22 
Dose. — “Average dose: 0.250 Gm. — 250 milligrammes (1 grains).” 
(U. 8. P.) 
“Should be kept in well stoppered bottles, protected from heat and 
light.” 
ANTIPYRINA. 
Antipyrine. 
C 3 HN 2 0(CH 3 ) 2 .C 6 H 5 
Official in the Austrian and Swiss Pharmacopoeias as Antipyn'inum; 
now official in the German Pharmacopoeia as Pyrazolonum phenyldi- 
methylicum (formerly as Antipyrinum); in the British as Phenazonum, 
and in the French as Analgesine. Other names that have been applied 
to it are cinodynin , metozin , oxydimethylcliinizin , parodyn , phenazon , 
phenylon , pyrazolin , sedatin. 
Chemistry. — Chemically it is phenyldimethylisopyrazolon; its deri- 
vation may be seen from the following formulas: 
HC— CH 
HC— CH 
HC— CH, 
II II 
II II 
II 1 
HC CH 
N CH 
N CH, 
\/ 
\/ 
\/ 
N 
N 
N 
H 
H 
H 
Pyrrol 
Pvrazol 
Pyrazolin 
HC— CH, 
hc=ch 
CH,C=CH 
N CO 
HN CO 
| 
CH.N CO 
\/ 
\/ 
V 
N 
Is T 
N 
H 
H 
c„h 5 
Pyrazolon 
Iso-pyrazolon 
Dimethyl-phenyl- 
iso-pyrazolon 
It is not obtained directly from the mother substance isop} T razolon, 
but is built up synthetically by condensation of phenylhydrazine with 
acetoacetic ether, and methylation of the product. 
Character. — “A colorless, almost odorless, crystalline powder, or 
tabular cn T stals, with a slightly bitter taste.” % 
Solubility. — Soluble in less than 1 part of water, and in 1 part of 
alcohol. 
Purity. — “Two Cc. of an aqueous solution of Antip} T rine (1 in 100) 
mixed with an equal volume of nitric acid assumes a yellowish color, 
passing to crimson on warming (distinction from acetanilide and 
acetphenetidin).” 
“On warming 0.1 Gm. of Antipyrine with sodium hydroxide T. S. 
[Liq. Sodii Hydroxidi] and again warming after the addition of chloro- 
form, the disagreeable odor of phenyl-isocyanide should not be 
developed (absence of acetanilide).'’ 
