Никлозамид

Химические свойства

Yellowish-white or yellowish, fine crystals.Yellow-white crystalline powder, odorless, tasteless. Melting point 225-230 ℃. Insoluble in water, soluble in hot ethanol, chloroform, cyclohexanone, diethyl ether and sodium hydroxide solution.

Использование

Niclosamide has been used extensively in the treatment of tapeworm infections caused by Taenia saginata, Taenia solium, Diphyllobothrium latum, Fasciolopsis buski, and Hymenolepis nana. It is an effective alternative to praziquantel for treating infections caused by T. saginata (beef tapeworm), T. solium (pork tapeworm), and D. latum (fish tapeworm) and is active against most other tapeworm infections. It is absorbed by intestinal cestodes but not nematodes.A single dose is usually adequate to produce a cure rate of 95%.With H. nana (dwarf tapeworm), a longer treatment course (up to 7 days) is necessary. Niclosamide is administered orally after the patient has fasted overnight and may be followed in 2 hours by purging (magnesium sulfate 15–30 g) to encourage complete expulsion of the cestode, especially T. solium, although this is not always considered necessary. Cure is assessed by follow-up stool examination in 3 to 5 months.With the availability of other agents, niclosamide is no longer widely used.The most widely employed agents are praziquantel and the benzimidazoles.

Антимикробная активность

Useful activity is restricted to intestinal tapeworms, including Taeniarhynchus saginatus (syn. Taenia saginata), Taenia solium, Diphyllobothrium latum and Hymenolepis nana. It is not effective against larval stages of tapeworms.

Общее описание

A cell-permeable salicylanilide that, in addition to its well-known antihelmintic efficacy, acts as a mammalian mTORC1, but not mTORC2, signaling inhibitor mechanistically distinct from rapamycin. Likely a direct consequence of autophagy activation, Niclosamide is demonstrated to induce Wnt-independent Frizzled1 and Dishevelled-2 downregulation. Unrelated to its autophagy induction activity, Niclosamide is also shown to inhibit Stat3 signaling (IC₅₀ = 0.25 M in HeLa reporter assays). Efficiently inhibits breast cancer stem-like cells in vitro and in vivo.

Фармацевтические приложения

A synthetic chlorinated nitrosalicylanilide available for oral administration.

Механизм действия

For many years, niclosamide (Niclocide) was widely used to treat infestations of cestodes. Niclosamide is a chlorinated salicylamide that inhibits the production of energy derived from anaerobic metabolism. It may also have adenosine triphosphatase (ATPase) stimulating properties. Inhibition of anaerobic incorporation of inorganic phosphate into ATP is detrimental to the parasite. Niclosamide can uncouple oxidative phosphorylation in mammalian mitochondria, but this action requires dosages that are higher than those commonly used in treating worm infections.
The drug affects the scolex and proximal segments of the cestodes, resulting in detachment of the scolex from the intestinal wall and eventual evacuation of the cestodes from the intestine by the normal peristaltic action of the host's bowel. Because niclosamide is not absorbed from the intestinal tract, high concentrations can be achieved in the intestinal lumen.The drug is not ovicidal.

Фармакокине?тика

Conflicting data exist relative to the level of absorption of niclosamide from the gut. The metabolized drug is passed in the feces and urine, staining them yellow.

Клиническое использование

5-Chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamideor 2,5 -dichloro-4 -nitrosalicylanilide (Cestocide, Mansonil,Yomesan) occurs as a yellowish white, water-insolublepowder. It is a potent taeniacide that causes rapid disintegrationof worm segments and the scolex. Penetration of thedrug into various cestodes appears to be facilitated by thedigestive juices of the host, in that very little of the drug isabsorbed by the worms in vitro. Niclosamide is well toleratedfollowing oral administration, and little or no systemicabsorption of it occurs. A saline purge 1 to 2 hours after ingestion of the taeniacide is recommended to remove thedamaged scolex and worm segments. This procedure ismandatory in the treatment of pork tapeworm infestation toprevent possible cysticercosis resulting from release of liveova from worm segments damaged by the drug.

Побочные эффекты

No serious side effects are associated with niclosamide use, although some patients report abdominal discomfort and loose stools.

Профиль безопасности

Poison by intravenous and intraperitoneal routes. Moderately toxic by ingestion. Experimental reproductive effects. Human mutation data reported. When heated to decomposition it emits very toxic fumes of Cl and NOx.