A Teratological Evaluation and Postnatal Behavioral Screen of KF-868 In Rats

Abstract

The effects of a new experimental drug, KF-868, were investigated after administration to pregnant Spirague-Dawley rats at O(vehicle), 0.1,2.0, and 40.0 mg/kg per day during Days 7 through 17 of gestation by examination of term fetuses and naturally delivered offspring. Pregnant rats administered 0.1, 2.0, and 40.0 mg/kg per day gained significantly Tore weight dering the dosage period than did the vehicle control group. Treatment-related physical signs, bloody crust on nose and stains on fur, were observed in the high dosage group. Fetal viability was significantly increased, and resorptions were significantly decreased for the mid and high dosage groups, when compared with the control group. Average fetal body weights for cesarean-delivered fetuses were less for the 40.0 mg/kg per day dosage groups than for the vehicle control group. Visceral and skeletal evaluations of fetuses revealed no difference between the control and test groups. Percent survival of pups was significantly less for the high dosage group than for the control group. Average rat body weights prior to mating for the high dosage group were generally less than for the control group. All physical and functional developmental values were comparable among the control and test groups. Evaluation of postweaning parameters of pups revealed no significant difference in sex maturation, behavior (open-field and water maze), and reproductive capacity. Average body weight gains during the 9-week growth period before mating were significantly less for the 40.0 mg/kg per day dosage group F1 generation female rats. Toxicity in fetuses and offspring was observed only at the highest dosage level. Dosage-dependent, significant increases in maternal body weight gain, as compared with control values, occurred for doses in the 3 KF-868-administered groups. These results indicate that 0.1 and 2.0 mg/kg per day dosages of KF-868 were not lethal and did not produce any adverse effects on the morphological or functional development of offspring. Toxicity was evident in offspring and fetuses of dams administered 40.0 mg/ kg per day KF-868, 40,000 times as high as the daily therapeutic dose. T ha1 hydrochloride (KF-868), was synthesized by Karl Thomae GmbH. KF-868 is a bronchodilator that differs from isoproterenol and salbutamol in 3 ways: (1) its long duration of action, (2) its