Subchronic toxicity and toxicokinetics of long-term intranasal administration of bencycloquidium bromide: a 91-day study in dogs.

The subchronic toxicity and toxicokinetics of Bencycloquidium bromide (BCQB) were evaluated after 91-day intranasal administration in dogs at daily dose levels of 2.5, 5.0, and 10.0 mg/kg. Following repeated exposure to medium- or high-dose of BCQB, apparent changes were observed in the levels of blood glucose, creatinine or blood urea nitrogen in both male and female dogs. The no-observed-adverse-effect level (NOAEL) of BCQB was considered to be 2.5 mg/kg/day under the present study conditions. There were no significant gender differences in most indexes of subchronic toxicity throughout the experimental period with the exception of food consumption and body weight, or in the parameters of plasma toxicokinetics after either single-dose or repeated administrations of BCQB at each dosage. In dog, BCQB did not accumulate in blood plasma, while much higher concentrations of BCQB residues were found in most tissues examined (especially the kidney) following 91-day repeated exposure relative to a single dose. In all tissues except the reproductive organs, BCQB concentrations reverted to low levels by 2 weeks post-dosing. The results indicate that blood glucose levels and renal function should be closely monitored when BCQB is used in long-term therapy.