Supportive use of cyclodextrins as decontamination agents for herbicides: the case of fenoxaprop-p-ethyl

The inclusion complexes of herbicides in cyclodextrins (CDs) have been considered in an attempt to assess the potentiality of CDs as new formulation additives for both delivery improvement, and reduction of toxicity in terms of environmental impact. The aim of this work was to evaluate the role of three different types of CDs-namely beta-CD and its two derivatives, randomly methylated beta-CD and hydroxypropyl beta-CD-towards the herbicide fenoxaprop-p-ethyl (FE) properties. The toxicity of both pure FE (either alone or as inclusion complex) and a commercial product has been evaluated by an amperometric biosensor based on a Clark electrode as a respirometry study on Saccharomyces cerevisiae strain. Such a technique results more sensitive with respect to FE toxicity methods based on cell growth. The toxic effect of the commercial product was higher than that of the pure chemical entity. Photochemical studies on FE and FE-CD complexes in the presence of different soil colloidal components showed the catalytic effect of some of CDs on photodegradation. The obtained results suggest that CDs could be useful excipients to promote enhancement of solubility, photodegradation inductive effect, and bioremediation in case of FE-like hydrophobic herbicides. (c) 2012 Curtin University of Technology and John Wiley & Sons, Ltd.