4.3 Etofenprox

Part B - Final decisions on matters not referred to an expert advisory committee

4. Delegate-only decisions on agricultural and veterinary chemicals

4.3 Etofenprox

On this page: Delegate's final decision | Applicant's scheduling proposal and reasons for proposal | Current scheduling status | Scheduling history | Australian regulations | International regulations | Substance summary | Delegate's considerations | Delegate's final decision

Delegate's final decision

Applicant's scheduling proposal and reasons for proposal

In November 2017, the Australian Pesticides and Veterinary Medicines Authority (APVMA) submitted a proposal not to include etofenprox in any schedule in the Standard for the Uniform Scheduling of Medicines and Poisons (SUSMP) - the Poisons Standard.

The applicant's reasons for the request are:

• The available toxicological data for etofenprox is considered to be sufficient for the purposes of recommending a scheduling decision.
• The Advisory Committee on medicines Scheduling (ACCS) may consider that the toxicity hazard profile for acute exposure to etofenprox does not warrant a schedule.
• Etofenprox is available in the European Union (EU) as an agricultural insecticide.
• Etofenprox is a non-ester pyrethroid insecticide with comparable toxicity and a similar mode of action to other pyrethroids.
• ACCS has never previously considered a non-ester type pyrethroid insecticide.

Current scheduling status

Etofenprox is not currently scheduled and has not been previously considered for scheduling. Therefore a scheduling history is not available.

Australian regulations

Etofenprox is not currently approved in Australia.

Etofenprox does not appear to be in any products on the Australian Register of Therapeutic Goods (ARTG).

Etofenprox does not appear in the current Therapeutic Goods (Permissible Ingredients) Determination No. 4 of 2017.

International regulations

• USA: Etofenprox was listed as a pesticide by EPA in the USA in 2007 under the Federal Insecticide, Fungicide and Rodenticide Act (EPA-HQ-OPP-2007-0804).
• Canada: Etofenprox was granted full registration in Canada for the sale and use of etofenprox-containing products.
• EU: Etofenprox is approved for use by ECHA as a biocidal active substance with hazard classifications that etofenprox is very toxic to aquatic life, very toxic to aquatic life with long lasting effects and may cause harm to breastfed children.

Substance summary

Table 4.3.1: Chemical information for etofenprox

Property	Etofenprox
Chemical structure
Molecular formula	C25H28O3
CAS names	1-[[2-(4-ethoxyphenyl)-2-methylpropoxy]methyl]-3-phenoxybenzene
CAS numbers	80844-07-1
IUPAC and/or common and/or other names	2-(4-ethoxyphenyl)-2-methylpropyl 3-phenoxybenzyl ether; ethofenprox; MTI-500

Table 4.3.2: Acute toxicity end-points for ETOFENPROX

Toxicity	Species	Etofenprox	SPF (2015) Classification[2]
Acute oral toxicity LD50 (mg/kg bw)	Rat	> 2000	-
	Dog	> 5000	-
Acute dermal toxicity LD50 (mg/kg bw)	Rat	> 2000	-
Acute inhalational toxicity LC50 (mg/m3/4h)	Rat	> 5880	-
Skin irritation	Rabbit	Not irritating	-
Eye irritation	Rabbit	Not irritating	-
Skin sensitisation (GPMT)	Guinea pig	Not sensitising	-

Etofenprox is a pyrethroid-like insecticide, which has activity via contact or ingestion against a range of insect pests. In the EU, the product has been approved for insecticidal control in many crops including rape (canola), cabbage, grapes, peach and apples.

Toxicology data on etofenprox were submitted with the application and have been assessed by ECHA/ EFSA, and publically available reports are available, including the EFSA review, and etofenprox Draft Assessment Reports (DAR) 2007. Following initial appraisal of the submission in 2003, further data were supplied and assessed in 2007-11 and 2016 to allow completion of EU registration. Etofenprox has been reviewed by JMPR (Etofenprox 184 - toxicology and residues).

*Scheduling Policy Framework for Medicines and Chemicals (SPF, 2015)

Acute toxicity

Based on the available data from studies done according to OECD guidelines, etofenprox has low acute oral, dermal and inhalation toxicity in rats.

Skin and eye irritation

OECD guideline-compliant studies in rabbits showed that etofenprox is not a skin or eye irritant.

Sensitisation

In an OECD guideline-compliant study, etofenprox was not a skin sensitiser using the guinea pig maximisation test.

Repeat-dose toxicity

In a 28-day dermal toxicity study in rabbits, the NOAEL was 1000 mg/kg bw/d, the highest dose tested.

The liver is a common target for toxicity in mouse, rat and dog. The liver, kidneys and haemo-lymphoreticular system were target organs in the mouse. The liver and thyroid gland were target organs in rats.

In a 90-day dietary toxicity study in mice, the NOAEL was 375 mg/kg bw/d, based on increased mortality and reduced body weight gain, minor haematological effects, histopathological alterations indicative of kidney damage, and minor changes in the liver at 1975 mg/kg bw/d.

In a 90-day dietary toxicity study in rats, the NOAEL was 20 mg/kg bw/d, based on liver toxicity (hepatocyte enlargement and clinical evidence of liver dysfunction affecting fat metabolism and synthesis of clotting factors) and thyroid toxicity (increased number of micro-follicles and reduced circulating T4) at 120 mg/kg bw/d.

In a 1-year dietary toxicity study in dogs, the NOAEL was 32.2 mg/kg bw/d, based on hepatotoxicity, including increased liver weights and histopathological alterations at 339 mg/kg bw/d. The effects were reversible.

Neurotoxicity

There was no evidence that etofenprox was neurotoxic in rats in an acute neurotoxicity study, or in a 13-week neurotoxicity study, or in a neurodevelopmental toxicity study.

Mutagenicity, Genotoxicity and Carcinogenicity

In an adequate range of in vitro and in vivo assays, there was no evidence that etofenprox is mutagenic, genotoxic or carcinogenic in mice and rats. JMPR concluded that etofenprox is unlikely to pose a carcinogenic risk to humans at dietary exposure levels.

Reproduction and developmental toxicity

No reproductive toxicity was observed in two multi-generation reproduction dietary studies in rats at doses up to 246 mg/kg bw/d or by gavage 5000 mg/kg bw/d by gavage. The NOAEL for parental toxicity was 37 mg/kg bw/d based on reduced body weight gain and histopathological findings in the liver, kidneys and thyroid at 246 mg/kg bw/d.

In two oral gavage developmental toxicity studies in rabbits, the overall NOAEL for developmental and maternal toxicity was 100 mg/kg bw/d based on reduced maternal body weight gain and feed consumption on the first day of dosing (gestation day 6), mortality and increased post-implantation loss at the high dose of 250 mg/kg bw/d.

JMPR concluded that etofenprox is not teratogenic in rats or rabbits.

Delegate's considerations

The delegate considered the following in regards to this proposal:

• Scheduling proposal
• Section 52E of the Therapeutic Goods Act 1989
• Scheduling Policy Framework (SPF 2018)
• Other relevant information

Delegate's final decision

The delegate's final decision to be implemented on 1 June 2018 is not to schedule etofenprox and so create an Appendix B entry for etofenprox as follows:

The matters under subsection 52E (1) of the Therapeutic Goods Act 1989 considered relevant by the delegate include:

1. the risks and benefits of the use of a substance:
   • Nil.
2. the purposes for which a substance is to be used and the extent of use of a substance:
   • Etofenprox is a pyrethroid-like insecticide, which has activity via contact or ingestion against a range of insect pests and is used for insecticidal control in crops including canola, cabbage, grapes, peach and apples.
3. the toxicity of a substance:
   • Etofenprox has low acute toxicity and is not a skin or eye irritant and is not a skin sensitiser in animal studies.
4. the dosage, formulation, labelling, packaging and presentation of a substance:
   • Nil.
5. the potential for abuse of a substance:
   • Nil.
6. any other matters that the Secretary considers necessary to protect public health:
   • Etofenprox is not currently scheduled in Australia.

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Footnotes

2. See TGA website for SPF classification guideline - AHMAC - Scheduling policy framework for medicines and chemicals