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The toxicity of 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-2′-deoxythymidine, 3′-[2-cyanoethyl N,N-bis(1-methylethyl)phosphoramidite] was tested according to OECD guidelines 201 and 202 for acute toxicity studies with aquatic invertebrates (Daphnia magna) and algae (Pseudokirchneriella subcapita. No toxic effect on D. magna or P. subcapitata was observed up to the limit of water solubility (NOEC ≥ 100 mg/L nominal; no analytical determination possible; solubility too low).

This information is used in a read-across approach in the assessment of Cytidine, N-benzoyl-5′-O-[bis(4 methoxyphenyl)phenylmethyl]-2′-deoxy-, 3′-[2-cyanoethyl bis(1-methylethyl)phosphoramidite] (target substance). For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Additional information

Daphnia magna Straus was exposed for 48 hours to 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-2′-deoxythymidine, 3′-[2-cyanoethyl N,N-bis(1-methylethyl)phosphoramidite] in a semi-static short-term toxicity study according to the OECD guideline 202 (2004) and in compliance with the OECD-GLP principles. The study was conducted as limit test with a nominal concentration of 100 mg/L.

The freshwater algae Pseudokirchneriella subcapitata was exposed to 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-2′-deoxythymidine, 3′-[2-cyanoethyl N,N-bis(1-methylethyl)phosphoramidite] for 72 hours in a static toxicity study according to the OECD guideline 201 (2006) and in compliance with the OECD-GLP principles. The study was conducted as limit test with a nominal concentration of 100 mg/L). No effect on P. subcapitata was observed.

 

The test concentrations were determined analytically by HPLC-UV in both tests and showed that the concentration of the test item was below the LOD of 0.01 mg/L. As the test item is hardly soluble, the preparation of the test solution followed the recommendation of the OECD Guidance Document No. 23. The test item was stirred or shaken for 48 hours in the medium to achieve maximum solubility. Therefore, it can be concluded that the maximum amount of substance was solubilized, and no toxic effect is to be expected up to the limit of water solubility. 

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the attached report in section 13 of IUCLID.