N-nitrosamines impurity testing

Nitrosamine compounds are potent genotoxic carcinogens in several non-human species and are classified as probable human carcinogens by the International Agency for Research on Cancer (IARC).

Since June 2018, several N-nitrosamines have been detected in several batches of drug substances, initially from Sartans, but now the concern of the heath agencies has been extended to all drug substances and also to drug products. 

Although initially were detected N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) also by the time other N-nitrosamines were added to these two.

Heath agencies required to the pharmaceutical companies to do a risk assessment about the possible presence of such N-nitrosamines in their products and experimentally demonstrate that are not present in the case of the risk assessment anticipate their possible presence. The list of the N-nitrosamines that must be tested should be obtained from the risk assessment.

We offer our experience in testing N-nitrosamines impurities. We have available general methods by HS-GC-MS and LC-MS/MS for the N-nitrosamine analysis in API and drug products. These methods can be adapted with minor modifications to the client API or drug product.

The N-nitrosamines available are described in the list below. New nitrosamines will be added in the future and under request of the clients.

  • NDMA: N-Nitrosodimethylamine
  • NDEA: N-Nitrosodiethylamine
  • NDIPA: N-Nitrosodiisopropylamine
  • NEIPA: N-Nitrosoethylisopropylamine
  • NDBA: N-Nitroso-di-n-butylamine
  • NMEA: N-nitrosomethylethylamine
  • NDPA: N-nitroso-di-n-propylamine
  • NMBA: N-Nitroso-N-methyl-4-aminobutyric acid
  • NPYR: N-Nitrosopyrrolidine
  • NPIP: N-Nitrosopyperidine
  • NMOR: N-Nitrosomorpholine
  • NDELA: N-Nitrosodiethanolamine
  • MNPZ: mono-N-Nitrosopiperazine 
  • DNPZ: di-N-Nitrosopiperazine
  • NDPhA: N-nitroso-di-phenylamine
  • NMPA: N-nitrosomethyl-phenylamine

Kymos proposes an approach to comply with the request of the Regulatory Agencies, optimizing costs and time. This proposal consists in two steps:

a. Screening of the target nitrosamines requested by the client from the list of above. Default screening limits originally established by the health agencies (0.03ppm) have been gradually improved, with our current sensitivity levels having reached 0.1ppb. Other limits can be established depending on the product or client’s request. 
b. In the case that one or more nitrosamines are at or above the established limits, a development and validation of a quantitative method will be required and agreed with the client. If quantitative testing is performed to justify skip testing, the LoQ of the analytical procedure employed should be ≤ 30% of the acceptable limit  based on the acceptable intake (AI) and maximum daily dose of the API (MDD). If quantitative testing is performed to justify omission of specification, the LoQ of the analytical method employed should be ≤ 10% of the acceptable limit based on the AI and MDD. 

Acceptable Intake Limits: FDA recommends the following acceptable intake (AI) limits for the nitrosamine impurities NDMA, NDEA, NMBA, NMPA, NIPEA, and NDIPA (Table below). We further recommend that manufacturers use these AIs when determining limits for nitrosamine impurities in APIs and drug products.




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