Thermal Behaviour, Biological Activity and Conformational Study of a [Methoprene/β-Cyclodextrin] Complex in a Smoke Generating Formulation

Methoprene, an insect growth regulator, was complexed with β-cyclodextrin, yielding a stable inclusion complex. TGA, X-ray powder diffraction and conformational analysis have been used to confirm the nature of this inclusion complex. The interaction between methoprene and β-cyclodextrin was investigated by means of Molecular Mechanics. The results account for the formation of a 1:1 inclusion complex stabilised by Van der Waals forces and hydrogen bonds. The [methoprene–β-cyclodextrin] complex included in smoke generating formulations and protected from thermal decomposition by the foaming agent azodicarbonamide was shown to be stable enough to release methoprene in fumes with good yields. The improved stabilty of the methoprene complex showed a correlation with increased biological activity against Musca domestica.