Nitrosamine impurity tests are used in the pharmaceutical industry to to detect and quantify potentially harmful nitrosamine contaminants in drug products and active pharmaceutical ingredients (APIs). These types of assessments are required in order ensure compliance with regulatory guidelines set by agencies like the FDA and Health Canada.

Why Nucro-Technics is Your Best Choice for Nitrosamine Impurity Test

Nucro-Technics has been performing nitrosamine impurities testing since early 2019, when regulatory agencies, like the FDA, began asking for this type of analysis. This work has been performed for dozens of companies and for hundreds of APIs and marketed products. More than just following USP <1469> or the FDA-published methods, Nucro-Technics has developed and validated methods from first principles across multiple therapeutics indications and for product-specific (exotic) nitroso-compounds. We have pioneered novel approaches for the analysis of nitrosamine impurities in challenging samples. These include, but are not limited to, samples that have high salt content, and samples that have high daily dosing limits.

How Nitrosamine Impurity Testing is Performed

Nitrosamine testing is commonly performed using LC-MS/MS and/or GC-MS/MS equipment. There are two approaches that are offered at Nucro-Technics:

1. General Screening for the most common nitrosamines
2. Product-Specific nitrosamine impurity testing using validated methods

General Screening for Common Nitrosamine Impurities
Within our nitrosamine testing lab, Nucro-Technics has developed a general screening method for the most common nitrosamines. This can be used as part of the risk assessment process required by regulatory agencies. This screening will typically incorporate an analysis of the following nitrosamine impurities:

• NDMA (N-Nitrosodimethylamine); CAS # 62-75-9;
• NMBA (N-Nitroso-N-methyl-4-aminobutyric acid); CAS # 61445-55-4
• NDEA (N-Nitrosodiethylamine); CAS # 55-18-5
• NEIPA (N-Nitroso-ethyl-isopropylamine); CAS # 16339-04-1
• NDIPA (N-Nitrosodiisopropylamine); CAS # 601-77-4
• NDBA (N-Nitrosodi-n-butylamine) ; CAS # 924-16-3
• NMPA (N-Nitrosomethylphenylamine); CAS # 614-00-6;
• MENP (1-Methyl-4-nitrosopiperazine); CAS # 16339-07-4
• NMButA (N-Nitroso-N-methylbutylamine) ; CAS # 7068-83-9

Although this screening methodology is the most sensitive, if a different approach is warranted, Nucro-Technics can also perform an Enhanced Ames test.

Product-Specific Nitrosamine Impurity Testing Using Validated Methods
If nitrosamines are detected in the screen, Nucro-Technics recommends developing a method specific to these nitrosamine impurities, performing a full method validation, and routine sample analysis using the validated method.

What Regulatory Agencies are Asking For

Regulatory agencies have developed a comprehensive approach to nitrosamine impurity testing in drug products. At a minimum, a regulatory agency would expect to see the following:

1. Risk Assessment:
   • Manufacturers are required to conduct a risk assessment for all their products to evaluate the potential for nitrosamine formation or contamination.
   • This assessment should consider factors such as manufacturing processes, raw materials, packaging, and storage conditions.
   • As part of this risk assessment, Nucro-Technics can perform a nitrosamine impurity screening assay on the most common nitrosamines as described in the previous section
2. Confirmatory Testing:
   • If the risk assessment indicates a potential for nitrosamine presence, or for high-priority drug products, confirmatory testing is required.
   • This involves using validated analytical methods to detect and quantify specific nitrosamines.
   • Nucro-Technics can develop and validate product-specific methods to fulfill this obligation
3. Ongoing Monitoring:
   • Even after initial assessments and testing, manufacturers are expected to implement ongoing monitoring programs to ensure continued compliance and safety.

What Drug Products and Drug Classes Require Nitrosamine Impurity Testing?

The scope of required testing has expanded significantly over the years. The current regulatory approach has the following drug categories as being considered high priority:

• Drugs containing chemically synthesized active pharmaceutical ingredients (APIs);
• Drugs with manufacturing processes that could potentially lead to nitrosamine formation; and
• Drugs that use certain types of excipients or packaging materials known to potentially contribute to nitrosamine formation.

Specific drugs and drug classes have also been subject to greater scrutiny. These include but are not limited to:

• Losartan, Valsartan and other ARBs;
• Metformin;
• Ranitidine (Zantac);
• Rifampin/Rifapentine; and
• Varenicline (Chantix).

Related Articles

Over the years, Nucro-Technics has developed a significant amount of expertise regarding nitrosamine impurity testing. The following articles may provide some additional information:

• NDMA Testing in Ranitidine / Zantac
• Nitrosamine Testing of Impurities
• Nitrosamine Impurities Testing With the Updated FDA Guidance