Determination of N-Nitroso-Nebivolol in Nebivolol Drug Substance by LCMS-2050

Importance of the Topic

The control of nitrosamine impurities in pharmaceuticals has become a critical safety and regulatory requirement worldwide. N-Nitroso-nebivolol is an example of a drug substance-related nitrosamine impurity (NDSRI) that may form during nebivolol synthesis and pose carcinogenic risk. Reliable detection of trace levels of this impurity is essential to meet stringent FDA acceptable intake limits and ensure patient safety.

Objectives and Study Overview

This study aimed to develop and validate a rapid, sensitive, and accurate method using the Shimadzu LCMS-2050 system for quantifying N-Nitroso-nebivolol in nebivolol drug substance. The method needed to achieve a detection range covering 1 to 180 ng/mL, meet FDA’s AI limit of 1500 ng/day, and demonstrate robust performance characteristics for routine quality control.

Methodology

• Sample Preparation: 0.5 mg of nebivolol drug substance was dissolved in 50% methanol-water, ultrasonicated, filtered through a 0.22 µm nylon membrane, and diluted to yield working standards of 1, 5, 10, 50, 100, and 180 ng/mL.
• Chromatographic Conditions: Separation was achieved on a Shim-pack GIST-HP C18 column (100 mm × 2.1 mm I.D., 2 µm) using gradient elution with 0.1% formic acid in water (A) and acetonitrile (B) at 0.35 mL/min. The gradient ramped from 40% to 90% B over 3.5 minutes and returned to initial conditions by 8 minutes.
• Flow Path Switching: A valve switch diverted the main nebivolol peak to waste until 2.8 minutes, allowing only the late-eluting N-Nitroso-nebivolol (retention time 3.408 min) to enter the mass spectrometer and prevent API overload.

Used Instrumentation

• Nexera XR UHPLC system with photodiode array detector (PDA)
• Shimadzu LCMS-2050 single quadrupole mass spectrometer equipped with DUIS ion source (combining ESI and APCI)
• Shim-pack GIST-HP C18 column (100 mm × 2.1 mm I.D., 2 µm)

Key Findings and Discussion

• Linearity: Calibration exhibited excellent linearity over 1–180 ng/mL with a correlation coefficient of 0.9999.
• Specificity: SIM chromatograms showed no interfering peaks at the target m/z 479.02, confirming selectivity for N-Nitroso-nebivolol.
• Precision: Repeatability RSD for retention time and peak area ranged from 0.09% to 0.40% and 1.36% to 2.02%, respectively, across 1, 10, and 100 ng/mL standards (n=6).
• Recovery: Spiking experiments at 0.03 µg/mg and 0.3 µg/mg of nebivolol yielded mean recoveries of 100.4% (RSD 0.77%) and 100.2% (RSD 1.89%), meeting pharmacopoeial requirements.

Benefits and Practical Applications

• The method provides high sensitivity and accuracy for trace nitrosamine detection in drug substance.
• Short analysis time (<8 minutes) supports high throughput in quality control laboratories.
• Flow switching protects the mass spectrometer from high-concentration API, extending instrument uptime and reducing maintenance.
• Compliance with FDA nitrosamine guidance ensures reliable monitoring of NDSRIs in pharmaceutical manufacturing.

Future Trends and Applications

Advancements in high-resolution mass spectrometry and automated sample preparation will further enhance sensitivity and specificity for nitrosamine impurity profiling. Expanding this approach to a broader range of NDSRIs and integrating with laboratory information management systems (LIMS) will support comprehensive risk assessments and regulatory compliance in pharmaceutical quality assurance.

Conclusion

The validated LCMS-2050 method offers a robust solution for the determination of N-Nitroso-nebivolol in nebivolol drug substance, combining sensitivity, precision, and speed. This approach enables pharmaceutical manufacturers to meet regulatory limits and safeguard product quality and patient safety.