IODEX AND LIQUID IODEX
The A. M. A. Chemical Laboratory examined Iodex in 1915.[213] The claims made, at that time, by the exploiters, Menley & James, were shown to be contrary to facts in that Iodex contained only traces of free iodin while they claimed “5 per cent. Therapeutically Free Iodin.” Even the total quantity of iodin was shown to be only about one half of the 5 per cent. claimed to be present as free iodin.
An examination of the advertising matter sent out by Menley & James in 1919 showed that substantially the same claims were being made as in 1915. This at once suggested the inquiry: Since the claims are the same as previously made, have the manufacturers altered the composition to conform to the claims? The answer is found in the results of the analysis of two samples purchased in the open market early in 1919.
This analysis shows conclusively that Iodex is essentially the same as in 1915, that is, that it contains no free iodin and only about three fifths of the total amount of iodin claimed.
It would seem that Iodex (Ung. Iodi., M. & J.) is in obvious conflict with Section 7 of the Food and Drugs Act. While it is sold under a name recognized by the U. S. Pharmacopeia, namely, Ung. Iodi., it does not conform to the standards of the U. S. Pharmacopeia for that product. Iodin ointment U. S. P. is made with 4 per cent. of free iodin, 4 per cent. of potassium iodid, 12 per cent. of glycerin, and a benzoinated lard base. It should then contain approximately 7 per cent. of total iodin. It has been shown by Warren[214] that about 75 per cent. of the iodin in the U. S. P. ointment remains in the free state even after months of standing. Ung. Iodi., U. S. P., then, should contain about 3 per cent. of free iodin. Iodex contains no free iodin, or but traces, and no potassium iodid. Furthermore, the Iodex label declares the presence of 5 per cent. of “therapeutically free” iodin. As a matter of fact, the amount of iodin is variable, the highest amount found being 3.5 per cent. and samples containing as low as 2.63 per cent. have been examined.
It would seem further that Iodex is misbranded under the Sherley amendment in that it is said that it “may be used externally with advantage in all cases where the action of iodin is desired.” Since it contains no iodin as such this cannot possibly be true. It is also stated in a circular accompanying the trade package that “Thirty minutes after inunction iodin can be found in the urine.” This statement has also been shown to be untrue.—(Annual Reports A. M. A. Chem. Lab., 1915, p. 89.)
Details of Analysis
Iodex.—This is a rather soft ointment, almost black but with a decided greenish cast in thin layers. It is soluble in chloroform but is only partly saponified and dissolved by alcoholic potassium hydroxid. Iodex has a distinct odor like oleic acid.
Free Iodin.—When examined by the method previously used[215] only minute traces of free iodin were found.
Total Iodin.—The methods employed were as follows: 1. Iodex was saponified by boiling for from two to three hours with alcoholic potassium hydroxid. The alcohol was then evaporated and the iodin determined by the method described in the U. S. Pharmacopeia for thymol iodid.
2. The same as Method 1, except that after ignition of the saponified mixture the halogen was determined by weighing as silver iodid.
3. The Carius method.
It should be noted that Methods 2 and 3 determine chlorin and bromin should any be present with the iodin.
When 5 gm. of Sample 1 was assayed by Method 1, it required 73.56 c.c. of tenth-normal sodium thiosulphate, equivalent to 3.11 per cent. of iodin. In a duplicate, 2.7565 gm. of Iodex required 38 c.c. of tenth-normal sodium thiosulphate, equivalent to 2.92 per cent. of iodin; average of the two, 3.02 per cent. of iodin.
A weight of 2.5800 gm. of Sample 1, assayed by Method 2, gave 0.1582 gm. of silver halid, equivalent to 0.0855 gm. of iodin, or 3.31 per cent.
A weight of 0.588 gm. of Sample 2, assayed by the Carius method, gave 0.0388 gm. of silver halid, indicating 0.02096 gm. of iodin, or 3.52 per cent. In a duplicate, 0.5342 gm. gave 0.0338 gm. of silver halid, indicating 0.01826 gm. of iodin, or 3.42 per cent.; average, 3.49 per cent. of iodin.
Liquid Iodex.—This is sold by Menley & James, Ltd., the firm selling Iodex Ointment. According to a circular in a trade package “the valuable properties of Free Iodine are available in Liquid ‘Iodex’ in a state of greatly enhanced activity; but the irritating, corrosive and hardening drawbacks of ordinary solutions of the drug are absent.” The label on a bottle reads as follows: “Liquid ‘Iodex’ (Liq. Iodi. M. & J.). A nonirritant preparation of iodine (21⁄2%) ... This product contains Free Iodine....”
The sample of Liquid Iodex purchased on the open market was found to be a reddish liquid with an odor like oleic acid. It dissolved completely in chloroform.
Free Iodin.—A weight of 6.2936 gm. was dissolved in chloroform and the solution shaken with 25 c.c. of a solution of potassium iodid. The iodin which passed into the potassium iodid solution was titrated with tenth-normal sodium thiosulphate, 0.81 c.c. being required. This indicates 0.01022 gm. of iodin, or 0.16 per cent.
Total Iodin.—Total iodin was determined by Method 1 as given above under Iodex. A weight of 4.466 gm. required 32.93 c.c. of tenth-normal sodium thiosulphate, equivalent to 0.06964 gm. of iodin, or 1.55 per cent. In a duplicate, 5 gm. of material required 33.3 c.c. of tenth-normal sodium thiosulphate, equivalent to 0.7043 gm. of iodin, or 1.41 per cent.; average, 1.48 per cent. of iodin.
Liquid Iodex, then, contains but little (0.16 per cent.) free iodin and only about three fifths of the total iodin claimed.