Extractum Cannabis. U. S. (Br.) Extract of Cannabis.
Ext. Cannab. [Extractum Cannabis Indicae, U S. P. Vlll]
Related entries: Cannabis
"Extract of Cannabis, when assayed biologically, produces incoordination when administered to dog's in a dose of not more than 0.004 Gm. of Extract per kilogramme of body weight." U.S.
Extractum Cannabis Indicae, Br.; Extract of Indian Hemp: Br.; Extrait de Chanvre de l'Inde, Fr. Cod.; Indischer Hanfextrakt, G.
"Cannabis, in No. 20 powder, one thousand grammes [or 35 ounces av., 120 grains]; Alcohol, a sufficient quantity. Moisten the powder with sufficient alcohol, pack it firmly in a cylindrical percolator and add enough alcohol to saturate the powder and leave a stratum above it. When the liquid begins to drop from the percolator, close the lower orifice, and, having closely covered the percolator, macerate for forty-eight hours. Then allow the percolation to proceed, gradually adding alcohol, until the drug is exhausted. Recover the alcohol from the percolate by distillation and evaporate the residue with frequent stirring, at a temperature not exceeding 70° C. (158° F.), to a pilular consistence. Mix the mass thoroughly and weigh it. Assay a portion of this extract, and from the result thus obtained adjust the weight of the finished Extract, by the addition of glucose, to conform to the required biological standard.
"Assay.—Proceed as directed under Biological Assays." U. S. (See under Cannabis.)
"Exhaust Indian Hemp, in coarse powder, with Alcohol (90 per cent.) by the percolation process; recover the alcohol by distillation, and evaporate the residue to a soft extract." Br.
The continuation in the Br. Pharm. of the name of Indian Hemp is unfortunate because of the possibility of its being mistaken for the root of Apocynum cannabinum, which is also called Indian Hemp. Several mistakes have occurred through this unfortunate confusion of nomenclature.
Although there is some difference in the details of the two processes, the preparations of the U. S. and Br. Pharmacopoeias are practically identical. The U. S. P. IX provides a biological test.
Great care is necessary in the manufacture of this extract not only in the selection of the crude drug, but also there is reason to believe that excessive heat in evaporating may have an injurious effect on the quality of the preparation. The only means of ascertaining its activity is by means of the biological test. The preparation varies exceedingly in strength, so that it is wisest to begin with a small dose, one-quarter of a grain (0.016 Gm.), and rapidly increase the amount given until some effect is produced.
Dose, one-fourth to three-fourths of a grain (0.015-0.045 Gm.).
Off. Prep.—Tinctura Cannabis Indicae, Br.; Mistura Chlorali et Potassii Bromidi Composita, N.F.
