Sucralose: assessment of teratogenic potential in the rat and the rabbit.

The teratogenic potential of sucralose was examined following gavage administration to pregnant rats and rabbits during organogenesis. Groups of 20 mated rats were dosed on days 6-15 of gestation inclusive at 500, 1000 or 2000mg/kg/day; groups of 16 to 18 inseminated rabbits were dosed on days 6 to 19 of gestation inclusive at 175, 350 or 700mg/kg/day following preliminary studies at higher doses. Concurrent control groups received vehicle alone. Rats were killed on day 21 and rabbits on day 29 of gestation. Foetuses were evaluated at necropsy and after processing for possible soft tissue and skeletal alterations. There was no evidence of teratogenicity for either species. The only observed response to treatment in rats was a slight increase in water intake. Some adult rabbits receiving 700mg/kg/day exhibited marked gastrointestinal disturbance, also seen at higher doses in preliminary studies. Gastrointestinal effects such as these occur non-specifically in response to high doses of poorly absorbed compounds, and in the present study were considered to be responsible for two maternal deaths and four abortions. Full evaluation of rabbit foetuses in the main study (up to 700mg/kg/day) and necropsy of foetuses in a preliminary study with pregnant animals (up to 1000mg/kg/day) showed no evidence of adverse foetal response to sucralose. These teratology studies in both pregnant rodent and non-rodent animal models demonstrate that maternal consumption of high levels of sucralose during the period of organogenesis has no effect on normal foetal development in the rat or rabbit.

Reproductive studies of NY-198 in rats. I. Fertility study.

Lomefloxacin (NY-198), a new antibacterial agent, was administered daily by gavage to groups of 22 male and 22 female rats at dosages of 30, 100 or 300 mg/kg/day. Males were dosed for 71 days before pairing and then until termination, and females were dosed for 15 days before pairing, throughout mating and until Day 7 of gestation. Females were killed on Day 20 of gestation for examination of their uterine contents. Males were killed after approximately 14 weeks treatment and their reproductive organs were weighed and retained. At 300 mg/kg/day the majority of animals showed increased salivation, water intake was slightly increased throughout the treatment period in males and before pairing in females whereas food intake showed a slight, transient reduction during the first few days of treatment in both sexes. Body weight gain of males was marginally depressed during the first week of treatment, but no other signs of reaction to treatment were observed. At 30 and 100 mg/kg/day some animals exhibited increased salivation after being dosed. At all dosages, NY-198 was without adverse effects upon mating performance and fertility, or upon survival, growth and development in utero. On the basis of the above results it is considered that the no effect level with respect to reproduction and breeding performance of treated F0 animals and the in utero development of the foetuses was 300 mg/kg/day. A dosage of 100 mg/kg/day was considered to be the no effect level for somatic changes in the F0 animals, and even at the highest dosage of 300 mg/kg/day only slight effects were recorded on the F0 animals.

Reproductive studies of NY-198 in rats. II. Teratology study.

Lomefloxacin (NY-198), a new antibacterial agent, was administered daily by gavage to groups of 32 pregnant female rats of the CD strain at dosages of 30, 100 or 300 mg/kg/day from Day 7 to Day 17 of gestation. Twenty-one females in each group were killed on Day 20 of gestation for examination of their uterine contents. Eleven females in each group were allowed to deliver their litters and the offspring were examined for growth and functional development. At the highest dosage (300 mg/kg/day), there was a small reduction in maternal weight gain and a transient reduction in food intake during the treatment period. Foetal and placental weights were markedly reduced. However, survival, growth and development of F1 offspring were unaffected and, with the possible exception of a slight reduction in F2 foetal weight, their reproductive performance was unimpaired. At the intermediate level (100 mg/kg/day), maternal body weight gain and food intake during the treatment period were slightly reduced but, with this exception, the performance of F0 females and of the F1 generation was essentially similar to that of the vehicle controls. At the lowest dosage (30 mg/kg/day), no adverse effects were recorded on either the F0 females or the F1 generation. On the basis of the above results 30 mg/kg/day was considered to be the no effect level for the F0 females treated during gestation while 100 mg/kg/day administered during gestation to F0 females had no effect upon performance of the F1 generation.

Reproductive studies of NY-198 in rats. III. Perinatal and postnatal study.

Lomefloxacin (NY-198), a new antibacterial agent, was administered daily by gavage to groups of 22 pregnant female rats of the CD strain at dosages of 30, 100 or 300 mg/kg/day from Day 17 of gestation to Day 21 of lactation. Females were allowed to deliver their litters and the offspring were examined for growth and functional development. There was a slight maternal response at the highest dosage (300 mg/kg/day), including increased salivation after dosing, reduced food intake in the treated period of gestation and increased water intake during the lactation period. Gestation length was slightly increased, although remaining within the laboratory background control range; in consequence, body weight of F1 offspring at Day 1 post partum was slightly increased. At 100 mg/kg/day, a few females showed increased salivation after dosing and there was a slight increase in gestation length. Birth weight of F1 offspring was slightly increased at 30 and 100 mg/kg/day but all values were within laboratory background control ranges. The survival, functional responses and fertility of F1 offspring were essentially unaffected by NY-198. On the basis of the above results, 30 mg/kg/day was considered to be the no-effect level for the F0 females treated during late gestation and lactation whilst 300 mg/kg/day administered to the F0 females had no adverse effect upon their offspring.