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Effects on fertility

Effect on fertility: via oral route
Dose descriptor:
NOAEL
874 mg/kg bw/day
Additional information

The effect of Beta-cyclodextrin upon the growth and reproductive performance of the rat was assessed in a 2 generations test according to OECD Guideline 416.The test compound was administered in the diet at fixed concentrations of 0 (Control), 10000, 25000 and 50000 ppm through two generations; achieved intake values of test compound (mg/kg bodyweight/day) for the first week of treatment were within the F0 generation for males (6 weeks old) was 1108, 2713 or 5444 and for females (14 weeks old) it was 655,1584 or 3164 whereas within the F1A generation for males (4 weeks old) it was 1531, 3882 or 7996 and for females (4 weeks old) it was1525, 3815 or 7819 respectively.

The first generation animals (F0)32 males/32 females per group were mated for the first time after 10 weeks of treatment for males, two weeks for females (both sexes same age). Pregnant females were allowed to give birth and the second generation (F1A).28 males/28 females per group were selected from litters of this mating. Shortly after all females had weaned their litters, all first generation animals (F0) were re-mated using alternative pairings, pregnant females being sacrificed at Day 20 of pregnancy.

The second generation (F1A) were mated after 12 weeks of treatment and dams were allowed to give birth; direct treatment was considered to have commenced at nominal 4 weeks of age although of course some exposure either directly or indirectly occurred prior to this in utero, through the milk during lactation and/or as weanlings made the transition to diet containing the test material. A limited number of second generation (F1A) animals were re-mated, including all those where proof of successful mating could not be established after the first mating. Dams of each generation which gave birth were allowed to rear their litters to weaning (Day 21 post partum) - culling was not performed. During the pre-weaning period a number of developmental landmark tests were performed on the F1A and F2A pups in excl. litter. All pups were subjected to macroscopic examination and additionally, for selected F1A pups selected organ weights were recorded.

For F0 generation dams mated for a second time and subsequently killed at Day 20 of pregnancy, their offspring (F1B foetuses) were examined for visceral and skeletal changes. Histopathological examinations were performed for the reproductive tract tissues of the F0 and F1A generations adults, and also the kidneys and liver of FIA generation adults treated at 0 (Control) and 50000 ppm. Additionally. tissues with macroscopic findings from adult animals of all groups including the controls, were also examined.

At 50000 ppm two deaths occurred. These deaths were not considered to be treatment-related. At this dose level marginally lower bodyweight gain during gestation (for F0 second mate and F1A females) as well as slightly longer median pre-coital time (F1A first mate only) and two total litter losses with evidence which may suggest three total resorptions among F1A dams were observed. Slightly increased embryonic death, mainly early at F0 second mate and slightly lower foetal bodyweight for F0 second mate as well as slightly lower pup bodyweight gain F0 first mate were seen in this group. Also a higher incidence of F0 second mate foetuses (F1B) with variant sternebrae was documented.

At 25000 ppm also two mortalities occurred, neither of these deaths were considered to be treatment-related. A marginally lower bodyweight gain during gestation (for F0 second mating and F1A females) was noted as well as slightly longer median pre-coital time (F1A first mate only). Further findings were two total litter losses(one in the F0 and the other in the F1A generations) and evidence which may suggest one total resorption among F1A dams, slightly increased embryonic deaths (mainly early, F0 second mate) and slightly lower pup bodyweight gain (F0 first mate). At 10000 ppm, all parameters inclusive of fertility and general reproductive performance were essentially similar to the controls throughout.

The pregnancy rate (% of pregnant females) at both 25000 and 50000 ppm was slightly lower than controls in the F1A generation. However, the differences were considered to be coincidental since the numbers of animals of either sex which were of unproven fertility in two matings of either generation was essentially similar compared with the controls. There was no effect on pup development tests and no macroscopic/ microscopic findings at any treatment level which were considered indicative of an adverse effect of treatment. For adults of the F0 and F1A generation, there were no macroscopic/microscopic findings at any treatment level which were considered indicative of an adverse effect of treatment with beta-cyclodextrin.

At dietary concentrations of 50000 ppm beta-cyclodextrin and to a lesser extent at 25000 ppm, there was some evidence of adverse effects on the parent animals and offspring although in general the effects were slight and there were few findings consistent through both generations. Reproductive performance and fertility of adults treated at these dietary concentrations were not unduly compromised. A dietary concentration of 10000 ppm was considered to show no adverse effect upon either the treated parent animals or their offspring, in terms of growth, development, fertility and general reproductive performance.

 

Beta-cyclodextrin (> 99% pure) was administered by admixture in the diet at dose levels of 5 %, 2.5 % and 1.25 % to groups of 30 male and 30 female Ico: OFA. SD (lOPS Caw) rats in a three generation reproduction test. The parental (P) generation males and females were maintained on the treated diets for ten and two weeks respectively before pairing and during the gestation and lactation periods of three successive mating periods. A similar group of rats received the untreated basal diet over the same periods and served as a control group. Two subsequent generations, comprised of 25 males and 25 females, randomly selected from the F1b and F2b litters, were treated with dietary concentrations of 1.25 %, 0.62 % and 0.31 % of beta-cyclodextrin (groups 4, 3 and 2 respectively). The dose levels were reduced three weeks before mating of the F1 generation in order to confirm the definition of a no effect level.

The offspring from the third mating of the P generation (P - F1c) were used to investigate the effects of vitamin D supplementation on pup growth. The F1 and F2 generations were each mated twice and allowed to raise their offspring to weaning. The study was terminated with a third mating phase of the F2 animals with caesarean examination of the pregnant females and soft tissue and skeletal examination of the foetuses. All animals were observed daily for clinical signs of toxicity. Body weight and food consumption were monitored during the respective pre-mating, gestation and lactation periods. Fertility and reproductive performance of the P, F1 and F2 generations were assessed by evaluation of mating performance, duration of gestation, parturition and viability, growth and development of the pups. Non-selected pups were submitted to a necropsy examination on or soon after day 21post partum.At terminal necropsy the adult males and females of each generation were given a detailed macroscopic examination ; selected organs were weighed and selected tissues were examined histopathologically.

The initial high dose level of 5 % beta-cyclodextrin caused minimal toxicity in the parental males only, characterised by a minor reduction in body weight gain. This dose level also caused a slight reduction in the rate of growth of the pups of the treated dams. A corresponding reduction in maternal food consumption during lactation was observed, but the magnitude of this difference was considered insufficient to account for the effect on pup growth. The available evidence would suggest a maternally-mediated nutritional influence arising from the physical and chemical nature of the test article rather than a direct toxic effect on the litter. Beta-cyclodextrin is intended for use in food as a carrier of smaller lipid-soluble molecules. It is possible that the observed effects in this study were caused by the test article in the diet encapsulating or otherwise interfering with the absorption of lipid-soluble vitamins or nutrients from the gastrointestinal tract. In the present study, however, the effect was not prevented by vitamin D supplementation, suggesting the involvement of another phenomenon.

Administration of the lower initial dose levels, of 2.5 % and 1.25 %. resulted in only minimal differences in pup growth. No clear no effect level was determined with these doses, but all of the observed differences with respect to the control group could be regarded as both minimal and equivocal. Further investigations on the two subsequent generations (each composed of two or three mating phases) did not reveal any indications of treatment-related toxicity with dose levels of 1.25 % or lower. Therefore after consideration of all of the data generated during this study, the dose level of 1.25 % was considered to represent a no adverse effect level.

The highest dietary concentration of 5 % beta-cyclodextrin tested in this study caused a slight reduction in perinatal pup growth. However, there were no subsequent adverse influences on the reproductive performance and development of the two subsequent generations derived from the affected litters, which were then continuously treated with 1.25 % beta-cyclodextrin. Moreover, the affected offspring of the first generation generally recovered the difference in body weight with respect to the control group after reduction of the dietary concentration to 1.25%.

The highest no adverse effect level, identified under the defined experimental conditions of this study was 1.25 %. No adverse effects on fertility, reproductive performance in utero foetal development or physical pup development were found with any of the dietary concentrations of beta-cyclodextrin tested in this study.

 


Short description of key information:
In a three generation reproduction test in rats only slight effects on body weight gain of the offspring were observed in the medium (2.5% of feed) and high dose group (5%). No effect was observed in the 1.25% group (874/1610 mg/kg bw/day [P males/females]).

Effects on developmental toxicity

Description of key information
In a teratogenicity assay in rats no effect could be observed in the low and medium dose groups (1250 and 2500 mg/kg bw/day). Only in the high dose group of 5000 mg/kg bw/day the body weight gain of the pregnat rats was reduced. The NOEL is set to be 2500 mg/kg bw/day  for maternal toxicity and 5000 mg/kg bw for teratogenicity. 
Effect on developmental toxicity: via oral route
Dose descriptor:
NOAEL
2 500 mg/kg bw/day
Additional information

A teratogenicity study of .beta.-cyclodextrin (92.5 % pure) according to OECD 414 was carried out in Sprague-Dawley rats. Four groups, each comprising 20 females, beta Cyclodextrin was administered by oral gavage at levels of 0; 1250; 2500 and 5000 mg/kg body weight/d respectively from day 7 to day 16. The day the presence of spermatozoa was observed on the vaginal smear was considered as day 1 of gestation and the females were sacrificed on day 21 of gestation. In the high dose group five females died from gavage accidents between day 7 and day 17. Necropsy revealed oesophageal perforation for the 5 females. On day 1, there were no statistically significant differences between control and each treated group concerning the body weight variability or mean. The treated animals presented a reduced body weight gain from the beginning of the treatment period. The difference was statistically significant for the high dose group from day 8. At cessation of treatment, the body weight gain of the animals of this group was similar to that of the controls but their body weight at day 21 was still significantly decreased. During the first and third weeks of the study there were no significant differences between control and treated groups concerning food consumption. During the second week which corresponds to the treatment period, a significant decrease in food consumption was noted for mid and high dose groups and (- 7.4 and -19,2 %). No statistical differences were noted on food conversion efficiency during the 3 weeks, between control and treated groups, despite an increase observed during week 2 for mid and high dose groups. Water consumption was similar in all groups during the first week. The visceral examination by technique and skeletal examination by alizarin technique of rat fetuses. from darns treated during the sensitive phase of embryogenesis with the test substance at the oral doses of 1250, 2500 and 5000 mg/kg/day did not reveal any detectable embryotoxic or teratogenic effect. Following parameters were examined in litters: weight of full and empty uterus, weight of placenta, number of live and dead foetuses, number of implantation sites and resorptions, number of corpora lutea, ratio - resorption/implantation. No differences are noted between the groups. The following parameters were examined in foetuses: weight and size of the foetuses, sex, ratio male/live foetuses, ratio female/male. The only significant difference in both sexes is the increased size of the foetuses in groups low and mid dose groups, compared with controls: +0 0.3 (0.84%) and + 0.4 mm (1.14%) respectively for males and females in low dose group + 0.6 (1.68%) and + 0.6 mrn (1.72%) respectively for males and females in the mid dose group.  During the study, it was observed that the administration of beta-cyclodextrin at doses of 0, 1250, 2500 or 5000 mg/kg induced at the high dose level only, a statistically significant reduction of body weight gain in females, accompanied by a reduction of food consumption. On the other hand, these females showed difficulty in swallowing the gavage suspension, and five of them died following oesophageal perforation. The dose level of 5000 mg/kg in a volume of 10 ml/kg is the limit of ingestion in this type of study . The lower dose of 2500 mg/kg per day had no toxic effect on the females. However this produced no observable differences in the weight of the uteri and placentae, the number of live (100%) or dead (0%) foetuses, the number of implantation sites, resorptions and corpora lutea The same applies to the following foetal parameters: size, body weight, sex ratio, visceral and skeletal examinations. which indicate no embryotoxic or teratogenic effects ascribable to the treatment. No embryotoxic or teratogenic effects were observed. It is concluded that beta-cyclodextrin administration at levels up to 2500 mg/kg bw/d had no adverse effect observable on pregnant females and at levels up to 5000 mg/kg bw/d had no adverse effect observable in that kind of study on litters and foetuses.

 

Following a pilot investigation at dose levels of 500 and 2 500 mg/kg bw/day a teratology study was performed in Wistar rats given beta-cyclodextrin as a suspension in 1.25% aqueous methyl cellulose by gavage at doses of 0, 100, 500 and 2 500 mg/kg bw/day on days 7-16 of pregnancy. The group sizes were 26-28 sperm positive females, of which 22-25/group proved to be pregnant. The dams were sacrificed on day 21 and the following parameters monitored: number of corpora lutea and implantations, preimplantation loss, embryonic and late fetal mortality, and number of viable fetuses. About 50% of the fetuses from each litter were examined for soft tissue defects ('s technique) and the remainder were cleared, stained (Alizarin Red or Alcian Blue/Alizarin red) and examined for skeletal anomalies. The doses used in this study had no effect on the clinical condition, food consumption or weight gain of the dams and there were no significant effects on intra-uterine mortality, viable fetuses or on the incidence or type of congenital malformation. The anomalies recorded in this study were regarded as sporadic and unrelated to treatment, and had been seen previously among fetuses from over 600 control dams. Under the conditions of this study, there was no evidence of fetotoxicity or teratogenicity

A teratogenicity study was conducted with beta-Cyclodextrin in CFY rats in which groups of 40 mated females (30 in control group) with positive vaginal smears were given beta-cyclodextrin by gavage in 1% methyl cellulose suspension at dose levels of 0, 200, 400 and 600 mg/kg bw/dy on days 7-11 post coitus. The animals were killed on day 21 and the number of implants, resorptions, live and dead fetuses, fetal weights and rates of congenital anomalies recorded (no details were given of the methodology of the teratological examinations). The conception rate was poor (about 30%) giving only 11-12 pregnant animals in each group. Five animals from the top and middose groups and 1 from the low-dose group died during the study, the deaths being attributed to bronchopneumonia due to misdosing. Maternal weight gain was reduced in a dose-related manner but there were no changes in mean number of implants (12.7 -14.1), resorptions (1.3-7.3%) fetal viability (93-99%) or fetal weight (3.5-3.9 g). There were 5 congenital anomalies reported out of 628 fetuses, 2 in the low-dose group (hydronephrosis, cardiac anomaly), 1 in the middose group (cardiac anomaly) and 2 in the top-dose group (both absence of right kidney); no anomalies were seen in the control group. No details were given of any examination for skeletal anomalies.

Justification for classification or non-classification