Solid formulation with specific size distribution can be exempted from inhalation test requirements. Formulations containing components indicated to be equal or less toxic on inhalation than technical material can be exempted from inhalation tests. The result of non-observable LC50 cannot be utilized for pesticide toxicological classification;
On 11 May 2016, Brazil National Health Surveillance Agency (ANVISA) published a technical note to specify two exemption conditions for acute inhalation toxicity test for pesticide formulation and the applicable result for toxicological classification of pesticide. In Brazil, the inhalation toxicity data are mandatorily required for pesticide registration and the study should be performed under internationally recognized methods and the OECD test protocols most often accepted. The latest OECD Test Guideline 403-Acute Inhalation Toxicity has been appended with new procedures and parameters for lethal concentration inhalation study. ANVISA deems it is necessary to consolidate the technical reference with the requirement, acceptability and interpretation of study result to determine the endpoint.
The formulated product may be exempted from the inhalation toxicity study under the following conditions:
Solid formulation containing a significant proportion(over 99%) of particles with diameter equal to or greater than 50 µm;
The acute inhalation toxicity data of all components(additives, adjuvants and other inert ingredients in a formulated product) or reliable prediction from validated method which indicated to be equal or less inhalation toxicity than the technical product;
If the data on the inhalation toxicity of the components was absent or there is the presence of evidence that it is more toxic than technical product, the inhalation study on formulated product will be required.
The toxicological classification of pesticide characterized as fumigant, vapor, volatile and powder with particle diameter less than 15 µm should be determined by the inhalation toxicity and expressed by different color bands and ratings on pesticide label to communicate the product hazard to the user. However, according to the OECD guideline, deaths of animal test subjects might not necessarily be observed during the exposure periods and LC 50(median lethal concentration) cannot be obtained. In such circumstances, no danger of respiratory toxicity in normal exposure conditions can be assumed.
If an inhalation toxicity study was conducted under GLP condition and LC50 was not found, the toxicological classification under such result will not be justified by ANVISA. On the contrary, the label should introduce the information that the inhalation LC50 has not been determined in test condition.
