Definition of Genotoxic Impurities
Genotoxic impurities (also known as GTIs) refers to chemical substances that have the potential to damage DNA and cause mutations, which can lead to cancer or other diseases. These impurities can be found in various products, including pharmaceuticals, pesticides, and industrial chemicals. GTIs can be produced during the manufacturing process or they may be present as contaminants in raw materials or intermediates used to make the product. The presence of genotoxic impurities in products is of concern to regulatory agencies, and manufacturers are required to monitor and control their levels to ensure the safety of the product.
Classification of Genotoxic Impurities
The classification of Genotoxic Impurities (GTIs) may vary from one country to another based on their regulatory requirements. Here are the classifications of GTIs in China and the United States:
China:
In China, the classification of GTIs is based on the “Guidelines for the Control of Genotoxic Impurities in Drugs” issued by the China Food and Drug Administration (CFDA). The guidelines classify GTIs into four categories:
Class A: Known human carcinogens. These impurities should not be present in the drug substance or product.
Class B: Probable human carcinogens. These impurities should be controlled to the lowest possible level.
Class C: Possible human carcinogens. These impurities should be monitored and controlled based on their toxicity and exposure.
Class D: Other genotoxic impurities. These impurities should be monitored and controlled based on their toxicity and exposure.
United States:
In the United States, the classification of GTIs is based on the “Guidance for Industry: Genotoxic and Carcinogenic Impurities in Drug Substances and Products: Recommended Approaches” issued by the US Food and Drug Administration (FDA). The guidance document classifies GTIs into three categories:
Class 1: Known human carcinogens. These impurities should not be present in the drug substance or product.
Class 2: Potential human carcinogens. These impurities should be controlled to the lowest possible level.
Class 3: Genotoxic impurities with limited human relevance. These impurities should be monitored and controlled based on their toxicity and exposure.
The classification of Genotoxic Impurities (GTIs) in China and the United States is generally similar, as both countries use a classification system based on the level of genotoxicity and carcinogenicity of the impurities. While there may be some differences in the specific classification criteria and guidelines, both China and the United States recognize the importance of controlling GTIs to ensure the safety of drugs and other products.
The Limits for Genotoxic Impurities
The limits for Genotoxic Impurities (GTIs) depend on the specific guidelines and regulations of each country or region. The limits are usually expressed as an acceptable daily intake (ADI) or a permitted level of exposure based on the toxicological data available for the GTI.
In general, the limits for GTIs are set to minimize the risk of exposure to these impurities and to ensure that the products are safe for human use. The limits may vary depending on the level of genotoxicity and carcinogenicity of the GTI, the route of administration of the drug, and the duration and frequency of exposure.
