Preparation of drug substances and ointment base. Preparation of drug substances consists of grinding, sieving through a sieve (with a given particle size) and mixing. If necessary, the raw materials are dissolved in the base or in water. Grinding raw materials is necessary not only to achieve greater therapeutic effect, but also for more accurate dosing: when grinding the particle size of drugs equalizes, then they are well mixed and do not stratify during dosing. For grinding solid drugs use three-roll maseter, mills with paddle stirrer-knife, ball and other types of mills, and for the finest grinding – dispersants. Crushed solid drugs or their aqueous solutions are added to the base with constant stirring.

Preparation of ointment base includes dissolution or fusion of its components with subsequent removal of mechanical impurities by filtration. Melting components of the base (vaseline, lanolin, wax, emulsion waxes, etc.) are melted in electric furnaces-melting (barrels with the base are rolled inside the furnace and melted, controlling the temperature and time) or in melting boilers or in boilers with steam jackets. Ointment boilers are made mostly of copper or cast iron and covered with a thin layer of tin – pomuda or enamel. In shape they are cylindrical or spherical, and to drain the melted mass they are made tipping or with drain valves. Ointment boilers are equipped with powerful agitators, suitable for work in very viscous media. Anchor, rake or planetary agitators are most suitable for this purpose.