Tinctura Pyrethri (U. S. P.)—Tincture of Pyrethrum.
Related entry: Pyrethrum (U. S. P.)—Pyrethrum
SYNONYM: Tincture of pellitory.
Preparation.—"Pyrethrum, in No. 40 powder, two hundred grammes (200 Gm.) [7 ozs. av., 24 grs.]; alcohol, a sufficient quantity to make one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏]. Moisten the powder with one hundred and fifty cubic centimeters (150 Cc.) [5 fl℥, 35♏] of alcohol, and macerate for 24 hours; then pack it firmly in a cylindrical percolator, and gradually pour alcohol upon it, until one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏] of tincture are obtained"—(U.S. P.). This acrid tincture has a brown-yellow color, and, when in contact with water, becomes milky and opalescent.
Action and Medical Uses.—Used only in tooth and month washes; intended as local irritants in toothache and paralytic states of the tongue and fauces.