Hamamelin is prepared by macerating hamamelis bark or leaves with alcohol for twenty-four hours, exhausting by percolation with alcohol, recovering most of the alcohol by distillation, evaporating the residue to dryness at a low temperature, and reducing it to fine powder. The product is a brownish powder, which is more or less hygroscopic. The leaves yield about 7 per cent. of dark brown extract; the bark yields about 16 per cent. of light brown extract, which is more easily reducible to powder than the former. Hamamelin prepared from hamamelis leaves is said to be more effective than that obtained from the bark. Commercial hamamelin may be coloured green by the addition of powdered hamamelis leaves, and mineral matter is sometimes added to counteract the hygroscopic tendency of the resinoid.
Action and Uses.—Hamamelin is used in the form of suppository for piles, 1 to 3 decigrams (2 to 5 grains) in each, prepared with oil of theobroma. It may be combined with cocaine, orthocaine, extract of belladonna, zinc oxide, or bismuth subgallate. It is given internally like Extractum Hamamelidis.
Dose.—½ to 3 decigrams (1 to 5 grains).
- Suppositoria Hamamelini et Zinci Oxidi, B.P.C.—HAMAMELIN AND ZINC OXIDE SUPPOSITORIES.
- Each 30-grain suppository contains 3 grains of hamamelin and 10 grains of zinc oxide.