Resin or colophony (Rosin, U.S.P.) is the residue left after the removal, by distillation, of the oil of turpentine from the crude oleoresin of Pinus palustris, Mill., P. Taeda, Linn., and other species (N.O. Coniferae) growing in Europe and the south-eastern United States. In the collection of the oleoresin in America a cavity is cut in the base of the tree-trunk during the winter, into which a small quantity of the secretion contained in the normal secretion ducts is discharged. The injury thus inflicted on the tree induces the abundant formation of abnormal oleoresin ducts in the new wood. In the following spring a triangular incision is cut above the cavity, from which a much larger discharge of the oleoresin contained in these abnormal ducts takes place. Further hacking, carried on at intervals during the summer, results in further formation of abnormal oleoresin ducts and discharge of the oleoresin, large quantities of which are thus produced. The oleoresin is then distilled with water, oil of turpentine passing over, and resin (colophony) remaining in the still; the fused resin is poured while still hot through wire strainers into barrels, where it solidifies. The oleoresin obtained at first yields about 80 per cent. of pale yellow (amber) resin; later products contain more resin but it is darker in colour (black resin). Long-continued application of heat also causes darkening in the colour of the resin, while if the water is not entirely removed an opaque resin is obtained. Resin should occur in amber-coloured, translucent, compact masses, with a brittle, glassy fracture. The odour and taste are slightly terebinthinate. It is easily fusible, and burns with a dense, yellowish smoke, leaving no appreciable ash. Specific gravity, 1.070 to 1.080. Acid number, 150 to 180, and practically identical with the saponification number. For pharmaceutical use resin should be pale in colour, possess a high acid number, and be almost entirely soluble in petroleum spirit. By destructive distillation it yields "resin spirit" and "resin oil." Resin spirit has, when rectified, a specific gravity about 0.864, and distils mainly between 160° and 200°. Resin oil is used for lubricating purposes. Venice turpentine is collected in South Tyrol by boring the trunk of the larch and collecting the oleoresin that slowly fills the cavity. It is a yellowish, turbid oleoresin, consisting chiefly of a- and b-larinolic acid (55 to 60 per cent.), volatile oil (20 per cent.), and resene (14 per cent.). A mixture of turpentine and resin is often substituted for Venice turpentine (see Terebinthina Veneta Factitia).
Soluble in almost all proportions of alcohol, oil of turpentine, ether, benzene, and carbon bisulphide, fixed and volatile oils, and in solutions of caustic soda or potash.
Constituents.—The composition of resin is still a matter of uncertainty. It appears to consist of three isomeric abietic acids (α, β, and γ), together with a small quantity (5 to 6 per cent.) of resene, traces of volatile oil, and a bitter principle. The resin acids appear to undergo change (probably oxidation) when exposed to the air, and become less soluble in petroleum spirit.
Action and Uses.—Resin is an ingredient of ointments and plasters to be used as stimulating applications to the skin. Emplastrum Resinae, is used as an adhesive plaster in minor surgery for strapping wounds. Unguentum Resinae, is applied as a stimulant to indolent ulcers, boils, etc. Resin was formerly given internally in rheumatism, sometimes with guaiacum resin. It is partly absorbed, and excreted by the urine, and during excretion excites the kidneys to diuresis. Sometimes so much is excreted in the urine that nitric acid causes a precipitate of the resin, simulating albumin; the precipitate is readily distinguished from albumin in that it is soluble in alcohol.
Dose.—3 to 6 decigrams (5 to 10 grains).
- Ceratum Resinae, U.S.P.—ROSIN CERATE.
- Rosin 35; yellow beeswax, 15; lard, 50.
- Ceratum Resinae Compositum, U.S.P.—COMPOUND ROSIN CERATE.
- Rosin, 22.5; yellow wax, 22.5; prepared suet, 30; turpentine, 11.5, linseed oil, 13.5
- Emplastrum Resinae, B.P.—RESIN PLASTER. Syn.—Adhesive Plaster.
- Resin, 10; lead plaster, 80; hard soap, 5. Melt separately, using as little hear as possible, then mix. Resin plaster is used in minor surgery to draw together the edges of wounds, to apply dressings and as a protective. For these purposes a thin backing of calico is usually preferred. For greater protection the plaster may be spread on chamois leather, and for strength and support on brown holland or moleskin.
- Parogenum Terebinthinae, B.P.C.—TURPENTINE PAROGEN. Syn.—Turpentine Vasoliment. 1 (factitious turpentine) in 5.
- Terebinthina Veneta Factitia, B.P.C.—FACTITIOUS VENICE TURPENTINE.
- Resin, 62.5; linseed oil, 22.5; oil of turpentine, 15. The properties of this mixture resemble those of oil of turpentine, and the preparation is sometimes given internally as a diuretic, in doses of 2 decigrams (3 grains). It is, however, used chiefly in the arts, and in veterinary medicine,
- Unguentum Resinae, B.P.—RESIN OINTMENT. Syn.—Basilicon Ointment.
- Resin, in powder, 8, yellow beeswax, 8; olive oil, by weight, 8; lard, 6. Melt the resin and beeswax together, add the lard and oil, strain and stir until cold. Resin ointment is mildly stimulating; it is applied on lint to indolent sores and ulcers.
- Unguentum Resinae Compositum, B.P.C.—COMPOUND RESIN OINTMENT.
- Resin, 20; oil of eucalyptus, by weight, 15; hard paraffin, 10; soft paraffin, 55.
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.