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Endpoint:
additional toxicological information
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Non-GLP, follows a standard operating procedure, available as an unpublished report, reliable without restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Standard Operating Procedure (SOP) prepared by Eurometaux on November 2010
Deviations:
no
Principles of method if other than guideline:
A bio-accessibility testing study has been designed to assay the metal release of Diammonium sodium hexakis(nitrito-N) rhodate (Rhodium salt) compounds in gastric synthetic media. Metals or metallic compounds are subjected to a media that mimic gastric juice, in terms of pH and body temperature (pH 1.5 and 37 °C), for an exposure time of 1 hour with agitation. Then the compounds are incubated for another hour without agitation, before aliquots are taken, filtered and bio-accessible metal quantified by ICP-MS.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Rhodium salt
- Analytical purity: 15.302 % w/w Rh
- Purity test date: 20/10/2011
- Lot/batch No.: RHL 586
- Other: Particle size distribution and specific surface area (BET analysis) values were taken from: Fraunhofer IKTS report N° 4198_4208_4214_4216 of 12.11.2012.
- d50 = 9.301 µm (50th percentile of the particle size cumulative distribution as measured by volume)
- d90 = 43.077µm (90th percentile of the particle size cumulative distribution as measured by volume)
- BET = 1.09 m2/g

Results and discussion

Any other information on results incl. tables

Table 1. Diammonium sodium hexakis(nitrito-N) rhodate 2 hours bio-elution test in gastric mimetic fluid: Rhodium released from blanks and samples at pH 1.5 ( 200 mg/L mass loading), were recorded before the sample was added and after 2 hours of incubation. The results are reported in µg/L and µg/g.

 

 

Gastric test parameters

Vessel 1

Vessel 2

Vessel 3

Rhodium, µg/L

Rhodium, µg/g

Blanks

Time, hr

Temp., °C

O2,mg/L

pH

R1

R2

R3

Mean, µg/L

St. Dev.

CV, %

Mean, µg/g

CV, %

 

Before

37.0

6.6

1.49

BDL

BDL

BDL

-

-

-

-

-

 

2

37.0

6.6

1.51

0.12

“0.40”

0.20

0.16

0.06

36

-

-

(NH4)2·N6O12Rh·Na

Time, hr

Temp., °C

O2,mg/L

pH

R1

R2

R3

Mean, µg/L

St. Dev.

CV, %

Mean, µg/g

CV, %

 

Before

37.0

6.6

1.49

BDL

BDL

BDL

-

-

-

-

-

 

2

37.0

6.6

1.50

33757

35756

36915

35476

1598

5

176498

5

CV: corresponds to the coefficient of variation between vessels (the ratio between the standard deviation and the mean of metal released).

Values between quotes are regarded as outliers and are not considered in the calculations (see outliers criteria in the Quality control section).

BDL: Below detection limit.

 

Table 2. Summary of metals solubility from Palladium powder sample; submitted to bio-elution tests in synthetic gastric media. Metal release from the bio-elution tests is reported, as percentage of solubility, after 2 hours of incubation in gastric fluid. SD = Standard Deviation, calculated from the 3 measurements performed to the 3 replica vessels.

 

Sample

% solubility in gastric fluid

2h

SD

Rhodium salt

115*

5.2

*Solubility above 100% is due to errors associated with the bio-elution method (mass and volume uncertainties) added to possible errors in the metal content of the compound reported in the certificate of analysis.

Table 3. Results of the metal release per surface area exposed to the medium. The ratio between metal released in the bio-elution test, expressed in µg/g, and the specific surface area in m2/g are presented for Palladium powder.

Sample

Metal release in gastric fluid [µg/m2]

2 h

Rhodium salt

161924.8

The control standards used to assure the quality of the measurements obtained with ICP-MS, demonstrated an adequate stability and accuracy of the instrument during the metal quantification of the bio-elution samples. All the QC samples showed metal concentration measurements in the range of 20% around the certified value of the standards; criterion used to assure the quality of the measurements.   

Applicant's summary and conclusion

Conclusions:
Diammonium sodium hexakis(nitrito-N) rhodate showed solubility of 115 % after 2 hours in gastric juice. After incubation in gastric juice, 35476 µg/L of Rh (176498 µg/g) was released from samples after 2 hours.
Executive summary:

A study to estimate metal bio-accessibility for Diammonium sodium hexakis(nitrito-N) rhodatei n synthetic gastric juice was performed following Standard Operating Procedure (SOP, Eurometaux, November 2010).

 

The test item was subjected to a media that mimic gastric juice, in terms of pH and body temperature (pH 1.5 and 37 °C), for an exposure time of 1 hour with agitation. Then the compounds are incubated for another hour without agitation, before aliquots are taken, filtered and bio-accessible metal quantified by ICP-MS.

Diammonium sodium hexakis(nitrito-N) rhodate showed solubility of 115 % after 2 hours in gastric juice. Solubility above 100% is considered to be due to errors associated with the bio-elution method (mass and volume uncertainties) added to possible errors in the metal content of the compound reported in the certificate of analysis.

After incubation in gastric juice, 35476 µg/L of Rhodium (176498 µg/g) was released from samples after 2 hours.