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Environmental fate & pathways

Adsorption / desorption

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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
19 - 21 December 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in GLP compliance and in accordance with an internationally established guideline (EPA, see below). BIBR 277 CL is the hydrochloride of Telmisartan (free acid).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report date:
2007

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EPA OPPTS 835.1110 (Activated Sludge Sorption Isotherm)
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)
Type of method:
batch equilibrium method
Media:
sewage sludge

Test material

Constituent 1
Reference substance name:
Telmisartan
IUPAC Name:
Telmisartan
Constituent 2
Reference substance name:
144701-48-4
Cas Number:
144701-48-4
IUPAC Name:
144701-48-4
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Telmisartan
- Molecular formula (if other than submission substance): C33H30N402
- Molecular weight (if other than submission substance): 514.6 g/mol
- Substance type: slight yellowish powder
- Physical state: solid
- Analytical purity: 99.8% (HPLC)
- Lot/batch No.: 04061
- Expiration date of the lot/batch: Nov. 2007
- Stability under test conditions: see expiry date
- Storage condition of test material: at room temperature, dark and dry
Radiolabelling:
no

Study design

Test temperature:
20°C

Batch equilibrium or other method

Analytical monitoring:
yes
Details on matrix:
The activated sludge was taken from the activation basin of the sewage treatment plant of Stadtentsorgung Neustadt in D-67435 Lachen-Speyerdorf. The plant is treating mostly household sewage. Date of taking: 11. Dec. 2006.

The sludge was centrifuged, washed with tap water and then freeze-dried. The residue was pressed through a sieve and then dried at 105° C for three hours. The organic matterwas determined as 33%.
Details on test conditions:
Aqueous samples were centrifugated before analysis at 4000 rpm for 15 minutes at 20 °C. The SPE C8 tubes were pre-conditioned with 2 mL methanole and 1 mL citric buffer. A mixture of 1 mL citric buffer and 2 mL centrifugated sample was sucked slowly through a SPE-tube, the tube was rinsed with 1 mL washing solution. After drying for 20 min in full vacuum, elution was performed using 0.7 mL methanole. After addition of 0.3 mL phosphate buffer pH 3, the samples were measured using HPLC.

The test was performed at a temperature of 20 ± 1°C. All vessels were sterilised before use. For equilibration, the sludge samples were shaken
for 30 minutes with the appropriate volume of buffer-solution pH 7 to reach a total volume of 50 mL before addition of the test item. After equilibration and measurement of pH, the appropriate volume of Telmisartan stock solution to result in the concentrations to be tested was added. The mixtures were shaken on an orbital shaker until sampling after 24h. The time of reaching the equilibration (24h) was determined in a pre-test. Before sampling at equilibrium, the mixtures were centrifugated. The aqueous phases were prepared as described (see above) and measured using HPLC.
Computational methods:
see attached study for details

Results and discussion

Adsorption coefficientopen allclose all
Type:
Kd
Value:
94.2
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:25
Type:
Koc
Value:
283.6
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:25
Type:
Kd
Value:
148.71
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:50
Type:
Koc
Value:
448.6
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:50
Type:
Kd
Value:
188.56
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:75
Type:
Koc
Value:
568.8
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:75
Type:
Kd
Value:
242.24
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:100
Type:
Koc
Value:
646.3
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:100
Type:
Kd
Value:
290.94
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:200
Type:
Koc
Value:
877.7
Temp.:
20 °C
Remarks on result:
other: Ratio: 1:200

Any other information on results incl. tables

see attached study report

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The adsorption study at one concentration of the test item (25 pg/L) was performed using eight different sludge-solution-ratios. No relevant adsorption on the surface of the test vessels and no signs of instability were observed. The adsorption isotherm function of Telmisartan showed a good linear correlation with a regression factor r of 0.9977. The sorption constants at 20 °C and pH = 7.01 ± 0.01 were determined as:
log KF = 7.6363 and 1/n = 2.6322