Reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide

Endpoint summary

Description of key information

There is no evidence of adverse effects arising from repeated exposure to substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide".
There were no treatment related adverse effects at all in a 28-day oral toxicity study performed according to OECD Guideline No. 407 and EEC Directive 84/449/EEC, Part B.7. Up to and including the highest dose tested of 1000 mg/kg bw/day, no mortality occurred and there were no changes in clinical appearance, body weights, food consumption, ophthalmoscopic examination, clinical laboratory investigations, macroscopic examinations, organ weights and microscopic examination that were considered to be an adverse effect of treatment. Thus, up to and including the guideline limit dose the substance was non-toxic.
Considering the unlikeliness of dermal absorption of an inorganic, sparingly soluble ionic solid of lamellar structure, systemic effects via this exposure route are hardly probable. Inhaled and subsequently swallowed amounts may decompose under the strong acidic conditions of the stomach and the released ions may become bioavailable. However, even under worst case considerations no toxicity deriving from the released ions is expected. Further on, from assessment data on structurally related substances, there are also no indications on an intrinsic systemic activity. Thus, no adverse effects to humans are expected to occur from repeated exposure to the substance. Nonetheless, the general dust limits apply and used in accordance with ECHA REACH TGD R.8 as DNEL surrogate.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-03-26 to 1991-05-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP, Guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

EEC Directive 84/449 EEC, EEC Publication No. L251, September 1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Mai 12, 1981

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: US Food and Drug Administration, Bureau of Foods, Toxicological Principles for the Safety Assessment of Direct Food Additives and Colour Additives used in Food

Version / remarks:

1982

Deviations:

no

GLP compliance:

yes

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

- Source: BRL Ltd., Basel, Switzerland
- Age at study initiation: approximately 6 weeks
- Housing: Group housing of 5 animals per sex per cage in stainless steel suspended cages with wire mesh floors.
- Diet: standard pelleted laboratory animal diet (Kliba, Klingentalmühle AG, Kaiseraugst, Switzerland) ad libitum
- Water: tap water ad libitum
- Acclimation period: At least 7 days. Veterinary examination was performed prior to commencement of treatment to ensure that animals were in a good state of health.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21°C
- Humidity (%): 55 %
- Air changes (per hr): 15
- Photoperiod: Lighting was 12 hours artificial fluorescent light and 12 hours dark per day.

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Details on oral exposure:

TEST SUBSTANCE FORMULATION

Method: The test substance was weighed into a glass flask on an analytical balance and the vehicle (w/w) added. Adjustement was made for specific gravity of vehicle (1.127).
Frequency of test substance formulation: Daily immediately prior to dosing.
Homogeneity of test substance in vehicle: By use of a magnetic stirrer, an electric shaker and a homogeniser. Homogeneity during treatment was maintained using a magnetic stirrer.
Storage instructions for test substance formulation: At ambient temperature.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of formulations prepared were analysed to check homogeneity and accuracy of preparation.

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily, approximately the same time each day, 7 days per week.

Dose / conc.:

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

Remarks:

negative control (vehicle only): gavage, dose volume: 5 mL/kg body weight, actual dose volume: calculated weekly according to the latest body weight

Dose / conc.:

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

Remarks:

gavage, dose volume: 5 mL/kg body weight, actual dose volume: calculated weekly according to the latest body weight

Dose / conc.:

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

Remarks:

gavage, dose volume: 5 mL/kg body weight, actual dose volume: calculated weekly according to the latest body weight

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

Remarks:

gavage, dose volume: 5 mL/kg body weight, actual dose volume: calculated weekly according to the latest body weight

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: A 5-day range finding study was performed (with 3 rats/sex/group at dose levels of 50, 200 and 1000 mg/kg bw/day) to provide a basis for selection of dose levels for a study of longer duration.
No differences of biological significance were observed in clinical appearence, body weight, food consumption, macroscopic appearance or liver weights between the treated groups.
Based on these observations, a high treatment level of 1000 mg/kg bw/day was selected for a study of 28 days duration.

Positive control:

no

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule:
-- clinical signs: at least once daily
-- mortality/viability: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Severity of observations were graded

BODY WEIGHT: Yes
- Time schedule for examinations: weekly and on the day preceding termination, prior to overnight fasting

FOOD CONSUMPTION: Yes
- Time schedule: weekly

FOOD EFFICIENCY: No

WATER CONSUMPTION: Yes
- Subjective appraisal was maintained during the study period, but no quantitative assessment introduced as no effect was suspected

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: before commencement of treatment and during the last week of treatment
- Both eyes were examined following instillation of tropicamide solution (5 mg/mL)
- Dose groups that were examined: all

HAEMATOLOGY: Yes
- Time schedule for collection of blood: immediately prior to post mortem examination
- Anaesthetic used for blood collection: Yes (light ether anesthesia)
- Animals fasted: Yes (overnight before blood sampling, but water was provided)
- How many animals: all rats/sex/group
- Parameters examined: erythrocyte count, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelet count, red cell distribution, total leucocyte count, differential leucocyte count (neutrophils, eosinophils, basophils, lymphocytes, monocytes)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: immediately prior to post mortem examination
- Animals fasted: Yes (overnight before blood sampling, but water was provided)
- How many animals: all rats/sex/group
- Parameters examined: glucose, urea, creatinine, bilirubine, aspartate aminotransferase (ASAT/GOT), alanine aminotransferase (ALAT/GPT), gamma-glutamyl transferase (G-GT), sodium, potassium, chloride, calcium, phosphorus, total protein, albumin

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
- How many animals: all rats/sex/group

ORGAN WEIGHTS: Yes
- How many animals: all rats/sex/group
- Organs examined: adrenal glands, heart, kidneys, liver, spleen, testes

HISTOPATHOLOGY: Yes
- How many animals: all rats/sex/group
- Tissues and organs samples fixed: adrenal glands, aorta, brain, cecum, cervix, clitoral gland, colon, duodenum, epididymides, esophagus, eyes with optic nerve and Harderian gland, female mammary gland area, femur including joint, heart, ileum, jejunum, kidneys, larynx, lacrimal gland (exorbital), liver, lung (infused with formalin), lymph nodes (mandibular, mesenteric), nasopharynx, ovaries, pancreas, pituitary gland, preputial gland, prostate gland, rectum, salivary glands (mandibular, sublingual), sciatic nerve, seminal vesicles, skeletal muscle, skin, spinal cord (cervical, midthoracic, lumbar), spleen, sternum with bone marrow, stomach, testes, thymus, thyroid including parathyroid, tongue, trachea, urinary bladder, uterus, vagina, all gross lesions
- Slides of tissues and organs examined: adrenals, heart, kidneys, liver, spleen, stomach

Statistics:

The following statistical methods were used to analyse the body weight, organ weights and clinical laboratory data:
- Univariate one-way analysis of variance was used to assess the significance of intergroup differences.
- If the variables could be assumed to follow a normal distribution, the Dunnett-test (many to one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups.
- The Steel-test (many-one rank test) was applied when the data could not be assumed to follow a normal distribution.
- All tests were two-sided and in all cases p<0.05 was accepted as the lowest level of significance.
- Group means were calculated for continuous data and medians were calculated for discrete data (scores) in the summary tables.
- The exact Fisher-test was applied to the ophthalmoscopic examination data.

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):

no effects observed

Food efficiency:

not examined

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

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY

There were no relevant clinical signs of toxicity or behavioural changes considered to be related to treatment over the 29 day observation period.

Excessive salivation was noted intermittently in treated males and females receiving 50, 200 or 1000 mg/kg bw/day. Since this may be attributed to a possible irritant effect or bad taste of the test substance, it was considered not to represent a clear sign of toxicity.

Incidental findings (i.e. scabs, alopecia and rough coat) as noted in single animals receiving 200 or 1000 mg/kg bw/day, showed no relationship to treatment and were therefore considered to have occurred fortuitously.

MORTALITY

No mortality occurred during the study period.

BODY WEIGHT AND WEIGHT GAIN

Body weights and body weight gain of treated animals remained in the same range as controls over the 4 week study period.

A minor statistically significant difference arising between body weight gain of females receiving 1000 mg/kg bw/day and control females was within normal biological variation for rats of this age and strain and considered to have arisen by chance.

FOOD CONSUMPTION

There were no differences in food consumption before and after allowance for body weight between treated and control animals.

OPHTHALMOSCOPIC EXAMINATION

There were no differences between the pretest examination and the examination at week 4 that could be attributed to treatment with the test substance.

HAEMATOLOGY

Haematological parameters of treated rats were considered not to have been affected by treatment.

The incidentally statistically significantly decreased relative number of monocytes between control females and females receiving 1000 mg/kg bw/day was considered not to have been arisen as a result of toxicity.

CLINICAL CHEMISTRY

There were no differences noted between control and treated rats that could be related to treatment with the test substance.

Statistically significantly increased glucose values between treated and control males were, in the absence of a treatment-related distribution, considered to have occurred fortuitously.

ORGAN WEIGHTS

Organ weights and relative organ weights of treated animals were indistinguishable from those of control animals.

GROSS PATHOLOGY

Macroscopic observations at necropsy did not reveal any alterations that were considered to have arisen as an effect of treatment.

Pelvic dilatation in the kidney, which was noted incidentally among control and treated females, is commonly noted in rats of this age and strain and considered not to represent a sign of toxicity.

HISTOPATHOLOGY: NON-NEOPLASTIC

There were no microscopic findings noted that were considered to be treatment related. The small number of changes recorded in treated animals were within the range commonly seen for rats of this age and strain.

Key result

Dose descriptor:

NOEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat. (total fraction)

Sex:

male/female

Basis for effect level:

other: no adverse effects up to and including the highest dose tested which is the guideline limit dose

Remarks on result:

other:

Remarks:

No mortality occurred during the study. There were no changes in clinical appearance, body weights, food consumption, ophthalmoscopic examination, clinical laboratory investigations, macroscopic examinations, organ weights and microscopic examination that were considered to be an adverse effect of treatment up to and including the highest tested dose level of 1000 mg/kg bw/day.

Key result

Critical effects observed:

no

Conclusions:

No mortality occurred during the study. There were no changes in clinical appearance, body weights, food consumption, ophthalmoscopic examination, clinical laboratory investigations, macroscopic examinations, organ weights and microscopic examination that were considered to be an adverse effect of treatment up to and including the highest tested dose level of 1000 mg/kg bw/day, which is the guideline limit dose.

Executive summary:

In a subacute toxicity study according to OECD Guideline No. 407, Mai 12, 1981 and EEC Directive 84/449/EEC, Part B.7, September 1984, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" (90 % a.i.) was administered to groups of 5 Wistar rats per dose and sex by gavage at dose levels of 0, 50, 200, and 1000 mg/kg bw/day.

In this study up to and including the highest dose tested (1000 mg/kg bw/day), no mortality occurred and there were no changes in clinical appearance, body weights, food consumption, ophthalmoscopic examination, clinical laboratory investigations, macroscopic examinations, organ weights and microscopic examination that were considered to be an adverse effect of treatment.

The NOAEL is 1000 mg/kg bw/day.

This subacute oral toxicity study in the rat is acceptable and satisfies the guideline requirements.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Reliable, adequate and relevant data from guideline study available.

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Critical effects observed:

not specified

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Critical effects observed:

not specified

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There is no evidence of adverse effects arising from repeated exposure to substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide".

There were no treatment related adverse effects at all in a 28-day oral toxicity study performed according to OECD Guideline No. 407 and EEC Directive 84/449/EEC, Part B.7. Up to and including the highest dose tested of 1000 mg/kg bw/day, no mortality occurred and there were no changes in clinical appearance, body weights, food consumption, ophthalmoscopic examination, clinical laboratory investigations, macroscopic examinations, organ weights and microscopic examination that were considered to be an adverse effect of treatment. Thus, up to and including the guideline limit dose the substance was non-toxic.

Repeated dose toxicity studies by dermal application are not available. The substance is non-toxic by acute dermal application (LD₅₀ dermal rat > 2000 mg/kg bw) and in a reliable, relevant and adequate skin irritation study, the treated animals were free of any symptom of irritation. Systemic dermal absorption of the substance is highly unlikely as it is an inorganic, crystalline, sparingly soluble solid of lamellar clay mineral (hydrocalumite)-like structure. Such substances are generally expected not to be absorbed via the dermal route. Thus, neither local nor systemic dermal toxicity is likely to be an intrinsic activity of substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide".

No animal or human data are available on the acute or repeated dose inhalation toxicity. Particle size distribution of measured total dustiness (119.32 mg/g) was determined and the calculated MMAD and GSD values were used as input parameters for the prediction of the fractional deposition behaviour in the respiratory tract applying the Multiple Path Particle Dosimetry model (MPPD) (ver.2.11). Only very few amounts of the total dustiness fraction (4.3 %) will reach the pulmonary (alveolar) region. The vast majority of inhaled durst will be withheld in the naso-pharyngeal (head) region (89.1 %) and minor amounts in the tracheobronchial region (1.4 %). However, as the substance is an inorganic, crystalline sparingly soluble solid of lamellar clay mineral (hydrocalumite)-like structure, systemic absorption and subsequent systemic activity via the inhalative route is also highly unlikely. Inhaled sparingly soluble solids are not absorbed via the respiratory tract but cleared from the deeper respiratory tract mainly via the mucociliary escalator resulting in swallowing of some amounts of the substance and thus oral exposure. For solid substances at all size ranges, the general assumption is that the fraction of particulate matter that reaches the deep lung, and is not transported to the gut or expired, is quite small (c.f. European Chemicals Bureau, Technical Guidance Document on Risk Assessment Part 1, European Commission Joint Research Centre EUR 20418 EN/1 (2003) or US EPA, Methods for Derivation of Inhalation Reference concentrations (RfCs) and application of Inhalation Dosimetry, US EPA/600/8-90/066F (1994) as cited in ECETOC TR 110 (2010)). Considering the missing systemic toxicity by repeated oral exposure, no other than unspecific reactions are expected after inhalation of respirable amounts of the substance. The occupational exposure is limited by the generally accepted OELs derived for inert (nuisance) dust/Particulates Not Otherwise Classified (PNOCs). The general dust limits are not harmonised within Europe. For chronic exposure to alveolar (respirable) dust, values in the range from 1.25 to 5 mg/m³ have been enacted in European countries. Germany has enacted the lowest values (1.25 mg/m³ for chronic and of 2.5 mg/m³ for acute exposure, Technische Regeln für Gefahrstoffe (TRGS) 900, v. 08.08.2019), which were selected as DNEL surrogate in compliance with ECHA REACH TGD R.8.

From structural considerations there are also no indications on substantial systemic absorption and subsequent systemic toxicity. Substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" has a lamellar mineral structure, or rather a layered double hydroxide structure of hydrocalumite type.

Structurally related compounds to substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" are natural layered double hydroxides like hydrotalcite and the natural phyllosilicates like mica (e.g. muscovite) or clay minerals (e.g. montmorillonite). The mentioned minerals including muds and clays containing these minerals as well as synthetic analoga have a long history of save use. Their wide application range as excipient or active ingredient covers e.g. the synthetic oral lattice structure OTC antacides Talcid or Magaldrat, montmorillonite as feed and food additive (e.g. NovaSil, Mycofix, Toxfin), dermal applications of various phylosilicates as dermatological protectors, or anticaking, diluting, binding and thickening agents in cosmetic creams, powders and masks, spa and beauty therapies with muds or clays, the very recent inventions of layered double hydroxide nanoforms as drug carrier systems even for intravenous medicals, and also technical applications of diverse synthetic or natural layered double hydroxide minerals e.g. as acid adsorbents, which is the main use of "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide". None of these uses is associated with considerable risks to human health (c.f. Carretero, MI, et al., Clays and human health, in Handbook of clay science, pp. 717 - 741, ed. by Bergaya, F, et al., Developments in Clay Sciences, Vol 1., Elsevier Ltd. (2006); Del Hoyo, C, Layered double hydroxides and human health: an overview, Appl. Clay Sci., 36 (2007), 109 - 121; Carretero, MI and Pozo, M, Clay and non-clay minerals in the pharmaceutical industry, Part I. Excipients and medical applications, Appl. Clay Sci., 46 (2009) 73 - 80; Carretero, MI and Pozo, M, Clay and non-clay minerals in the pharmaceutical and cosmetic industries, part II. Active ingredients, Appl. Clay Sci., 47 (2010) 171 - 181; EFSA (European Food Safety Authority), Scientific option on the safety and efficacy of bentonite (dioctahedral montmorillonite) as feed additive for all species; EFSA Journal 2011: 9(2): 2007; EFSA (European Food Safety Authority), Scientific option on the safety and efficacy of a preparation of bentonite-and sepiolite (Toxfin® Dry) as feed additive for all species; EFSA Journal 2013:11(4):3179; Marroquin-Cardona, A, Characterization and safety of uniform particle size NovaSil clay as a potential aflatoxin enterosorbent, Appl. Caly Sci., 54 (2011) 248 -257; Choi,SO, Safety aspects of inorganic layered nanoparticles: Size-dependency in vitro and in vivo, J. Nanosci. Nanotech. 8 (2008) 5297 - 5301; Oh, JM, Layered nanomaterials for green materials, J. Materials Chem., 19 (2009) 2553 - 2563); Cavani, F, Hydrotalcite-type anionic clays: preparation, properties and applications; Catatysis Today, 11 (1991) 173 -301). Epidemiological studies reporting harmful inhalative effects of clay minerals to human health indicate that these effects are related to the presence of quartz or fibrous parts like asbestos in the parent rock of the mined minerals (c.f., Carretero, MI et al.(2006) cited above). However, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" as synthetic clay mineral like substance is free of quartz and does not have a fibrous structure.

Consumer exposure is considered negligible, as in service life, the substance is embedded in polymer matrices. Workplace exposure complies with established general workplace threshold limit values for dust. In the available studies on systemic toxicity, which comprise the application of the acute oral, acute dermal and subacute oral guideline limit doses, there were no indications on any intrinsic systemic toxicity of the substance. Considering the unlikeliness of systemic absorption via the dermal or inhalative route as well as assessment data on structurally related substances, there are also no indications on an intrinsic systemic activity. Thus, from exposure as well as toxicological considerations, no adverse effects to humans are expected to occur from repeated exposure to the substance. Nonetheless, the general dust limits apply and used in accordance with ECHA REACH TGD R.8 as DNEL surrogate. In accordance with REACH Regulation, Annex IX, 8.6.2, column 2 as well as Annex XI, 1., the performance of additional repeated dose toxicity studies is not justified due to exposure as well as toxicological considerations.

 

 

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Only study available. Study according to OECD and EU guidelines, no deviations, GLP.

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
Waiver in accordance with REACH Regulation, Annex IX, 8.6.2, column 2 as well as Annex XI, 1.

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:
Waiver in accordance with REACH Regulation, Annex IX, 8.6.2, column 2 as well as Annex XI, 1.

Justification for classification or non-classification

There is no evidence for intrinsic toxic properties relevant to humans obtained from the results of a reliable, adequate and relevant subacute oral study on rats with substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide". The tested dose range includes the guideline limit dose of repeated dose toxicity studies. Considering the unlikeliness of dermal absorption of an inorganic, sparingly soluble ionic solid of lamellar structure, systemic effects via this exposure route are hardly probable. Inhaled and subsequently swallowed amounts may decompose under the strong acidic conditions of the stomach and the released ions may become bioavailable. However, even under worst case considerations no toxicity deriving from the released ions is expected. Further on, from assessment data on structurally related substances, there are also no indications on an intrinsic systemic activity. Thus, no adverse effects to humans are expected to occur from repeated exposure to the substance.

In accordance with CLP Regulation (EC) No 1272/2008, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is not classified for repeated dose toxicity and labelling is not required.