The composition of salvarsan / by Robert George Fargher and Frank Lee Pyman.
- Fargher, Robert George.
- Date:
- 1920.]
Licence: Public Domain Mark
Credit: The composition of salvarsan / by Robert George Fargher and Frank Lee Pyman. Source: Wellcome Collection.
3/8 page 372
![The Sulphur Content of Salvarsan. The presence of a considerable proportion of sulphur in com¬ mercial salvarsan—not disclosed in the reputed formula,—calls for comment. Ehrlich and Bertheim (Ber., 1911, 44, 1264; 1912, 45, 762) mention that crude salvarsan base, prepared by means of hyposulphite, contains inorganic matter and slight quantities of a substance containing arsenic united with sulphur, but indicate that these impurities are removed by converting the base into the hydro¬ chloride. Myers and Du Mez (JJ.S.A. Public Health Reports, 1918, 33, 1003), and Kober (loc. cit.), have recently recorded the bare fact that commercial salvarsan contains sulphur. Several years ago the present authors (compare Medical Research Committee, Special Report Series, No. 44, “Reports of the Special Committee upon the Manufacture, Biological Testing, and Clinical Administration of Salvarsan and its Substitutes,” No. 1, p. 8) found that commercial salvarsan of both British and German origin invariably contained sulphur, of which the amount varied from 1 to 2 per cent., and, exceptionally, up to 3 per cent. In our opinion, the sulphur occurs at least in part in the form of the sulphamo-group, ’NH’SOgH. Our reasons for this view are as follows: (1) It is well known that the reduction of nitro-compounds with hyposulphite in alkaline solution leads, sometimes in part and some¬ times wholly, to the formation of sulphamic acids of the type R'NH’SOgH. Karrer (Ber1915, 48, 1061) states that “ nitro- carboxyphenylarsinic acid does not give the normal arseno-deriv- ative when reduced with hyposulphite, but gives an easily soluble substance, probably a sulphamic acid, as has frequently been observed in other cases.’’ Moreover, in the somewhat analogous case of 3:5-dinitro-4-aminophenylarsinic acid, an alkali-soluble reduction product containing sulphur has been obtained which, on treatment with warm acids, yields free sulphur dioxide and salts of hexa-aminoarsenobenzene (E.P. 8041 of 1913). Although no constitution is assigned in the patent, Giemsa (Deut. mecl. Wocli., 1919, 45, 95) describes the product as a monosulphamic acid of hexa-aminoarsenobenzene, HS03*NH*C6H2(NH2)2*As2*C6H2(NH2)3. (2) Whilst Ehrlich and Bertheim’s analysis of pure, as distinct from commercial, salvarsan shows a chlorine content of 15*4 per cent., we have found considerably less chlorine in commercial salvarsan of both British and German origin, the content of samples taken direct from sealed ampoules varying generally from 12*5 to 14*5 per cent. It is thus always lower than that calculated for C12H]202N2As2,2HCl,21I20, which requires Cl = 14'9 per cent.,](https://iiif.wellcomecollection.org/image/b3062275x_0003.jp2/full/800%2C/0/default.jpg)
