Alpha-Cypermethrin

Alpha-Cypermethrin (FMC 45497; Fendona; WL 85871) is a type II pyrethroid insecticide. Alpha-Cypermethrin acts by delaying the inactivation of voltage-gated sodium channels, prolonging sodium tail currents, and triggering repetitive neural discharges. Alpha-Cypermethrin exhibits knockdown and lethal activity against target insects such as Musca domestica and Anopheles culicifacies. Alpha-Cypermethrin induces neurotoxicity in mammals, alters placental and fetal neurodevelopment, and causes acute mortality in fish. Alpha-Cypermethrin can be used in studies related to neurotoxicity, vector-borne diseases, and malaria^{[1][2][3][4][5][6]}. In Vitro:Alpha-Cypermethrin is mainly metabolized to cyclopropanecarboxylic acid via ester hydrolysis by liver microsomal preparations from rats, rabbits, and humans^[2].
Alpha-Cypermethrin shows no mutagenicity in in vitro tests against Salmonella typhimurium, Escherichia coli, and Saccharomyces cerevisiae^[2].
Alpha-Cypermethrin (48-96 h) exhibits low growth inhibitory activity against the freshwater alga Selenastrum capricornutum, with an EC₅₀ value greater than 100 µg/litre^[2].
Alpha-Cypermethrin (3 mg/litre) does not inhibit the growth of sewage bacteria in a closed in vitro system^[2].
Polyamide nylon bed nets treated by immersion with Alpha-Cypermethrin (25 mg/m²) exhibit knockdown and killing activity against Anopheles culicifacies, making them suitable for vector control applications^[6].
In Vivo:Alpha-Cypermethrin (14.5 mg/kg; p.o.; daily; 4 weeks) induces cerebellar neurotoxicity in rats, reduces GABA levels and the activities of AChE, CAT, SOD and GPx respectively, and increases MDA levels^[1].
Alpha-Cypermethrin (35-798 mg/kg) exhibits moderate to high acute oral toxicity in CD mice, and induces typical poisoning symptoms of cyano-containing pyrethroids, including ataxia, choreoathetosis, salivation, and clonic convulsions^[2].

Alpha-cypermethrin (40-368 mg/kg; p.o.; single dose) exhibits moderate to high acute oral toxicity, low acute dermal toxicity, and moderate acute intraperitoneal toxicity when administered to Wistar rats with corn oil as the solvent, with its toxic symptoms consistent with those of cypermethrin-containing insecticides^[2].
Alpha-cypermethrin (0.4 g/m³; inhalation; single 4 h exposure) shows low acute inhalation toxicity in Fischer-344 rats^[2].
At low doses, Alpha-cypermethrin (25-800 mg/kg in feed; oral administration; daily; for 5 weeks) causes no obvious adverse effects in Wistar rats, but at high doses, it induces intoxication, growth retardation, alterations in blood biochemical parameters, and increased organ weights^[2].
At low doses of alpha-cypermethrin (20-540 mg/kg in feed; p.o.; daily; for 13 weeks), no adverse effects are observed in Wistar rats; only slight growth effects occur at medium doses; while toxic symptoms, growth retardation and mild neurodegeneration appear at high doses^[2].
For alpha-cypermethrin (dietary dose: 30-270 mg/kg; oral administration; daily; for 13 consecutive weeks), the no-observed-effect level (NOEL) is 90 mg/kg diet. At the high dose, dogs exhibit typical pyrethroid intoxication symptoms, but no detectable changes occur in physiological or pathological parameters^[2].
Alpha-cypermethrin (semi-occlusive percutaneous application; single dose; 24 h) causes only mild irritation to rabbit skin^[2].
Alpha-Cypermethrin (0.05% (v/v) in corn oil; 50% (m/m) in vaseline; guinea pig percutaneous GPMT with intradermal induction + topical application/topical challenge; single procedure; 7 d induction with 48 h application, 24 h after 14 d challenge) shows no skin sensitization in guinea pigs^[2].
Exposure to Alpha-Cypermethrin (0.3-10 mg/kg/day; oral administration; daily dosing; for 11 consecutive days (gestational days 6-16)) causes dose-dependent fetal growth restriction, alterations in placental morphology and gene expression, as well as changes in microglia and transcriptome of the fetal dorsal forebrain in pregnant CD1 mice^[4].