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) = 1.5*10^-6*A(100-R)

PEC = 0.0842 μg/L

Where:

A =561.265 kg (total sold amount API in Sweden year 2019, data from IQVIA).

R = 0% removal rate (conservatively, it has been assumed there is no loss by adsorption to sludge particles, by volatilization, hydrolysis or biodegradation)

P = number of inhabitants in Sweden = 9 *10⁶

V (L/day) = volume of wastewater per capita and day = 200 (ECHA default)(Reference 1)

D = factor for dilution of waste water by surface water flow = 10 (ECHA default) (Reference 1)

Predicted No Effect Concentration (PNEC)

Ecotoxicological studies

Green Algae (Selenastrum capricornutum):

IC50 72h (inhibition of growth rate) = 70 μg/L (OECD 201) (Reference 3)

Water flea (Daphnia magna):

Acute toxicity

EC50 48 h (immobility) = 70 μg/L (OECD 202) (Reference 3)

Orange red Killfish (Juvenile Poecilia reticulata):

Acute toxicity

LC50 96 h (immobility) = 240 μg/L (OECD 203) (Reference 3)

Other ecotoxicity data:

Microorganisms in activated sludge

EC50 3 hours (Inhibition) = 35,000 μg/L (OECD 209) (Reference 3)

PNEC = 70/1000 = 0.07 μg/L

PNEC (μg/L) = NOEC/1000, where 1000 is the assessment factor recommended for three acute toxicity studies (Reference 1). The EC50 for green algae (= 70 µg/L) has been used for this calculation.

Environmental risk classification (PEC/PNEC ratio)

PEC/PNEC = 0.0842/0.07 = 1.20, i.e. 1 < PEC/PNEC ≤ 10 which justifies the phrase “Use of benzoyl peroxide has been considered to result in moderate environmental risk”.

Degradation

Biotic degradation

Ready degradability:

83%, 20 day MITI Test, OECD 301C (Reference 3)

Inherent degradability:

No data

Abiotic degradation

Hydrolysis:

No data

Photolysis:

No data

Justification of chosen degradation phrase:

Benzoyl peroxide is readily biodegradable the phrase “Benzoyl peroxide is degraded in the environment" is thus chosen.

Bioaccumulation

Partitioning coefficient:

Log Kow = 3.43 (Reference 3)

Justification of chosen bioaccumulation phrase:

Since log Kow < 4, the substance has low potential for bioaccumulation.

Excretion (metabolism)

The presence of benzoyl peroxide in the formulation did not have an effect on the percutaneous absorption of clindamycin. Radio-label studies have shown that absorption of benzoyl peroxide through the skin can only occur following its conversion to benzoic acid. Benzoic acid is mostly conjugated to form hippuric acid, which is excreted via the kidneys. (Reference 2)

PBT/vPvB assessment

Benzoyl peroxide does not fulfil the criteria for PBT and/or vBvP.

All three properties, i.e. ‘P’, ‘B’ and ‘T’ are required in order to classify a compound as PBT (Reference 1). Benzoyl peroxide does not fulfil the criteria for PBT and/or vBvP based on a log Kow < 4 and is readily biodegradable.

Please, also see Safety data sheets on http://www.msds-gsk.com/ExtMSDSlist.asp.

References

1. ECHA, European Chemicals Agency. 2008 Guidance on information requirements and chemical safety assessment.

2. Pharmacokinetic properties: Metabolism and Elimination. Summary of Product Characteristics DUAC once Daily 10mg/g and 30mg/g Gel. Stiefel, March 2018.

3. DUAC Topical Gel. MSDS ID 133364, version # 6. GlaxoSmithKline, September 2018

4. Instant J Chem Log P and LogD. Sep 2012. Chemaxon Inc.