Improvement of the ISO 10634 guidance document for the preparation and treatment of poorly water-soluble organic compounds for the evaluation of their biodegradability in aqueous media

Abstract : Current regulations on chemicals in most regions of the world recommend or require the assessment of biodegradability. It is commonly agreed that the assessment of biodegradability starts with a ready biodegradability test. To perform these tests, the recommendations of the ISO standards or OECD guidelines should be followed. Nevertheless, relevant infomation is missing when the chemical under test is not soluble in water. Since 2011, L'Oréal has worked on the preparation techniques in order to incorporate this type of compound in the media before the test. The systematic review of ISO 10634 standard dealing exclusively with this subject, was found as a good opportunity to disseminate the work carried out in this context. The recast of this standard is based on the updating of the methods already described as well as the proposal of new adapted methods. These bioavailability improvement methods in ready biodegradability tests were discussed to AFNOR and ISO working groups in order to revise the document ISO 10634. The performed experimental work made it possible to propose new bioavailability improvement methods and an subsequent update of ISO 10634 standard. This revised standard will make available to CROs all the information needed to improve the assessment of the readily biodegradability of water-insoluble chemicals. If the modification of an existing standard may seem long (several years), this must be put into perspective given the necessary scientific and bibliographic work and discussion between experts within the ISO/TC 147/SC5/WG 1. A new version of the 10634 ISO standard is expected to be published in 2018.