TECHNICAL --- INSECTICIDE: Niclosamide

CAS No.: 50-65-7
Content: BP (British Pharmacopoeia): 98% min
96%TC, 95%TC

NOMENCLATURE
niclosamide
Common name:
niclosamide (BSI, E-ISO, (m) F-ISO, BAN, Germany (for veterinary use))
IUPAC name:
2',5-dichloro-4'-nitrosalicylanilide
Chemical Abstracts name:
5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide
CAS RN: [50-65-7]
niclosamide-olamine
Common name:
niclosamide-olamine (BSI, E-ISO, (m) F-ISO, BAN); clonitralid (Germany, for public health use)
CAS RN: [1420-04-8]

PHYSICAL CHEMISTRY
niclosamide
Mol. wt.: 327.1
M.f.: C₁₃H₈Cl₂N₂O₄
Form: Almost colourless crystals.
M.p.: 230 篊
V.p.: <1 mPa (20 篊)
KOW: logP = 1 (pH 9.6)
Solubility: In water 1.6 (pH 6.4), 110 (pH 9.1) (both in mg/l, 20 篊). Soluble in common organic solvents such as ethanol and diethyl ether.
Stability: Hydrolysed in aqueous solution, DT₅₀ (20 篊) c. 7 d (pH 6.9), 18.8 d (pH 13.3). Stable to heat. Decomposes under u.v. irradiation. Hydrolysed by concentrated acid or alkali.
niclosamide-olamine
Mol. wt.: 388.2
M.f.: C₁₅H₁₅Cl₂N₃O₅
Form: Yellow, crystalline solid.
M.p.: Decomposes at 208 篊
V.p.: <<1 mPa (20 癈)
Solubility: In water 0.1 g/l (20 篊). In n-hexane, toluene <0.1, dichloromethane 0.015, isopropanol 0.25 (all in g/l, 20 篊).

APPLICATIONS

Mode of action: Molluscicide with respiratory and stomach action.
Uses: Niclosamide is a lampricide and molluscicide. It kills a wide variety of snails, cestodes and Cercariae by affecting the respiration and the carbohydrate metabolism. It probably disturbs oxidation processes by inhibiting oxygen uptake. The main target pest in agricultural use is the golden apple snail (Pomacea canaliculata) in paddy fields (rice-cultivation) but it is also applied in public health and hygiene programs to control/eradicate snails such as Biomphalaria glabrata, which are intermediate hosts for Schistosoma spp., the infectious agents of schistosomiasis in open waters in tropical Africa. The pesticide is quickly metabolized in water and does not exhibit a long-term effect.

It is also applied to commercially managed fish ponds, in order to clean them from undesirable fish prior to re-filling the pond. Niclosamide is highly toxic to fish but, due to its short half-life in water, the batch of new fish may be added only a few days after application of the pesticide.