Barium, 1,4-bis (C13-rich C11-14-isoalkyl) 2-sulfobutanedioate phosphate complex

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 11 February and 04 August 2008.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 21/08/2007 Date of Signature: 15/10/2007

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

dibarium(2+) bis(1,5-dioxo-1,5-bis(tridecyloxy)pentane-3-sulfonate) hydrogen phosphate

EC Number:

931-037-9

Molecular formula:

Molecular formula for each combination of chain length. C13,13: (C30H57O7S)2 Ba @ BaHOP4 C11,12: (C27H51O7S)2 Ba @ BaHOP4 C12,12: (C28H53O7S)2 Ba @ BaHOP4 C12,13: (C29H55O7S)2 Ba @ BaHOP4 C13,14: (C31H59O7S)2 Ba @ BaHOP4 C14,14: (C32H61O7S)2 Ba @ BaHOP4

IUPAC Name:

dibarium(2+) bis(1,5-dioxo-1,5-bis(tridecyloxy)pentane-3-sulfonate) hydrogen phosphate

Details on test material:

Identification : Barium di(bistridecylsulfosuccinate) in mixture with barium hydrogen phosphate
Description : Pale yellow solid
Batch number : Y-T-1
Storage conditions: room temperature in the dark

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (U.K) Limited, Margate, Kent
- Age at study initiation: 5 to 8 weeks old.
- Weight at study initiation: Males weighed 249 to 284g and the females weighed 176 to 215g.
- Fasting period before study: Animals were not fasted prior to sampling.
- Housing: The animals were housed in groups of five by sex in solid polypropylene cages with stainless steel mesh lids and softwood flake bedding.
- Diet: A pelleted diet (Rodent 5LF2 (Certified) Diet, BCM IPS Limited, London, UK) was used (ad libitum).
- Water (e.g. ad libitum): Mains water was supplied from polycarbonate bottles attached to the cage. The diet and drinking water was considered not to contain any contaminant at a level that might have affected the purpose or integrity of the study.
- Acclimation period: The animals were acclimatised for nine days during which time their health status was assessed.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): The temperature was set to achieve target values of 21 +/- 2°C
- Humidity (%): Relative humidity controls were set to achieve 55 +/- 15%.
- Air changes (per hr): The rate of air exchange was at least fifteen air changes per hour.
- Photoperiod (hrs dark / hrs light): The low intensity fluorescent lighting was controlled to give twelve hours continuous light and twelve hours darkness.

IN-LIFE DATES: From: Day1 To:Day 28

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: Dimethylsulphoxide/polyethylene glycol 400 at a ratio of 10:90

Details on oral exposure:

Method of administration:
Gavage
PREPARATION OF DOSING SOLUTIONS: For the purpose of this study the test material was prepared at the appropriate concentrations as a suspension in Dimethylsulphoxide/polyethylene glycol 400 at a ratio of 10:90

DIET PREPARATION
- Rate of preparation of diet (frequency): Not applicable
- Mixing appropriate amounts with (Type of food): Not applicable.
- Storage temperature of food: Not applicable.


VEHICLE
- Justification for use and choice of vehicle: The stability and homogeneity of the test material fromulations were determined. Results show the fromulations to be stable for at least fourteen days.
- Concentration in vehicle: 0 mg/ml (for 0 mg/kg/day dose level), 3.75 mg/ml (for 15 mg/kg/day dose level), 37.5 mg/ml (for 150 mg/kg/day dose level). 62.5 mg/ml (for 250 mg/kg/day dose level)
- Amount of vehicle (if gavage): 4 ml/kg bodyweight
- Lot/batch no. (if required): Not stated
- Purity: Not stated

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of each test material formulation were taken and analysed for concentration of Barium di (bistridecylsulfosuccinate) in mixture with Barium hydrogen phosphate at Safepharm Analytical Laboratory. The method used for analysis of formulations and the results obtained are given in Appendix 15 (see attached background material). The results indicate that the prepared formulations were within acceptable levels of the nominal concentration.

Duration of treatment / exposure:

Test duration: 28 days

Frequency of treatment:

Dosing regime: 7 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:

Basis:
other: Dose levels of 15, 150 and 250 mg/kg/day

No. of animals per sex per dose:

Male and Female: 5 animals per sex at 0 mg/kg/day (control group)
Male and Female: 5 animals per sex at 15 mg/kg/day
Male and Female: 5 animals per sex at 150 mg/kg/day
Male and Female: 5 animals per sex at 250 mg/kg/day

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
PRELIMINARY FOURTEEN DAY REPEATED DOSE ORAL (GAVAGE) RANGE-FINDER IN THE RAT
The range-finder was performed to establish the maximum tolerated dose level (up to 1000 mg/kg/day) of the test material following repeated oral administration to rats, and to provide information for selection of dose levels for use in the twenty-eight day oral toxicity phase.

Preliminary sighting work treating one male and one female was undertaken at dose levels of 1000, 500 and 250 mg/kg/day for up to three days. This resulted in interim deaths at 1000 mg/kg/day on Day 3, and bodyweight losses at 500 mg/kg/day. Three groups, each of six rats (three males and three females) were therefore dosed as follows:

Dose Level (mg.kg/day) Treatment Volume (ml/kg) Concentration (mg/ml)
0 (control) 4 0
150 4 37.5
250 4 62.5

The test material was administered daily, for fourteen consecutive days, by gavage using a stainless steel cannula attached to a disposable plastic syringe. Control animals were treated in an identical manner with 4 ml/kg/day of Dimethlysulphoxide/polyethylene glycol 400 at a ratio of 10:90.

The volume of test and control material administered to each animal was based on the most recent bodyweight and was adjusted Days 4, 8 and 11.

Clinical Observations:
All animals were examined for overt signs of toxicity, ill health or behavoiural change immediately before, after dosing, and one hour after dosing. Allobservations were recorded.

Bodyweight:
Individual bodyweights were recorded on Days 1, 4, 8, 11 and 15.

Necropsy:
On completion of the dosing period, all animals were killed by cerevical dislocation and immediately subjected to an internal and external macroscopic examination. No tissues were retained.

Evaluation of Data:
Necropsy data, bodyweights and clinical observations were examined for any adverse effects resulting from treatment. The data obtained was summarised in tabular form and used to provide the basis for selection of dose levels for the twenty-eight day phase.

Results:
Mortality:
There were no unscheduled deaths during the study.

Clinical Observations:
Animals of either sex treated with 250 mg/kg/day showed episodes of increased salivation immediately after dosing from Day 1 onwards, whilst female 150 mg/kg/day animals showed sporadic episodes of increased salivation immediately after dosing from Day 4. In addition noisy and decreased respiration was evident in one male treated with 250 mg/kg/day on Day 1. Furthermore noisy respiration was also observed in this male and one 250 mg/kg/day female on Day 11.
No such effects were detected in males treated with 150 mg/kg/day.

Bodyweight
No adverse effect on bodyweight development was detected for treatment animals, in comparison to controls.

Necropsy
There were no macroscopic abnormalities detected in the test or control animals at terminal kill.

CONCLUSION
The dose levels for the twenty-eight day phase of the study were chosen, following consultation with the Sponsor, as:
High dose: 250 mg/kg/day
Intermediate dose: 150 mg/kg/day
Low dose: 15 mg/kg/day
- plus a control group treated with vehicle alone.




- Rationale for animal assignment (if not random): The rat was selected for this study as it is a readily available rodent species rodent historically used in safety evaluation studies and is acceptable to appropriate regulatory authorities.
- Rationale for selecting satellite groups: Not applicable
- Post-exposure recovery period in satellite groups: 14 days: Not applicable
- Section schedule rationale (if not random): Not applicable

Positive control:

None

Examinations

Observations and examinations performed and frequency:

Clinical Observations:
All animals were examined for overt signs of toxicity, ill-health or behavioural change immediately before dosing, immediately post dosing and one and five hours after dosing during the working week. Animals were observed immediately before and after dosing and one hour after dosing at weekends and public holidays. All observations were recorded.

Functional Observations:
Prior to the start of treatment and on Days 5, 12, 18 and 25, all animals were observed for signs of functional/behavioural toxicity. Functional performance tests were also performed on all animals during Week 4, together with an assessment of sensory reactivity to different stimuli. Observations were carried out from at least two hours after dosing on each occasion.

Behavioural Assessments:
Detailed individual clinical observations were performed for each animal using a purpose built arena. The following parameters were observed:
Gait Hyper/Hypothermia
Tremors Skin colour
Twitches Respiration
Convulsions Palpebral closure
Bizarre/Abnormal/Stereotypic behaviour Urination
Salivation Defecation
Pilo-erection Transfer arousal
Exophthalmia Tail elevation
Lachrymation
The scoring system used is outlined in The Key to Scoring System and Explanation for Behavioural Assessments and Sensory Reactivity Tests (see attached background material).

Functional Performance Tests:
Motor Activity: Twenty purpose built 44 infra-red beam automated activity monitors were used to assess motor activity. Animals of one sex were tested at each occasion and were randomly allocated to the activity monitors. The evaluation period was one hour for each animal. The time in seconds each animal was active and mobile was recorded for the overall one hour period and also during the final 20% of the period (considered to be the asymptotic period).
Forelimb/Hindlimb Grip Strength: An automated grip strength meter was used. Each animal was allowed to grip the proximal metal bar of the meter with its forepaws. The animal was pulled by the base of the tail until its grip was broken. The animal was drawn along the trough of the meter by the tail until its hind paws gripped the distal metal bar. The animal was pulled by the base of the tail until its grip was broken. A record of the force required to break the grip for each animal was made. Three consecutive trials were performed for each animal.

Sensory Reactivity:
Each animal was individually assessed for sensory reactivity to auditory, visual and proprioceptive stimuli. The scoring system used is outlined in The Key to Scoring System and Explanation for Behavioural Assessments and Sensory Reactivity Tests (see attached background material).
The following parameters were observed:
Grasp response Touch escape
Vocalisation Pupil reflex
Toe pinch Blink reflex
Tail pinch Startle reflex
Finger approach

Bodyweight:
Individual bodyweights were recorded on Day 1 and at weekly intervals thereafter. Bodyweights were also performed prior to terminal kill.

Food Consumption:
Food consumption was recorded for each cage group at weekly intervals throughout the study.

Water Consumption:
Water intake was observed daily, for each cage group, by visual inspection of the water bottles for any overt changes, except during Week 3 when water intake was measured and recorded daily for each cage group.

Laboratory Investigations:
Haematological and blood chemical investigations were performed on all surviving animals from each test and control group at the end of the study (Day 28). Blood samples were obtained from the lateral tail vein. Where necessary repeat samples were obtained by cardiac puncture prior to necropsy on Day 29. Animals were not fasted prior to sampling.
The methods used for haematological and blood chemical investigations are given in Appendix 16 and normal ranges are shown in Appendix 17 (see attached background material).

Haematology:
Haemoglobin (Hb)
Erythrocyte count (RBC)
Haematocrit (Hct)
Erythrocyte indices - mean corpuscular haemoglobin (MCH)
- mean corpuscular volume (MCV)
- mean corpuscular haemoglobin concentration (MCHC)
Total leucocyte count (WBC)
Differential leucocyte count - neutrophils (Neut)
- lymphocytes (Lymph)
- monocytes (Mono)
- eosinophils (Eos)
- basophils (Bas)
Platelet count (PLT)
Reticulocyte count (Retic) - Cresyl blue stained slides were prepared but reticulocytes were not assessed.

Prothrombin time (CT) was assessed by ‘Innovin’ and Activated partial thromboplastin time (APTT) was assessed by ‘Actin FS’ using samples collected into sodium citrate solution (0.11 mol/l).

Blood Chemistry:
The following parameters were measured on plasma from blood collected into tubes containing lithium heparin anti-coagulant:
Urea Calcium (Ca++)
Glucose Inorganic phosphorus (P)
Total protein (Tot.Prot.) Aspartate aminotransferase (ASAT)
Albumin Alanine aminotransferase (ALAT)
Albumin/Globulin (A/G) ratio (by calculation) Alkaline phosphatase (AP)
Sodium (Na+) Creatinine (Creat)
Potassium (K+) Total cholesterol (Chol)
Chloride (Cl-) Total bilirubin (Bili)

Sacrifice and pathology:

Pathology:
On completion of the dosing period all surviving animals were killed by intravenous overdose of sodium pentobarbitone followed by exsanguination.
All animals were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded.

Organ Weights:
The following organs, removed from animals that were killed at the end of the study, were dissected free from fat and weighed before fixation:
Adrenals Liver
Brain Ovaries
Epididymides Spleen
Heart Testes
Kidneys Thymus

Normal ranges for these organ weights are given in Appendix 18 (see attached background material).

Histopathology:
Samples of the following tissues were removed from all animals and preserved in buffered 10% formalin:
Adrenals Oesophagus
Aorta (thoracic) Ovaries
Bone & bone marrow (femur including stifle joint) Pancreas
Bone & bone marrow (sternum) Pituitary
Brain (including cerebrum, cerebellum and pons) Prostate
Caecum Rectum
Colon Salivary glands (submaxillary)
Duodenum Sciatic nerve
Epididymides ♦ Seminal vesicles
Eyes Skin (hind limb)
Gross lesions Spinal cord (cervical, mid-thoracic and lumbar
Heart
Ileum Spleen
Jejunum Stomach
Kidneys Testes ♦
Liver Thymus
Lungs (with bronchi)# Thyroid/parathyroid
Lymph nodes (cervical and mesenteric) Trachea
Muscle (skeletal) Urinary bladder Uterus
♦ = preserved in Bouin’s fluid then transferred to Industrial Methylated Spirits (IMS) up to 48 hours later
# = Lungs were inflated to approximately normal inspiratory volume with buffered 10% formalin before immersion in fixative


All tissues were despatched to the Test Site (RCC Ltd, Zelgliweg, 422 Itingen, Switzerland) for processing (Principal Investigator: K Weber). The tissues shown in bold from all control and 250 mg/kg/day dose group animals were prepared as paraffin blocks, sectioned at nominal thickness of 5 µm and stained with haematoxylin and eosin for subsequent microscopic examination. Any macroscopically observed lesions were also processed together with the liver and spleen from all 15 and 150 mg/kg/day dose group animals.
Microscopic examination was conducted by the Study Pathologist. All findings were entered into the ROELEE Pathology computerisation system for tabulation and report production.

Other examinations:

None.

Statistics:

Evaluation of Data
Data were processed to give group mean values and standard deviations where appropriate.
All data was summarised in tabular form. Where appropriate, quantitative data were analysed by the Provantis™ Tables and Statistics Module. For each variable, the most suitable transformation of the data was found, the use of possible covariates checked and the homogeneity of means assessed using ANOVA or ANCOVA and’s test. The transformed data were analysed to find the lowest treatment level that showed a significant effect, using the Williams Test for parametric data or the Shirley Test for non-parametric data. If no dose response was found, but the data showed non-homogeneity of means, the data were analysed by a stepwise Dunnett (parametric) or Steel (non-parametric) test to determine significant differences from the control group. Finally, if required, pair-wise tests were performed using the Student t-test (parametric) or the Mann-Whitney U test (non-parametric).
Probability values (p) are presented as follows:
p < 0.01 **
p < 0.05 *
p ≥0.05 (not significant)

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

no effects observed

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not specified

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY:
Mortality: There were no unscheduled deaths attributed to test material toxicity.
One female treated with 250 mg/kg/day was killed in extremis on Day 19. The cause of death was unknown following histopathological examination. There were no further unscheduled deaths during the study.

Clinical Observations:
A summary incidence of daily clinical observations is given in Table 1.
No clinically observable signs of toxicity were detected.
Incidental findings of increased salivation up to one hour post dose were observed for the 250 and 150 mg/kg/day males with increased salivation detected up to ten minutes after dosing for females treated with 150 mg/kg/day. Increased salivation up to ten minutes after dosing was also observed for one 15 mg/kg/day male on Days 26 and 27 only. Increased salivation is often reported following oral administration of an unpalatable or slightly irritant test material formulation and in the absence of any supporting data is considered not to be an indication of systemic toxicity. In addition an isolated episode of noisy respiration was evident for one 250 mg/kg/day male and scab formation was observed for one 15 mg/kg/day male between Days 16 to 20. In isolation these findings are considered incidental and of no toxicological importance.
Prior to being killed in extremis the 250 mg/kg/day female showed laboured, gasping and decreased respiration with loss of righting reflex, prostration, lethargy and pallor of the extremities.
No such effects were detected for females treated with 15 mg/kg/day.



BODY WEIGHT AND WEIGHT GAIN:
Group mean weekly bodyweights and standard deviations are given in Table 6 and are presented graphically in Figure 1 and Figure 2. Group mean weekly bodyweight gains and standard deviations are given in Table 7 (statistically significant differences are indicated). Individual data are given in Appendix 4 and Appendix 5.
Males treated with 250 mg/kg/day showed a statistically significant increase in bodyweight gain (p<0.05) during Week 1 of treatment, with recovery evident thereafter.
No such effect was detected for females treated with 250 or animals of either sex treated with 150 and 15 mg/kg/day.



FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
Not applicable.

FOOD EFFICIENCY:
Group mean weekly food consumptions are given in Table 8 and are presented graphically in Figure 3 and Figure 4. Weekly food efficiencies are given in Table 9.
No adverse effects on dietary intake or food efficiency were detected for treated animals in comparison to controls.


WATER CONSUMPTION:
Group mean daily water consumptions are given in Table 10.
Daily visual inspection of water bottles and daily measurements undertaken during Week 3 of treatment did not reveal any inter-group differences for treated animals when compared to controls.


OPHTHALMOSCOPIC EXAMINATION:
No data.


HAEMATOLOGY:
Group mean values and standard deviations for test and control group animals are given in Table 11 (statistically significant differences are indicated). Individual data are given in Appendix 6 and Appendix 7.
There were no toxicologically significant changes detected in the haematological parameters measured.
A slight but statistically significant increases in haematocrit counts (p<0.05) was evident for females treated with 250 and 15 mg/kg/day. In the absence of any supporting findings this is considered to be of no toxicological significance.
No such effects were detected for males treated with 250 mg/kg/day, animals of either sex treated with 150 mg/kg/day or 15 mg/kg/day males.



CLINICAL CHEMISTRY:
Group mean values and standard deviations for test and control group animals are given in Table 12 (statistically significant differences are indicated). Individual data are given in Appendix 8.
A statistically significant increase in alanine aminotransferase levels (p<0.01) was observed in animals of either sex treated with 250 mg/kg/day and males treated with 150 mg/kg/day. In addition, a statistically significant increase in alkaline phosphatase was also apparent for females treated with 250 mg/kg/day and 150 mg/kg/day (p<0.05 and p<0.01 respectively).
Females treated with 250 and 150 mg/kg/day showed a slight but statistically significant increase in urea levels (p<0.05). All values were within the normal range for rats of the strain and age used and in the absence of any supporting findings this is considered to be of no toxicological significance.
No such effects were detected for animals of either sex treated with 15 mg/kg/day.



URINALYSIS:
No data


NEUROBEHAVIOUR:
Functional Observations-
A summary incidence of behavioural assessments is given in Table 2 and 3. Group mean functional test values and standard deviations are given in Table 4 (statistically significant differences are indicated). Individual values are given in Appendix 1 and Appendix 2. A summary incidence of sensory reactivity assessments is given in Table 5. Individual responses are given in Appendix 3.


Behavioural Assessments:
There were no treatment-related changes in the behavioural parameters measured.
All remaining inter and intra group differences in urination, defecation, tail elevation and transfer arousal scores were considered to be a result of normal variation for rats of the strain and age used and are considered to be of no toxicological importance.

Functional Performance Tests:
There were no toxicologically significant changes in the functional performance parameters measured.
A statistically significant increase in forelimb grip strength was seen in females treated with 250 and 150 mg/kg/day in comparison to controls (p<0.05). The increase was observed in only one out of three tests performed on this parameter and in the absence of any supporting clinical observations to suggest an effect of neurotoxicity, this finding is considered to be of no toxicological significance.
No such effect was detected for male treatment animals.

Sensory Reactivity Assessments:
There were no treatment-related changes in sensory reactivity.
Statistical analysis of the data revealed no significant inter-group differences.



ORGAN WEIGHTS:
Group mean absolute and relative organ weights and standard deviations for test and control group animals are presented in Table 13 (statistically significant differences are indicated). Individual data are given in Appendix 9 and Appendix 10.
A statistically significant reduction in liver weights (p<0.05) both absolute and relative to terminal bodyweight was evident for females treated with 250 mg/kg/day. Females treated with 150 mg/kg/day showed a statistically significant increase in absolute liver weights with a statistically significant reduction in relative liver weights (p<0.05), in comparison to terminal bodyweight.
A statistically significant increase in spleen weights (p<0.05); both absolute and relative to terminal bodyweights was detected for females treated with 15 mg/kg/day. In the absence of a convincing dose related response this finding is considered to be of no toxicological significance.
No such effects were detected for male treatment animals.



GROSS PATHOLOGY:
A summary incidence of necropsy findings is given in Table 14. Individual data are given in Appendix 11.
No treatment-related macroscopic abnormalities were detected at terminal kill.
Findings were confined to three 250 mg/kg/day males observed with enlarged kidneys and one 250 mg/kg/day male showed a reddened, patchy caudal lobe of the lung. In the absence of an effect on organ weight measurements or any histopathological correlates these findings were considered to be of no toxicological significance.
The interim death female showed gaseous distension of the stomach, duodenum, jejunum and ileum together with reddened lungs. In the absence of any histopathological correlates these findings were considered to be of no toxicological importance.
No such effects were observed for the remaining 250 mg/kg/day females or animals of either sex treated with 150 mg/kg/day and 15 mg/kg/day.



HISTOPATHOLOGY: NON-NEOPLASTIC:
A summary incidence of histopathological findings is given in Table 15. Individual data and the grading system are given in Appendix 12.
The following treatment-related changes observed:
LIVER: Periportal hepatocyte vacuolation was evident in females treated with 250 mg/kg/day and 150 mg/kg/day. One female treated with 15 mg/kg/day was similarly affected but periportal hepatocyte vacuolation is occasionally seen in the liver of control animals such that an association with treatment cannot be reliably inferred at this dose level.
A greater incidence of higher grades of severity of scattered lipid vacuolation was also seen in the 250 mg/kg/day females, in comparison to controls; this is more likely to be associated with periportal lipid accumulation in these animals at this treatment level rather than a separate effect of treatment.
Similar effects were not seen for male treatment animals; there being no instances of periportal hepatocyte vacuolation and the group distribution of scattered hepatocyte vacuolation did not demonstrate a relationship to treatment.
There was no histopathological indication as to the poor condition of the 250 mg/kg/day female which was killed in extremis.



HISTOPATHOLOGY: NEOPLASTIC (if applicable)
Not applicable.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

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

Sex:

male/female

Basis for effect level:

other: There were no treatment-related effects seen in animals at 15 mg/kg/day, therefore the “No Observed Effect Level” (NOEL) was considered to be 15 mg/kg/day.

2

Dose descriptor:

NOAEL

Effect level:

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

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Please refer to the attached background material for all scoring system, result tables, figures and Appendixes referred to above.

Applicant's summary and conclusion

Conclusions:

Oral (gavage) administration of Barium di (bistridecylsulfosuccinate) in mixture with Barium hydrogen phosphate to rats for a period of up to twenty-eight days at dose levels of up to 250 mg/kg/day resulted in treatment-related effects at 250 and 150 mg/kg/day. The changes observed were confined to minimal changes observed in the blood chemistry and the liver and considered not to be adaptive in nature. Therefore the “No Observed Adverse Effect Level” (NOAEL) for animals of either sex was considered to be 250 mg/kg/day. There were no treatment-related effects seen in animals at 15 mg/kg/day, therefore the “No Observed Effect Level” (NOEL) was considered to be 15 mg/kg/day.

Executive summary:

Introduction.

The study was designed to investigate the systemic toxicity of the test material. It complies with the requirements for notification of a new chemical substance in the EC and follows the testing method described in Commission Directive 96/54/EC (Method B7) and OECD Guidelines for Testing of Chemicals No. 407 "Repeated Dose 28 Day Oral Toxicity Study in Rodents" (Adopted 27 July 1995).

Methods.

The test material was administered by gavage to three groups, each of five male and five female Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, for up to twenty-eight consecutive days, at dose levels of 15, 150 and 250 mg/kg/day. A control group of five males and five females was dosed with vehicle alone (DMSO/PEG 400).

Clinical signs, functional observations, bodyweight development and food and water consumption were monitored during the study. Haematology and blood chemistry were evaluated for all surviving animals at the end of the study.

All animals were subjected to gross necropsy examination and histopathological evaluation of selected tissues was performed.

Results.

Mortality.

There were no unscheduled deaths attributed to test material toxicity.

One female treated with 250 mg/kg/day was killedin extremison Day 19. The cause of death was unknown following histopathological examination. There were no further unscheduled deaths during the study.

Clinical Observations.

No clinically observable signs of toxicity were detected.

Behavioural Assessment.

There were no treatment-related changes in the behavioural parameters measured.

Functional Performance Tests.

There were no toxicologically significant changes in the functional performance parameters measured.

Sensory Reactivity Assessments.

There were no treatment-related changes in sensory reactivity.

Bodyweight.

Males treated with 250 mg/kg/day showed an increase in bodyweight gain during Week 1 of treatment only, in comparison to controls.

No such effect was detected for females treated with 250 mg/kg/day or animals of either sex treated with 150 and 15 mg/kg/day.

Food Consumption.

No adverse effects on dietary intake or food efficiency were detected for treated animals in comparison to controls.

Water Consumption.

No adverse effect on water consumption was detected for treated animals in comparison to controls.

Haematology.

There were no toxicologically significant changes detected in the haematological parameters measured.

Blood Chemistry.

An increase in alanine aminotransferase levels was observed in animals of either sex treated with 250 mg/kg/day and males treated with 150 mg/kg/day. In addition an increase in alkaline phosphatase was also apparent for females treated with 250 and 150 mg/kg/day.

No such effect was detected for animals of either sex treated with 15 mg/kg/day.

Organ Weights.

A reduction in liver weights both absolute and relative to terminal bodyweight was evident for females treated with 250 mg/kg/day. Females treated with 150 mg/kg/day showed an increase in absolute liver weights with a reduction in relative liver weights, in comparison to controls.

No such effect was detected for male treatment animals and no toxicologically significant effect was seen in the 15 mg/kg/day females.

Necropsy.

No treatment-related macroscopic abnormalities were detected for the interim death female or the remaining animals at terminal kill.

Histopathology.

The following treatment-related changes were observed:

LIVER:Periportal hepatocyte vacuolation was evident in females treated with 250 mg/kg/day and 150 mg/kg/day. 

A greater incidence of higher grades of severity of scattered lipid vacuolation was also seen at the 250 mg/kg/day females, in comparison to controls.

There was no histopathological indication as to the condition of the 250 mg/kg/day female which was killedin extremis.

Conclusion.

Oral (gavage) administration of Barium di (bistridecylsulfosuccinate) in mixture with Barium hydrogen phosphate to rats for a period of up to twenty-eight days at dose levels of up to 250 mg/kg/day resulted in treatment-related effects at 250 and 150 mg/kg/day. The changes observed were confined to minimal changes observed in the blood chemistry and the liver and considered not to be adaptive in nature. Therefore the “No Observed Adverse Effect Level” (NOAEL) for animals of either sex was considered to be 250 mg/kg/day. There were no treatment-related effects seen in animals at 15 mg/kg/day, therefore the “No Observed Effect Level” (NOEL) was considered to be 15 mg/kg/day.