Formulation research into water dispersible granules has increased greatly in recent years because of the regulatory pressures put on solvent based formulations and the concerns about operator exposure during the use of wettable powders.

Initially the popular methods of manufacture were pan granulation and spray drying. In recent years, attention has become more focused on fluid bed 70granulation and extrusion. Each of these methods will be described and will be compared and contrasted. The underlying physicochemical factors influencing each method of granulation will also be discussed.

The problems of solidifying low melting active ingredients and increasing the biological activity of active ingredients formulated as water dispersible granules with low toxicity using globally acceptable inert ingredients remain formidable challenges to the formulation chemist.