By Karen Roldán
Phytosanitary regulation in Argentina is evolving toward more modern, scientific approaches that are aligned with international standards. With the entry into force of SENASA Resolution 458/2025 and its amendment 843/2025, a key opportunity has opened up for companies seeking to register new or equivalent active substances, incorporating QSAR and in silico methodologies as valid tools within the regulatory process.
As of January 5, 2026, these provisions will be officially implemented, so preparing in advance is essential to avoid delays in registration.
A new approach to phytosanitary registration with SENASA
The updated regulations recognize the need to optimize evaluation times, reduce the use of animal studies, and strengthen science-based decision-making. In this context, SENASA adopts a Weight of Evidence approach, where all available information—experimental, bibliographic, and predictive—is integrated to support the toxicological safety of active substances.
This change positions QSAR studies and in silico methods as key components of the regulatory dossier.
Justification of impurities through QSAR studies
When evaluating an equivalent active substance, it is possible to identify:
- New impurities, or
- Impurity levels higher than those of the reference substance.
In these cases, Resolution 458/2025 allows the use of QSAR models to demonstrate that these impurities do not have more severe chronic effects than the parent substance. To do so, the analysis must be applied to at least two relevant chronic toxicological parameters, following robust scientific criteria.
This approach facilitates registration without the need to repeat extensive studies, provided that the technical justification is sound and aligned with international guidelines.
In silico alternatives for mutagenicity assessment
For new active substances, when in vivo studies are not available, SENASA accepts the use of alternative in silico or in vitro methods, provided that:
- Be recognized by international convergence regulatory authorities.
- They are accompanied by adequate technical and scientific justification.
This represents a significant step toward more ethical, efficient, and predictive assessments, without compromising the protection of human health or the environment.
Weight of evidence: fewer animals, more science
The regulation emphasizes the importance of integrating all available information to reduce or refine animal testing, prioritizing computational methods and modern approaches. This philosophy is aligned with international frameworks such as the SGA/GHS, promoting globally harmonized toxicological classification.
All studies submitted must be conducted under recognized protocols (OECD, EPA, EFSA) and supported by laboratories that comply with Good Laboratory Practices (GLP).
How can we help you?
At QSAR Analytics, we support the agrochemical and phytosanitary industry by:
- (Q)SAR studies to justify impurities under regulatory criteria.
- In silico assessments of mutagenicity and other toxicological endpoints.
- Analyses aligned with the Weight of Evidence required by SENASA.
Our mission is clear: to provide the world with safer molecules, helping our partners comply with regulations without resorting to unnecessary animal testing.
Are you interested in applying these approaches to your registry in Argentina?
If you are about to start or update a phytosanitary registration with SENASA, and you wish to integrate QSAR studies or in silico methodologies in accordance with Resolution 458/2025, we invite you to contact us using the form on our website.
Our team can guide you in building a solid, technically justified dossier that is aligned with the new regulatory requirements.