Horses elimination

Odberg, F. O. and Francis-Smith, K. (1977). Studies on the formation of ungrazed eliminative areas in fields used by horses. Applied Animal Ethology 3,27-34. 

In the horse, hydroxylation is more important than acetylation as a metabolic pathway, with hydroxylation at the 5 position being dominant over hydroxylation of the 6-methyl group. Low percentages of metabolites are present in plasma, for N -SDM, 0.6 to 0.9 % for SCH2OH, 0.38 to 0.71 % and for SOH, 0.38 to 6.7 %. The plasma concentration-time curves of the metabolites run parallel to that of SDM. The elimination half-life of sulfadimidine varies between 5 and 14 h. The main metabolite in urine, accounting for 50 % of the drugs present (Table III), is the SOH and its glucuronide. 

Nitrofurantoin has been used as an urinary antiseptic in calves and horses at an oral dosage of 10 mg/kg bw/day. It is absorbed rapidly and completely from the gastrointestinal tract. About 40% of the drug is eliminated in the urine, while the remainder is catabolized. 

After a single oral administration of 0.4 mg radiolabeled moxidectin/kg bw to horses, a mean peak serum concentration of 0.134 ppm moxidectin equivalents was attained at 6 h postdose (63). Oral availability was estimated at 40%, while the terminal elimination half-life was approximately 80 h. Within 168 h, 77% of the total radioactivity was excreted mostly by Ure fecal route. In feces, the parent drug represented approximately 70% of the fecal radioactivity, whereas a fraction of 0.28-3.45% was due to four minor metabolites resulting from oxidation mainly on Ci4, C24, and/or C28 positions. 

Propiopromazine has been used in all the domesticated animals. Although very limited information is available on the absorption, distribution, metabolism, and elimination of propiopromazine in animals, several studies (103) have reported the presence of propiopromazine in pig kidney collected from abattoirs, so that human exposure should therefore be presumed. Both pigs and horses are able to metabolize propiopromazine, at least in part. The drug binds extensively to tissue proteins, and also accumulates in fatty tissues. 

The /-butyl group provided us with some useful work-horses for developing the scope of the cyclisation, since A-t-butylbenzylamine is cheap and readily available. However, we found it was almost impossible to remove from the products, even on extended treatment with acid. Replacing one of the methyl groups of the /-butyl with a phenyl group, however, stabilised the positive charge formed during El elimination and allowed us to deprotect the products to yield A-unsubstituted... 

Ivanov (1983) reported that the natural mortality of horse-mackerel in the Black Sea was 45% and the removal by commercial fishery 13%, making 58% elimination (losses from predators being disregarded) or 21 kt. However, our calculations showed that the total annual production of this fish was 26 kt, a difference of 20%. This value may be reduced if the losses from predators are taken into account. Assuming such losses to be 10%, as in the case of sprat, the total elimination of horse-mackerel would be 68% or about 25 kt. The difference between production and elimination is then only 4%. 

The radiographic study eliminated the most important arguments used against the authenticity of the horse. However the fact that the horse was proven to be cast with the lost-wax process did not automatically reestablish its authenticity. Careful visual examinations, elemental analyses, studies on corrosion products, metallurgical investigations, and various other technical studies were necessary to demonstrate that all physical characteristics of the bronze were entirely consistent... 

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