Emplastrum Ichthyocollae (U. S. P.)—Isinglass Plaster.
Related entry: Ichthyocolla (U. S. P.)—Isinglass
SYNONYMS: Court plaster, Sparadrapum adhaesivum, Taffetas adhaesivum, Emplastrum adhaesivum anglicum, Sericum anglicum.
Preparation.—"Isinglass, ten grammes (10 Gm.) [154 grs.]; alcohol, forty grammes (40 Gm.) [1 oz. av., 180 grs.]; glycerin, one gramme (1 Gm.) [15 grs.]; water, tincture of benzoin, each, a sufficient quantity. Dissolve the isinglass in a sufficient quantity of hot water to make the solution weigh one hundred and twenty grammes (120 Gm.) [4 ozs. av., 102 grs.]. Spread one-half of this, in successive layers, upon taffeta (stretched on a frame), by means of a brush, waiting after each application until the layer is dry. Mix the second half of the isinglass solution with the alcohol and glycerin, and apply it in the same manner. Then reverse the taffeta, coat it on the back with tincture of benzoin, and allow it to become perfectly dry. Cut the plaster in pieces of suitable length and preserve them in well-closed vessels. The above-directed quantities are sufficient to cover a piece of taffeta thirty-eight centimeters (38 Cm.) [about 16 inches] square"—(U.S. P.). The glycerin is added to this plaster to give it pliability, while the benzoin renders it partially water-proof. Pharmacists now purchase all their court plaster from plaster manufacturers.
Action and Medical Uses.—This is the ordinary isinglass plaster employed for covering minor injuries, as abrasions, slight cuts, pimples, etc. It should be applied by moistening it with clean water, and never with saliva.
Related Preparations.—GELANTHUM. Gelanthum is a kind of varnish of the collodion class, having about the consistency of Unguentum Glycerini. It was devised by Dr. Unna. It is made by W. Mielck in Hamburg, apothecary of the Schwanen-Apotheke, who is also the proprietor of the copyrighted name Gelanthum. Unna endeavored to find a vehicle that would allow the fixing of the various medicaments upon the skin, and which would be capable of drying quickly. This he at last accomplished by means of a combination of gelatin and tragacanth. Unguentum Caseini, which has hitherto been considered the best substance for this purpose, does not possess the property of absorbing all medicaments without decomposition, nor does it keep for an indefinite length of time. Nevertheless, Unna states that, in certain cases, unguentum caseini is preferable to gelanthum, since the casein salve is a better medium for carrying the different kinds of tar, and since casein itself exerts a beneficial influence in the case of thickening of the epidermis.
Preparation of Gelanthum.—The tragacanth, in pieces, is to be treated with 20 times its weight of cold water for 3 to 4 weeks, with frequent agitation; then heated over steam for one day, and pressed through cheese cloth. The gelatin likewise is swollen in cold water (4 to 5 parts), exposed for some time to steam under pressure, in order to deprive it of the tendency to gelatinize, and is then filtered through a steam filtering funnel. This filtrate is mixed with the tragacanth mucilage and the mixture heated for about 2 days in a steam bath, again strained, and finally mixed with 5 per cent of glycerin, some rose water (preferably a few drops of oil of rose), and thymol (2:10,000). The finished gelanthum contains about 2 per cent each of gelatin and tragacanth. This gelanthum may safely be mixed with as much as 50 per cent of ichthyol, 40 per cent salicylic acid, resorcin and pyrogallol, 5 per cent carbolic acid, or 1 per cent mercuric chloride without impairing its qualities as a varnish. Incompatibles incorporated into gelanthum are said not to act upon each other, still it is recommended to first triturate them, if in powder form, or as a viscid liquid, with water or spirits as the case may require; fats and oils should first be emulsified by means of gum Arabic. An addition of 20 per cent glycerin, or of 40 per cent ichthyol does not affect the drying qualities of gelanthum.
GELANTHE CRÊME is a preparation introduced by the Schwanen-Apotheke in Hamburg as a cosmetic, and consists of 10 per cent of fat and some perfume admixed with gelanthum (Pharm. Centralhalle, 1896, pp. 183 and 815).