TY - JOUR

T1 - Aquatic photochemistry, abiotic and aerobic biodegradability of thalidomide

T2 - Identification of stable transformation products by LC-UV-MS(n.)

AU - Mahmoud, Waleed M M

AU - Trautwein, Christoph

AU - Leder, Christoph

AU - Kümmerer, Klaus

N1 - Copyright © 2013 Elsevier B.V. All rights reserved.

PY - 2013/10/1

Y1 - 2013/10/1

N2 - Thalidomide (TD), besides being notorious for its teratogenicity, was shown to have immunomodulating and anti-inflammatory activities. This is why recently TD became a promising drug for the treatment of different cancers and inflammatory diseases. Yet nothing is known about the environmental fate of TD, which therefore was assessed experimentally and by in silico prediction programs (quantitative structure activity relationship (QSAR) models) within this study. Photolytic degradation was tested with two different light sources (medium-pressure mercury lamp; xenon lamp) and aerobic biodegradability was investigated with two OECD tests (Closed Bottle test (CBT), Manometric Respirometry test (MRT)). An additional CBT was performed for TD samples after 16min of UV-photolysis. The primary elimination of TD was monitored and the structures of its photo-, abiotic and biodegradation products were elucidated by HPLC-UV-Fluorescence-MS(n). Furthermore, elimination of dissolved organic carbon was monitored in the photolysis experiment. LC-MS revealed that new photolytic transformation products (TPs) were identified, among them two isomers of TD with the same molecular mass. These TPs were different to the products formed by biodegradation. The experimental findings were compared with the results obtained from the in silico prediction programs where e.g. a good correlation for TD biodegradation in the CBT was confirmed. Moreover, some of the identified TPs were also structurally predicted by the MetaPC software. These results demonstrate that TD and its TPs are not readily biodegradable and not fully mineralized by photochemical treatment. They may therefore pose a risk to the aquatic environment due to the pharmacological activity of TD and unknown properties of its TPs. The applied techniques within this study emphasize the importance of QSAR models as a tool for estimating environmental risk assessments.

AB - Thalidomide (TD), besides being notorious for its teratogenicity, was shown to have immunomodulating and anti-inflammatory activities. This is why recently TD became a promising drug for the treatment of different cancers and inflammatory diseases. Yet nothing is known about the environmental fate of TD, which therefore was assessed experimentally and by in silico prediction programs (quantitative structure activity relationship (QSAR) models) within this study. Photolytic degradation was tested with two different light sources (medium-pressure mercury lamp; xenon lamp) and aerobic biodegradability was investigated with two OECD tests (Closed Bottle test (CBT), Manometric Respirometry test (MRT)). An additional CBT was performed for TD samples after 16min of UV-photolysis. The primary elimination of TD was monitored and the structures of its photo-, abiotic and biodegradation products were elucidated by HPLC-UV-Fluorescence-MS(n). Furthermore, elimination of dissolved organic carbon was monitored in the photolysis experiment. LC-MS revealed that new photolytic transformation products (TPs) were identified, among them two isomers of TD with the same molecular mass. These TPs were different to the products formed by biodegradation. The experimental findings were compared with the results obtained from the in silico prediction programs where e.g. a good correlation for TD biodegradation in the CBT was confirmed. Moreover, some of the identified TPs were also structurally predicted by the MetaPC software. These results demonstrate that TD and its TPs are not readily biodegradable and not fully mineralized by photochemical treatment. They may therefore pose a risk to the aquatic environment due to the pharmacological activity of TD and unknown properties of its TPs. The applied techniques within this study emphasize the importance of QSAR models as a tool for estimating environmental risk assessments.

KW - Sustainability Science

KW - Chemistry

KW - Aquatic environment

KW - Biodegradation

KW - Dead-end transformation product

KW - Pharmaceuticals

KW - Photodegradation

KW - QSAR

UR - http://www.scopus.com/inward/record.url?scp=84879488074&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/60c0bbd7-d392-3ed4-84ed-0a868ad3c265/

U2 - 10.1016/j.scitotenv.2013.05.082

DO - 10.1016/j.scitotenv.2013.05.082

M3 - Journal articles

C2 - 23792256

VL - 463-464

SP - 140

EP - 150

JO - The Science of The Total Environment

JF - The Science of The Total Environment

SN - 0048-9697

ER -