Cyclodextrins in Pesticides

Abstract

Many synthetic pesticides (herbicides, insecticides, fungicides, etc.) can be complexed with cyclodextrins. This “molecular encapsulation” frequently results in advantageous modifications of the properties of complexed substances. The hydrophilicity is strongly reduced, i. e. wettability, rate of dissolution and extent of solubility is enhanced, which generally results in enhanced bioavailability. Volatile, liquid, and gaseous substances, or substances of intolerable stink can be converted into microcrystalline, stable, well formulable substances. Incompatible substances can be mixed when at least one of the reacting components is complexed. The selectivity between herbivorous/non‐herbivorous insects toxicity can be enhanced. CD‐complexes are per se micronized substances, they are easily dispergable, no electric charging was observed. Long lasting effect can be ensured (e. g. in soil) because the complexed substances are released only on contacting with water. Cyclodextrins exert a direct auxin‐like effect on plants therefore phytotoxic effect of pesticides can be reduced, etc. .

Complexation of capsaicin with β-cyclodextrins to improve pesticide formulations: effect on aqueous solubility, dissolution rate, stability and soil adsorption

“…The most important structural feature of CDs is the hydrophobic central cavity capable of forming stable complexes with properly sized drug molecules [11,12]. The formation of inclusion complexes between CDs and pesticides often results in an improvement in physical, chemical, and biological properties of pesticides, such as an increase in stability of degradable pesticides, the enhancement of bioactivity, and the acceleration in degradation of pesticides [13,14]. Pesticides are formulated not only to improve their efficacy to pests but also to reduce the environmental risk associated with overdosing.…”

Study on Properties of Inclusion Complexation of Triclopyr Butoxy Ethyl Ester with Mixed Surfactant System

“…[4] The mechanism of complex formation is well discussed. [5] These inclusion complexes find a variety of applications in pharmaceuticals, [6] pesticides, [7] and the like. In the field of agrochemicals, these inclusion complexes are finding many important applications.…”

Cyclodextrins and Their Complexes

“…Pérez-Martínez et al [9] employed 1 H NMR spectroscopy (see Chapter 9) to confirm the complexation and study structural aspects of the inclusion complexes formed between the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) and a-and b-CyDs. Also Consonni et al [10] have used 1 H and 13 C NMR spectroscopic techniques to establish the three-dimensional structure of the fungicide imazalil@ b-CyD complex. A study of the interaction of 18 pesticides with a water-soluble b-CyD polymer (BCDP) demonstrated that the lipophilicity of the majority of them decreased in relation to the strength of the BCDP-pesticide inclusion complex [11].…”

“…Their ability to alter the physical, chemical, and biological properties of guest molecules has been used for the preparation of new formulations of pesticides. CyDs form complexes with a wide variety of agricultural chemicals including herbicides, insecticides, fungicides, repellents, pheromones, and growth regulators [1,2].Each CyD has its own ability to form inclusion complexes with specific pesticides, depending on a proper fit of the pesticide molecule into the hydrophobic CyD cavity. The principal advantage is that the binding of pesticide molecules within the host molecule is not fixed or permanent but rather is a dynamic equilibrium.…”

“…Their ability to alter the physical, chemical, and biological properties of guest molecules has been used for the preparation of new formulations of pesticides. CyDs form complexes with a wide variety of agricultural chemicals including herbicides, insecticides, fungicides, repellents, pheromones, and growth regulators [1,2].…”