Assessment on the effects on ecosystems and the environment

Title of Research:
12_S04-01

Development of in silico Prediction Model on Environmental
Fate of Chemical Substances
Principal Investigator:
Tatsuya Takagi, Graduate School of Pharmaceutical Sciences, Osaka University; Genome
Information Research Center, Research Institute for Microbial Diseases, Osaka Univ.
1-6, Yamadaoka, Suita, Osaka, Japan, 565-0871, (tel) +81-6-6879-8243,(e-mail) ttakagi@phs.osaka-u.ac.jp
Collaborators:
Norihito Kawashita, Graduate School of Pharmaceutical Sciences, Osaka University; Genome
Information Research Center, Research Institute for Microbial Diseases, Osaka Univ.
1-6, Yamadaoka, Suita, Osaka, Japan, 565-0871, (tel) +81-6-6879-8244, (e-mail)kawasita@gen-info.osaka-u.ac.jp
Kousuke Okamoto, Graduate School of Pharmaceutical Sciences, Osaka University;
1-6, Yamadaoka, Suita, Osaka, Japan, 565-0871, (tel) +81-6-6879-8242, (e-mail)okamotok@phs.osaka-u.ac.jp
Summary of Research:
In 2009, since the Act on the Evaluation of Chemical Substances and Regulation of Their
Manufacture, etc., was revised, chemical substances which are readily degradable have become
subject to control under the law. Chemical industries are required to examine various physical,chemical, and biological properties of compounds such as toxicity, accumulation behavior, anddegradation property. If there is a procedure which enables us to predict any properties of new orexisting chemical substances without experiments, we are able to plan the efficient order of theexperiments based on the ranking of the predicted properties. Because most existing prediction
models on abiotic degradation, especially photolysis and hydrolysis are targeted to similar
chemical substances, the development of the prediction models on the photolysis and hydrolysis
of more various chemical substances would be contributed to obtain the effective ranking ofcandidates for experimentation.
The experimental results of the direct photolysis and hydrolysis under certain conditions
were collected and then the datasets of hydrolysis and direct photolysis consisted of the results of143 and 106 compounds, respectively. Although the experimental results of indirect photolysis
were also checked, since there were few results whose experimental conditions were under theEPA guideline, we decided that the prediction on photolysis of this project was focused on directone. We are intended to collect the information on photolysis and hydrolysis and to add it into thedataset continuously. The quantitative model on hydrolysis of “unstable” compounds whose
half-lives are less than a year was built by using publicly available software, and its prediction
performance was adequate. We are preparing to calculate an excited state that is regarded as akey factor for the prediction of direct photolysis of a compound using publicly available software.
The trial system which provides the prediction models through the WWW was constructed. We areadding several functions and improving usability of this web site.
Timeline: November 1, 2012 –Topics:
The 2th Annual Conference of New LRI, “Development of new tool for in silico prediction ofenvironmental fate of compounds”, Aug 30, 2013
Publications:
The 40th Symposium of Structure-Activity Relationships, Aichi, Japan, Nov 2012

Annual Report 201317