Detaljerad miljöinformation

1. PREDICTED ENVIRONMENTAL CONCENTRATION (PEC):

The Predicted Environmental Concentration is calculated according to the following formula:

PEC (µg/L) = A x 10⁹ x (100-R) / 365 x P x V x D x 100

Where:

A (kg/year)	=	325.0107482 kg (total sold amount API in the most recent sales data for Sweden (2019) was distributed by IQVIA/LIF in 2020)
R (%)	=	removal rate (due to loss by adsorption to sludge particles, by volatilization, hydrolysis or biodegradation)
	=	0% (worst-case scenario: no removal)
P	=	number of inhabitants in Sweden (9 x 106)
V (L/day)	=	volume of waste water per capita and day
	=	200 (ECHA default) [11]
D	=	factor for dilution of waste water by surface water flow
	=	10 (ECHA default) [11]
PEC (µg/L)	=	0.049468911 µg/L

2. PREDICTED NO EFFECT CONCENTRATION (PNEC)

2.1. Ecotoxicological studies

2.1.1. Algae

Growth inhibition test with green algae (Pseudokirchneriella subcapitata) (OECD 201) [4]:

E_bC₅₀ 72 h > 43 mg/L

NOEC_b = 43 mg/L

E_rC₅₀ 72 h > 43 mg/L

NOEC_r = 43 mg/L

2.1.2. Crustacean

Acute

Acute

EC₅₀ 48 h (immobilization) Acute toxicity to water-flea (Daphnia magna) (OECD 202) [2]:

EC₅₀ 48 h > 44 mg/L (immobilization)

NOEC = 2.6 mg/L (immobilization)

Following 48 hours of exposure, immobilization of 10% was observed among daphnids

exposed to the highest treatment level tested (44 mg a.i./L). Several surviving daphnids exposed to this treatment level were observed to be either on the bottom of the test vessel or lethargic and on the bottom of the test vessel. Immobilization of 5% was observed among daphnids exposed to the 10 mg a.i./L treatment level. Several daphnids exposed to this treatment level were observed to be lethargic and on the bottom of the test vessel. No immobilization was observed among daphnids exposed to the 5.4 and 21 mg a.i./L treatment levels, but several daphnids were also observed to be lethargic and on the bottom of the test vessel. No immobilization or adverse effects were observed among daphnids exposed to the remaining treatment level tested (2.6 mg a.i./L) or the controls.

Since no concentration tested resulted in ≥ 50% immobilization, the 48-hour EC50 value for Darunavir and Daphnia magna was empirically estimated to be > 44 mg a.i./L, the highest mean measured concentration tested.

The No-Observed-Effect Concentration (NOEC) was determined to be 2.6 mg a.i./L.

The highest concentration producing 0% immobilization was 21 mg a.i./L. The lowest concentration producing 100% immobilization was > 44 mg a.i./L. Additional testing at higher concentrations to further define the EC50 was not performed since the concentration of the test substance in the highest nominal test concentration approximated the water solubility limit of Darunavir under the maintained test conditions.

Chronic

Reproduction test with water-flea (Daphnia magna) (OECD 211) [5]:

NOEC 21 days = 19 mg/L

2.1.3. Fish

Acute

Acute toxicity to rainbow trout (Oncorhynchuss mykiss) (OECD 203) [3]:

LC₅₀ 96 h > 38 mg/L

NOEC = 38 mg/L

Chronic

NOEC 28 days (Length and Dry Weight) Fish early life stage test with fathead minnow (Pimephales promelas) (OECD 210) [6]:

NOEC 28 days = 9.4 mg/L

2.1.4. Other ecotoxicity data

Activated sludge respiration inhibition test (OECD 209) [1]:

EC50 3 h > 1000 mg/L

NOEC 3h ≥ 1000 mg/L

2.2. Calculation of Predicted No Effect Concentration (PNEC)

PNEC (µg/L) = lowest NOEC from long-term ecotoxicity/10, where 10 is the assessment factor used. NOEC for fathead minnow (Pimephales promelas) (9.4 mg/L) has been used for this calculation since it is the most sensitive of the three tested species.

PNEC = 9.4 mg/L/10 = 940 µg/L

2.3. Environmental risk classification (PEC/PNEC ratio)

PEC/PNEC = 0.049468911/940 = 0.0000526265 i.e. PEC/PNEC ≤ 0.1

Conclusion for environmental risk:

The calculated PEC/PNEC ratio is ≤ 0.1.

Use of Darunavir has been considered to result in insignificant environmental risk.

3. DEGRADATION

3.1. Biotic degradation

3.1.1. Ready biodegradation

Darunavir was investigated for its ready biodegradation in a 28-day manometric respirometry test according to OECD 301B [7]:

Result: Not readily biodegradable.

3.1.2. Simulation study: Aerobic degradation in aquatic sediment systems

Darunavir was investigated for its aerobic degradation in a 106-day aquatic sediment test, according to OECD 308 [9]:

Overall, [¹⁴C]TMC114 ethanolate underwent gradual depletion from the Taunton (TR) and Weweantic (WR) sediment/water systems with a significant amount of the radioactivity accumulating as non-extractable vound residues in the sediments. Depletion rates (DT₅₀) from the TR and WR sediment/water systems were 38.9 and 37.1 days, respectively. Bound residues accounted for 67% and 43% of the applied dose at day 106 in the TR and WR, respectively. Very little formation of [¹⁴C]CO₂ (<3% of the applied dose) occurred over the 106-day study. Multiple small radioactive peaks, both more polar and less polar, were observed primarily in the TR sediments. However non accumulated to more than 10% of the applied dose.

For extraction samples containing the test substance were extracted twice with methanol, concentrated by rotary evaporation and reconstituted in acetonitrile and acidified water. Samples were analyzed by a liquid scintillation counter (LSC) and automated injection on a high performance liquid chromatographic system equipped with radiochemical detection (HPLC/RAM).

3.1.3. Simulation study: Anaerobic degradation in aquatic sediment systems

Darunavir was investigated for its anaerobic degradation in a 101-day aquatic sediment test, according to OECD 308 [10]:

Overall, [¹⁴C]TMC114 ethanolate underwent gradual depletion from the Taunton (TR) and Weweantic (WR) sediment/water systems with a significant amount of the radioactivity accumulating as non-extractable bound residues in the sediments. Depletion rates (DT₅₀) from the TR and WR sediment/water systems were 104.9 and 74.0 days, respectively. Bound residues accounted for 41.3% and 55.3% of the applied dose at day 101 in the TR and WR, respectively. Very little formation of [¹⁴C]CO₂ or [¹⁴C]CH₄ (<1% of the applied dose) occurred over the 101-day study. Multiple small radioactive peaks, both more polar and less polar, were observed primarily in the TR sediments. However, none accumulated to more than 5% of the applied dose.

Conclusion for degradation:

Darunivir is slowly degraded in the environment.

4. BIOACCUMULATION

4.1. Partition coefficient octanol/water

The partition coefficient octanol/water was determined using the shaking flask method. [8]
log D_ow = 2.4 (pH = 4, 7 and 9)

Conclusion for bioaccumulation:

Darunivir has low potential for bioaccumulation.

5. PBT-ASSESSMENT

	PBT-criteria	Results for Darunavir
Persistence	Half-life in freshwater: DT50 > 40 days Half-life in sediment: DT50 > 120 days	DT50, sediment/water system = 104.9 days
Bioaccumulation	BCF > 2000	-
Toxicity	Chronic NOEC < 10 µg/L	NOECalgae = 43 mg/L  NOECdaphnia = 19 mg/L NOECfish = 9.4 mg/L

Conclusion for PBT-assessment:

According to the established EU-criteria Darunavir should not be regarded as a PBT substance.

6. REFERENCES

1. McLaughlin SP., TMC114 Ethanolate – Activated sludge respiration inhibition, Springborn Smithers Laboratories, Study TMC114-NC318 (SSL 13844.6103), July 2005.

2. Hogerg JR., TMC114 Ethanolate – Acute toxicity to water fleas (Daphnia magna) under static conditions, Springborn Smithers Laboratories, Study TMC114-NC323 (SSL 13844.6108), September 2005.

3. Hogerg JR., TMC114 Ethanolate – Acute toxicity to rainbow trout (Oncorhynchus mykiss) under static conditions, Springborn Smithers Laboratories, Study TMC114-NC324 (SSL 13844.6109), August 2005.

4. Hoberg JR., TMC114 Ethanolate – Acute toxicity to freshwater green alga (Pseudokirchneriella subcapitata), Springborn Smithers Laboratories, Study TMC114-NC322 (SSL 13844.6107), September 2005.

5. Sayers LE., TMC114 Ethanolate – Full life-cycle toxicity test with water fleas (Daphnia magna) under static renewal conditions, Springborn Smithers Laboratories, Study TMC114-NC313 (SSL 13844.6114), June 2006.

6. Cafarella MA., TMC114 Ethanolate – Early life-stage toxicity test with fathead minnow (Pimephales promelas), Springborn Smithers Laboratories, Study TMC114-NC314) (SSL 13844.6115), June 2006.

7. Gledhill WE., TMC114 Ethanolate – Determination of the ready biodegradability by CO2 evolution modified Sturm test, Springborn Smithers Laboratories, Study TMC114-NC320 (SSL 13844.6105), August 2005.

8. Jacobs A., TMC114 – Solubility, pKa, log D, log P, Janssen Pharmaceutica N.V., Report No. PC-CHAR 05-007, July 4, 2005.

9. Gledhill, W.E., Determination of the Aerobic Transformation of [¹⁴C]TMC114 Ethanolate in Aquatic Sediment Systems, Springborn Smithers Laboratories, Study TMC114-TiDP3-NC332 (SSL 13844.6112), February 28, 2007.

10. Gledhill, W.E., Determination of the Anaerobic Transformation of [¹⁴C]TMC114 Ethanolate in Aquatic Sediment Systems, Springborn Smithers Laboratories, Study TMC114-TiDP3-NC335 (SSL 13844.6116), March 16, 2007.

11. 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

Detaljerad miljöinformation

1. PREDICTED ENVIRONMENTAL CONCENTRATION (PEC):

The Predicted Environmental Concentration is calculated according to the following formula:

PEC (µg/L) = A x 10⁹ x (100 - R) / 365 x P x V x D x 100

Where:

A (kg/year)	=	409.317 kg (total sold amount API in the most recent sales data for Sweden (2019) was distributed by IQVIA/LIF in 2020)
R (%)	=	removal rate (due to loss by adsorption to sludge particles, by volatilization, hydrolysis or biodegradation)
	=	0% (worst-case scenario: no removal)
P	=	number of inhabitants in Sweden (9 x 106)
V (L/day)	=	volume of waste water per capita and day
	=	200 (ECHA default) [8]
D	=	factor for dilution of waste water by surface water flow
	=	10 (ECHA default) [8]
PEC (µg/L)	=	0.0623009 µg/L

2. PREDICTED NO EFFECT CONCENTRATION (PNEC)

2.1 Ecotoxicological studies

2.1.1 Algae

Algal growth inhibition test with the green alga (Pseudokirchneriella subcapitata) (OECD 201) [1]:

EγC₅₀ 72 h (yield) > 110 mg/L

NOECγ (yield) ≥ 110 mg/L

E_rC₅₀ 72 h (growth) > 110 mg/L

NOEC_r (growth) ≥ 110 mg/L

2.1.2 Crustacean

Chronic

Reproduction test with water-flea (Daphnia magna) (OECD 211) [2]:

NOEC 21 days ≥ 110 mg/L (Reproduction)

2.1.3 Fish

Chronic

Fish early life stage test with fathead minnow (Pimephales promelas) (OECD 210) [3]:

NOEC 28 days = 6.10 mg/L (growth, weight)

2.1.4 Other ecotoxicity data

Activated sludge respiration inhibition test (OECD 209) [4]

EC₅₀ 3h > 1000 mg/L

NOEC 3h ≥ 1000 mg/L

2.2 Calculation of Predicted No Effect Concentration (PNEC)

PNEC (µg/l) = lowest NOEC/10, where 10 is the assessment factor used. NOEC for fathead minnow Pimephales promelas of 6.10 mg/L has been used for this calculation since it is the most sensitive of the three tested species.

PNEC = 6.10mg/L/10 = 610 µg/L

2.3 Environmental risk classification (PEC/PNEC ratio)

PEC/PNEC = 0.0623009/610 = 0.0001021 i.e. PEC/PNEC ≤ 0,1

Conclusion for environmental risk:

The calculated PEC/PNEC ratio is < 0.1.

Use of emtricitabine has been considered to result in insignificant environmental risk.

3. DEGRADATION

3.1 Biotic degradation

3.1.1 Ready biodegradation

Emtricitabine was investigated for its ready biodegradation in a 28-day Closed Bottle test according to OECD 301D [5]:

Result: Not readily biodegradable.

3.1.2 Simulation study: Aerobic degradation in aquatic sediment systems:

Emtricitabine was investigated for its aerobic degradation in a 100-day aquatic sediment test, according to OECD 308 [6].

Distribution

Emtricitabine was degraded at a moderate rate under the aerobic water sediment conditions of this study. Emtricitabine decreased from an average of 102.9 and 106.7% of applied radioactivity on day 0 to 66.0 and 14.5% of applied radioactivity at study termination (day 100) for the aerobic Taunton River and Weweantic River sediments, respectively. Percent of applied radioactivity (11.7 and 54.3%, respectively) was converted to 14CO2 in the Taunton River aerobic and Weweantic River aerobic water/sediments (sandy loam and sand), respectively.

Fumigation/extraction biomass results for the aerobic sediments were typical and confirmed a viable microbial population was present over the course of the study.

The whole system DT₅₀ was calculated using single first-order (SFO) kinetics. The primary FTC degradation product was CO₂.

Dissipation half life times total system:

Taunton River: DT₅₀ = 150.65 days

Weweantic River: DT₅₀ = 35.91 days

Transformation

Overall mass balance for the transformation of emtricitabine in the aerobic sediment/water systems: the average mass balance ranged from 95.4 to 108.3% of the applied radioactivity for the samples tested over the course of the 100-day study.

Mass Balance (% Applied radioactivity) - [14C]FTC Overall Average & Average Range:

Evolution of 14CO2 reached 11.7% of the applied radioactivity for the Taunton River aerobic test samples and 54.3% of the applied radioactivity for the Weweantic River aerobic test samples by day 100. Negligible quantities of [14C] were detected in the volatile organic compound traps.

Conclusion for degradation:

Emtricitabine is slowly degraded in the total system of the Weweantic River (DT50 = 35.91 days), but is potentially persistent in the total system of the Taunton River (DT50 = 150.65 days). Due to two different degradation phrases the conclusion is that Emtricitabine is slowly degraded in the environment.

4. BIOACCUMULATION

4.1 Partition coefficient octanol/water

The partition coefficient octanol/water of emtricitabine was determined according to OECD 107 [7]

Log P_ow = -0.693, -0.670, -0.693 at pH 4, 7 and 10 respectively.

Log P_ow = -0.670 at pH 7, so this Log P_ow is < 4 at pH 7 which result in following conclusion: Emtricitabine has low potential for bioaccumulation.

Conclusion for bioaccumulation:

Emtricitabine has low potential for bioaccumulation

5. PBT-ASSESSMENT

	PBT-criteria	Results for Emtricitabine
Persistence	Half-life in freshwater: DT50 > 40 days Half-life in sediment: DT50 > 120 days	DT50,system = 35.91- 150.65 days
Bioaccumulation	BCF > 2000	Emtricitabine has low potential for bioaccumulation.
Toxicity	Chronic NOEC < 10 µg/L	NOECalgae ≥ 110 mg/L NOECdaphnia ≥ 110 mg/L NOECfish = 6.10 mg/L

Conclusion for PBT-assessment:

According to the established EU-criteria, emtricitabine should not be regarded as a PBT substance.

6. REFERENCES

1. Acute Toxicity of Emtricitabine to the Freshwater Green Alga Pseudokirchneriella subcapitata Following OECD Guideline 201; Study Report Number TX-162-2002.

2. Emtricitabine – Full Life-Cycle Toxicity Test with Water Fleas, Daphnia magna, Under Static Renewal Conditions, Following OECD Guideline Number 211; Study Report Number TX-162-2006.

3. Early Life-Stage Toxicity Test of Emtricitabine with Fathead Minnow (Pimephales promelas), following OECD Guideline 210; Study Report Number TX-162-2005.

4. Activated Sludge Respiration Inhibition Test to Emtricitabine Following OECD Guideline 209; Study Report Number AD-162-2003.

5. Emtricitabine: Ready biodegradability Evaluation (OECD 301D); Study 1784.

6. Emtricitabine – Aerobic and anaerobic Transformation in Aquatic Sediments Systems Following OECD Guideline 308; Study Report Number AD-162-2004.

7. Determining the Partitioning Coefficient (n-Octanol/Water) of Emtricitabine by the Flask-shaking Method Following OECD Guideline 107; Study Report Number AD-162-2002.

8. 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

Detaljerad miljöinformation

1. PREDICTED ENVIRONMENTAL CONCENTRATION (PEC):

The Predicted Environmental Concentration is calculated according to the following formula:

PEC (µg/L)	=	A x 109 x (100-R) / 365 x P x V x D x 100
Where:
A (kg/year)	=	38.3715 kg (total sold amount API in the most recent sales data for Sweden (2019) was distributed by IQVIA/LIF in 2020)
R (%)	=	removal rate (due to loss by adsorption to sludge particles, by volatilization, hydrolysis or biodegradation)
	=	0% (worst-case scenario: no removal)
P	=	number of inhabitants in Sweden (9 x 106)
V (L/day)	=	volume of waste water per capita and day
	=	200 (ECHA default) [9]
D	=	factor for dilution of waste water by surface water flow
	=	10 (ECHA default) [9]
PEC (µg/L)	=	0.005840411 µg/L

2. PREDICTED NO EFFECT CONCENTRATION (PNEC)

2.1 Ecotoxicological studies

2.1.1 Algae

Algal growth inhibition test with the green alga (Pseudokirchneriella subcapitata) (OECD 201) [1]:

EγC₅₀ 72 h (yield) > 29.3 mg/L

NOECγ (yield) = 29.3 mg/L

E_rC₅₀ 72 h (growth) > 29.3 mg/L

NOEC_r (growth) = 29.3 mg/L

2.1.2 Crustacean

Chronic

Reproduction test with water-flea (Daphnia magna) (OECD 211) [2]:

NOEC 21 days = 17.48 mg/L (Reproduction)

2.1.3 Fish

Chronic

Fish early life stage test with fathead minnow (Pimephales promelas) (OECD 210) [3]:

NOEC 28 days = 4.84 mg/L (growth, weight)

2.1.4 Other ecotoxicity data

Activated sludge respiration inhibition test (OECD 209) [4]

EC₅₀ 3h > 1000 mg/L

NOEC 3h ≥ 1000 mg/L

2.2 Calculation of Predicted No Effect Concentration (PNEC)

PNEC (µg/l) = lowest NOEC/10, where 10 is the assessment factor used. NOEC for fathead minnow Pimephales promelas of 4.84 mg/L has been used for this calculation since it is the most sensitive of the three tested species.

PNEC = 4.84 mg/L/10 = 484 µg/L

2.3 Environmental risk classification (PEC/PNEC ratio)

PEC/PNEC = 0.005840411/484 = 0.0000120669

Conclusion for environmental risk:

The calculated PEC/PNEC ratio is < 0.1.

Use of cobicistat has been considered to result in insignificant environmental risk.

3. DEGRADATION

3.1 Biotic degradation

3.1.1 Ready biodegradation

Cobicistat was investigated for its ready biodegradation in a 28-day CO₂-evolution test according to OECD 301B [5]:

Result: Not readily biodegradable.

3.1.2 Simulation study: Aerobic degradation in aquatic sediment systems:

Cobicistat was investigated for its aerobic degradation in a 100-day aquatic sediment test, according to OECD 308 [6].

Under aerobic water/sediment conditions, cobicistat degraded at a slow rate. Total system cobicistat residues decreased from an average of 97 and 98% of applied radioactivity on day 0 to 72 and 66% AR (excluding non-extractable residues) at day 100 for aerobic silt loam and sand sediments, respectively.

Disappearance time of 50% AR (DT50) and disappearance time of 90 % AR (DT90) of the test item were estimated using the combined [14C]-GS-9350 values (expressed as % applied Gilead Sciences Ref. No. TX-216-2048 Page 34 Test Facility Study No. 810165 radioactivity) obtained from the surface water and sediment extract phases at each sampling timepoint.

DT₅₀ values of 241 and 171 days and DT₉₀ values of 801 and 568 days were obtained for the total system dissipation of cobicistat in the silt loam and the sand sediments respectively.

The values obtained indicate the dissipation of the test item from the total system but will also include incorporation of the test item into sediments in a non-extractable form.

For surface water dissipation, DT₅₀ values of 5.6 and 12 days and DT₉₀ values of 19 and 40 days were obtained for silt loam and sand sediment systems respectively. Based on negligible mineralization in both systems, degradation DT values were greater than the 100 day duration of the study.

Determination of Single First Order (SFO) Kinetics: the rate of disappearance of GS-9350 in two aerobic sediment systems was determined for the reported data using kinetic analysis. Optimisation of model parameters, including estimation of parameter standard errors, was performed using the software KinGUI version 1.1.

Conclusion for degradation:

Cobicistat is potentially persistent.

4. BIOACCUMULATION

4.1 Partition coefficient octanol/water

The partition coefficient octanol/water of cobicistat was determined according to OECD 117 [7]

Log P_ow = 3.05, 4.00 and 4.10 at pH 5, 7 and 9 respectively.

4.2 Bioconcentration

The bioconcentration and depuration characteristics of cobicistat in the rainbow trout in a flow through system were examined according to OECD 305 [8].

BCF_k,_low dose = 1.67

BCF_k,_high dose = 1.37

The BCF value of the low and high dose indicates that cobicistat has low potential to bioconcentrate in the rainbow trout.

Conclusion for bioaccumulation:

Cobicistat has low potential for bioaccumulation

5. PBT-ASSESSMENT

	PBT-criteria	Results for BDQ
Persistence	Half-life in freshwater: DT50 > 40 days Half-life in sediment: DT50 > 120 days	DT50,water = 5.6-12 days DT50,system = 171-241 days
Bioaccumulation	BCF > 2000	BCFk = 1.67 (low dose) and 1.37 (high dose)
Toxicity	Chronic NOEC < 10 µg/L	NOECalgae = 29.3 mg/L NOECdaphnia = 17.48 mg/L NOECfish = 4.84 mg/L

Conclusion for PBT-assessment:

According to the established EU-criteria, cobicistat should not be regarded as a PBT substance.

6. REFERENCES

1. Knight B. Determination of Acute Toxicity (EC₅₀) of GS-9350 to Algae (72 h). OECD 201. Gilead Report No. TX-216-2038. September 2011.

2. Knight B. The Effect of GS-9350 on Daphnia magna Reproduction (21 Day Semi-Static Test). OECD 211. Gilead Report No. TC-216-2036. November 2011.

3. Knight B. The Effect of GS-9350 on the Early Life Stages of the Fathead Minnow (Continuous Flow). OECD 210. Gilead Report No. TC-216-2037. November 2011.

4. Knight B. GS-9350: Activated Sludge Respiration Inhibition Test. OECD 209. Gilead Report No. TX-216-2034. September 2011.

5. Hall B. E. GS-9350: Determination of Ready Biodegradation by the CO₂ Evolution (Modified Sturm) Test. OECD 301. Gilead Study No. TX-216-2035. June 2011.

6. Bell S. The Aerobic Transformation of [¹⁴C]-GS-9350 in Two Aquatic Sediment Systems. OECD 308. Gilead Report No. TX-216-2048. March 2012.

7. Ballco S. and Allan G. The Determination of the Partition Coefficient (Log P_ow) of GS-9350 to Meet the Requirements of the OECD Guidelines for Testing of Chemicals, Section 1, No. 117 “Partition Coefficient”. Gilead Report No. TX-216-2040. March 2011.

8. Knight B. Bioconcentration of [¹⁴C]-GS-9350 in Rainbow Trout. OECD 305. Gilead Report No. TX-216-2049. April 2012.

9. 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

Detaljerad miljöinformation

1. PREDICTED ENVIRONMENTAL CONCENTRATION (PEC)

The Predicted Environmental Concentration is calculated according to the following formula:

PEC (µg/L) = A x 10⁹ x (100 - R) / 365 x P x V x D x 100

Where:

A (kg/year)	=	19.8296112 kg (total sold amount API in the most recent sales data for Sweden (2019) was distributed by IQVIA/LIF in 2020)
R (%)	=	removal rate (due to loss by adsorption to sludge particles, by volatilization, hydrolysis or biodegradation)
	=	0% (worst-case scenario: no removal)
P	=	number of inhabitants in Sweden (9 x 106)
V (L/day)	=	volume of waste water per capita and day
	=	200 (ECHA default) [8]
D	=	factor for dilution of waste water by surface water flow
	=	10 (ECHA default) [8]
PEC (µg/L)	=	0.003018206 µg/L

2. PREDICTED NO EFFECT CONCENTRATION (PNEC)

2.1 Ecotoxicological studies

2.1.1 Algae

Algal growth inhibition test with the green alga (Pseudokirchneriella subcapitata) (OECD 201) [1]:

EγC₅₀ 72 h (yield) > 100 mg/L

NOECγ (yield) = 32 mg/L

E_rC₅₀ 72 h (growth) > 100 mg/L

NOEC_r (growth) = 32 mg/L

2.1.2 Crustacean

Chronic

Reproduction test with water-flea (Daphnia magna) (OECD 211) [2]:

NOEC 21 days ≥ 100 mg/L (Reproduction)

2.1.3 Fish

Chronic

Fish early life stage test with fathead minnow (Pimephales promelas) (OECD 210) [3]:

NOEC 28 days ≥ 10 mg/L (hatch, post-hatch, growth)

2.1.4 Other ecotoxicity data

Activated sludge respiration inhibition test (OECD 209) [4]

EC₅₀ 3h > 1000 mg/L

NOEC 3h ≥ 1000 mg/L

2.2 Calculation of Predicted No Effect Concentration (PNEC)

PNEC (µg/l) = lowest NOEC/10, where 10 is the assessment factor used. NOEC for fathead minnow Pimephales promelas of 10 mg/L has been used for this calculation since it is the most sensitive of the three tested species.

PNEC = 10 mg/L/10 = 1000 µg/L

2.3 Environmental risk classification (PEC/PNEC ratio)

PEC/PNEC = 0.003018206 /1000 = 3.0182 × 10^-6 i.e. PEC/PNEC ≤ 0,1

Conclusion for environmental risk:

The calculated PEC/PNEC ratio is < 0.1.

Use of tenofovir alafenamide has been considered to result in insignificant environmental risk.

3. DEGRADATION

3.1 Biotic degradation

3.1.1 Ready biodegradation

Tenofovir alafenamide was investigated for its ready biodegradation in a 28-day CO₂ Evolution test according to OECD 301B [5]:

Result: Not readily biodegradable.

3.1.2 Simulation study: Aerobic degradation in aquatic sediment systems:

Tenofovir alafenamide was investigated for its aerobic degradation in a 100-day aquatic sediment test, according to OECD 308 [6].

The sediment layer was transferred to a centrifuge bottle and extracted four times with 100 mL 50/45/5 (v/v/v) acetonitrile/Milli-Q water/NH₃ on a shaker (200 rpm) for 10 minutes. After centrifugation (5 minutes at 706 g and 20°C) the supernatant was collected. The extracts were combined and weighted, and radioactivity was determined by LSC of a weighed µ100 L aliquot.

Water/sediment systems:

• SL = Swiss Lake

• SW = Schoonrewoerdsewiel

After 100 days of incubation, Tenofovir alafenamide degraded to 29% (SL) and 18% (SW) of applied radioactivity, of which all was recovered in the sediment extract. No organic volatiles were detected and mineralization to CO2 was low (<10%) in both systems. Three significant degradation products were formed.

The DT50 and DT90 values are shown below in both water/sediment systems.

For sediment, no meaningful calculations could be performed as still significant amounts of parent compound were detected in the water layer of the SW system after 63 days of incubation and in the SL system no significant degradation of parent was observed at the end of the incubation period (100 days).

Conclusion for degradation:

Tenofovir alafenamide is slowly degraded in the environment.

4. BIOACCUMULATION

4.1 Partition coefficient octanol/water

The partition coefficient octanol/water of tenofovir alafenamide was determined according to OECD 107 [7]

Log P_ow = -3.8 and -4.3 at pH 2 and 7, respectively.

Conclusion for bioaccumulation:

Tenofovir alafenamide has low potential for bioaccumulation

5. PBT-ASSESSMENT

	PBT-criteria	Results for BDQ
Persistence	Half-life in freshwater: DT50 > 40 days Half-life in sediment: DT50 > 120 days	DT50,system = 10.4 - 32.7 days
Bioaccumulation	BCF > 2000 or log Pow < 4	Log Pow at pH 7 = -4.3
Toxicity	Chronic NOEC < 10 µg/L	NOECalgae = 32 mg/L NOECdaphnia ≥ 100 mg/L NOECfish ≥ 10 mg/L

Conclusion for PBT-assessment:

According to the established EU-criteria, tenofovir alafenamide should not be regarded as a PBT substance.

6. REFERENCES

1. Fresh Water Algal Growth Inhibition Test with Tenofovir; Study Report Number TX-120-2015.

2. Daphnia magna, Reproduction test with Tenofovir (Semi-Static); Study Report Number TX-120-2018.

3. Fish Life-Stage Toxicity Test with Tenofovir (Semi-Static); Study Report Number TX-120-2017.

4. Activated Sludge Respiration Inhibition Test (Carbon and Ammonium Oxidation) with Tenofovir; Study Report Number TX-120-2016.

5. Determination of Ready Biodegradability: Carbon Dioxide (CO₂) Evolution Test (Modified Sturm Test) of Tenofovir; Study Report Number TX-120-2019.

6. Aerobic degradation of Tenofovir in two water/sediment systems; Study Report Number AD-120-2029.

7. Determination of Physico-Chemical Properties of Tenofovir; Study Report Number AD-120-2030.

8. 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