Pancreatine possesses greater emulsifying power than any agent we are acquainted with, 1 gr. of this article prepared by the writer having been found sufficient to emulsify 1 oz. of cod liver oil; and by careful manipulation, after having been rendered slightly alkaline by soda, as much as 3 oz. were emulsified, or over 1200 times its weight. An emulsion of this strength is, however, not permanent, and requires the addition of some heavier emulsifying agent in reduced proportion. A pancreatic emulsion, owing probably to its partially decomposed condition, while a desideratum from a therapeutie standpoint, is not so pharmaceutically, unless prepared within a reasonable period of the time when wanted for administration.
As an illustration, we now submit a formula for a somewhat largely used preparation originating in the Bellevne Medical College Hospital, New York :
Cod Liver Oil...... 8 ox.
Oil Gaullheria......15 in.
Gum Acacia ...... 2 oz.
Pancreatine, 90 per cent. 15 gr.
Pepsin, U.S. ......60 „
Calcium Hypophos .. .. 60 „
Sodium ........60 „
Water ........ 5 oz.
Spirit Frumenti...... l 1/2 ,,
Mix the oils and gum acacia, dissolve the hypophosphites, pepaine, and pancreatine in the water, make an emulsion to which add the spirit frumenti.
In conclusion, we call apparatus for making emulsions in a larger way than can be done economically in a mortar.
Fig. 116 shows an ordinary vessel in which sets a narrow tin cylinder with a valve at the top, fastened with a hinge, a bell-shaped and perforated terminus being attached mediately above which is also a wooden diaphragm b. The mixture to be emulsified must half fill the vessel, and by working the cylinder perpendicularly the air, being confined by the valve closing at the top when the cylinder is plunged downward, is forced all through the mixture, and a perfect emulsion is. formed in a very short time. (C. S. Hallberg.)
The successful formation of emulsions, whether of fixed or volatile oils, is dependent upon certain rules, well understood by accomplished pharmacists, which when deviated from will invariably embarrass the operator, either by retarding or completely preventing, perfect emulsification. These rules are: -
1. That the water and gum arabic * shall be in definite and absolute proportion to each other. This proportion is 3 parts of water to 2 of gum, both by weight.
2. That the relation of oil to gum (and water) shall be definite within certain limits; that is to say, the mucilage formed in the above proportions is capable of perfectly emulsifying a minimum and a maximum proportion of oil. The minimum proportion is 2 parts of oil to 1 of gum; the maximum proportion is 4 of oil to 1 of gum.
3. That the trituration of the oil, gum and water be continued until a perfect homogeneous, milky white, thick creamy mixture is formed, i. e. until perfect emulsification takes place, before the addition of a further quantity of water or other liquid.
The thick creamy emulsion obtained, if the above conditions are. fulfilled, must be the basis of all perfect emulsions. It will bear dilution to any extent with water, forming mixtures varying, according to the proportion added, from the appearance and consistence of cream to that of very thin milk. Obviously the water may be replaced by solutions of saline compounds, syrups, etc, and this permits the production of the various combinations of cod liver oil in current use from the above thick creamy emulsion, which for distinction may be designated as -
I. Concentrated Emulsion of Cod Liter Oil. - Take of fresh Norwegian cod liver oil, 8 oz.; powdered gum arabic, 2 oz.; distilled water, 3 oz. First weigh the gum into a wedge wood or porcelain mortar, then the oil, and triturate till the gum is well mixed with the oil; then weigh into the mixture the distilled water, and triturate the whole briskly until the mixture thickens and acquires a pasty consistence and milky whiteness, Now scrape down the portions adhering to the sides of the mortar and to the pestle, and continue the trituration for a short time, after which add such other ingredients as may be desirable, or transfer the concentrated emulsion to a wide-mouthed bottle for future use.
This concentrated emulsion will keep for a reasonable time in cold weather, and, if placed in the ice chest, also during warm weather. It may, therefore, be kept in stock if the demand for emulsions is brisk enough to justify it; but inasmuch as its preparation does not consume more than 5 or 10 minutes, it is advised to always prepare it fresh, or at all events, never to prepare more than a week's supply, particularly in summer. Its consistence is such that it is poured out of the containing vessel with difficulty; hence the necessity of using one with a wide mouth, which should be as securely stoppered as possible, and should be cleaned very carefully each time it is refilled. All this takes time and involves trouble, which is prevented by preparing the concentrated emulsion only as required.
II. Simple Emulsion of Cod Liver Oil, - Take of concentrated emulsion of cod liver oil, 13 oz.: oil of wintergreen, 24 drops; syrup, 1 fl. oz.; water, 3 fl. oz Weigh the concentrated emulsion into a mortar, add the oil of wintergreen, and triturate thoroughly; then gradually add first the water and then the syrup.
The manipulation for this emulsion is typical for all the other cod liver oil emulsions given below. It has the consistence of very thick cream, but is l2
* The writer is well aware that other emul-sifying agents have been proposed and are used, but he is satisfied that none of these answers as well as does gum arabic readily poured out of narrow-mouthed bottles, is milky white, and mixes readily with water or other liquids that may be administered with it. It contains exactly 50 per cent. (by volume) of oil, the quantity that manufactured emulsions are said to contain, although some of them do not contain that proportion. The oil of wintergreen disguises the odour of the cod liver oil admirably, and has the further advantage that it acts as a preservative.