The Art of dispensing : a treatise on the methods and processes involved in compounding medical prescriptions.

Date:
1901
Catalogue details

Licence: In copyright

Credit: The Art of dispensing : a treatise on the methods and processes involved in compounding medical prescriptions. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

    382/510 (page 368)
    Here an abundant precipitate renders the lotion almost creamy, and hecessitates mixing half the water with the ex^ tract, and the remainder with the liquor before mixing, else a disagreeable lumpy mixture is produced. Such combinations may be dispensed as written, and sent out with a ' shake' label. Occasionally, however, the decompositions are of such a character that the chemist may feel pretty sure that the writer of the prescription is unacquainted with the reaction, or has overlooked it. For example :— Sodii sulphat. . . gr. xv. Potass, cit. . • . 9j. M. Ft. pulv. Mitte vj. Zinci sulphat. . . • Sj- Plumbi acet. . . . jij. M. Ft. pulv. Modo diet, utend. In these cases metathesis takes place, the water of crystal- lisation of the sulphates is liberated, and the powders become wet. The use of an equivalent quantity of the dried salts removes the difficulty. The following prescription has become famous in text- books :— StrychnincE sulph ^ • gf- j- Potassii bromid. ...... r^vij. Aquas ad 3viij. Fiat mistura. This solution deposits in a few hours the greater part of the strychnine salt as an insoluble bromide in transparent crystals. A lady in England lost her life by taking a similar mixture. She carefully refrained from shaking the bottle, the precipitated strychnine collected at the bottom, and in taking the last dose she swallowed nearly all of it. One of the most remarkable cases of incompatibility is the following, which at first sight appears perfectly harmless, but at least one case of death is on record from the administration of a similar mixture :— Potassii chlorat. . Syr. ferri iodidi Vin. aiitim.' i^^ther. chldr. . ' Aq. . Fiat mistura. • r)ij- ad 5viij.