Indian hemp (Indian Cannabis, U.S.P.) consists of the dried flowering or fruiting tops of the pistillate plant of Cannabis sativa, Linn. (N.O. Urticaceae), grown in India. It is also official in the U.S.P. The hemp plant is an annual dioecious herb, indigenous to Central India and Western Asia. When grown in tropical countries the pistillate plant produces an oleoresinous secretion, to which the physiological action of the drug is due. This secretion is formed in stalked glands, which are particularly abundant on the upper leaves and bracts, to increase the number of which the plants are carefully pruned. The staminate plants are eradicated before they arrive at maturity, but the pistillate plants produce a few staminate flowers, which fertilise many of the plants. The tops are collected, allowed to wilt, and pressed by treading with the feet into flattened masses, which remain more or less compacted together by the adhesive resinous secretion. In this form the drug is exported from Bombay, and known commercially as guaza. A more active variety is the Bengal drug, which is termed ganjah. This is in smaller, shorter masses which are rounded instead of flattened, and hence sometimes called round ganjah. It is exported from Calcutta, but such as reaches this country is re-exported, and practically none is offered on the market. It is largely consumed in India, but rapidly deteriorates in activity. In addition to the ganjah (or guaza) the larger leaves of the plant are also collected, and form, when dried, "bhang" or "hashish"; this is generally consumed by making it into a confection or drink. Sometimes the plants are beaten on to cloths, and the resin which adheres to them collected; this is known as charas or churrus, and like ganjah, is commonly smoked. It is on account of the possible separation of the resin that the British Pharmacopoeia specifies the drug "from which the resin has not been removed." Preparations are most active when made from an extract prepared in India from the fresh drug, and exported in sealed tubes. Hemp tops grown in more temperate climates have been offered in place of Indian hemp, but may be distinguished by their brighter colour and less resinous nature. Indian hemp occurs in rough, flattened, brownish-green masses, from 5 to 30 centimetres long, consisting of the branched upper part of the stem, bearing leaves and pistillate flowers or fruits matted together.
Constituents.—The narcotic effect of Indian hemp appears to be produced by the resinous secretion of the glands. This resin has been obtained as a soft, brown substance (cannabinone), the chief constituent of which is cannabinol, C21H30O2. This compound has been obtained from charas in the form of a viscid, reddish oil, possessing a powerful narcotic action, but resinifying and becoming less active on exposure to the air; cannabinol may also be obtained from hashish, etc. In addition to the resin and its important constituent cannabinol, Indian hemp also contains fat, wax, the alkaloid choline, and traces of volatile oil. The names cannabin (a resinoid), cannabene, cannabine (an alleged alkaloid), and cannabindon have been applied to different impure substances obtained from Indian hemp; the name cannabinine has been applied to a volatile, liquid alkaloid, resembling nicotine in odour, which is said to have been extracted from the drug in minute quantity. Indian hemp yields from 10 to 18 per cent. of substances soluble in alcohol, and leaves, when incinerated, about 15 per cent. of ash. Hemp resin of different seasons and from different districts contains different amounts of cannabinol; the attempt has therefore been made to standardise preparations of Indian hemp, by determination of the amount of cannabinol and by experiments on animals.
Action and Uses.—Indian hemp acts chiefly on the central nervous system. It first produces excitement with hallucinations, a feeling of happiness and indifference to surroundings, this stage being followed by deep sleep. The hallucinations include inability to estimate time and space. In the East the hemp is smoked and almost immediately produces symptoms of pleasurable excitement, followed by depression and lethargy. It is used as an anodyne sedative or hypnotic, in mania, spasmodic coughs, phthisis, asthma, acute neuralgia, dysmenorrhoea, and tetanus. It does not produce constipation nor loss of appetite. An alcoholic extract of Indian hemp is the basis of medicinal preparations of this drug, and from it the tincture is prepared. The extract is usually administered in pills, which may be massed with lycopodium or powdered liquorice. Tincture of Indian hemp is a constituent of, and gives the green colour to, compound tincture of chloroform and morphine. Indian hemp is sometimes smoked by the asthmatic. Used thus, its action is more rapid than when taken internally. In cases of poisoning, the stomach should be evacuated, and the usual methods adopted to prevent collapse and respiratory failure.
- Extractum Cannabis Indicae, B.P.—EXTRACT OF INDIAN HEMP.
- Exhaust Indian hemp, in coarse powder, with alcohol, by percolation, and evaporate the percolate to form a soft extract. Commercial extracts of Indian hemp vary considerably, containing, with the green ether-soluble substance, indefinite amounts of a brown extractive insoluble in ether. Some specimens contain a considerable amount of residue insoluble in alcohol; this should not exceed 2 per cent. The extract deteriorates on keeping owing to slow oxidation; it should be stored in small full jars hermetically sealed, or better, in collapsible tubes from which small quantities can be easily weighed. Dose.—15 to 60 milligrams (1/4 to 1 grain).
- Extractum Cannabis Indicae, U.S.P.—EXTRACT OF INDIAN CANNABIS.
- Indian cannabis, in No. 20 powder, 100; alcohol (95 per cent.), a sufficient quantity. Average dose.—1 centigram (1/5 grain).
- Fluidextractum Cannabis Indicae, U.S.P.—FLUIDEXTRACT OF INDIAN CANNABIS.
- Indian cannabis, in No. 30 powder, 100; alcohol (95 per cent.), sufficient to produce 100. Average dose.—5 centimils (0.05 milliliters) (1 minim).
- Tinctura Cannabis Indicae, B.P.—TINCTURE OF INDIAN HEMP.
- Extract of Indian hemp, 5; alcohol, sufficient to produce 100. Add the extract to 90 of the alcohol, dissolve, filter if necessary, and add sufficient alcohol to make up to the required volume. This tincture should be preserved in closely-stoppered bottles and kept in a dark place. Mixtures containing tincture of Indian hemp require the addition of one-eighth of their bulk of mucilage of gum acacia. The mucilage should be diluted with twice its bulk of water and the tincture—measured in a dry measure—added in successive small portions, shaking after each addition. Dose.—3 to 10 decimils (0.3 to 1. milliliters) (5 to 15 minims).
- Tinctura Cannabis Indicae, U.S.P.—TINCTURE OF INDIAN CANNABIS.
- Indian cannabis, in No. 40 powder, 10; alcohol (95 per cent.), sufficient to produce 100. Average dose.—6 decimils (0.6 milliliters) (10 minims).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.