to synthesize a solifenacin impurity and a new HPLC-MS technique to detect it in tablets.

## Contribution

A one-step synthesis of Impurity K and a novel HPLC-MS method for its determination in solifenacin tablets.

## Key findings

- Impurity K was successfully synthesized using cerium(IV) ammonium nitrate in water/acetonitrile.
- An HPLC-MS method was developed for detecting Impurity K in solifenacin succinate tablets.

## Abstract

Solifenacin (SFC) is a potent muscarinic antagonist that effectively reduces bladder muscle contraction, thereby alleviating symptoms such as frequency of micturition and urgency. Oxidation of SFC leads to the formation of impurities like Impurity K. Effective analysis and control of this impurity is crucial for ensuring compliance with regulatory standards and safeguarding patient health. To address these challenges, we propose a novel one-step synthesis of Impurity K from SFC. Impurity K was synthesized using cerium(IV) ammonium nitrate (CAN) in water/acetonitrile as the solvent. Additionally, we describe a new HPLC-MS method for the detection of Impurity K in solifenacin succinate tablets.