Ammoniacum, B.P. Ammoniacum.

Ammoniacum is a gum-resin obtained from the flowering and fruiting stem of Dorema Ammoniacum, D. Don (N.O. Umbelliferae), and probably other species. The plants are widely distributed throughout Persia, extending into Southern Siberia. They are visited by numbers of beetles, which puncture the stem and thus cause an exudation of the milky substance contained in the numerous ducts situated in the cortex. Part of the secretion thus exuded dries on the stem, part falls to the ground and becomes mixed with earthy and other impurities. The gum-resin occurs in commerce in two forms, tear ammoniacum and block or lump ammoniacum. The former, which is alone official, is composed of separate pale yellow tears or nodular masses varying in size from a pea to a small walnut. They are brittle when cold, but soften on warming; the fractured surface is milky white or pale brownish in colour, and is coloured orange-red by solution of chlorinated soda. Lump ammoniacum consists of particles of gum-resin agglutinated together with a bluish resinous substance. It is often admixed with stones, fragments of the stems, fruits, and other debris, and although largely used is not official. The drug has a characteristic but not strong odour, and a bitter acrid taste. African ammoniacum or "feshook," from Ferula communis, L., var. brevifolia.N.O. Umbelliferae), does not give an orange-red colour with chlorinated soda; it is not a commercial article. Ammoniacum is harder than galbanum, has a different odour, and does not yield the umbelliferone reaction (compare Galbanum).

Constituents.—The drug contains volatile oil (1 to 2 per cent.), resin (65 to 70 per cent.), and gum. The resin consists of an indifferent resene (20 per cent.), associated with ammoresinotannol combined with salicylic acid. The gum resembles gum acacia, and is probably an acid calcium arabate. The drug also contains traces of free salicylic acid, which may be detected by streaking the creamy emulsion made with water over filter paper containing traces of ferric chloride, when the usual reaction will be obtained. Tear ammoniacum of good quality should yield not less than 60 per cent. to alcohol and leave not more than 7.5 per cent. of ash when incinerated.

Action and Uses.—Applied externally ammoniacum acts as a slight irritant in virtue of the essential oil it contains. Taken internally it acts by facilitating expectoration, and is of value in chronic bronchitis especially in the aged, when the secretion is tough and viscid. The resin has a mild diuretic action. It is administered as Mistura Ammoniaci, or in pills; it is a constituent of Pilula Scillae Composita and Pilula Ipecacuanhae cum Scilla.

Dose.—3 to 10 decigrams (5 to 15 grains).


Emplastrum Ammoniaci cum Hydrargyro, B.P.—AMMONIACUM AND MERCURY PLASTER.
Ammoniacum 16; mercury, 41; olive oil, 1.75; sublimed sulphur, 0.25. This plaster is used to promote absorption in glandular enlargements; cut into strips, it is applied over and round the knee and other joints in chronic synovitis.
Mistura Ammoniaci, B.P.—AMMONIACUM MIXTURE. Syn.—Lac Ammoniaci.
Ammoniacum, in coarse powder, 1; syrup of balsam of tolu, 2; distilled water, 30. This mixture is employed in chronic bronchitis, especially in the aged, and when there is much expectoration. Dose.—15 to 30 mils (½ to 1 fluid ounce).

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.