Absorption, Distribution and Excretion
Dermal adsorption of (+)trans- and (+)cis-phenothrin into body of male rats from dust or emulsifiable concentrate (EC) was estimated to be 3-7% and 8-17%. The rate of absorption was 4-5 times faster with EC than with dust and T/2 in blood was 2-3 times longer.
(14)C-phenothrin labeled at the hydroxymethyl group of the alcohol moiety was orally admin at ... 200 mg/kg to male Sprague-Dawley rats. Absorption and elimination was rapid. About 60% of radioactivity was eliminated in urine and 40% in feces in 3 days. In addn to phenothrin, 3-phenoxybenzyl alcohol and 3-phenoxybenzoic acid were found in brain, liver, kidney, and blood. Unidentified water and ether solubles were also present.
Dermal adsorption of (+)trans- and (+)cis-phenothrin into body of male rats from dust or emulsifiable concentrate (EC) was estimated to be 3-7% and 8-17%. Rate of absorption was 4-5 times faster with EC than with dust. Amount absorbed through skin was almost completely excreted into urine and feces within 6 days. When admin once orally, at rate of 2 mg/kg (either isomer), about 96% of dose was recovered in excreta during following 6 days. A larger amt of (+)cis-isomer was excreted in feces than (+)trans-isomer and a larger amt of (+)trans-isomer was excreted in urine than (+)-cis-isomer.
The tissue residues in rats 7 days after a single oral dose of (14)C-(1R,cis)- or (14)C-(1R,trans)-phenothrin at 10 mg/kg body weight were generally very low although the fat showed somewhat higher residue levels (1-2.5 mg/kg). Similarly, high 14C residue levels (up to 23 mg/kg) were found in the fat, 7 days after a single oral dose of the [1R,cis] isomer at 200 mg/kg body weight.
For more Absorption, Distribution and Excretion (Complete) data for PHENOTHRIN (13 total), please visit the HSDB record page.

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Metabolism / Metabolites
(14)C-Phenothrin ... was orally admin at ... 200 mg/kg to male Sprague-Dawley rats. ... Urine contained low levels of 3-phenoxybenzoic acid and its glycine conjugate and some ether and water sol material. In addn ... 3-(4'-hydroxyphenoxy)benzoic acid was present and accounted for 42.3% of radioactivity ... This cmpd was ... major metab in feces but accounted for only 11.9% of ... radioactivity. In addn to unchanged phenothrin and unidentified water and ether solubles, feces contained 3-phenoxybenzoic acid and the glycine conjugate. 3-phenoxybenzyl alcohol was not observed in urine or feces.
Dermal and oral admin of (+)trans- and (+)cis-phenothrin to male rats from dust or emulsifiable concentrate produced nearly the same metabolites. Major metabolites from (+)trans-isomer were 3-phenoxybenzoic acid and its glycine conjugate and (3,4'-hydroxyphenoxy)benzoic acid and its sulfate. The cis-isomer gave larger amounts of ester metabolites.
When [1R,trans]-phenothrin was given to rats at 4, 10, or 200 mg/kg body weight (oral single dose) or 4 mg/kg body weight (repetitive oral dose for 14 days), the sulfate conjugate of 4'-OH-phenoxy benzoic acid was predominant, accounting for 28, 43, 28, and 55%, respectively, of the dose. In addition, phenoxy benzoic acid (4, 10, 5, and 6%), its glycine conjugate (1,3,2, and 2%) and glucuronide (2,3,1, and 3%), and free 4'-OH-phenoxybenzoic acid (2,11,3, and 3%) were found. The sulfate conjugate of 3-(2'-hydroxyphenoxy)benzoic acid (2'-OH-PBacid) was also found as a minor metabolite.
When Sprague Dawley rats were administered a single oral dose of [1R,trans]-phenothrin at 4 or 200 mg/kg body weight level or given an oral dose of 4 mg/kg body weight per day for 14 days, unmetabolized compound was found in the feces (44-45, 44-60, and 14-16% of the dose, respectively). An ester-form metabolite, the 4'-hydroxy phenoxy benzoic acid derivative of trans-phenothrin, was also detected (0.4-0.6%).
For more Metabolism/Metabolites (Complete) data for PHENOTHRIN (14 total), please visit the HSDB record page.
d-Phenothrin is a fast acting insecticide, effective by contact and stomach action. It is rapidly metabolized and excreted by humans and has low human toxicity. For both cis- and trans- isomers, the product was metabolized by hydrolysis, oxidation and conjugation and a large part of d-Phenothrin is excreted unchanged in the urine and the faeces. Following oral administration of the (1R)- trans - isomer, the urine is the major excretory route. The isomer is extensively metabolized to oxidative and conjugated derivatives of the hydrolysed ester. Oxidative and conjugated derivatives of the
(1R)- cis -isomer are also observed but hydrolysis of the ester linkage is a minor metabolic pathway. With this isomer the faeces is the major excretory route. The metabolic profiles aree similar following dermal application, although the rates of excretion for each isomer showed some differences between the two routes of administration. The major metabolite is 3-phenoxybenzyl alcohol (PBalc). Smaller amounts of PBacid and trace amounts of 4'-OH-PBacid are also found. It is stable to storage in the dark; d-Phenothrin is relatively unstable to sunlight or ultra violet irradiation, or in alkaline media. (L866, A561)

Toxicity Summary
Both type I and type II pyrethroids exert their effect by prolonging the open phase of the sodium channel gates when a nerve cell is excited. They appear to bind to the membrane lipid phase in the immediate vicinity of the sodium channel, thus modifying the channel kinetics. This blocks the closing of the sodium gates in the nerves, and thus prolongs the return of the membrane potential to its resting state. The repetitive (sensory, motor) neuronal discharge and a prolonged negative afterpotential produces effects quite similar to those produced by DDT, leading to hyperactivity of the nervous system which can result in paralysis and/or death. Other mechanisms of action of pyrethroids include antagonism of gamma-aminobutyric acid (GABA)-mediated inhibition, modulation of nicotinic cholinergic transmission, enhancement of noradrenaline release, and actions on calcium ions. They also inhibit calium channels and Ca2+, Mg2+-ATPase. (T10, T18, L857)

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Toxicity Data
LD50: > 5000 mg/kg (Oral, Rat) (A561)
LD50: 10 000 mg/kg (Dermal, Rat) (A561)

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Interactions
/Pyrethroid/ detoxification ... important in flies, may be delayed by the addition of synergists ... organophosphates or carbamates ... to guarantee a lethal effect. ... /Pyrethroid/

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Non-Human Toxicity Values
LD50 Rat oral greater than 500 mg/kg
LD50 Mouse oral greater than 500 mg/kg
LD50 Rat oral greater than 10000 mg/kg /(1R)-cis,trans-isomeric mixture/
LD50 Mouse oral greater than 10000 mg/kg /(1R)-cis,trans-isomeric mixture/
For more Non-Human Toxicity Values (Complete) data for PHENOTHRIN (18 total), please visit the HSDB record page.

Therapeutic Uses
Pyrethrins with piperonyl butoxide are used for topical treatment of pediculosis (lice infestations). Combinations of pyrethrins with piperonyl butoxide are not effective for treatment of scabies (mite infestations). Although there are no well-controlled comparative studies, many clinicians consider 1% lindane to be pediculicide of choice. However, some clinicians recommend use of pyrethrins with piperonyl butoxide, esp in infants, young children, & pregnant or lactating women ... . If used correctly, 1-3 treatments ... are usually 100% effective ... Oil based (eg, petroleum distillate) combinations ... produce the quickest results. ... For treatment of pediculosis, enough gel, shampoo, or solution ... should be applied to cover affected hair & adjacent areas ... After 10 min, hair is ... washed thoroughly ... treatment should be repeated after 7-10 days to kill any newly hatched lice. /Pyrethrins/
One hundred and one subjects with head louse infestation were entered into two separate studies, in which a phenothrin aqueous/alcoholic lotion was compared to a carbaryl lotion and a malathion lotion. Fifty subjects were treated with a single application of the phenothrin lotion, 28 with the carbaryl lotion and 23 with the malathion lotion. In the comparative study of the phenothrin and malathion lotions an inspection on the day following treatment showed no live lice remained, but that six of the subjects treated with malathion lotion still had evidence of viable eggs (p < 0.05). In one subject viable eggs were still evident at two weeks post-treatment. There were no cases, however, of live lice or viable eggs at four weeks post-treatment. Mild cutaneous side-effects were reported in five subjects, the incidence of which was not significantly different by treatment group. One subject in the phenothrin and carbaryl lotion comparative study had evidence of live lice at one week post-treatment with phenothrin lotion. This subject received no further treatment and was clear of both live lice and viable eggs at subsequent visits. A separate case of live lice infestation was found at two weeks post-treatment in a subject treated with phenothrin lotion and at four weeks post-treatment in two subjects treated with carbaryl lotion. As these subjects were free of live lice infestation at previous follow-up visits it was highly probable that these were cases of re-infestation from another source.

C23H26O3

350.458

350.188

26002-80-2

D-Phenothrin;26046-85-5

4767

Colorless liquid
Pale yellow to yellow-brown clear liquid

1.1±0.1 g/cm3

437.0±45.0 °C at 760 mmHg

186.6±23.3 °C

0.0±1.0 mmHg at 25°C

1.588

7.47

0

3

7

26

512

0

O=C(C1C(C)(C)C1/C=C(C)\C)OCC2=CC=CC(OC3=CC=CC=C3)=C2

SBNFWQZLDJGRLK-UHFFFAOYSA-N

InChI=1S/C23H26O3/c1-16(2)13-20-21(23(20,3)4)22(24)25-15-17-9-8-12-19(14-17)26-18-10-6-5-7-11-18/h5-14,20-21H,15H2,1-4H3

(3-Phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate

KC-1001 KC 1001KC1001 Phenothrin umithrin and d-phenothrin

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~285.35 mM)

Solubility in Formulation 1: 2.5 mg/mL (7.13 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 2.5 mg/mL (7.13 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (7.13 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)