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Physical and Chemical Properties

Identity and physical and chemical properties of the active substance and formulation

The following page is intended to provide guidance to applicants on the requirements for the chemical and physical properties of active substances and preparations as regulated by Regulation (EC) No 1107/2009. In addition to consulting the below guidance and resources applicants should check that their applications are complete using the Chemistry section of the common omissions checklist.

Active substance

For each source of an active substance a technical specification is required. The technical specification details:

  1. The minimum content (g/l or %w/w) of the pure active substance; and,
  2. The nature and maximum levels (g/l or %w/w) of all the impurities, isomers or additives present at or greater than 0.1% of the total content of the active substance (ie those impurities deemed significant). There may also be a specific requirement to set a maximum level for certain toxicologically relevant impurities that are present at less than 0.1% w/w. Significant and relevant impurities are discussed further in the following document:

    Guidance document on the assessment of the equivalence of technical materials of substance regulated under Regulation (EC) No 1107/2009, SANCO /10597/2003 – rev. 10.1 ) (see resources below)

A ‘source’ refers to a technical material manufactured by a specific process in a particular location (see what is a source? below) and is described by an individual technical specification and its supporting data package. A number of sources may be approved for an individual active substance based on different supporting data packages. In addition a number of sources of an active substance may be approved in a product.

All technical specifications must be supported by batch data and validated methods of analysis (see Technical Material and Preparations: Guidance for generating and reporting methods of analysis in support of pre- and post-registration data requirements for Annex II (part A, Section 4) and Annex III (part A, Section 5) of Directive 91/414. (SANCO/3030/99 rev.4 - see resources below) so that we can ensure the technical specification reflects the minimum level of the active substance and the maximum levels of impurities found in routine manufacturing.

What is a source?

The source is dependent on many factors, including the manufacturing location, manufacturing process, and scale of manufacture. If any of these factors change, then the source is considered to have changed and it is necessary to provide data to support the new source or a reasoned case as to why data are not required. If the new source is different to that which is authorised, an assessment of equivalence to the reference source (usually that considered for approval of the active) is required, and it may be necessary to amend the technical specification in line with the new source.

What constitutes a change to the technical specification?

Various changes can impact upon the composition of the technical specification (eg change of method of manufacture, moving from pilot plant to full production and improved methods of analysis).

How do we assess technical equivalence?

In all instances we determine technical equivalence in accordance with the Guidance document on the assessment of the equivalence of technical materials of substance regulated under Regulation (EC) No 1107/2009 (SANCO 10597/2003) (see resources below). This approach is used both at Step 1 of re-registration (to confirm existing approved sources comply with the conditions of approval under Regulation (EC) No 1107/2009) and to assess the acceptability of new sources.

Where a technical equivalence check is conducted, we will complete an Equivalence Report which is made available to competent authorities in other Member States.


The formulation details of a product/preparation consist of the technical specification and the formulation ‘recipe’. The formulation recipe consists of:

  1. The nominal target content for the pure active substance, with acceptable tolerance limits in line with FAO guidance (Manual on development and use of FAO and WHO specifications for pesticides, November 2010).
  2. The chemical name, trade name and/or CAS number, structure and quantity of all other components (the co-formulants) in the formulation.

Further guidance on the chemical and physical data required to support the registration/authorisation of a preparation are available in:

Guidance document for the generation of data on the physical, chemical and technical properties of plant protection products under Regulation (EC) No. 1107/2009 of the EU Parliament and Council on placing plant protection products on the market. (see resources below)


Updated 2016-10-05