Encapsulation of active ingredients

A process for preparing free-flowing and during handling dust-free micro-particles, at least 90% by weight having a diameter of 100-400 mu m, containing one or more active ingredients in a glassy matrix, using a multi-stage spray drying unit, by forming an aqueous solution which contains on solid basis from 40 to 70 % by weight of at least one low molecular weight carbohydrate and/or polyhydroxy compound and 30-60% by weight of at least one high molecular weight film forming agent, whereby the aqueous solution contains at least 50% by weight of said agent(s); incorporating at least one active ingredient into the solution and building an emulsion or suspension, whereby said emulsion or suspension contains on aqueous basis between 1-35% by weight of the active ingredient(s); spray drying the emulsion or suspension into a spray drying tower at an air inlet temperature of 100-180 DEG C and an air outlet temperature of 60-95 DEG C; transferring to a fluid bed section the resulting surface dried semi-solid micro-particles having a water content of about 10-20% by weight and having a particle size of about 10-200 mu m and continuing drying and simultaneously agglomerating said micro-particles at an air temperature of between 25 DEG C and 55 DEG C resulting in solid, free-flowing particles with a glassy matrix having mainly a size of 400 mu m or lower and having a water content of about 2-6% by weight; collecting the particles, at least 90% by weight of that particles having a size in the range of 100-400 mu m and a water content of 0.5-4% by weight and recycling the particles having a size mainly below about 100 mu m from the fluid bed either into the spray dying tower to allow growth of these particles by wetting the particles with fresh sprayed in emulsion or suspension or to the upper part of the fluid bed to allow growth of these particles by agglomeration to a size in the range of 100-400 mu m.