Pharmacology

Pharmacokinetics
Toltrazuril is absorbed at a rate of at least 50%. The highest equivalent concentrations are found in the kidney and liver.

Acute toxicity
The oral acute toxicity of toltrazuril in rats, mice and chickens is very low. The LD₅₀ ranged between 1000-5000 mg/kg body weight, which is more than 100 time the recommended therapeutical dose of 7mg/kg body weight.

Repeated dose toxicity studies
Toltrazuril has no effects on respiratory functions, cardiovascular and central nervous system, gastrointestinal tract, kidney and liver functions, blood pharmacology in therapeutical and multitherapeutical dosages. Toltrazuril has not embryo- or reproductive toxicity and is not mutagenic.

Activity spectrum
The spectrum of activity of Baycox is extremely wide. It is highly effective not only against all important coccidia in poultry. Baycox proved to be fully effective against numerous field isolates and strains, some of which are highly resistant to other commercial products.

Mode of action
Light and electron microscopic pictures showed that all intracellular development stages of Eimeria are damaged.

These findings suggest that toltrazuril interferes with the division of the nucleus and with the activity of the mitochondria, which are responsible for the respiratory metabolism of the parasites. In the macrogametes it damages the so-called wall-forming bodies II. In all intracellular development stages a severe vacuolisation due to inflation of the endoplasmatic reticulum occurs. Baycox thus has coccidiocidal rather than coccidiostatic action and its efficacy is independent of the severity of the infection. The special mode of action results in the following product advantages:

• As Baycox acts on all intracellular development stages, a 2-day treatment period is sufficient.
  
• As the product does not interfere with the development of immunity, a follow-up treatment is usually not necessary; moreover, this mode of action permits a strategic administration.
  
• Even an advanced infection (after 3-5 days: gametogony) can still be treated successfully with Baycox.
  
• Due to the different mode of action (intracellular stages) an additive effect is achieved in conjunction with ionophores (extracellular stages).