The effects of simulated rain and sun exposure on the plasma disposition of ivermectin following pour‐on administration in heifers

Comparative plasma and milk dispositions, faecal excretion and efficacy of per os ivermectin and pour‐on eprinomectin in horses

“…Although the pour‐on formulation of endectocides was administered at higher dosage, their plasma availabilities via the topical route were much lower compared with per os or subcutaneous administration due to their poor or limited absorption through the skin, as previously reported in different equine (Gokbulut et al ., , , ) and ruminant species (Alvinerie et al ., ,b; Dupuy et al ., , ; Laffont et al ., ; Sallovitz et al ., ; Gokbulut et al ., , ) and as recently reviewed by McKellar and Gokbulut (). Our data obtained in horses were consistent with previous findings, with significantly higher C max (25.84 ng/mL) and greater AUC (80.91 ng·d/mL) values of per os IVM compared with those of pour‐on EPM ( C max : 5.03 ng/mL and AUC: 17.69 ng·d/mL).…”

“…This faster absorption process of pour‐on EPM could be correlated to different environmental or climatic conditions. It was shown that the exposure of animals to rain or direct sunlight (UV‐radiation) changed the plasma dispositions of IVM in cattle after pour‐on administration (Gokbulut et al ., ) and the researchers have suggested that the exposure of rain could result in removing of active compound from body surface of animals and the exposure to direct UV radiation from sun could cause an increase in cutaneous blood circulation at the administration site and ⁄ or decrease in the viscosity of the pour‐on administered drug. However, it should be mentioned that the study with pour‐on IVM (Gokbulut et al ., ) was performed in December (beginning of the winter season in the study area) when the UV radiation is not effective, and the current study was performed in June (beginning of the summer season) when the UV radiation is relatively more effective.…”

“…These differences may be attributable to species differences (e.g. physiological or anatomical, such as the difference in body size, length of haircoat) or to environmental and climatic conditions, which may affect the absorption and systemic availability of drugs following pour‐on administrations (Gokbulut et al ., ; McKellar & Gokbulut, ).…”

Plasma disposition and milk excretion of eprinomectin following pour‐on administration in lactating donkeys

“…The reason for the lower systemic exposure of EPM in this study, compared with previous one, is unclear. These differences may in part be due to differences in methodology as different body size, length of haircoat and environmental conditions such as sun exposure can be caused differences in drug absorption and systemic availability of drugs following pour‐on administration (Gokbulut et al ., , ; McKellar & Gokbulut, ). The difference in the faster elimination processes of EPM in this research compared with previous study (Gokbulut et al ., ) could be due to different physiologic status of study animals.…”