In medicine: defining is the production of drug and prescription dispensing with excipients and additives, namely, general term for everything but the main active ingredient items, are important components of pharmaceutical preparations.
In industrial production, to improve the production process, improve product quality and yield, or to give the product a certain unique auxiliary chemicals added to application performance. Also called additive. But as important components of the product matrix, product shape, structure, significantly impact the performance of high-dose supplement, generally classified into the category of additives. Auxiliary application range is very wide, usually dubbed the object name, such as polymer additives, water treatment, metal surface treatment agent. Additive selection are some common considerations, such as: ① the use of additive requirements. Appearance of the additive, odor, pollution, durability, electrical properties, and weather have a direct impact on the usage. ② additives on the adaptability of processing conditions. ③ additive for durability. Losses by evaporation of additives, extraction and migration 3 ways, must be used according to the product environment and processing conditions to select the appropriate species. ④ additive and polymer compatibility. Includes compatibility between them and the interaction in terms of stability and other issues. ⑤ additive toxicity. Food and drug packaging materials, tubes for drinking water, medical equipment and other products of polymer materials, its health depends primarily on the use of additives. ⑥ synergy between additive and phase effects. Such as matching, increase efficiency, and reduce the total amount of additives.