Volume 8, Issue 6 (June 2011)
Approaches towards Design of Green Matrices to Formulate Agricultural and Bio-active Materials and Provide Improved Efficacy
Agricultural formulations containing hydrophobic active ingredients and spray solutions are used in aqueous medium. Typical concentrates are formulated as (a) solvent-based emulsifiable concentrates, (b) water-based suspension concentrates, (c) oil-based suspensions, and (d) solid forms like water-dispersible granules form the bulk of agricultural formulations. Efficacy of the active ingredients depends upon the particle/droplet size distribution in the spray solution and it is advantageous to have submicron size distribution with additional protection against wash off. Global awareness and strong regulatory initiative are the driving force for the design of green and environmentally friendly delivery matrices. Following approaches are viable solutions to address the green delivery targets. This paper will address typical examples of solvent pairs to formulate solvent-based formulations; stable micro-emulsion concentrates using all EPA approved (exemption from tolerance) components usable for food-crops. Water-based suspension concentrates with excellent suspensibility were developed by using newly developed polymer composites. Proprietary derivatized vegetable oils were used as self-emulsifying oils to formulate stable concentrates with good emulsification on dilution in water, without having to use conventional emulsifiers. Additional benefit with such compositions would be sustained release capability. Solventless zero volatile organic compounds (VOC) compositions were also developed for end-use applications with acceptable bio-activity by using proprietary polymer surfactant pairs.