Photodegradation kinetics, transformation, and toxicity prediction of ketoprofen, carprofen, and diclofenac acid in aqueous solutions

Abstract

Photodegradation of 3 commonly used nonsteroidal anti-inflammatory drugs, ketoprofen, carprofen, and diclofenac acid, was conducted under ultraviolet (UV) irradiation. The kinetic results showed that the 3 pharmaceuticals obeyed the first-order reaction with decreasing rate constants of 1.54 × 10 , 5.91 × 10 , and 7.78 × 10 s for carprofen, ketoprofen, and diclofenac acid, respectively. Moreover, the main transformation products were identified by ion-pair liquid-liquid extraction combined with injection port derivatization-gas chromatography-mass spectrometry and high-performance liquid chromatography-quadrupole-time of flight mass spectrometric analysis. There were 8, 3, and 6 transformation products identified for ketoprofen, carprofen, and diclofenac acid, respectively. Decarboxylation, dechlorination, oxidation, demethylation, esterification, and cyclization were proposed to be associated with the transformation of the 3 pharmaceuticals. Toxicity prediction of the transformation products was conducted on the EPI Suite software based on ECOSAR model, and the results indicate that some of the transformation products were more toxic than the parent compounds. The present study provides the foundation to understand the transformation behavior of the studied pharmaceuticals under UV irradiation. Environ Toxicol Chem 2017;36:3232-3239. © 2017 SETAC.

Structure Determination of Naproxen Photoproducts in the Tablet Generated by the UV Irradiation

“…UV irradiation at longer wavelength. There are some reports showing effects of the photodegradation on the biological activities of irradiated medicines [20][21][22][23][24]. In the case of naproxen, some photoproducts of it were more ecotoxic than naproxen, both in acute and chronic conditions [17,25].…”

Distribution, Removal, and Risk Assessment of Pharmaceuticals and Their Metabolites in Five Sewage Plants

“…Some organic compounds will decompose under certain natural light conditions. In an experiment of DCF irradiation by ultraviolet light, Li et al [23] found that six kinds of conversion products were produced. Some drugs have high degradation efficiency in the process of biodegradation.…”

Photosensitivity Reactions Induced by Photochemical Degradation of Drugs

“…It is worth to be mentioned that decomposition compounds (A) and (C) are toxic free radicals (figure 4). 33 Benzodiazepine derivatives are used in therapy mainly as anxiolytics and are generally photolabile, but their degradation path depends on the structure of each derivative and on the degradation conditions. 34 A typical example of the photochemical reactivity of 1,4-benzodiazepines is the one of diazepam (7-chloro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one) decomposition (figure 5).…”