How to choose the matrix according to the nature of the drug?

① drug insoluble in the matrix, it must be crushed into a powder that can pass the six sieve. ② drug soluble in the matrix, oil-soluble drugs dissolved in liquid oil, and then mixed with the greasy matrix, made of greasy matrix ointment. ③ Semi-solid viscous drugs such as ichthyol, have a certain polarity, it is not easy to mix with a couple of serum, can be mixed with an equal amount of castor oil or lanolin, and then added to petroleum jelly and other greasy base. ④When the prescription contains *** melting ingredients, such as camphor, menthol, musk vanillin, etc., it can be ground first to make it *** melting, and then mixed with the matrix; when used alone, it can be dissolved in a small amount of suitable solvent, and then added to the matrix to be mixed, or dissolved in the matrix at about 40 ℃. ⑤ When the extract of traditional Chinese medicine is liquid, it can be concentrated to thick paste before adding into the matrix; if it is solid extract, it can be added with a small amount of water or diluted yeast and so on to make a paste before mixing with the matrix. (6) heat destruction or volatile drugs, the preparation of research and method and emulsification method, should be used until the matrix cooled to below 40 ℃ before adding to reduce damage or loss.