| Popis: |
The influence of formulation and adjuvants on the biological activity of a pesticidal active ingredient (AI) is a complex interactive phenomenon, with many factors possibly influencing the final response observed. These factors include the many steps and processes between the spray tank and the biochemical site of action in the target organism, be it plant, pathogen or insect. However, some of them are beyond the control of the formulation chemist. For example, the movement and metabolism of an active ingredient are determined by the physicochemical properties of the compound and the physiological/biochemical characteristics of the target organism, respectively. Changes to the physicochemical properties of the active ingredient by synthesis of analogues may lessen the desired biological impact. The physicochemical properties which the formulation chemist must work with are therefore fixed by biological screening data, unless the AI is suitable for the synthesis of a salt. The resultant physicochemical properties of an active compound may not necessarily be optimal for easy delivery to the biochemical site of action (Stock 1991). Optimising delivery of the active ingredient within the constraints imposed by its physicochemical properties depends upon the skill of the formulation chemist married with the experience and experimental expertise of the biologist. |
