An overview of the latest development of microencapsulation for agricultural products
For the production of controlled-release agricultural formulations microencapsulation technologies are now the most used. Over the past two decades enormous progress has been made in order to develop the technologies which allow us to produce formulations tailor made to reach the target and fitting our toxicological requirements. This lecture is devoted to the definition of the criteria for selection of an active ingredient for microencapsulation and to a detailed review of the various techniques used today in commercal microencapsulated formulations. Resources are increasingly allocated into microencapsulation research & development by many agrochemical companies. Therefore the next 20 years should continue to yield innovative ideas including significant improvement of the physico-chemical and toxicological properties of the actual formulations on the market. Some of this new ideas are applied by our company in order to modify or improve those properties playing the key role in the intent for targeted activity : ? Recombination during production or upon storage. New protective colloides Dermal toxicity (LD 50) - secondary protective colloides. ? Release rate parameters. Modification by the change of mobility of the active ingredient from the core (solvent or fluid type) affecting transit time and therefore LD 50 values. ? Oral toxicity (LD 50). Graft copolymers irreversibly adsorbed to the capsule surface.