Menadione sodium bisulphite was microencapsulated with a polydimethylsiloxane membrane using spray-drying technology. Tests were performed using laboratory equipment and a Niro Atomizer pilot plant to scale up the process. The products were characterized with differential thermal analysis (DTA) and chemical and physical methods. Many differences between raw material and microencapsulated powder result from DTA data. The thermal characterization confirms that the spray-drying microcoating could be used to protect powder from the oxidative actions of the atmosphere.