| Brand | Melting Point Corrected | Free Salicylic Acid Colorimetrically |
| Acetylsalicylic acid, P. W. R.¹ | 130.0–131.0° | Colored, but showing less than 0.1 per cent. |
| Acetylsalicylic acid, Millikin² | 130.0–131.0° | No color |
| Acetylsalicylic acid, Millikin² | ||
| 5-grain capsules | 129.0–130.0° | No color |
| Acetylsalicylic acid, Millikin,¹ | ||
| 5-grain capsules³ | 128.0–129.0° (a) | Colored, but showing less than 0.1 per cent. (a) |
| 125.5–126.5° (b) | Considerably more than 0.1 per cent. (b) | |
| Acetylsalicylic acid, Squibb² | 131.0–132.0° | No color |
| Acetylsalicylic acid (Aspirin),¹ Monsanto | 131.0–132.0° | No color |
| Acetylsalicylic acid, M. C. W.¹ | 130.5–131.5° | Colored, but showing less than 0.1 per cent. |
| Acetylsalicylic acid, M. C. W.¹ | 131.5–132.5° | Colored, but showing less than 0.1 per cent. |
| Acetylsalicylic acid, M. C. W.¹ | 131.0–132.0° | Colored, but showing less than 0.1 per cent. |
| Aspirin, Bayer¹ (before patent expired) | 131.5–132.5° | No color |
| Aspirin, Bayer¹ ⁴ (after patent expired) | 128.5–129.5° | Colored, but showing less than 0.1 per cent. |
| Aspirin, Bayer¹ ⁴ (after patent expired) | 129.5–130.5° | Colored, but showing less than 0.1 per cent. |
| Aspirin, Lehn and Fink² | 130.5–131.5° | 0.1 per cent. |
| Aspirin, Lehn and Fink² | 130.5–131.5° | Colored, but showing less than 0.1 per cent. |
| Aspirin, Lehn and Fink¹ | 131.0–132.0° | Colored, but showing less than 0.1 per cent. |
1: Obtained on the open market.
2: Obtained from manufacturer.
3: One-third of the capsules (a) contained a white powder; two-thirds of the capsules (b) contained a pink powder having strong odor of acetic acid and not complying with the tests.
4: Not described in “New and Nonofficial Remedies, 1917”; the other products are.
OTHER TESTS
New and Nonofficial Remedies, 1917, requires that acetylsalicylic acid shall form a clear solution with warm sodium carbonate solution; that sulfates, chlorides and heavy metals shall be absent; that 0.5 gm. shall leave no weighable ash. All the brands reported in this paper complied with these requirements.
So far there has been no satisfactory quantitative estimation of acetylsalicylic acid. True, various methods have been proposed, but they are objectionable. It was thought that hydrolysis of acetylsalicylic acid and then titrating the solution by comparing the color formed by ferric chloride with that of a standard control might yield interesting results, providing that the conditions were alike. For this purpose 1 gm. of acetylsalicylic acid was dissolved in 10 c.c. of alcohol and diluted to 1,000 c.c. The solution was then heated at 98 to 100 C. for two hours, allowing the alcohol to evaporate, then allowed to stand at room temperature (22 C.) for twenty-two hours. After adding water sufficient to make 1,000 c.c., it was compared colorimetrically for salicylic acid strength. The amount of hydrolysis varied so with different samples under the same conditions, that it was realized that an approximate assay by this method was unreliable. If the assay were made under more exact conditions, quantitative comparisons might be possible. In one experiment, after sixty days the hydrolysis of the acetylsalicylic acid was 61 per cent., which is in rough agreement with the work of Tsaklatos and Horsh.[210]
DISCUSSION
Apart from the proposed revision of the standards for the melting point and limit of salicylic acid in acetylsalicylic acid, the examination shows that there is no appreciable difference between the various brands of acetylsalicylic acid examined, all of them with one exception (acetylsalicylic acid, Millikin, 5-grain capsules, purchased on the open market) complying with the tests described in this paper. The Journal of the American Medical Association, in past years, has protested repeatedly against the monopoly given to the Bayer Company for their “Aspirin,” contending that acetylsalicylic acid (aspirin) was not new, and that “Aspirin, Bayer” was simply a good brand of acetylsalicylic acid which could be bought in foreign countries at much lower prices than here. Although the patent in the United States has expired, “Aspirin, Bayer” is still being retailed at higher prices than other products which are now enjoying the privilege of American manufacture.
Mr. Paul Bakewell,[211] in an opinion answering the warning circular of the Bayer Co. in reference to the use of the word “aspirin” by firms other than Bayer, argues very ably that acetylsalicylic acid, before the patent was granted, meant the impure substance which was not used therapeutically, while “aspirin” was designated as the improved product (a new article of manufacture, the particular acetylsalicylic acid made under the Hoffman patent) and “is the substance now known in pharmacy as aspirin” (statement made by an officer of the Farbenfabriken of Elberfeld Co. in U. S. Circuit Court, 1909). The products reported in this paper are (with the one exception) the same as described in the Hoffman patent, and, in the sense of Mr. Bakewell’s argument, are “aspirin.” However, it would seem better if the name acetylsalicylic acid, instead of aspirin, were used, especially by physicians in their prescriptions because (1) it is a generic, scientific name; (2) “Aspirin, Bayer” is sold at higher prices than other products, whereas chemically equivalent products sold under the descriptive name may be purchased at a lower price. Finally, the manufacture of acetylsalicylic acid in this country is another example of the fact that American chemists can produce the drug synthetics, and at the same time make products as good as, if not better than, those of German origin.
I express my appreciation to Dr. W. A. Puckner for his kind interest.—(From the Journal of Industrial and Engineering Chemistry, April, 1918.)