USE OF CLAY/β-CYCLODEXTRIN FORMULATIONS TO

The study aimed to prepare slow release formulations of the hydrophobic herbicide norflurazon (4-chloro-5-methyl-amino-2-(α,α,α)-trifluoro-m-tolypyridazin-3-(2H)-one) based on a standard montmorillonite, a pillared montmoril-lonite and an organo-montmorillonite. For this purpose, a β-cyclodextrin-norflurazon solution was used, due to its ability to form an inclusion complex which yields an in-crease in norflurazon solubility in water (up to 5 times). The amount of herbicide adsorbed on the standard montmoril-lonite was directly proportional to the herbicide concentra-tion in solution, obtaining an herbicide adsorption 5 times higher when β-cyclodextrin-norflurazon solutions were used. The organo-clay was prepared modifying the surface of montmorillonite from hydrophilic to hydrophobic preadsorb