Cannabine tannate is a substance prepared commercially by distilling Indian hemp with steam to deprive it of its volatile oil, extracting with water, precipitating the aqueous extract with lead acetate, decomposing this with hydrogen sulphide and combining the cannabine thus set free with tannic acid; or the aqueous extract may be directly precipitated with tannic acid. It is assumed to be the salt of an alkaloid, but the dark-brown viscid mass to which the name cannabine is applied does not appear to be a pure substance. Cannabine tannate occurs in the form of a brownish powder, having a somewhat bitter and strongly astringent taste, and a not unpleasant odour. It should dissolve without residue in 10 parts of alcohol containing 10 per cent. of hydrochloric acid, and should be free from narcotic odour.
Sparingly soluble in water, alcohol, or ether; soluble in acidified alcohol, or in water made alkaline.
Action and Uses.—Cannabine tannate is used as a hypnotic in nervous insomnia, also in dysmenorrhoea and menorrhagia, and is said to be free from the intoxicating properties of Cannabis Indica. Its activity varies very greatly, but it is generally of little value, often being quite inert. It is usually administered in pills, massed with glycerin of tragacanth, or in cachets; it may be dissolved in sal volatile and water, but has a disagreeable astringent taste.
Dose.—2 1/2 to 5 decigrams (4 to 8 grains).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.