Pyridinium, 1-[[(6R,7R)-7-[[(2Z)-(2-amino-4-thiazolyl)[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]-, chloride, hydrochloride (1:1:1)

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

Cas Number:

73547-70-3

Molecular formula:

C22-H22-N6-O7-S2.2 H-Cl

Specific details on test material used for the study:

Identification : Ceftazidime dihydrochloride
Identification Number : 73547-70-3 (CAS number)
Physical State/Appearance : White powder
Assigned Purity (%w/w) - dry : 99.2% w/w (as dihydrochloride)
Assigned Purity (%w/w) : 95.663% w/w (as dihydrochloride)
Batch Number : G317308
Storage Conditions : Store in darkness and cold (approximately 4 °C);
used/formulated in light and at ambient temperature
(10 to 30 °C)
Expiry Date : 26 October 2018
Re-Test Date : 26 October 2018
No correction for purity was made.

Test animals

Species:

rat

Strain:

Wistar

Details on species / strain selection:

Wistar Han™:RccHan™:WIST strain

Sex:

male/female

Details on test animals or test system and environmental conditions:

A sufficient number of male and female Wistar Han™:RccHan™:WIST strain rats were
obtained from Envigo RMS (UK) Limited, Blackthorn, Bicester, Oxon, UK. On receipt the
animals were examined for signs of ill-health or injury. The animals were acclimatized for
nineteen days during which time their health status was assessed. Following the day of
arrival, vaginal smears were performed for all females throughout the acclimatization period
and females considered not showing appropriate estrous cycling activity were excluded from
treatment groups at least five days before the start of treatment. A total of ninety six animals
(forty eight males and forty eight females) were accepted into the study. At the start of
treatment the males weighed 286 to 367g, and were approximately eleven weeks old. The
females weighed 194 to 231g, and were approximately fourteen weeks old.
3.3.2 Animal Care and Husbandry
Initially, all animals were housed in groups of three in solid floor polypropylene cages with
stainless steel mesh lids and softwood flake bedding (Datesand Ltd., Cheshire, UK). During
the pairing phase, animals were transferred to polypropylene grid floor cages suspended over
trays lined with absorbent paper on a one male: one female basis within each dose group.
Following evidence of successful mating, the males were returned to their original cages.
Mated females were housed individually during gestation and lactation in solid floor
polypropylene cages with stainless steel mesh lids and softwood flakes.
The animals were allowed free access to food and water. A pelleted diet (Rodent 2018C
Teklad Global Certified Diet, Envigo RMS (UK) Limited, Oxon, UK.) was used. A
certificate of analysis of the batch of diet used is given in Annex 6. Mains drinking water
was supplied from polycarbonate bottles attached to the cage. Environmental enrichment
was provided in the form of wooden chew blocks and cardboard fun tunnels (Datesand Ltd.,
Cheshire, UK) except for paired animals and mated females during gestation and lactation.
Mated females were also given softwood flakes, as bedding, throughout gestation and
lactation. The diet, drinking water, bedding and environmental enrichment was considered
not to contain any contaminant at a level that might have affected the purpose or integrity of
the study.
The animals were housed in a single air-conditioned room within the Envigo Research
Limited, Shardlow, UK Barrier Maintained Rodent Facility. The rate of air exchange was at
least fifteen air changes per hour and the low intensity fluorescent lighting was controlled to
give twelve hours continuous light and twelve hours darkness. Environmental conditions
were continuously monitored by a computerized system, and print-outs of hourly
temperatures and humidities are included in the study records. The Study Plan target ranges
for temperature and relative humidity were 22 ± 3 °C and 50 ± 20% respectively. Short term
deviations from these targets were considered not to have affected the purpose or integrity of
the study; see deviations from Study Plan.
The animals were randomly allocated to treatment groups using a stratified body weight
randomization procedure and the group mean body weights were then determined to ensure
similarity between the treatment groups. The cage distribution within the holding rack was
also randomized. The animals were uniquely identified within the study by an ear punching
system routinely used in these laboratories.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Remarks:

MW 400 avg

Details on exposure:

For the purpose of this study the test item was prepared at the appropriate concentrations as a
suspension in Polyethylene glycol 400. The stability and homogeneity of the test item
formulations were determined by Envigo Research Limited, Shardlow, UK, Analytical
Services. Results showed the formulations to be stable for two hours at 2.5, 12.5 and 50
mg/mL and for thirteen days at 187.5 mg/mL. Formulations were therefore prepared daily
for the low and intermediate dose levels and weekly for the high dose level and stored at
approximately 4 ºC in the dark.

Details on mating procedure:

Animals were paired on a 1 male: 1 female basis within each dose group, for a period of up to
fourteen days. Cage tray-liners were checked each morning for the presence of ejected
copulation plugs and each female was examined for the presence of a copulation plug in the
vagina. A vaginal smear was prepared for each female and the stage of estrus or the presence
of sperm was recorded. The presence of sperm within the vaginal smear and/or vaginal plug
in situ was taken as positive evidence of mating (Day 0 of gestation) and the males were
subsequently returned to their original holding cages. Mated females were housed
individually during the period of gestation and lactation.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of test item formulations were taken on two occasions and analyzed for
concentration of Ceftazidime dihydrochloride at Envigo Research Limited, Shardlow, UK,
Analytical Services. The results indicate that the prepared formulations were 95-107% of
the nominal concentration.

Duration of treatment / exposure:

Males - Daily upto Day 45
Females- daily upto 13 days post partum

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

50 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

200 mg/kg bw/day (actual dose received)

Doses / concentrations 4

Dose / conc.:

750 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

12 (twelve)

Control animals:

yes, concurrent vehicle

Details on study design:

The animals were randomly allocated to treatment groups using a stratified body weight
randomization procedure and the group mean body weights were then determined to ensure
similarity between the treatment groups. The cage distribution within the holding rack was
also randomized. The animals were uniquely identified within the study by an ear punching
system routinely used in these laboratories.

Positive control:

N/A

Examinations

Parental animals: Observations and examinations:

Clinical Observations
All animals were examined for overt signs of toxicity, ill-health and behavioral change
immediately before dosing, soon after dosing, and one hour after dosing during the working
week (except for females during parturition where applicable). All observations were
recorded.

Body Weight
Individual body weights were recorded on Day 1 (prior to dosing) and then weekly for males
until termination and weekly for females until pairing. During pairing phase females were
weighed daily until mating was confirmed. Body weights were then recorded for females on
Days 0, 7, 14 and 20 post coitum, and on Days 1, 4, 7 and 14 post partum. Body weights
were also recorded at terminal kill.

Food Consumption
During the pre-pairing period, weekly food consumption was recorded for each cage of
adults. This was continued for males after the mating phase. For females showing evidence
of mating, food consumption was recorded for the periods covering post coitum Days 0-7,
7-14 and 14-20. For females with live litters, food consumption was recorded for the periods
covering post partum Days 1-4, 4-7 and 7-14.
Food efficiency (the ratio of body weight change/dietary intake) was calculated
retrospectively for males throughout the study period (with the exception of the mating
phase) and for females during the pre-pairing phase. Due to offspring growth and milk
production, food efficiency could not be accurately calculated during gestation and lactation.

Water Consumption
Water intake was observed daily by visual inspection of water bottles for any overt changes.

Pregnancy and Parturition
Each pregnant female was observed at least three times a day (early morning, mid-day and as
late as possible during the normal working day) around the period of expected parturition.
Observations were carried out at approximately 0830 and as late as possible at weekends and
public holidays. The following was recorded for each female:
i. Date of pairing
ii. Date of mating
iii. Date and time of observed start of parturition
iv. Date and time of observed completion of parturition

Oestrous cyclicity (parental animals):

Vaginal smears were taken daily for females throughout the two week pre-pairing treatment
period and in the morning of the day of necropsy. The stage of the estrous cycle was
recorded for each day.

Sperm parameters (parental animals):

Detailed qualitative examination of the testes was undertaken, taking into account the tubular
stages of the spermatogenic cycle. The examination was conducted in order to identify
treatment-related effects such as missing germ cell layers or types, retained spermatids,
multinucleated or apoptotic germ cells and sloughing of spermatogenic cells into the lumen.
Any cell-or stage-specificity of testicular findings was noted.

Litter observations:

On completion of parturition (Day 0 post partum), the number of live and dead offspring was
recorded. Offspring were individually identified within each litter by tattoo on Day 1 post
partum.
All live offspring were assessed for ano-genital distance on Day 1 post partum. Additionally,
visible nipple count was performed for all male offspring on Day 13 post partum.
For each litter the following was recorded:
i. Number of offspring born
ii. Number of offspring alive recorded daily and reported on Days 1, 4, 7 and 13 post
partum
iii. Sex of offspring on Days 1, 4 and 13 post partum
iv. Clinical condition of offspring from birth to Day 13 post partum
v. Individual offspring weights on Days 1, 4, 7 and 13 post partum (litter weights were
calculated retrospectively from this data)

Postmortem examinations (parental animals):

SACRIFICE
Adult males were killed by intravenous overdose of suitable barbiturate agent followed by
exsanguination on Day 44 or 45. Adult females were killed by intravenous overdose of
suitable barbiturate agent followed by exsanguination on Day 14 post partum. Surviving
offspring were terminated by carbon dioxide asphyxiation followed by cervical dislocation on
Day 13 post partum. Offspring required for blood sampling were terminated by cervical
dislocation with death confirmed by decapitation during the sampling procedure with blood
samples collected immediately following decapitation. Any females which failed to achieve
pregnancy or produce a litter were killed around the same time as littering females.

GROSS NECROPSY
For all females, the uterus was examined for signs of implantation and the number of uterine implantations in each horn was recorded. This procedure was enhanced; as necessary, by staining the uteri with a 0.5% ammonium polysulphide solution (Salewski 1964).
All adult animals and offspring, including those dying during the study, were subjected to a
full external and internal examination, and any macroscopic abnormalities were recorded.
Examination of offspring was restricted to a macroscopic external examination except where abnormalities were observed, then an additional internal examination was performed.

Organ Weights
The following organs were dissected free from fat and weighed before fixation from five
selected males and five selected females from each dose group. Tissues with asterisk were
weighed from all remaining animals:
Adrenals
Prostate*
Brain
Seminal Vesicles (with coagulating gland)*
Epididymides*
Spleen
Heart
Testes
Kidneys
Thymus
Liver
Thyroid (weighed partially fixed with Parathyroid)*
Ovaries*
Uterus (weighed with Cervix)*
Pituitary (weighed partially fixed)*

Histopathology
Samples of the following tissues were removed from five selected males and five selected
females from each dose group and preserved in buffered 10% formalin, except where stated.
Tissues with asterisk were preserved from all remaining animals:
Adrenals                                                                      Muscle (skeletal)
Aorta (thoracic)                                                         Ovaries*
Bone & bone marrow (femur including stifle joint)        Pancreas
Bone & bone marrow (sternum)                                   Pituitary*
Brain (including cerebrum, cerebellum and pons)           Prostate*
Cecum                                                                          Rectum
Colon                                                                          Salivary glands (submaxillary)
Cowpers Glands*                                                        Sciatic nerve
Duodenum                                                                      Seminal vesicles (with coagulating gland)*
Epididymides ♦*
Esophagus                                                                      Skin
Eyes *                                                                             Spinal cord (cervical, mid-thoracic and lumbar)
Glans Penis*
Gross lesions*                                                                      Spleen
Heart                                                                                   Stomach
Ileum (including peyer’s patches)                                         Testes ♦*
Jejunum                                                                             Thyroid/Parathyroid
Kidneys                                                                             Trachea
LABC (levator ani-bulbocavernous) muscle*                        Thymus
Liver                                                                                  Urinary bladder
Lungs (with bronchi)#                                                           Uterus & Cervix (with oviducts)*
Lymph nodes (mandibular and mesenteric)                            Vagina*
Mammary gland*  


*  Eyes fixed in Davidson’s fluid
♦  preserved in Modified Davidsons fluid
# lungs were inflated to approximately normal inspiratory volume with buffered 10% formalin before
immersion in fixative

Postmortem examinations (offspring):

Examination of offspring was restricted to a macroscopic external examination except where
abnormalities were observed, then an additional internal examination was performed.

Statistics:

See below

Reproductive indices:

The following parameters were calculated from the individual data during the mating period
of the parental generation:
i. Pre-coital Interval
Calculated as the time elapsing between initial pairing and the observation of positive
evidence of mating.

ii. Fertility Indices
For each group the following were calculated:

Mating Index (%) = (# mated animals / # paired animals) x 100

Pregnancy Index (%) = (# pregnant females / # animals mated) x100

Gestation and Parturition Data
The following parameters were calculated from individual data during the gestation and
parturition period of the parental generation:

i. Gestation Length
Calculated as the number of days of gestation including the day for observation of
mating and the start of parturition.

ii. Parturition Index

The following was calculated for each group:
Parturition Index (%) = (# females delivering live offspring /# pregnanat females) x100

Offspring viability indices:

The standard unit of assessment was considered to be the litter, therefore values were first
calculated for each litter and the group mean was calculated using their individual litter
values. Group mean values included all litters reared to termination (Day 13 of age).

i. Implantation Losses (%)
Group mean percentile post-implantation loss was calculated for each female/litter as
follows:

Post–implantation loss (%) = [(# implantation sites- # offspring born) / #implantation sites] x100

ii. Live Birth and Viability Indices
The following indices were calculated for each litter as follows:

Live Birth Index (%) = (# offfspring born alive day 1/ # offspring born ) x100

Viability Index 1 (%) = (# offfspring alive day 4/ # offspring alive day 1 ) x100

Viability Index 2 (%) = (# offfspring alive day 13/ # offspring alive day 4 ) x100


Viability index 2 takes into consideration the offspring used for blood sampling on
Day 4 post partum.

iii. Sex Ratio (% males)

Sex ratio was calculated for each litter value on Days 1, 4 and 13 post partum, using
the following formula:

(# male offspring/ total # offspring) x 100

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Animals of either sex treated with 750 mg/kg bw/day showed incidences of increased
salivation from Day 3 (females) and Day 9 (males) onwards. Three males treated with 200
mg/kg bw/day also showed incidences of increased salivation between Days 31 and 37 and
one female treated with 200 mg/kg bw/day showed an isolated instance on Day 51. Instances
of noisy respiration were evident in the majority of animals of either sex treated with 750 and
200 mg/kg bw/day from Day 1 (males) and Day 2 (females) onwards and in four males and
six females treated with 50 mg/kg bw/day from Day 1 (males) and Day 22 (females)
onwards. Observations such as increased salivation and noisy respiration are commonly
observed following the oral administration of an unpalatable or irritant test item formulation
and represent difficulties in dosing particular animals rather than evidence of true systemic
toxicity.
Incidental observations, unrelated to test item administration, included noisy respiration in
three control males on one occasion only, an open wound and then scab formation in one
male treated with 50 mg/kg bw/day, vocalization in one female treated with 50 mg/kg bw/day
on one occasion only, generalized fur loss in one female treated with 200 mg/kg bw/day and
pilo-erection and hunched posture in one female treated with 750 mg/kg bw/day on one
occasion only.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males treated with 750 mg/kg bw/day showed a reduction in body weight gain during Weeks
1 and 3 of treatment. Body weight gain for these males was comparable to controls during
Weeks 2 and 4; however, body weight gain was again reduced during Weeks 5 and 6 of
treatment. Statistical significance (p<0.01) was achieved for these males during Weeks 3 and
5. Overall body weight gain for males treated with 750 mg/kg bw/day was 27% lower than
controls.
No adverse effects were evident in males treated with 200 or 50 mg/kg bw/day.
A statistically significant reduction (p<0.01) in body weight gain was evident in males treated
with 200 and 50 mg/kg bw/day during Week 5, however, body weight gain prior to and after
this week was comparable to controls and no effect was evident on overall body weight gain.
The intergroup difference was therefore considered of no toxicological significance.
No adverse effect in body weight development was evident in treated females during
maturation, gestation or lactation.
Females treated with 750 and 200 mg/kg bw/day showed statistically significant increases
(p<0.05) in body weight gain during the first week of treatment and subsequently, higher
overall body weight gain during maturation was evident in these females. An increase in
body weight gain is considered not to represent an adverse effect of treatment.
Females treated with 750 mg/kg bw/day showed a statistically significant reduction (p<0.05)
in body weight gain during the first week of gestation. Body weights for these females on
Day 0 and Day 7 of gestation were actually higher than control females, therefore, a lower
body weight gain during this period is not unexpected and is considered not to be of
toxicological significance. Females treated with 750 mg/kg bw/day also showed a
statistically significant reduction (p<0.01) in body weight gain during the final week of
lactation. Body weight gain for these females throughout gestation and lactation were within
historical control ranges and no effect on body weight was evident. Body weight gain for
these females during the first week of lactation also exceeded control females, therefore, the
intergroup difference was considered not to be of toxicological significance.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Males treated with 750 mg/kg bw/day showed a reduction (7%) in overall food consumption,
with the reduction being most significant during Weeks 1, 2, 4 and 6. Females from this
treatment group also showed a reduction (13%) in food consumption during maturation.
No such effects were evident in animals of either sex treated with 200 or 50 mg/kg bw/day.
No effect on food conversion efficiency was evident in treated males or in treated females
during maturation.
Females treated with 750 mg/kg bw/day showed a statistically significant reduction (p<0.05)
in food consumption during the second Week of gestation. Individual values were within
historical control ranges and no effect was evident in the first or final week of gestation. The
intergroup difference was therefore considered not to be of toxicological significance.

Food efficiency:

no effects observed

Description (incidence and severity):

No effect on food conversion efficiency was evident in treated males or in treated females
during maturation.

Water consumption and compound intake (if drinking water study):

no effects observed

Description (incidence and severity):

There was no effect of treatment on water consumption for either sex at 50, 200 or 750 mg/kg
bw/day; daily visual inspection of water bottles revealed no overt intergroup differences.

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

There were no toxicologically significant changes in the hematological parameters examined.
Males treated with 750 mg/kg bw/day showed statistically significant reductions in
erythrocyte count (p<0.01), hematocrit (p<0.05), neutrophils (p<0.01) and eosinophils
(p<0.01). With the exception of two individual values for erythrocyes and hematocrit, all
remaining individual values for these parameters were within the historical control ranges.
Two control values for neutrophils and four control values for eosinophils were actually
above the historical control ranges. In the absence of any associated histopathological
correlates the intergroup differences were considered not to be of toxicological significance.
Males from all treatment groups showed statistically significant reductions (p<0.05-0.01) in
total leukocyte count and lymphocytes. With the exception of one individual value for both
parameters, all remaining individual values were within the historical control ranges and one
control value for lymphocytes and two control values for total leukocyte count were above
the historical control ranges. A true dose related response was not observed for either
parameter, and in the absence of any associated histopathological correlates, the intergroup
differences were considered not to be of toxicological significance.
Females treated with 750 mg/kg bw/day showed statistically significant reductions in mean
corpuscular hemoglobin, mean corpuscular volume and platelet count. All of the individual
values for mean corpuscular hemoglobin and mean corpuscular volume were within the
historical control ranges, however, three individual values for platelet count were below the
historical control range. In the absence of any associated histopathological correlates, the
intergroup differences were considered not to be of toxicological significance.
Females treated with 200 mg/kg bw/day showed a statistically significant increase in mean
corpuscular hemoglobin concentration. All of the individual values were within the historical
control range and in the absence of a similar effect at 750 mg/kg bw/day, the intergroup
difference was considered not to be of toxicological importance.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Males treated with 750 mg/kg bw/day showed statistically significant increases (p<0.05) in
cholesterol, alanine aminotransferase and albumin/globulin ratio and a statistically significant
reduction (p<0.05) in total protein.
No such effects were evident in females treated with 750 mg/kg bw/day or in animals of
either sex treated with 200 or 50 mg/kg bw/day.
Males from all treatment groups showed statistically significant reductions (p<0.05-0.01) in
alkaline phosphatase and bile acids. With the exception of one individual alkaline
phosphatase value at 750 and 200 mg/kg bw/day, all remaining values were within the
historical control ranges and therefore were considered not to be of toxicological importance.
Males treated with 750 and 200 mg/kg bw/day also showed a statistically significant increase
(p<0.05) in potassium concentration and a statistically significant reduction (p<0.05) in
calcium concentration. The majority of individual values were within the historical control
ranges and in the absence of a true dose related response, the intergroup differences were
considered not to be of toxicological importance.
Females treated with 750 and 200 mg/kg bw/day showed a statistically significant reduction
in bile acids. Females treated with 750 mg/kg bw/day also showed statistically significant
increases (p<0.05-0.01) in albumin and albumin/globulin ratio. All of the individual values
were within the historical control ranges, therefore, the intergroup differences were
considered not to be of toxicological importance.

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

There were no toxicologically significant changes in functional performance.
Females treated with 750 mg/kg bw/day showed a statistically significant reduction (p<0.05)
in forelimb grip strength, however, the effect was confined to one out of the three tests.
Females from all treatment groups also showed a statistically significant reduction (p<0.05)
in the final 20% of activity. In the absence of a true dose related response, any similar effects
in males or any clinical signs of neurotoxicity, the intergroup differences were considered not
to be toxicologically significant.

Sensory Reactivity Assessments
Intergroup differences observed in the scores for sensory reactivity did not indicate any effect
of treatment for either sex at 50, 200 or 750 mg/kg bw/day.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

The following treatment-related microscopic abnormalities were detected:
Liver: Centrilobular eosinophilia was present in four females treated with 750 mg/kg bw/day.
Centrilobular necrosis was present in two females and centrilobular vacuolation was present
in one other female treated with 750 mg/kg bw/day.
Increased rarefaction in the centrilobular region was present in two males treated with 200
mg/kg bw/day and in all males treated with 750 mg/kg bw/day.
No changes related to treatment were present in the liver of any males or females treated with
50 mg/kg bw/day or females treated with 200 mg/kg bw/day.
There were no test item-related microscopic findings in the reproductive tracts following the
qualitative examination of the stages of spermatogenesis in the testes (no test item-related
abnormalities in the integrity of the various cell types present within the different stages of
the sperm cycle) or the evaluation of the uterus or of follicles and corpora lutea in the ovaries.

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Description (incidence and severity):

Evaluation of Thyroxine (T4) in adult males and offspring at Day 13 of age did not identify
any obvious effect of treatment or indication of endocrine disruption at 50, 200 or 750 mg/kg
bw/day.
Statistical analysis of the data did not reveal any significant intergroup differences.

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

Assessment of estrous cycles during the pre-pairing phase of the study or at necropsy did not
indicate any obvious effect of treatment at 50, 200 or 750 mg/kg bw/day.

Reproductive function: sperm measures:

no effects observed

Description (incidence and severity):

There were no test item-related microscopic findings in the reproductive tracts following the
qualitative examination of the stages of spermatogenesis in the testes (no test item-related
abnormalities in the integrity of the various cell types present within the different stages of
the sperm cycle)

Reproductive performance:

no effects observed

Description (incidence and severity):

Mating performance as assessed by the number of paired animals that mated was unaffected
by treatment at dosages of 50, 200 or 750 mg/kg bw/day.
There was no effect on fertility, as assessed by the number of females that achieved
pregnancy, at dosages of 50, 200 or 750 mg/kg bw/day.
One control female failed to achieve pregnancy following positive evidence of mating and
another control female had implantation sites but failed to give birth to any live offspring.
Histopathological examinations of the females and respective male partners did not show any
significant changes to account for the lack of pregnancy or offspring born. In view of the fact
these findings were in the control group, they were considered incidental.
The intergroup distribution of gestation lengths observed during the study did not indicate
any obvious effect of treatment at 50, 200 or 750 mg/kg bw/day.

Details on results (P0)

Litter Responses
In total ten females from the control group and twelve females from the 50, 200 and
750 mg/kg bw/day dose groups gave birth to a live litter and successfully reared young to
Day 13 of age. The following assessment of litter response is based on all litters reared to
termination on Day 13 of lactation/age.

Offspring Growth and Development
Group mean values for total litter weights, offspring body weights and body weight changes,
a summary incidence of clinical signs, ano-genital distance and visible nipple counts (male
offspring) are given in Tables 14, 17, 18 and 19. Individual values and observations are
given in Appendices 13, 16, 17 and 18.
There was no effect of treatment with the test item indicated by offspring body weight or
body weight gain, visible nipple count in male offspring on Day 13 post partum, or
anogenital distance at 50, 200 or 750 mg/kg bw/day.
Statistical analysis of the data did not reveal any significant intergroup differences.
Clinical signs apparent for the offspring during the study were generally typical of the age
observed and neither the distribution nor incidence of these findings indicated any effect of
maternal treatment.
Statistical analysis of the data did not reveal any significant intergroup differences.

Offspring Litter Size, Sex Ratio and Viability

There was no effect of maternal treatment on the number of implantations, post-implantation
loss and live birth index, and subsequent offspring survival to Day 13 of age at dosages of 50,
200 or 750 mg/kg bw/day. Sex ratio for the offspring was similar to control in all treated
groups and did not indicate any selective effect of maternal treatment on survival for either
sex at any of the dosages investigated.

Effect levels (P0)

Dose descriptor:

NOEL

Effect level:

ca. 750 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive function (oestrous cycle)

reproductive function (sperm measures)

reproductive performance

Target system / organ toxicity (P0)

1

Critical effects observed:

no

Lowest effective dose / conc.:

750 mg/kg bw/day (actual dose received)

System:

male reproductive system

2

Critical effects observed:

no

Lowest effective dose / conc.:

750 mg/kg bw/day (actual dose received)

System:

female reproductive system

Results: F1 generation

Effect levels (F1)

Dose descriptor:

NOEL

Generation:

F1

Effect level:

ca. 750 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

clinical signs

body weight and weight gain

other: visible nipple count in males; anogenital distance

Overall reproductive toxicity

Reproductive effects observed:

no

Applicant's summary and conclusion

Conclusions:

The oral administration of Ceftazidime dihydrochloride to rats by gavage, at dose levels of
50, 200 and 750 mg/kg bw/day, resulted in reduced body weight gains in males treated with
750 mg/kg bw/day and microscopic liver changes in animals of either sex treated with
750 mg/kg bw/day and in males treated with 200 mg/kg bw/day. The ‘No Observed Effect
Level’ (NOEL) for systemic toxicity was therefore considered to be 200 mg/kg bw/day for
females and 50 mg/kg bw/day for males.
The increased cytoplasmic rarefaction in the liver of males was most likely due to variation in
glycogen storage within the cells and is generally considered to be an adaptive response,
therefore, a No Observed Adverse Effect Level (NOAEL) for males was considered to be
200 mg/kg bw/day.
The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be
750 mg/kg bw/day.