Reproductive and developmental toxicity study of gadobenate dimeglumine formulation (E7155) (1)--Fertility study in male rats by intravenous administration

The influence of gadobenate dimeglumine formulation (E7155) on general reproductive performance and fertility in male rats of the Sprague-Dawley strain was assessed in this study. E7155 was administered by intravenous injection at a dosage of 0.3, 1.0, or 2.0 mmol/kg/day to groups of 22 male rats for 13 weeks. Control animals received 0.9% sterile physiological saline throughout the same period. After four weeks of treatment, each male was paired with an untreated female of the same strain. Each male was paired again after 10 weeks of treatment with another untreated female of the same strain. All females were killed on Day 14 of gestation for examination of pregnancy status. No significant toxicological signs associated with systemic exposure to E7155 were observed. There were no effects of treatment with E7155 on body weight gain, food consumption, macroscopic findings, reproductive organ weights and sperm count or sperm motility in male rats. Mating performance after pairing at Weeks 4 and 10 of treatment as well as litter size and number of survival embryos on Day 14 of gestation were not affected by paternal treatment with E7155. From these results, the No Observed Adverse Effect Level (NOAEL) of E7155 was 2.0 mmol/kg/day for general and reproductive toxicity parameters in male rats treated with E7155 and for development in their embryos.