Nitrosamines, or more appropriately Nitrosamines, refer to any molecule containing the nitroso functional group. Because of nitrosamine impurities are probable human carcinogens, they are the reason of worry. Although they may be present in some foods and drinking water supplies and also in medicines. Its presence is nevertheless considered unacceptable.

Nitrosamines are classified by the ICH M7(R1) Guideline as Class 1 impurities, “known mutagenic carcinogens,” based on both rodent carcinogenicity and mutagenicity data. They are categorized by the International Agency for Cancer Research (IARC) as 2A – Probable Carcinogens based on data on a number of species studied. More other impurities including like N-nitrosodiethylamine (NDEA), N-nitrosoethylisopropylamine (NIEPA), N-nitrosodiisopropylamine (NDIPA), N-nitrosodibutylamine (NDBA), and N-nitrosomethyl-4-amino-butyric acid (NMBA) are also classified as potential nitrosamine impurities. In February 2021, the FDA has issued a guidance “Control of Nitrosamine Impurities in Human Drugs, Guidance for Industry”. This document provides guidance on steps to detect and prevent unacceptable levels of nitrosamine impurities in pharmaceutical products.

Methods for determination of Nitrosamine impurities as per FDA:

(1) Headspace Gas Chromatography Mass Spectrometry (GCHS-MS/MS): The FDA research team has developed a GC-MS headspace method for the simultaneous evaluation of four nitrosamine impurities in angiotensin II receptor blockers (ARBs) drug product. These impurities are N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodiisopropylamine (NDIPA), and Nnitrosoethylisopropylamine (NEIPA). This method was developed & validated on valsartan drug product and drug substance. We at Chromak Research also have well experienced team to perform these types of testing of nitrosamine impurities. Our team has ability to perform these techniques to determine LOD and LOQ values of nitrosamine impurities.

(2) Liquid Chromatography Mass Spectrometry (LC-MS/MS): Liquid chromatography- mass spectrometry (LC-MS/MS) method is applicable for the determination of NDMA in ranitidine drug product and drug substance. FDA published testing method of LC-MS for the detection of MNP in rifampin and CPNP in rifapentine drug substance and drug products. We at Chromak research also use this technique for nitrosamine impurity detection in ranitidine drug product.

(3) Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS): The FDA has observed that the method for testing angiotensin II receptor blockers (ARBs) for nitrosamine impurities is not suitable for testing ranitidine because heating the sample generates NDMA. So that LC-HRMS method was subsequently developed by the FDA to measure the levels of NDMA in ranitidine drug product
following ICH Q2(R1), with LOD value 10ng/g, lower LOQ value 33ng/g and upper LOQ value 3333ng/g. LC-MS method is also used for the detection of NDMA in metformin drug substance and drug products. We also have developed the method with this technique to determine NDMA in ranitidine products.

Requirements of new tests:

In manufacturing process, there may be possibility of the formation of nitrosamine impurities in drug products. Therefore, it becoming very important to control or reduce the possibility of these carcinogenic impurities. The pharmaceutical industry needs to look into it and have to maintain the quality of the substances or reagents which are used in the manufacturing process because its directly affected to the final product’s quality.

The European Medicines Agency (EMA) has sent a notice to marketing authorization holders to review their human medicinal drug products containing chemically synthesized APIs on the potential risk of containing nitrosamines impurities before April 2020.

Risk Assessment: EU Marketing Authorization Holders (MAH) should perform risk assessment of their medicinal products containing chemically synthesized APIs

Confirmatory Testing: Confirmatory testing should be carried out using appropriately developed and validated methods in MAHs should inform the Competent Authorities immediately if tests confirm the presence of a nitrosamine impurity irrespective of the amount detected.

Changes to the Marketing Authorization: MAHs should apply for a variation in a timely manner to introduce any required changes, such as an amendment of the manufacturing process or changes in product specifications.

Chromak Research provides nitrosamine impurity testing services to the pharmaceutical and medical industries. We can perform impurity identification and testing of LOD and LOQ value in accordance with FDA and ICH guidelines. Our team has rich experience to perform the testing related to these carcinogenic impurities in your projects and we can assist you to support in your product throughout the manufacturing process to the finished products

Interim Limits for NDMA, NDEA, and NMBA in Angiotensin II Receptor Blockers (ARBs)
Drug Maximum Daily Dose (mg/day) Acceptable Intake NDMA (ng/day)* Acceptable Intake NDMA (ppm)** Acceptable Intake NDEA (ng/day)* Acceptable Intake NDEA (ppm)** Acceptable Intake NMBA (ng/day)* Acceptable Intake NMBA (ppm)**
Valsartan 320 96 0.3 26.5 0.083 96 0.3
Losartan 100 96 0.96 26.5 0.27 96 0.96***
Irbesartan 300 96 0.32 26.5 0.088 96 0.32
Azilsartan 80 96 1.2 26.5 0.33 96 1.2
Olmesartan 40 96 2.4 26.5 0.66 96 2.4
Eprosartan 800 96 0.12 26.5 0.033 96 0.12
Candesartan 32 96 3.0 26.5 0.83 96 3.0
Telmisartan 80 96 1.2 26.5 0.33 96 1.2