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Appendices 1-18 to: Report on the Health Effects of Selected Pesticide Coformulants

 42   Human toxicity

42.1   Single dose toxicity

42.1.1   Inhalation

No relevant data have been found.

42.1.2   Oral intake

No data have been found.

42.1.3   Dermal contact

See section 3.2 Repeated dose toxicity.

No evidence of phototoxicity was observed in 10 volunteers when a bath oil containing 43% isopropyl myristate was applied dermally at 4.25 mg/cm² under an occlusive patch for 24 hours. The application site was exposed to ultraviolet irradiation (UV-range A) from a solar simulator after 6 and 24 hours. (CTFA 1978 – quoted from BIBRA 1988 and CIR 1982).

42.1.4   Other routes

No data have been found.

42.2   Repeated dose toxicity

42.2.1   Inhalation

No data have been found.

42.2.2   Oral intake

No data have been found.

42.2.3   Dermal contact

42.2.3.1     Local effects

In studies with single or repeated dermal administration of undiluted isopropyl myristate, no or minimal skin irritation was seen. The studies lasted up to 21 days and were performed on groups of 5-200 subjects and included both covered and uncovered application. (Anon 1953, Avon 1971, 1975, Campbell & Bruce 1981, Hill top research 1976, Motoyoshi et al. 1979 – all quoted from BIBRA 1988, CIR 1982 and/or IUCLID 2000). In one study the skin was scratched (scarified) beforehand (Frosch & Kligman 1976 – quoted from BIBRA 1988).

When applied in petrolatum under cover for 48 hours to the backs of 50 subjects, the highest non-irritant concentration of isopropyl myristate was 10%. No details were given of effects seen at higher concentrations. (Meneghini et al. 1971 – quoted from BIBRA 1988 and IUCLID 2000). 

42.2.3.2     Skin sensitisation

Negative results were obtained in patch tests with 5% isopropyl myristate in petrolatum on 290 patients with eczema (Meneghini et al. 1971 – quoted from BIBRA 1988), and with 30% isopropyl myristate in petrolatum in an unspecified number of patients at a dermatological clinic (Hjort & Trolle-Lassen 1963 – quoted from BIBRA 1988).

Several experimental studies with healthy volunteers have failed to detect any skin sensitising potential (Anon 1953, CTFA 1976, 1978a, b, Kligman 1974 – all quoted from BIBRA 1988, CIR 1982, and/or IUCLID 2000).
In one such study, flannel impregnated with 170 mg undiluted isopropyl myristate under cellophane was allowed to remain on the backs of 200 volunteers for 5 days, and in another study, material saturated with 1.28-1.70 g undiluted isopropyl myristate was applied for 24 hours every other day for 15 applications to 50 volunteers. In these two studies a 48-hour challenge application was given 3 weeks later. (Anon 1953 – quoted from BIBRA 1988 and IUCLID 2000).
In a maximization test on 25 volunteers, pre-treatment of the forearm with an irritant (sodium lauryl sulphate) was followed by five 48-hour applications of 20% isopropyl myristate in petrolatum with 24 hours between each application, and a challenge application was given 10 days later (Kligman 1974 – quoted from BIBRA 1988, CIR 1982, and IUCLID 2000).
Other studies involving repeated contact with various cosmetic preparations containing 15-58% isopropyl myristate also gave negative skin sensitisation results in groups of 25-320 volunteers (CTFA 1976, 1978a, b – quoted from BIBRA 1988 and CIR 1982).

No photo-allergic reactions were induced in 25 volunteers when a bath oil containing 43% isopropyl myristate was applied dermally at 4.25 mg/cm² under an occlusive patch for 24 hours, twice weekly for 3 weeks. Each application was followed by three exposures to ultraviolet irradiation (UV-range A) from a solar simulator sufficient to produce slight redness, and a challenge patch followed by irradiation was applied 10 days later. (CTFA 1978 – quoted from BIBRA 1988, CIR 1982 and IUCLID 2000).

A woman developed a mild dermatitis after using a feminine hygiene spray containing isopropyl myristate at an unspecified concentration for 6 months. On closed patch testing she had a strong positive reaction to undiluted or 10% isopropyl myristate. (Fisher 1973 – quoted from BIBRA 1988 and CIR 1982).

Three of 41 hospital workers with hand eczema had positive skin-prick test reactions to 20% isopropyl myristate. It was not stated what isopropyl myristate was diluted in. None of 55 patch-tested with the same concentration under cover for 48 hours showed a positive response. It is unclear whether these 55 included any of the 41 tested by skin-prick. (Nielsson 1985 – quoted from BIBRA 1988).

42.2.4   Other routes

No data have been found.

42.3   Toxicity to reproduction

No data have been found.

42.4   Mutagenic and genotoxic effects

No data have been found.

42.5   Carcinogenic effects

No data have been found.

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