This article from Issue 14 of the Analytix Reporter shows intriguing findings from work with USP Chapter <1469>, Procedure 1, and a successful implementation of Procedure 3 where all system method suitability requirements were met.
Introduction
Nitrosamines are unwanted side products present in many substances and are suspected to have toxic and carcinogenic properties. In pharmaceutical raw materials and finished drug products, nitrosamines may also be formed as side-products from synthesis, during storage, or from packaging, etc. A demand for nitrosamine analysis has rapidly increased worldwide. The list of nitrosamine impurities manufactured from drug substances using specific synthetic routes has grown after extensive synthetic route assessments.
The United States Pharmacopeia (USP) published in December 2021 new procedures in response to the unexpected detection of nitrosamines, such as N-nitrosodimethylamine (NDMA) impurity, in certain active pharmaceutical ingredients (API) and corresponding final formulations. The new USP chapter <1469> provides recommendations regarding the creation of controls of nitrosamine impurities limits to ensure their elimination or reduction, and analytical method performance characteristics for nitrosamine testing procedures using both GC-MS (procedures 2 and 4) and LC-MS (procedures 1 and 3).
This paper focuses on the LC-MS based test procedures (procedure 1 and 3) for quantitative analysis of known nitrosamine impurities in drugs and pharmaceutical raw materials using liquid chromatography and mass spectrometric detection. Even though both methods were evaluated, final run conditions and data from the procedure 3 will be presented. System suitability criteria for the procedure 1 could not be met with the instrumentation available, but will be described.
Procedure 1 designates the use of a high-resolution mass spectrometer (HRMS) and can be used for the quantitation of NDMA, NDEA (nitrosodiethylamine), NDBA (nitrosodibutylamine), NDIPA (N-nitrosodiisopropylamine), NEIPA (N-nitrosoethylisopropylamine), NMBA (N-nitrosomethylaminobutyric Acid), and NMPA (N-nitrosomethylphenylamine) in selected sartans (valsartan, irbesartan, and losartan potassium). Procedure 3 uses MS/MS and can be used for the quantitation of NDMA, NDEA, NDIPA, NEIPA, NMBA, and NDBA in selected sartans (valsartan, losartan potassium, olmesartan medoxomil, candesartan cilexetil, and telmisartan).
Results and Discussion
Evaluation of Procedure 1
The USP procedure 1 method describes the use of liquid chromatography and high-resolution mass spectrometric detection (LC-HRMS), but the given experimental conditions appear not generic enough to allow implementation and validation on any given HRMS platform. Our laboratory experienced sensitivity issues with an ultra-modern HRMS detector (Agilent 6546 Q-TOF), and to verify the results different HPLC columns, solvents, and reagents were tested. Chromatographic system suitability criteria could be met, but it was not possible to meet system suitability for overall identification and sensitivity. See the full article for more details.
Evaluation of Procedure 3
This method describes the use of liquid chromatography and tandem-mass spectrometric detection (LC-MS/MS), for the quantitation of NDMA, NDEA, NDIPA, NEIPA, NMBA, and NDBA in selected sartans (valsartan, losartan potassium, olmesartan medoxomil, candesartan cilexetil, and telmisartan). The procedure listed two system suitability criteria: 1. Correlation coefficient: NLT 0.99 and 2. y-Intercept: Not more than (NMT) 25% of the response of the medium concentration solution used in standard curve generation. Going forward, analytical data will be presented from the work establishing a validated analytical procedure 3 using a 150 x 3.0 mm Ascentis® Express C18 column (USP L1 packing) with 2.7 μm particles. An example of a nitrosamine impurity standard on this column is shown in Figure 3. See the full article for more details.
Conclusion
This paper shows intriguing findings from work with USP Chapter <1469>, Procedure 1, and a successful implementation of Procedure 3 meeting all system suitability requirements.
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