Storage Stability Data In Agricultural Chemical Products

Dr Yasser Sokeirik

Agricultural chemical products can undergo chemical and physical changes on storage. When registering products in Australia the APVMA (Australian Pesticides and Veterinary Medicines Authority) requires evidence that the product will remain fit for use and any changes in the storage environment will not produce adverse effects when using the product.

The APVMA provides extensive advice on:

  • trial design,
  • technical characteristics of product types,
  • and parameters to be tested in trials

Like all Regulatory Authority advice it has to be generic in nature, however in our experience, agricultural products rarely follow this generic path.

There are key areas which need close attention to ensure that the storage stability is performed in agreement with the APVMSA guidelines.

  1. The size of the tested batch: stability testing should be conducted on laboratory, pilot or production scale batches of the product. The minimum production size of the batches used in stability trials is normally 5 kilograms or 5 litres, but is product and production size dependant. Full data about this batch should be recorded and presented with the stability trial.
  2. Correct choice of the stability trial conditions: The FAO/WHO pesticide specifications recommend testing of the relevant product parameters before and after storage at 54 ˚C for 14 days. However, for preparations that may not be stable at 54 ˚C for 14 days, the trial can be performed at lower temperature for extended time. The real time testing at room temperature is required only in certain cases when the accelerated stability test is not enough to address the stability of the formulation.
  3.  Container: It is necessary to carry out the stability trial in a suitable  container. The packaging material and size should be considered carefully to address the stability of the final container of the commercial product. The effect of the formulation on the primary pack and vice versa is important. Containers should be examined to ensure that no significant interaction with the formulation (affecting the stability or integrity of the packaging material) has taken place during storage.
  4. Stability parameters: It is necessary to test all the parameters relevant to the formulation type as indicated by the APVMA before and after the storage period. Failing to test all parameters may result in adding some label statements to address the missing parameters or even to repeat the stability trial to test these parameters. The parameters should be tested in accordance to the recommended standard methods (CIPAC, OEDC, etc.)
  5. Analytical method: the full details of the analytical method used to monitor the product during the stability trial should be provided. In addition, the validation data which confirm the reliability and the accuracy of this analytical method should be provided as well.

It is necessary to have the stability trials done in accordance with the correct guidelines. Trial protocols and draft test reports should be reviewed by an experienced regulatory expert to avoid any mistakes that could lead to a regulatory problem during the product registration, and hence costly delays.

At DTS, we offer this service as a part of the product development plan. We believe that early engagement of a regulatory expert in the data package development is the best solution to avoid issues during the regulatory registration process.