Miljöpåverkan
Temozolomid
Miljörisk:
Användning av temozolomid har bedömts medföra försumbar risk för miljöpåverkan.
Nedbrytning:
Temozolomid bryts ned långsamt i miljön.
Bioackumulering:
Temozolomid har låg potential att bioackumuleras.
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Detaljerad miljöinformation
Environmental Risk Classification
Predicted Environmental Concentration (PEC)
PEC is calculated according to the following formula:
PEC (μg/L) = (A*109*(100-R))/(365*P*V*D*100) = 1.37*10-6*A(100-R)
PEC = 0.0015 μg/L
Where:
A = 11 kg (total sold amount API in Sweden year 2022, data from IQVIA) (Ref. I)
R = 0 % removal rate (worst case assumption)
P = number of inhabitants in Sweden = 10 *106
V (L/day) = volume of wastewater per capita and day = 200 (ECHA default) (Ref. II)
D = factor for dilution of waste water by surface water flow = 10 (ECHA default) (Ref. II)
Predicted No Effect Concentration (PNEC)
Ecotoxicological studies
Green Algae (Pseudokirchneriella subcapitata) (OECD 201) (Ref. III):
EC50 72 h (growth rate) > 90 mg/L
NOEC = 40 mg/L
Crustacean, water flea (Daphnia magna):
Acute toxicity
EC50 48 h (growth rate and biomass) > 100 mg/L (OECD 202) (Ref. IV)
NOEC = 100 mg/L
No effects seen up to highest concentration tested
Fish, rainbow trout (Oncorhynchus mykiss):
Acute toxicity
LC50 96 h (mortality) > 100 mg/L (OECD 203) (Ref.V)
NOEC = 100 mg/L
No effects seen up to highest concentration tested
PNEC =90 μg/L (90,000 μg/L/1000 based on the most sensitive acute EC50 for the green algae with an assessment factor (AF) of 1000)
Environmental risk classification (PEC/PNEC ratio)
PEC/PNEC = 0.0015/90 = 0.000017, i.e. PEC/PNEC ≤ .1 which justifies the phrase "Use of temozolomide has been considered to result in insignificant environmental risk.”
Degradation
Biotic degradation
Test results: 61% elimination (loss of parent) at Day 21, 83% to CO2 at Day 35 (OECD 301B) (Ref. VI)
Abiotic degradation
Hydrolysis:
Half-life = 69 days at pH 4 and < 1 day at pH 7 and pH 9 (OECD 111) (Ref. VII)
Justification of chosen degradation phrase:
83% of temozolomide degrades to the nonhazardous CO2 within 35 days. Therefore, significant mineralization is expected and thus the phrase “Temozolomide is slowly degraded in the environment” is chosen.
Bioaccumulation
Partitioning coefficient:
Log Kow = 1.35 at pH 7
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The partition coefficient (Kow) was determined for the equilibrium distribution of temozolomide between n-octanol and 0.1N HCl, and n-octanol and pH 7 phosphate buffer. Equal volumes of the aqueous component, containing about 1 mg/mL temozolomide, and n-octanol were agitated for 6 hours at ambient temperature. After centrifugation, both layers were assayed for temozolomide content by HPLC (Ref VIII).
Justification of chosen bioaccumulation phrase:
Since log Kow < 4 at pH 7, the substance has low potential for bioaccumulation.
References
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Data from IQVIA ”Consumption assessment in kg for input to environmental classification - updated 2023 (data 2022)”.
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ECHA, European Chemicals Agency. 2008 Guidance on information requirements and chemical safety assessment. http://guidance.echa.europa.eu/docs/guidance_document/information_requirements_en.htm
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Huntington Life Sciences, 2006. "SCH 52365 Algal Growth Inhibition Assay," Study No. ESN 213/052201, HLS, England, 22 February 2006.
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Huntington Life Sciences, 2006. "SCH 52365 Acute Toxicity to Daphnia magna," Study No. ESN 212/052200, HLS, England, 22 February 2006.
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Huntington Life Sciences, 2006. "SCH 52365 Acute Toxicity to Rainbow Trout," Study No. ESN 211/052199, HLS, England, 22 February 2006.
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Huntington Life Sciences, 2005. "SCH 52365 Assessment of Ready Biodegradability: Modified Sturm Test," Study No. ESN 209/043479, HLS, England, 19 April 2005.
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Huntington Life Sciences, 2005. "SCH 52365 Abiotic Degradation: Hydrolysis as a Function of pH," Study No. ESN 208/043624, HLS, England, 20 July 2005.
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Schering Plough Research Institute. CMC Section 4.A.1.2 Temozolomide (SCH 52365) Capsules - Physical Chemical Characterization.