Impurities – the ‘pest’ in pesticides

May 17, 2022

Dr Luminita Velea, Senior Scientific Consultant, defines impurities, the nuanced requirements associated with them, and why regulatory support might be necessary.

What are impurities?

Impurities are defined as something that renders something else impure, a contaminant, an inferior component or additive. These chemical compounds, both organic and inorganic, are introduced or formed during the manufacturing process, therefore they can be of known or unknown identity. Their presence can have various origins, including starting materials, by-products, intermediates, degradation products, reagents, ligands, catalysts, heavy metals (or other residual metals), inorganic salts, residual solvents, and other materials. According to the Environmental Protection Agency (EPA), impurities are defined as any substance (or group of structurally similar substances if specified by the Agency) in a pesticide product other than an active ingredient or inert ingredient.

So, why is this information important for your company to consider?

The specifics

Per FIFRA regulation (OCSPP 830.1670), all product registrations must include a confidential statement of formula (CSF) which identifies the active ingredient(s), inert ingredient(s), and, where applicable, present impurities. The presence of some impurities can be addressed with a scientific rationale, while other impurities require testing. The test, otherwise known as the preliminary analysis, is designed to measure the amount of active ingredient(s) present in a product and identify and quantify any impurity present with special attention placed on those associated with the active ingredient(s). If identified impurities are present at ≥ 0.1% in the product, or in some cases lower for impurities with toxicological concerns, they will have to be listed on the CSF.

Regulatory guidance

Navigating EPA guidelines for impurities requires both chemical expertise and regulatory insight. A company will need to understand whether a scientific rationale or test is necessary, and if the latter, how to conduct such a test and produce samples for Agency review. Submission of the registration package to EPA is not complete without addressing impurities, whether present or not. Looping in a regulatory expert to ensure EPA requirements are satisfied means your company is one step closer to market.

How can Dr. Velea help you?

Dr. Velea specializes in product chemistry of antimicrobial, biochemical, and conventional pesticides, ensuring compliance under FIFRA (US) and PMRA (Canada), and providing guidance on Good Laboratory Practices (GLP) testing requirements and standards. Struggling with a FIFRA application? Not sure how to address the presence of impurities in your CSF? Dr. Velea can provide the technical and regulatory support that your company needs to effectively and efficiently see your product to market. Whether you have questions about impurities or want to know about other pesticide product chemistry guidelines, don’t hesitate to get in touch. Contact us: [email protected]


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