Denehurst Chemical Safety Ltd

Reduction in the use of laboratory animals is importand and ECHA guidance makes it clear that new testing on animals should only be considered if there is no alterantive.  Denehurst will help work towards finding alteranatives through computer modelling, read-across and other assessment methods.  Where possible, in-vitro testing must be performed. 


Denehurst has a very strict policy on animal testing and will discourage animal work unless there is no alternative and only if it not possible to waive such testing.  Justification for data waiving can be provided.

The first stage of any test programme is to ensure that such testing is justified and that alternatives such as modelling, read-across or use of published data are not possible.
Denehurst encourages clients to enter contracts directly with test laboratories to reduce unnecessary administrational work.  However, when requested, Denehurst can place test work on behalf of clients.
Modelling work and literature searches can be performed and it is essential that these options are explored before conducting new testing.
Denehurst has close links with major contract research laboratories involved with GLP and non-GLP chemical safety testing.  Services include advice on protocols, preparing contracts, monitoring test work and interpretation of data.  Data interpretation will include recommendations for CLP / GHS classification and labelling and for transport hazard class.
A table describing the key IUCLID 5 endpoints is provided below; this can be provided as a Word doc, together with short summaries for each type of test; please request by e mail to  


Link to Reduced Testing and Waivers page


Link to Animal Testing page 




This short guide has been provided to give a brief overview of the typical ‘base-set’ of testing needed to provide classification and labelling endpoints and to enable a reasonable risk assessment to be constructed.  A full list of OECD study types is described in Annex 1 of this document, but only key endpoint studies are covered in detail. 


Before considering the individual test methods, it is necessary to look at the studies in context of the ‘intelligent testing strategy’ that describes the order in which the testing should be performed.  Although each test is described separately, the results of one study can have a major impact on planning the next test – this is an essential part of constructing the intelligent testing strategy and such strategy is described in guidance provided by ECHA.   This basically means that you should resist the temptation  to place all studies in one go without waiting for the result of initial work. 


If you do not have data ready in time for registration, there is scope in IUCLID to state that testing is planned or underway.  Indeed, ECHA insist that you obtain permission for animal testing to prevent unnecessary duplication or in case opportunities to ‘read-across’ from other substances are missed.


In this guide, the methods are listed in order of the IUCLID 5 data entry ‘end-points’ and cross-references given to OECD numbers and EU Annex V test methods (Annex V to Directive 67/548/EEC).  The list at the end of this guide places the study types in OECD number order to allow easier cross-referencing.


Guidelines and GLP

Guidelines are provided by ECHA and have not changed from the methods described under Annex V of Directive 67/548/EEC, but are not provided in Regulation (EC) No 440/2008, published in May 2008.


Full regulatory testing for environmental and health effects must be performed compliance with international Good Laboratory Practice (GLP). However, older test reports for animal studies that were not performed to GLP can be accepted under certain circumstances if it can be demonstrated that repeating animal work can be avoided.


Chemical identity and physico-chemical properties do not need to be performed to GLP.


Intelligent test strategy


A large amount of guidance has been provided to cover what is known as the ‘intelligent test strategy’ to ensure that animal testing is minimised through stressing the importance of using existing data, modelling and read-across techniques.  This is found along with the risk assessment and exposure guidance (Chemical Safety Report and Exposure Scenario) on the following ECHA link:



Each of these end points are described  in detail in the later section on laboratory testing and on data evaluation. 


Note that all end-points in each respective tonnage band must be assessed either by testing, consideration of non-test data (modelling etc) or by exposure consideration.  Certain studies may be impossible or irrelevant according to the nature of the substance; for example, biodegradation cannot be performed on inorganic substances. 



IUCLID endpoint

Key studies



Recommended for all registrants

The first set of studies are typically necessary for transport classification as a minimum

Section 1

Product characterisation, spectra, analysis etc


Required for all registrants, including those involved in joint registrations













Physical state

Melting point/setting point

Boiling point

Relative density

Water solubility – assess


Flash point*



Autoflammability (self-ignition)*

Oxidising properties (solids)*

Particle size (granulometry)



DSC analysis usually sufficient.  May indicate purity.

DSC analysis. May indicate purity.


Initial rough check – will determine further testing

Stability in water also needs assessing

Essential for substances liquid below 60°C

Essential for substances solid below 60°C

Structure analysis as a minimum

Test if chemical structure or DSC indicates concern

Structure analysis as a minimum

Solids only – indicates need for inhalation toxicity




Required for 1 – 10 tonnes

The results of the first set are necessary to plan these studies in phase 2

Phase 2 end-points are needed to allow full use of models and to allow a reasonable level of confidence for read-across as well as enabling planning for further tests.
























Vapour pressure



Water solubility


Surface tension in water



Partition coefficient*


Skin irritation*

Eye irritation*

Skin sensitisation*


Bacterial gene mutation (Ames test)


Acute toxicity (oral ?)*


Daphnia immobilisation*


Inhibition to algae*


Ready biodegradation*

May not be required if boiling point is over 200°C.  Results will help predict inhalation risk or environmental fate.

Normal to assess to 1 mg/l minimum by analysis.

Will impact on further testing.  Check stability.

Only possible to perform satisfactorily if water solubility is above 10 mg/l.  Will impact on partition coefficient.

Key study for environmental fate.  Difficult to assess if surface active

In-vitro.  Animal work only if results negative.

In-vitro.  Animal work only if skin results negative.

Mouse local lymph node assay preferred.  Old guinea pig studies accepted if positive

The first level of mutagenicity assessment – a positive result will lead to further immediate testing

Unless a gas, or under other exceptional circumstances, oral administration is the first method

Easiest (cheapest) of the short-term environmental effects end-points

Consider results of other end points to assess biological activity potential

Water solubility, stability and vapour pressure will help determine the method.  Check for biocidal properties; eg results of bacterial gene mutation or bacterial (sludge) inhibition study


Required for 10 – 100 t

These tests should only be performed after considering results of phase 1 and 2 evaluation.



























Acute toxicity (inhalation or dermal)*

Skin irritation*

Eye irritation*

In vitro cytogenetic (mutagenicity)

In vitro gene mutation, mammal cells


Sub-acute toxicity (28 day)*



Reproduction screen


Abiotic degradation (hydrolysis)






Short term fish toxicity*

Bacterial inhibition



Adsorption screening




Choice of route determined by risk of exposure

Animal work only if in vitro results negative.

Animal work only if skin results negative.

For example, chromosome aberration

Choice of method determined by results of bacterial gene mutation (Ames)

Typically oral, gavage, but other routes and methods may be considered in view of potential exposure risk.  Consider 90 day (8.6.2) if > 100 tonnes.

Required if insufficient evidence form sub-acute study or from modelling and other assessments.  Indication of stability should be assessed early in the programme, and analysis from Daphnia or algal studies will indicate problems.  Only possible to  perform if water solubility is > 10 mg/l. Attempt to identify the degradation products.


Consider stability and vapour pressure for planning

This study can be performed before the ready-biodegradation test as an initial check on biocidal properties.  Results also link to cytotoxicity in mutagenicity testing and algal inhibition.

Basic HPLC method based on results of partition coefficient and structure analysis.  Full soil study if indication of high risk of soil contamination.



Toxicokinetic assessment

Use all available information derived by this stage to construct scientific assessment of behaviour in biological systems.  Essential conclusion to the robust summary.  Up-date if further testing performed after this stage


> 100 tonnes or as a result of adverse findings in earlier phases

These studies must not be performed without due consideration of exposure risk as a result of conclusions determined from the Chemical Safety Assessment.

Proposals for animal tests must be submitted to ECHA




























Solvent stability


Dissociation constant




In-vivo mutagenicity*




Sub-chronic mammalian toxicity*



Teratogenicity (rat or rabbit)*


One or two generation toxicity studies*


Toxicokinetic testing - ADME





Carcinogenicity studies*





Consider if breakdown in polar or non-polar solvents is likely from structure analysis

Consider if reasonably soluble in water and if structure analysis suggests dissociation.  Check pH.

For liquids where there is a risk of aspiration hazard (inhalation of low viscosity liquids)

As well as further in-vitro studies, in-vivo methods can be considered if results of earlier testing show positive or equivocal results or if very high exposure predicted to the consumer.

Typically 90 days.  Route determined by risk factors, but usually oral.  May be considered instead of earlier 28 days study if high volumes to be registered.

Pre-natal development.  Consider if high exposure to consumers

Reproduction studies are necessary for high exposure substances, especially if supplied to consumers. 

Metabolism studies (Absorption, Distribution, Metabolism and Excretion) should be performed to assess possible elimination and accumulation effects in mammals.  This may preclude chronic testing if removal is evident.

A full 2-year chronic / carcinogenicity needs to be considered if high exposure and if results of other studies, for example mutagenicity, suggest a cause for concern.



Exposure –based studies

Consider only if there is risk of exposure to the aquatic or terrestrial environment due to high levels of use, exposure scenarios, or as a result of biodegradation, solubility, stability or partitioning results













Environmental effects studies*





Inherent and soil biodegradation*






Terrestrial testing



A range of long-term and reproduction studies can be performed on fish or other aquatic organisms to examine chronic or life-cycle effects. Consider if high exposure to aquatic or marine environments or if poorly degradable in water.

Various methods possible to determine if there is a problem with persistence.  Consider if there substance is a candidate for vPvB or PBT.

Consider if partition coefficient is > log 4 and if poor biodegradability.  Not relevant if molecular weight above 1000. 

Soil organisms, plants and even birds can be tested, but only consider if there is a high risk of exposure to the soil and the substance is poorly degradable.


Advice and training on testing strategies and monitoring laboratory test work


Note that Denehustr does not provide testing services, but can advise on suitable laboratories and can provide services to help plan testing, monitor studies and interpret test results.


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