Formulated products also need characterization. Formulations are mixtures that contain one or more active ingredient as well as other ingredients. Formulations may be solids, such as dusts, granules or pellets, wettable products that require combination with a liquid (usually water), liquids such as emulsions or solutions, or aerosols and fumigants, which are gases. Formulations are tested for active ingredient content, impurities and other entities such as stabilizers or emulsifiers. The tests conducted on formulations depend on the formulation type, nature of the product, the application concentrations, the number and identity of active ingredients, and the analytical methods available.
Different types of formulation need to be handled, prepared and applied in specific ways. Understanding the technical characteristics of a formulation can identify possible handling and application issues, for example, risks related to applicator exposure or preparation issues such as excessive foaming when mixed. They can also pose unique challenges in assessing required endpoints.
How to approach testing for formulated agrochemical products
Active ingredients are used in formulations that contain other ingredients such as emulsifiers. The presence of these additional chemicals and the nature of the formulation can pose specific challenges for physicochemistry testing. Selecting appropriate validated analytical methods is one critical aspect and much depends on the formulation itself. Understanding the potential pitfalls is key to designing an appropriate testing strategy.
There are multiple things to consider: How do you determine the best way of establishing technical characteristics? What is required for different types of products, pesticides, conventionals, biopesticides and biocides? What endpoints are needed for different types of formulations? How do you handle different formulations for test purposes? What duration is appropriate for stability assessment of your formulation? How does the stability of individual elements in the formulation change with temperature, light or humidity, and how does this influence stability test design?
Experience with all types of formulations for all types of pesticide products
Covance has experience working with all manner of pesticides; conventional herbicides, fungicides and insecticides and biocidal products – and all types of formulations; solids, liquids and gases. We have worked with many difficult-to-handle materials such as insoluble molecules and UVCBs. This range of experience has given us vast scientific insight and practical expertise in technical characterization of formulations.
Standard physicochemical tests for formulated plant protection products
There are a variety of physicochemical tests required for formulated products. These depend on the type of formulation. Standard test available (but not limited to) include:
- Persistent Foaming
- Relative Density
- Bulk and tap density
- Corrosion to metals
- Low temperature stability
- pH and Acidity/Alkalinity
- Dilution Stability
Hazardous properties testing for formulated products
A range of hazardous endpoint tests are required for formulated products; some are similar to those for active ingredients. It is possible to evaluate these endpoints based on structural alerts and experience in handling similar test formulations. Tests for hazardous properties including:
- Explosive properties
- Oxidising properties
- Self-reactive substances
- Flammability Studies
- Pyrophoric properties
- Organic peroxides
Identification of technical characteristics for formulated products
The tests used for technical characterizations of formulated products depends on the formulation and the type of product. Our suite of tests covers the following endpoints for conventional pesticides including:
- Suspensibility, spontaneity and dispersion stability
- Wet sieve and dry sieve
- Emulsion stability
- Disintegration time
- Particle size, dust content and attrition, friability
- Persistent foaming
- Flowability, pourability and dustability
- Burning rate
For biocidal product formulations, some alternative tests may be required for endpoints including:
- Spraying pattern
- Physical and chemical compatibility
- Degree of dissolution and dilution stability
Storage stability testing tailored to your needs
Our facilities enable testing under a range of conditions by varying humidity, light and temperature. Covance can perform accelerated or long-term storage stability tests, dependent on the product and formulation:
- Accelerated tests are performed at various temperatures and durations, depending on the stability of the active ingredient or co-formulants
- Long-term storage tests are performed at ambient temperature (typically 25°C), generally for 2 years
For both tests, active ingredient analysis is performed at each timepoint. To replicate real life, samples are stored in commercial containers, where possible.