To a solution of about 0.1 gm. of procain in 5 c.c. of water add 3 drops of dilute sulphuric acid and mix with 5 drops of potassium permanganate test solution. The violet color of the latter disappears immediately (distinction from cocain).
Dissolve about 0.1 gm. procain in 1 c.c. sulphuric acid U. S. P. The solution is colorless (organic impurities).
Dissolve 0.1 gm. of the salt in 10 c.c. of water and saturate with hydrogen sulphid. No coloration or precipitation occurs (salts of the heavy metals).
Incinerate about 0.5 gm. of procain accurately weighed. Not more than 0.1 per cent. of residue remains.
To obtain specimens representing the market supply, orders for the three brands of procain were placed with pharmaceutical firms in New York, Baltimore and San Francisco. The Baltimore and San Francisco firms supplied specimens of procain-novocain brand and procain-Rector brand but reported that the Abbott brand was not procurable. The New York correspondent was able to supply procain-Rector only. As the entire output of the Abbott Laboratories was stated to go to the government, specimens of this product were obtained through the surgeon-general of the army from the general purchasing office, Medical Dept., U. S. Army. The following specimens were obtained and examined:
1. Procain-Abbott, 6 specimens: The first specimen bore no serial number but the five later specimens were designated respectively, No. 89999, No. 89998, No. 89997, No. 89996, and No. 810995, representing batches from which shipments are to be made on contracts placed by the general purchasing office, Medical Department, U. S. Army, with the Abbott Laboratories of Chicago.
2. Procain-novocain brand, 4 specimens: These were designated respectively, A56, A57, A63, and A67. The first two specimens were labeled “Manufactured by the Farbwerke-Hoechst Co. at the H. A. Metz Laboratories.” The third specimen (not in original container) was labeled “H. A. Metz Laboratories” and the fourth was marked “Manufactured by the H. A. Metz Laboratories.”
3. Procain-Rector, 3 specimens: Each bore the statement “Manufactured by the Rector Chemical Company” but had no “lot number.”
From this examination it appears that all the specimens of procain received complied satisfactorily with all tests of identity and purity with the following exceptions: (1) One specimen of procain-Abbott had a melting point slightly below the permitted range; however, the last five specimens had the required melting point. (2) Five specimens of procain-Abbott and the last three specimens of procain-Rector were not entirely colorless, but had a yellow or light brown tinge.
The toxicity experiments, which were carried out by Dr. R. A. Hatcher of the Cornell Pharmacologic Laboratory, were reported as being satisfactory.