Each ml contains
Closantel 15% w/v
Closantel is an antiparasitic active ingredient used in veterinary medicine against internal parasites (e.g. some roundworm species and liver flukes) and some external parasites (e.g. sheep nasal bots, cattle grubs, etc.) of livestock. It is not used against agricultural and household pests. It belongs to the chemical class of the salicylanilides.
Closantel is highly effective against adults and larvae (6 to weeks old) of liver flukes (Fasciola hepatica), and against several important gastrointestinal roundworms (e.g.Bunostomum, Haemonchus, oesophagostomum, Ostertagia, Teladorsagia, Strongloides, Trichostrongylus), as well as against screwworms (maggots of Cochliomyia spp and Chrysomya spp), sheep nasal bots (Oestrus ovis), and sheep keds (Melophagus ovinus).
Closantel has no efficacy against non-gastrointestinal roundworms such as lungworms (e.g. Dictyocaulus spp) and eyeworms (e.g. Thelazia spp ) or tapeworms.
After oral administration closantel is readily absorbed into the bloodstream. Four days after treatment up to 60% of the injected and 30% of the drenched closantel is absorbed to blood. In the blood, unchanged closantel binds strongly and almost completely (>99%) to plasma albumins. Peak plasma levels are reached 10 to 48 hours after administration, both after oral or intramuscular administration. Half-life in plasma is 3 to 4 weeks.
Mechanism of action
The molecular mode of action of salicylanilides, including closantel, is not completely elucidated. They all are uncouplers of the oxidative phosphorylation in the cell mitochondria, which disturbs the production of ATP, the cellular “fuel”. This seems to occur through suppression of the activity of succinate dehydrogenase and fumarate reductase, two enzymes involved in this process. This impairs the parasites motility and probably other processes as well. It seems that closantel also disturbs the liquid and ion transport mechanisms in the parasites membranes.