241 
REPORT ON THE PURITY OE SULPHATE OE QUININE OE 
COMMERCE. 
BY MR. W. WALTER STODDART. 
(Read at the Bath Meeting of the British Pharmaceutical Conference , Sept. 1864.) 
Probably quinine is one of the most important therapeutic remedies for the 
ills of the human body that has ever been introduced to the notice of the me¬ 
dical man ; so extensively is it used, and with such certainty may its effects be 
calculated, that no other substance can be advantageously substituted. Yet 
this very circumstance unfortunately gives the temptation for frauds and adul¬ 
terations so commonly said to be practised by unprincipled dealers. 
The smallness of the dose with which quinine gives such remarkable results, 
renders any sophistication all the more dangerous, and disappointing to the phy¬ 
sician ; indeed, the very turning-point of an illness may be frequently dependent 
on the purity of a sample of quinine. 
It is not by any means to be supposed that any suspicion is attached to the 
high respectability and probity of the well-known manufacturers of quinine. 
Existing adulterations, properly so called, such as the deliberate addition of sali- 
cine, sugar, boracic acid, quinidine, cinchonine, etc., are only made by second 
or third-rate dealers, or when it has passed through the hands of a third or 
fourth party. Such samples may still bo found in shops situated in secluded 
parts of the country or lowest streets of a city, and traceable to the same origin. 
On the other hand, probably from difference in the mode of preparation or 
separation of the cinchona alkaloids, quinine differs much from the presence of 
its isomeride quinidine. The latter is often, if not always associated with qui¬ 
nine in tire natural state, and has many of its reactions exactly similar, besides 
being nearly as soluble in the usual menstrua. 
It therefore becomes to a certain extent a natural mixture, and in proportion 
to the completeness of the extracting process, so will be the purity of the pro¬ 
duct. Opinions, it is true, vary greatly as to whether quinine and quinidine 
differ in their medicinal power, and therefore some may say that the presence of 
the latter (quinidine) is of no consequence ; this, however, is not the question at 
issue, and the points of this report are strictly confined to the commercial purity 
of quinine and its freedom from the cheaper salts. 
In carrying out this object the desired results are threefold :— 
First, Qualitative , or to find an easy and reliable test for the presence of the 
three most common cinchona alkaloids, quinine, quinidine, and cinchonine. 
Secondly, Quantitative , to find the most practical and reliable mode of sepa¬ 
rating and estimating these alkaloids; and, 
Thirdly, an application of the above to the examination of the sulphate of 
quinine as made by the principal manufacturers. 
Although the cinchona barks contain many alkaloids, only four occur in 
sufficient frequency and quantity to merit notice in a commercial investigation, 
quinine, quinidine, cinchonine, and cinclionidine. In actual practice the two 
last may be estimated together. 
The most prominent impurity in quinine is quinidine ; in none of the after- 
mentioned samples was cinchonine discovered in any quantity except one. The 
slight solubility of the cinchonine salts as compared with those of quinine and 
quinidine, and the boldness of its crystallization would, to the practised eye, soon 
lead to its detection ; experiments will easily show the truth of this, and that 
quinidine and not cinchonine must be generally sought as the chief impurity in 
commercial sulphate of quinine. 
Notwithstanding tests for the purity of quinine are so numerous and in some 
instances so trustworthy, still few apply to the separation of quinidine from 
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