2,4-D-α-cyclodextrin complexes -: Preparation and characterization by thermal analysis

The aqueous solubility of the pesticide 2,4-D was improved by inclusion complexation with alpha-CD. The formation of such inclusion compounds was studied via the phase-solubility diagram (solution state) and by DSC and HSM (solid state). 2,4-D presented a typical B-5 Higuchi solubility curve, coprecipitating a 1:2 pesticide-alpha-CD complex. In order to obtain solid complexes, three processing methods were checked: kneading, coprecipitation and spray-drying. DSC and HSM showed that only the last two of these yielded true inclusion compounds. Chemical analysis also revealed that the stoichiometry of such solid complexes corresponds to a 2,4-D-alpha-CD ratio of 1:2.