A Selective and Sensitive Method Development and Validation of 1,1-Dimethyl-3-Hydroxy-Pyrrolidinium Bromide Impurity in Glycopyrrolate Oral Solution by Liquid Chromatography-Tandem Mass Spectroscopy.

Objective: A selective and sensitive liquid chromatography-tandem mass spectrometer (LC-MS/MS) method has been developed for the quantification of 1,1-dimethyl-3-hydroxy-pyrrolidinium bromide impurity in glycopyrrolate oral solution.

Materials And Method: The LC-MS/MS analysis was done on X Bridge HILIC (100 × 4.6 mm, 5 μm) analytical column, and the mobile phase used was10 mM ammonium formate with 0.2% formic acid as mobile phase-A and acetonitrile as mobile phase-B with a gradient programme of 5.0 min. The flow rate used was 1.2 mL/min. Triple quadrupole mass detector coupled to positive electrospray ionization operated in multiple reactions monitoring mode was used for the quantification at m/z 116.10 ± 0.5.

Results: Retention time of impurity was found ~3.2 min. The method was validated in terms of specificity, linearity, accuracy, precision, range, limit of detection, limit of quantitation (LOQ) and robustness. Relative standard deviation (RSD) for system suitability was found 1.3%. Calibration plot was linear over the range of 0.050-2.000 μg/mL. Limit of detection and limit of quantification were found 0.017 and 0.051 μg/mL, respectively. The intra- and inter-day precision RSD was 2.3% and the obtained recovery at LOQ to 200% was in between 86.7 and 107.4%.

Conclusion: The low RSD values and high recoveries of the method confirm the suitability of the method.