This method is applicable for the preparation of most of the medicated ointments containing insoluble drug substances. Finely powdered solids are passed through sieve #85. The medicament is taken on an ointment slab and triturated lightly with a small amount of the base. A steel spatula with long, broad blade is used for this purpose. To this, additional quantities of the base are incorporated and triturated until the medicament is fully mixed with the base. Finally, liquid ingredients are incorporated to this semisolid mass.

Example:

Whitfield’s ointment (Compound benzoic acid ointment B.P.C.)

Benzoic acid and salicylic acid are sieved through #85 sieve. They are mixed on the tile with small amount of base and levigated until smooth and diluted gradually.