Method ··············································································································

In order to maintain consistency with the previous studies conducted the method described by Taylor et al (2014) was followed as much as possible; this method is described below.

Step 1.1 Initial selection of the dataset

A property search of the OEC ’s eChem ortal (www.echemportal.org) was undertaken to identify those chemicals for which there was both 28- and 90-day repeat dose data. The initial search was undertaken using eChemPortal as performing a property search of the ECHA CHEM database was not possible at the time. However, the ECHA CHEM database is the main provider of property data to eChemPortal, therefore, a search of eChemPortal was effectively a search of the ECHA CHEM database. In order to undertake the search of eChemPortal the procedure below was followed:

1) ‘ roperty search’ was selected

2) Under the subheading ‘Toxicological information’ ‘repeated dose toxicity:oral’ was selected

3) On the Query Block page that opens the search criteria input included:

a. Under the ‘Study result type’ dropdown menu only the box marked ‘experimental result’ was checked

b. Under the ‘Test guideline, uideline’ dropdown menu the following boxes were checked

i. EPA OPP 82-1 (90-day oral toxicity)

ii. EPA OPPTS 870.3100 (90-day oral toxicity in rodents) iii. EPA OPPTS 870.3150 (90-day oral toxicity in non-rodents)

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iv. EPA OTS 798.2650 (90-day oral toxicity in rodents)

v. EU Method B.26 (sub-chronic oral toxicity test: repeated dose 90- day oral toxicity study in rodents)

vi. EU Method B.27 (sub-chronic oral toxicity test: repeated dose 90- day oral toxicity study in non-rodents)

vii. OECD guideline 408 (repeated dose 90-day oral toxicity in rodents) viii. OECD guideline 409 (repeated dose 90-day oral toxicity in non-

rodents)

4) The search criteria were then saved by pressing ‘Save’ and the query was subsequently executed by pressing ‘Execute Query.’

Step 1.2 Inclusion criteria

A manual analysis was then conducted on the initial dataset to identify those chemicals that had oral, rat experimental data for both 28- and 90-day studies. This process involved opening the hyperlink in the ‘Results’ column for each chemical individually. n every case the results were held in the ECHA CHEM database. Chemicals for which there was no 28- or 90-day experimental study data, i.e. read across was used or no studies were included, were rejected at this stage.

Step 1.3 Exclusion criteria

The dataset was then reviewed to exclude all chemicals that had a ‘Key study’ with a No Observed Effect Level (NOEL) or NOAEL value of less than 1000mg/kg bw/day. Importantly, if a chemical had a NOAEL of 1000mg/kg bw/day but the NOEL value was lower these chemicals were also excluded. Additionally, where multiple key studies were present a chemical was excluded if any rodent study had a NOAEL below 1000mg/kg bw/day.

52 Step 1.4 Quality of data

Subsequently, the dataset was reviewed to remove those chemicals with poor quality data for either the 28- or 90-day studies. The criteria as to what constituted poor quality data, in the context of this study, are as follows:

 Any study which did not follow the OECD (or equivalent) guidelines for 28- or 90-day repeat dose testing with regards to duration, species, number of animals or main parameters measure were excluded.

 The study was not conducted up to the limit dose of 1000mg/kg bw/day.

 The study was conducted prior to 1981, as this was when both the OECD test guidelines were introduced.

 A study equivalent to the OECD guidelines but given a Klimisch score of 3 or 4 for any reason.

Step 1.5 Acute toxicity profile

Finally, chemicals were excluded if they did not have toxicity data conducted within acute toxicity, skin or eye irritation, skin sensitisation, or genotoxicity studies.

However, in order to perform the analysis in this chapter a few minor alterations to the method set out by Taylor et al (2014) were required. These alterations were required due to the variations in data held within the COSMOS database compared to eChemPortal, these being: the extraction of Highest No Effect Level (HNEL) data, as opposed to NOAEL data; a study completeness Klimisch score of ‘A, B or C’ (as defined in the COSMOS database) was accepted in instances where only one HNEL value was present; and no acute toxicity profile was gathered. The alterations were necessary as 1) the current version (v1.0) of the COSMOS database does not contain NOAEL data; 2) if more than one HNEL value above 1000mg/kg bw/day was present the value with the highest Klimisch score was used; and 3)

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information pertaining to acute toxic, skin/eye irritation, skin sensitisation and/or genotoxicity was not available for every chemical.

Step 2 Development of the 28- and 90-day repeat dose study dataset from the COSMOS database

The initial search of the COSMOS database was undertaken using the search term ‘C’. Within the COSMOS database the search term ‘C’ identifies all chemicals containing a carbon atom. Additionally, queries were added to identify chemicals that also had a short- term and/or subchronic toxicological studies associated with them; returning a total of 618 chemicals. However, the majority of these chemicals contained only one study and were, therefore, disregarded at this stage. Subsequently, each chemical with more than one study in the ‘# studies’ column was manually analysed in order to identify those chemicals containing toxicity data for both 28- and 90-day repeat dose studies conducted via the oral route in rats; reducing the dataset to 54 chemicals. The data gathered at this stage are available in the Appendix for this chapter (Appendix I). Further analysis was undertaken on the dataset to remove those chemicals that did not have a HNEL value at 1000mg/kg bw/day or greater for both the 28- and 90-day repeat dose study durations; reducing the final dataset to nine chemicals, constituting 15% of the dataset that contained both 28- and 90-day repeat dose study data (Table 2.3). This is in keeping with the previous studies conducted, whereby Taylor et al and the HSE identified 10% and 15%, respectively, of the original chemicals were present in the final dataset as having both 28- and 90-day repeat dose study data with a NOAEL value at, or greater than 1000mg/kg bw/day.

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Table 2.3: A comparison of the 28- and 90- day repeat dose studies with Highest No Effect Level data at, or greater than 1000mg/kg bw/day

Chemical name COSMOS ID Short-term toxicity study value (mg/kg bw/day) Length of short- term toxicity study (days) Sub-chronic toxicity study value (mg/kg bw/day)

Length of sub- chronic toxicity study (days)

Is the short-term study protective of sub-chronic study? Hydroxypropyl Methylcellulose CMS-7567 HNEL 10,000 30 HNEL 2339 HNEL 5000 HNEL 6500 HNEL 7700 HNEL 505 90 90 90 90 91

Yes (if using Weight of Evidence)

No (if using most protective value)

Ascorbic acid CMS-108 HNEL 10,000 28 HNEL 2500 90 Yes

Glycyrrhizin, ammoniated CMS-8524 HNEL 1000 HNEL 1000 30 35 HNEL 500 90 No Sucrose acetate isobutyrate CMS-5115 HNEL 2226 HNEL 2592 28 28 HNEL 5300 91 Yes

Maltodextrin CMS-5576 HNEL 10,000 30 HNEL 3882 90 Yes

Butyl acetate CMS-1941 HNEL 2000 28 HNEL 600 90 No

Hydroxypropyl cellulose

CMS-10327 HNEL 6000 30 HNEL 5000 90 Yes

Potassium bicarbonate CMS-1189 HNEL 2132 HNEL 4000 28 28 HNEL 1482 HNEL 2000 91 91 Yes Polyethylene, oxidised CMS-34680 HNEL 4650 32 HNEL 5000 HNEL 5000 90 90 Yes

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