Dr. Pereira's Elements of materia medica and therapeutics : abridged and adapted for the use of medical and pharmaceutical practitioners and students and comprising all the medicines of the British Pharmacopœia, with such others as are frequently ordered in prescriptions or required by the physician / edited by Robert Bentley and Theophilus Redwood ; with an appendix.

  • Jonathan Pereira
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: Dr. Pereira's Elements of materia medica and therapeutics : abridged and adapted for the use of medical and pharmaceutical practitioners and students and comprising all the medicines of the British Pharmacopœia, with such others as are frequently ordered in prescriptions or required by the physician / edited by Robert Bentley and Theophilus Redwood ; with an appendix. Source: Wellcome Collection.

    1119/1180 (page 1087)
    Dissolve the hydrochlorate of morphia in two ounces of distilled water, aiding the solution by a gentle heat; then add solution of ammonia so as to precipitate the morphia, and render the liquid slightly alkaline ; allow it to cool; collect the precipitate on a filter, wash it witk distilled water, and allow it to drain; tken transfer tke morphia to a small porcelain dish with about an ounce of dis- tilled water, apply a gentle heat, and carefully add acetic acid until the morphia is dissolved, and a very slightly acid solution is formed. Add now sufficient distilled water to make the solution measure exactly two fluid ounces. Filter and preserve the product in a stop- pered bottle excluded from the light. Characters and Tests.—A clear solution free from any solid particles. Very slightly acid to test-paper. A fluid drachm of it, rendered skghtly alkaline by the addition of solution of ammonia, yields a precipitate of morphia which, after being washed and dried, should weigh 4*3 grains, corresponding to 5 grains of acetate of morphia. Dose, by subcutaneous injection.—1 minim to 6 minims.] A strong and nearly neutral solution of acetate of morphia has for some time been used for subcutaneous injection, this salt being preferred over any of the other salts of morphia for such purpose. But commercial acetate of morphia cannot be advantageously used for making the hypodermic solution, because it is never perfectly soluble in water, and is rarely sufficiently definite in composition to admit of its being used in a preparation in which great purity and accuracy of composition are required. In the process now given in the Pharmacopoeia, the best known, most perfectly prepared and generally kept of the salts of morphia-—the hydrochlorate—is used as the source from which the acetate is made, by a process which yields it in a pure, definite, and perfectly soluble state. The 88 grains of hydrochlorate ordered in the process contain G6'8 grains of morphia, of which 60*74 grains are required for the production of 80 grains of acetate of morphia, the quantity con- tained in 2 fluid ounces of a solution of the required strength. There is thus a slight allowance made for the inevitable loss of a small portion of morphia in precipitating, washing, and collecting it preparatory to its combination with acetic acid and solution in water; but much care and some manipulative skill are required to avoid undue loss, and to produce a solution that will realise what is required. Therapeutics*^-See p. 979,