PARAFFINS AND PARAFFIN PREPARATIONS—TABLE A
| Formula | Substance | Melting Point, U. S. P. | Ductility Limit | Plasticity Limit | (a) Adhesiveness and Detachability (b) Strength of Film at 38 C. |
| 1 | “Parowax,” Stand. Oil Co. of Ind. | 50.8 | 32.5 | 29.0 | (a) Adheres and detaches well; rather hard (b) Pliable and strong |
| 3 | “Paraffin 118–120 F.,” Stand. Oil Co. of Ind. | 46.8 | 28.5 | 24.5 | (a) Does not adhere well; detaches easily (b) Pliable but not strong |
| 4 | “Paraffin 120–122 F.,” Stand. Oil Co. of Ind. | 47.2 | 29.0 | 24.5 | (a) Adheres well; detaches well (b) Pliable and fairly strong |
| 5 | “Paraffin 123–125 F.,” Stand. Oil Co. of Ind. | 48.8 | 31.5 | 28.5 | Same as 4 |
| 6 | “Paraffin 128–130 F.,” Stand. Oil Co. of Ind. | 52.0 | 33.0 | 30.0 | (a) Adheres well; detaches not so easily (b) Pliable and strong |
| 7 | “Texwax,” Texas Co., Port Arthur, Texas | 51.2 | 32.5 | 29.8 | Same as 6 |
| 8 | “Paraffin Wax 122–124 F.,” Warren Refining Co., Warren, Pa. | 50.6 | 36.0 | 34–35 | (a) Unsatisfactory; does not adhere (b) Only slightly pliable; too tough |
| 9 | “Paraffin No. 910,” Waverly Oil Works, Pittsburgh | 47.0 | 30.5 | 26–27 | (a) Adheres well; detaches well (b) Pliable and strong |
| 10 | “Paraffin No. 920,” Waverly Oil Works, Pittsburgh | 44.4 | 27.5 | 25.0 | (a) Adheres well; detaches well (b) Pliable and fairly strong |
| 11 | “Hard Paraffin,” Rob’t Stevenson & Co., Chicago | 48.0 | 28.5 | 24.5–25.5 | (a) Adheres well; detaches well (b) Pliable and strong |
| 12 | “Paraffin,” Island Petroleum Co., Chicago | 47.2 | 33.0 | 32.5 | Not quite as good as 11 |
| 13 | “Paraffin 122 F.,” Gulf Refining Co., Pittsburgh | 46.8 | 30.5 | 27.5–28 | (a) Does not adhere so well; detaches well (b) Very pliable |
| 14 | “Paraffin 125 F.,” Gulf Refining Co., Pittsburgh | 50.0 | 32.0 | 31.0 | About as 13 |
| 15 | “Paraffin 132 F.,” Gulf Refining Co., Pittsburgh | 54.8 | 35.5 | 34.0 | (a) Does not adhere well (b) Not very pliable, but strong |
| 16 | “Paraffin No. 301,” National Refining Co., Cleveland | 50.2 | 33.0 | 32–32.5 | (a) Does not adhere well (b) Not very pliable |
| 18 | Paraffin recovered from “Ambrine” | 48.6 | 30.5 | 28–28.5 | (a) Adheres well; detaches well (b) Pliable but not strong |
| 19 | “Hyperthermine” | 49.4 | 33.5 | 30.5–31 | (a) Does not adhere well; detaches well (b) Very pliable and strong |
| 20 | “Ambrine” | 48.4 | 30.5 | 27.0 | (a) Adheres well; detaches well (b) Very pliable and strong |
| 21 | Paraffin 120–122 F. (see 3), 97.5; olive oil, 1.5; asphalt, 4 drops | 45.4 | 29.0 | 28.5 | (a) Adheres excellently; detaches well (b) Very pliable and strong |
| 22 | “Parowax” (see 1), 97.5; olive oil, 1.5; asphalt, 4 drops | 49.2 | 32.0 | 30.5 | (a) Adheres well; detaches well (b) Pliable and strong |
| 23 | “Mulene” | 51.0 | 36.0 | 28.0 | (a) Adheres but detaches with difficulty (b) Pliable but not strong |
| 24 | “Parresine,” Abbott Laboratories, Chicago | 46.0 | 29.5 | 26.0 | (a) Adheres well; detaches easily (b) Pliable and fairly strong |
| 25 | “Paraffin 118–121 F.,” The Atlantic Refining Co., Philadelphia | 45.8 | 26.4 | 23.2 | (a) Adheres well; detaches easily (b) Pliable and fairly strong |
| TABLE B | |||||
| 26 | “Cerelene,” Holliday Lab.,* Pittsburgh | 50.0 | 30.5 | 26.5 | (a) Adheres well; detaches with pulling (b) Not strong at 38 C. |
| 27 | “Stanolind” Surgical Wax,† Standard Oil Co. of Ind. | 47.0 | 28.8 | 25.0 | (a) Adheres well; detaches easily (b) Fairly strong at 38 C. |
* On being heated, it readily loses eucalyptol, and a small amount of resinous substance forms in the bottom of the beaker. If “Cerelene” is heated to 145 C. and cooled, the resulting product no longer has the properties of the original “Cerelene.”
† Accepted by the Council on Pharmacy and Chemistry for inclusion in New and Nonofficial Remedies.
Iodine ointment is officialized also in several foreign pharmacopeias, although the iodine strength of the several preparations is not uniform. The formula in the British Pharmacopeia is exactly like that in the U. S. Pharmacopeia except that pure lard is directed to be used instead of benzoinated lard. Some of the foreign pharmacopeias also specify that the preparation must be freshly prepared when wanted. In the earlier editions the U. S. Pharmacopeia directed the ointment to be prepared by using water as the solvent for the potassium iodide. In the U. S. Pharmacopeia VIII the formula was changed so as to employ glycerin, and that solvent is now official. Water is still prescribed as the potassium iodide solvent by the Pharmacopeias of the Netherlands and of France.
From the examination of the literature it seems probable that iodine ointments which contain petrolatum products only as the ointment bases are apt to be relatively stable, so far as the content of free iodine is concerned. On the other hand, ointments the bases of which contain fats of the unsaturated fatty acid series, such as oleic acid, do not satisfactorily preserve the iodine in the free state. In the latter class it seems likely that the iodine enters into combination with the unsaturated fatty acids. Accordingly, on theoretical grounds, an ointment base composed of pure stearin (if such substance were available) but softened by an admixture of liquid petrolatum would preserve the iodine satisfactorily. Cocoanut oil (iodine No. 8) ought to be suitable also if mixed with hard paraffin.
Since the literature was not sufficiently concordant to warrant positive conclusions concerning the stability of ointments containing free iodine, it seemed worth while to conduct experiments with preparations of known origin. Accordingly, a number of preparations containing free iodine were made under varying conditions and each was assayed for its free iodine content immediately after its manufacture and from time to time later.
Leaf lard of the best quality obtainable was purchased from a butcher. This was rendered in an open dish on the steam bath. The preparation was of a fine color, and uniform consistence and had a faint but not unpleasant odor. Two specimens of lard were furnished by the research department of Armour and Company. An effort was made to procure specimens of lard having iodine absorption numbers as far apart as possible, i. e., one with a low and the other with a high iodine value. This was done in order to determine whether the keeping qualities of the ointments prepared from the two would be alike.