Sandarac is a resin obtained by incision from the stem of Callitris quadrivalvis, Ventenat (N.O. Coniferae), a small tree growing on the mountains of North-Western Africa. The resin occurs in pale yellow, brittle tears, about 5 to 15 millimetres long, usually of cylindrical or stalactitic form, and sometimes united into small masses. The fractured surface is clear and vitreous; when chewed the resin breaks up readily into a sandy powder, which does net agglomerate into a plastic mass. It has a slight terebinthinate odour and taste. Specific gravity about 1.07; melting-point about 135°. Completely soluble in alcohol and ether, partially soluble in chloroform, carbon bisulphide, and oil of turpentine. The resin should leave only traces of ash when incinerated. Australian sandarac, from Callitris robusta, R. Br., is occasionally exported, but most of it is used in Australia. It closely resembles the genuine, but is often a little softer. It contains the same constituents as the African, but a larger proportion of inactive pimaric acid and pinene; from 5 to 22 per cent. dissolves in petroleum spirit. Factitious sandarac made from colophony has an acid number about 175, and is almost entirely soluble in petroleum spirit, which dissolves but little from sandarac.
Constituents.—The resin of which sandarac: chiefly consists is associated with about 1 per cent. of volatile oil and traces of a bitter principle. The resin contains 85 per cent. of crystalline, inactive pimaric acid (sandaraco-pimaric acid), 2-3 per cent. of sandaracinic acid, and about to per cent. of amorphous callitrolic acid, together with a little sandaraco-resene. Callitrolic acid is easily converted into the lactone, which is insoluble in alcohol. The acid number obtained by adding excess of alkali and titrating back varies from 130 to 160, the ester number being almost nil; these characters, however, appear to vary a little with the age of the resin.
Action and Uses.—Sandarac is employed in alcoholic solution (2 parts and 1) on wool as a temporary stopping for teeth. In alcoholic or ethereal solution it is much employed as a pill-coating; the pills should be shaken in a china pot with a few drops of the solution and thrown on a plate to dry separately. Ethereal solutions dry very rapidly, but alcoholic solutions give the better coating.
- Liquor Sandaracae, B.P.C.—SANDARAC SOLUTION. Syn.—Pill Varnish.
- Sandarac, 50; absolute alcohol, sufficient to produce 100. This solution makes an excellent varnish for pills for which a transparent coating is desired. The pills , which should be without any adherent particles of powder, are placed in a covered pot of suitable size, with a few drops of the sandarac solution, the lid is placed on the pot, and the latter is rotated a few times in order to cover the pills with the varnish. The pills are then thrown on a smooth slightly oiled slab or plate, separated carefully, moved gently after a brief interval with a pointed glass rod dipped in alcohol, and allowed to dry.