Febantel [N-2-( [2,3-bis-(methoxycarbonyl)-guanidine] 5- phenylthio)-phenyl) -2-methoxyacetamide] is a new anthelmintic that is highly active against various species of nematodes and cestodes in rodents, sheep, cattle, and horses. In 1978, febantel was introduced to South Africa under the trade name of Rintal? as a sheep drench, and to New Zealand as a sheep and cattle drench, and the USA and Australia as a paste for horse[1].
Febantel is White to Off-White Solid
Rintal, Bayer,W. Germany,1979
ChEBI: Febantel is an aryl sulfide.
2-Amino-5-phenylthiornethoxyacetanilide in methanol solution is heated with
N,N'-bis-methoxycarbonyl-isothiourea-S-methyl ether with the addition of a
catalytic amount of p-toluenesulfonic acid for three hours with stirring under
reflux. The mixture is then filtered hot and after cooling the febantel product
crystallizes out. It is filtered off, rinsed with ether and dried under high
vacuum to give the final product, melting at 129°C to 130°C.
Combotel (Bayer AnimalHealth); Negabot Plus Paste (Bayer Animal Health);
Oratel (Bayer Animal Health); Rintal (Bayer Animal
Health).
In vivo assays indicated that febantel exhibited potent anthelmintic activity against G. kobayashii with an EC50 value of 0.03 mg/L and 100 % anthelmintic efficacy at 0.1 mg/L after 48 h of exposure. Moreover, in vivo trials also revealed a notable post-treatment effect of febantel, where infected goldfish transferred to drug-free water after short 6-h exposure could still result in full eradication of the worms, indicating febantel might induce persistent perturbations in parasite physiology[1].
In vitro assays showed a negative correlation between febantel concentrations and the survival of G. Kobayashi. However, increasing the febantel concentration to 2.0 mg/L did not result in the complete death of all worms. Oral administration of febantel demonstrated limited anthelmintic activity, with only 49 % efficacy at 200 mg/kg body weight daily over five days. Acute toxicity assays revealed that the 48-h LC50 value of febantel was 5.47 mg/L, 182.23 times higher than the 48-h EC50 value, indicating that febantel has a favorable safety profile. However, febantel exposure potentially interfered with hepatic metabolism and oxidative status, as indicated by variations in SOD, GST, and P450 gene expression[1].
[1] Thomas, H. “Ovacidal activity of febantel.” New Zealand veterinary journal 27 12 (1979): 273–5.
