Selamectin is a broad-spectrum antiparasitic agent used primarily in veterinary medicine for the prevention and treatment of internal and external parasites in dogs and cats. It is a semi-synthetic avermectin derivative, structurally related to ivermectin, and functions by activating glutamate-gated chloride channels in parasites, leading to paralysis and death.
Selamectin is typically administered as a topical (spot-on) solution.
Indications include (in companion animals):
∙ Prevention of heartworm disease
∙ Treatment of fleas, ear mites, sarcoptic mange
∙ Treatment of intestinal hookworms and roundworms
∙ Control of tick infestations (in some species and regions)
Impurities in selamectin can arise from its complex fermentation-derived and chemical modification processes, as well as from degradation during storage. As a veterinary drug used topically, impurity levels are controlled under VICH Q3A/B guidelines and applicable pharmacopeial standards (e.g., USP, EP).
Process-Related Impurities
Degradation Impurities
Elemental Impurities
Analytical Techniques for Impurity Detection
Selamectin is used to prevent heartworm disease and treat or control various parasites like fleas, mites, and intestinal worms in dogs and cats.
It binds to glutamate-gated chloride channels in nerve and muscle cells of parasites, increasing chloride ion influx, leading to paralysis and death of the parasite.
It is generally safe for dogs and cats when used as directed. However, dosage adjustments and precautions may be needed in underweight, sick, or very young animals.
Yes, selamectin is stable under normal storage conditions but should be protected from light and heat to avoid degradation.
