Fatty acids, tall-oil, manganese salts

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vitro / ex vivo

Remarks:

Bioelution in simulated interstitial medium

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 December 2021 to 12 February 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Bioelution in simulated interstitial medium according to Standard Operating Procedure for the Bio-accessibility Testing Programme of Eurometaux (November 10, 2010).

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids, tall-oil, manganese salts

EC Number:

232-445-3

EC Name:

Fatty acids, tall-oil, manganese salts

Cas Number:

8030-70-4

IUPAC Name:

Fatty acids, tall-oil, manganese salts

Test material form:

cream / paste

Details on test material:

Supplier: Hubergroup
CAS Number: 8030-70-4
Batch/Lot number: Lab Expt-80
Appearance: dark, paste
Purity: 100%
Metal content: 8.9% Mn
Expiry date: 03 August 2022

Specific details on test material used for the study:

The test item, Fatty acids, tall-oil manganese salts as received, was tested. Therefore, no further preparation of the test item at ECTX was needed.

Administration / exposure

Vehicle:

other: simulated interstitial fluid

Duration and frequency of treatment / exposure:

168 hours

Positive control reference chemical:

1001 mg/L Manganese standard

Results and discussion

Bioaccessibility (or Bioavailability)

Bioaccessibility (or Bioavailability) testing results:

Bio-elution refers to the in vitro extraction methods used to measure the degree to which a substance is dissolved in simulated biological fluids. The resulting value is the “bio-accessibility” and is defined as the “fraction of a substance that is soluble under physiological conditions and therefore potentially available for absorption into systemic circulation”. Simulated biological fluids (e.g. gastric fluid, interstitial fluid, lysosomal fluid,…) represents relevant exposure routes. In this study, the inhalation route was investigated. Therefore, simulated interstitial fluid, as provided in the test guidance, was used to measure the release/dissolution of manganese from Fatty acids, tall-oil manganese salts.

The temperature of the sampled test solutions fluctuated between 36.8 °C and 37.0 °C, which was in line with the test conditions of 37 °C ± 1 °C.

The measured pH of the test medium at the start of the test was 7.43, i.e. within the specifications of pH 7.4 ± 0.2. At the start of the trial, the pH measured in the additional test item vessel (replica X) was 7.45, i.e. within the specifications of pH 7.4 ± 0.2. At the sampling points, the pH in the blank control vessel and positive control were between 7.41 and 7.44. The pH in the test vessels was between 7.43 and 7.58 at the 24 hours and 168 hours sampling points.

Measurements of the blank control vessels showed no manganese concentrations above the reporting limit of 20 μg/L Mn in the high salt loaded matrix.

The following observations could be made in the Positive Control item vessel containing a soluble form of manganese:
- The Positive Control item solution remained clear at the tested concentration level. No precipitation could be observed on the filter and in the Erlenmeyer flask at the end of the experiment.
- The recovery of the dissolved manganese concentrations in the positive control item was 100 % for Mn at the 24 hours sampling point and 97 % for Mn at the 168 hours endpoint, respectively and met the criterion (recovery: 100 % ± 10 %).

The following observations could be made in the test vessels with a loading of 2 g/L Fatty acids, tall-oil manganese salts:
- Undissolved test item (dark pieces) could be observed in the Erlenmeyer flasks at the end of the experiment.
- Following amounts of manganese were measured:
1. 24 hours sampling point:
An average dissolved manganese concentration in solution of 0.291 ± 0.047 mg/L Mn (corresponding to a dissolved manganese concentration per g test item of 0.145 ± 0.023 mg/g Mn) was measured after 24 hours of exposure to the simulated interstitial fluid (pH 7.4) with a between-vessel variation of 16 %.
Based on the manganese content of the test item (i.e. 8.9 % Mn) and the average dissolved manganese concentration, a manganese release of 0.16 % could be calculated at the 24 hours sampling point.
2. 168 hours endpoint:
An average dissolved manganese concentration in solution of 2.74 ± 0.52 mg/L Mn (corresponding to a dissolved manganese concentration per g test item of 1.36 ± 0.26 mg/g Mn) was measured after 168 hours of exposure to the simulated interstitial fluid (pH 7.4) with a between-vessel variation of 19 %, which met the <20 % quality criterion at the 168 hours endpoint.
Based on the manganese content of the test item (i.e. 8.9 % Mn) and the average dissolved manganese concentration, a manganese release of 1.5 % could be calculated at the 168 hours endpoint.

Applicant's summary and conclusion

Conclusions:

During this study on Fatty acids, tall-oil manganese salts at a loading of 2 g/L in simulated interstitial fluid (pH 7.4), it was shown that for manganese, an average dissolved concentration in solution of 0.291 mg/L Mn (CVbetween-vessel = 16 %; N = 3) was found after 24 hours of extraction. This amount corresponds to a dissolved manganese concentration per g test item of 0.145 mg/g Mn or a manganese release of 0.16 % of the content.
At the 168 hours endpoint, an average value of 2.74 mg/L Mn (CVbetween-vessel = 19 %; N = 3) corresponding to a dissolved manganese concentration per g test item of 1.36 mg/g Mn was found or a manganese release of 1.5 % of the content.
The results are reliable since the test conditions stayed constant during the experiment and the recovery of the Positive Control met the criteria of acceptance for manganese.

Executive summary:

Bio-elution refers to the in vitro extraction methods used to measure the degree to which a substance (e.g., metal or mineral ion) is dissolved in artificial biological fluids. This study measured the release/ dissolution of manganese ions from Fatty acids, tall-oil manganese salts in a simulated interstitial fluid was measured. Simulated biological fluids represent relevant exposure routes. The resulting value is the “bio-accessibility” and is defined as the “fraction of a substance that is soluble under physiological conditions and therefore potentially available for absorption into systemic circulation”. 

The objective of this study was to obtain knowledge about the bio-elution characteristics of Fatty acids, tall-oil manganese salts in simulated interstitial fluid. This study has been conducted following the recommended Standard Operating Procedure (SOP) for the Bio-accessibility Testing Programme of Eurometaux (November 10, 2010). 

The extent of dissolution of Fatty acids, tall-oil manganese salts was tested in a simulated interstitial fluid at 37 °C and pH 7.4 during 168 hours (2 g/L loadings) at an agitation speed of 171 revolutions per minute (rpm). The bio-elution endpoint is based on the dissolved manganese (Mn) concentrations obtained after 24 and 168 hours of extraction. 

The measured pH of the test medium at the start of the test was 7.43, i.e. within the specifications of pH 7.4 ± 0.2. At the start of the trial, the pH measured in the additional test item vessel (replica X) was 7.45, i.e. within the specifications of pH 7.4 ± 0.2. At the sampling points, the pH in the blank control vessel and positive control were between 7.41 and 7.44. The pH in the test vessels was between 7.43 and 7.58 at the 24 hours and 168 hours sampling points. 

The temperature of the sampled test solutions, including the blank test vessel, was between 36.8 °C and 37.0 °C and corresponded to the required test conditions of 37 °C ± 1 °C. 

Measurements of the blank control vessels showed no manganese concentrations above the reporting limit of 20 μg/L Mn in the high salt loaded matrix. 

In the test item vessels with a loading of 2 g/L Fatty acids, tall-oil manganese salts at the 24 hours sampling point, the following average dissolved manganese concentration in solution of: 

• 0.291 ± 0.047 mg/L Mn (CVbetween-vessel = 16 %; N = 3), corresponding to a dissolved manganese concentration per g test item of 0.145 ± 0.023 mg/g Mn, was measured after 24 hours of exposure to the simulated interstitial fluid (pH 7.4). 

Based on the manganese content (i.e. 8.9 % Mn) in the test item and the average dissolved manganese concentrations in the test solutions, a release of: 

• manganese of 0.16 % of the content, could be calculated at the 24 hours sampling point. 

In the test item vessels with a loading of 2 g/L Fatty acids, tall-oil manganese salts at the 168 hours endpoint, the following average dissolved manganese concentration in solution of: 

• 2.74 ± 0.52 mg/L Mn (CVbetween-vessel = 19 %; N = 3), corresponding to a dissolved manganese concentration per g test item of 1.36 ± 0.26 mg/g Mn, was measured after 168 hours of exposure to the simulated interstitial fluid (pH 7.4). 

Based on the manganese content (i.e. 8.9 % Mn) in the test item and the average dissolved manganese concentrations in the test solutions, a release of: 

• manganese of 1.5 % of the content, could be calculated at the 168 hours endpoint.