Slow release herbicide formulation based on castor oil and its derivatives

Abstract

Castor oil and Its polyol derivatives have been used as a matrix to prepare controlled-release (2,4-dichlorophenoxy)acetlc acid (2,4-D) formulations, and their release characteristics have been studied both in vivo and in vitro. The initial release rate has been found to be dependent on the hydrophllicity of the formulations. The pH of the hydrolysis also strongly affects the release characteristics; the release rate Increases sharply in the alkaline range (pH 10). Cross-linking via carbamate linkage has been found to retard the release rate. Compared to formulations based on natural or synthetic polymer matrices, such castor oil-based preparations are likely to be more suitable for agricultural applications requiring shorter release period of the toxicant.

Controlled-release polymeric herbicide formulations with pendent 2,4-dichlorophenoxy acetic acid

“…The active agent may be covalently bound on a preformed synthetic or natural polymer macromolecule (Neogi, 1970;Allan et al, 1977;Bhattacharya et al, 1985). The toxicant is delivered from such formulations at a controlled rate, increasing the period of effectiveness of the biologically active component and obviating the need for overdose.…”

“…There are basically two approaches for preparing such controlled-release pesticides. The active agent may be covalently bound on a preformed synthetic or natural polymer macromolecule (Neogi, 1970;Allan et al, 1977; Bhattacharya et al, 1985). Another approach is to polymerize a herbicide containing monomer.…”