Guidance on quality requirements for biocides: Stability and shelf life

On this page

• Application requirements
• Conducting stability studies
• Referencing another biocide

Application requirements

You are responsible for ensuring that:

• you have information to support your biocide's quality (including stability)
• specifications and master formula for your biocide are established, followed and maintained (as defined in subsection 1(1) of the regulations)

Some biocides have more risk or uncertainty associated with them than others. For these biocides, we require that the initial application include stability data. This data is needed to demonstrate that the biocide's benefits continue to outweigh its risks throughout its shelf life considering related uncertainties.

Biocides that require stability data in their initial applications are those that are:

• not for household use only or
• for household use only and 1 or more of the following applies:
  • have a shelf life less than 1 year
  • packaged in a quantity greater than that which may reasonably be expected to be used within 1 year after it's sold
  • contain a novel active ingredient
  • contain an ingredient with known stability issues
    • for example, high rate of degradation, such as hypochlorous acid

Conducting stability studies

You can determine the shelf life and expiry date of your biocide by conducting stability studies and considering how your biocide degrades. New chemicals (including impurities) can form as ingredients degrade, which can affect the benefit-risk profile of your biocide.

You can determine the shelf life of your biocide by using either:

• stability studies or
• an identical comparison product

You should maintain records of the results and conclusions from stability testing for either:

• 6 years after the day you sold the biocide (if you are not aware of the shelf life) or
• at least 1 year after the last day of the month the shelf life expires for the biocide

You should also re-evaluate your biocide's shelf life when there are changes to, for example, the:

• facility
• equipment
• formulation
• raw material supplier
• manufacturing process
• packaging material or composition

If your biocide's composition changes or no longer meets your approved specifications, it could affect your biocide's safety, efficacy and quality. Your biocide should have a shelf life of at least 6 months, as products are generally not expected to be used within 6 months after manufacturing. However, a shorter shelf life may be acceptable if supporting information is provided on its suitability.

Stability testing should show:

• how long your biocide is able to remain within its approved specifications when stored appropriately (according to the directions for storage on the label)
• how your biocide's composition changes (or doesn't change over time), as a result of:
  • environmental factors
    • such as temperature, humidity, light
  • the packaging material
    • the container closure system
  • intrinsic factors
    • such as ingredient interactions, degradation, natural spoilage

Good laboratory practice

When testing for stability, you should use good laboratory practice (GLP). This will help to ensure your data is of high quality and is reliable.

Choose a testing laboratory that complies with our GLP compliance requirements. There are many test laboratories in North America that are able to conduct tests that meet these requirements.

Other types of GLP compliance standards include those published by the:

• Organisation for Economic Co-operation and Development (OECD)
• United States Environmental Protection Agency (US EPA)

For non-GLP compliant stability data, you should ensure that your chosen alternate standard are equivalent to GLP certification. F or example, certain International Organization for Standardization (ISO) certification standards are equivalent. This scenario is more common for testing done by European laboratories.

If you propose to use non-GLP compliant data (for example, non-GLP studies or GLP studies with outages), we will assess whether the deviations from GLP or alternative standards are acceptable. You should include rationales to demonstrate:

• how the alternate standards differ from GLP standards
• how they meet alternative standards
• your use of non-GLP compliant testing

We will assess whether the deviations from GLP or alternative standards are acceptable. While we will consider all rationales, we cannot guarantee that we will accept the submitted data.

Contact us if you want to verify the acceptability of your non-GLP compliant data prior to submitting your application.

Testing method

Your stability testing methods should include:

• at least 1 primary batch of the biocide at each strength manufactured and
• be packaged in each type of primary biocide packaging proposed for marketing

Testing of only the smallest package of the same construction and material would be acceptable for most products. If you plan to only test the smallest package size for stability, it is recommended to confirm the acceptability of the stability protocol with us prior to initiating the testing.

There are different test methods for stability testing. You can find details of stability testing options in Table 1. At each test point, you should determine:

• the concentration of every active ingredient
• any deterioration or degradation of the biocide during the test period

Data collection

All stability studies should use at least 1 batch of the same biocide product for each data collection stage.

Table 2: Stability testing for biocides

Type of testing	Conditions	Duration	Frequency	Shelf life
Real time (ambient temperature)	20°C or 25°C relative humidity 50%	Proposed shelf life	0, 3, 6 and 12 months	Equal to the test duration
Real time (warehouse conditions) Supplementary	Expected warehouse and storage temperature extremes (such as 0°C to 50°C)	at least 6 months	Every 6 months after for studies that are longer than a year
AcceleratedFootnote 1	54°C	14 days	0 and 14 days	1 year
AcceleratedFootnote 2 for 1 of these conditions and their corresponding duration and frequency	54°C	14 days	0 and 14 days	2 years
	50°C	4 weeks	0, 4 weeks
	45°C	6 weeks	0, 3, 6 weeks
	40°C	4 months	0, 2, 4 months
	40°C	6 months	0, 3, 6 months	3 years
	35°C	9 months	0, 3, 6, 9 months
Note, if the directions for storage on the label indicate storage at freezing temperatures, additional information may be required to confirm stability using freeze-thaw stability testing. Footnote 1 This can be considered instead of a study at real time. Return to footnote 1 referrer Footnote 2 You should commit to provide real-time stability studies following authorization to supplement accelerated studies. Return to footnote 2 referrer

Performance standard for significant change

Results of your stability testing should consider any significant changes to your tested batches and to its active ingredients. Significant changes can depend on the nominal concentration of the product:

• nominal concentration less than or equal to 1.0%, N plus-minus 10%
• 1.0% less than nominal concentration greater than or equal to 20.0%, N plus-minus 5%
• 20.0% less than nominal concentration greater than or equal to 100%, N plus-minus 3%

At the end of the test period, you should also examine for other significant changes, such as:

• pH
• changes to the container
  • appearance and functionality
• change in physical properties
  • phase separation or "clumping"
• any changes that would interfere with the usefulness or safe handling of the biocide if used according to the label directions
  • for example, total moisture loss from towelettes

Significant changes such as these may indicate failed stability, which would have a major impact on the quality of the biocide. Thus, you would need to file a post-authorization application for a major change to change your biocide's shelf life and specifications, as appropriate.

More information can be found in the post-authorization changes for biocides guidance.

Referencing another biocide

You can also determine your biocide's shelf life using information from other sources, when appropriate. You may be able to use this flexibility if you're proposing the same shelf life for an identical biocide (for example, has the same formulation or similar formulation with the only difference being in the fragrance and dyes under 1% weight per weight (w/w), packaging and manufacturing process).

In these situations, your application should include information that shows the proposed biocide is comparable to the referenced biocide, including its stability.