Manufacturing process

Manufacturing process

Suspensions are typically manufactured using a high-energy mill to dis-perse the insoluble powder ingredients in the suspension vehicle. A high-energy mill is required to ensure thorough mixing because the vehicle is usually viscous. In addition, the high-energy process can lead to the desired reduction or narrowing of the particle size distribution. A high-shear hand mixer is frequently used in laboratory scale for suspension manufacture. A colloid mill is usually used for the manufacture of pilot and production-scale manufacture of suspensions on a commercial scale.

The powder properties of incoming raw materials are critical and closely controlled to assure the quality attributes of powder blend. These include particle size, shape, charge, size distribution, residual moisture content, flowability, compatibility, and any aggregation tendency. Each ingredient is screened to ensure it is homogeneous and free of agglomerates, followed by mixing with other ingredients in an order that ensures uniform mixing. Preparation of a suspension involves the mixing of water-soluble compo-nents with water to form an aqueous solution. The solid ingredients are then added to this solution under high shear-mixing process in a sequen-tial manner to form a suspension. The suspension is dispensed into bottles using automated liquid dispensing machines.

PFSs are manufactured as dry powders. These formulations are designed to be rapidly redispersible by gentle mixing in the presence of water. The manufacturing process for PFSs involves mixing the bulk powders of the formulation components followed by dispensing into commercial contain-ers using an automated bottle or sachet-filling machine. Mixing of low quantity ingredients, such as colorants, can be challenging. Usually, such ingredients are premixed and/or adsorbed on the surface of another higher-quantity ingredient before being mixed with the rest of the material. In addition, ingredients that may be liquid at room temperature, such as liquid flavors, are adsorbed onto another material before mixing with the bulk of the ingredients. Ingredients can also be coscreened or comilled to ensure their thorough mixing.