The Stability of Nitroglycerin Tablets. - American Chemical Society

of the fatty acids all tend to place this oil in the group with the other oils of the grape family and with castor oil, with which the group is headed...
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T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY

THE OIL OF THE WILD GRAPE SEED, VITIS RIPARIA' By GEO. D. BEAL AND C. K. BEEBE

This oil has been examined in a series of studies which t h e senior author has been carrying out on t h e oils of t h e different members of t h e grape family. T h e source of t h e oil was t h e seeds from t h e wild grape, obtained during t h e manufacture of grape butter. T h e seeds, after freeing t h e m from t h e dried pulp, were ground in a mill a n d extracted with low boiling petroleum ether; after evaporation of t h e ether, t h e oil obtained amounted t o 19.38 per cent of t h e weight of seed taken. T h e oil h a d a greenish amber t i n t , tasted like castor oil, a n d had a peculiar acrid odor. Physical a n d chemical examination of t h e oil gave t h e following d a t a : Density Refractive Saponiat index fication 15'C. a t 15OC. value 0 9425 1.4781 187.8

TOTAL FATTY ACIDS

Liquid.. . . . . . . . . . . Solid. . . . . . . . . . . . . .

Iodine value 76.47

Per cent 95.00 5.01

Insoluble F a t t y acids Per neutralizacent tion value 90.00 173.4 Mean Iodine value molecular weieht 91.8 3.12 268: 6 Acetyl value 61.29

T h e low iodine value of the solid f a t t y acids may be assumed t o be caused b y t h e trace of liquid f a t t y acids which i t is impossible t o remove by t h e lead saltether method of separation. On t h e basis of t h e neutralization value of these solid acids a n d their calculated molecular weight, we have calculated t h a t these were a mixture of 64.28 per cent of palmitic acid a n d 3 5 . 7 2 per cent of stearic acid. T h e iodine values obtained for t h e liquid f a t t y acids are too low, a n d were probably due t o oxidation during t h e process of separation. Another portion of t h e oil was treated for the removal of t h e liquid acids, these were brominated, a n d t h e linolic a n d ricinoleic bromides separated b y fractional crystallization from petroleum ether. T h e bromides obtained by this method corresponded t o approximately 44 per cent of oleic a n d ricinoleic acids, a n d 56 per cent of linoleic acid. T h e q u a n t i t y of oil available a t t h e t i m e was too small for further studies on its composition, or for a n y determinations of its physiological properties. We hope during t h e present year t o obtain a further supply of t h e oil, a n d t o continue t h e investigation. The saponification value, iodine value, acetyl value a n d n a t u r e of t h e f a t t y acids all t e n d t o place this oil in t h e group with t h e other oils of t h e grape family a n d with castor oil, with which t h e group is headed. We have hopes t h a t i t will present, thougli doubtless t o a much less degree, t h e physiological properties of castor oil. LABORATORY OF ORGANIC ANALYSIS UNIVERSITY OF ILLINOIS, URBAKA

THE STABILITY OF NITROGLYCERIN TABLETS' By WILBURL. SCOVILLE

Tablets of nitroglycerin for medicinal use, are manufactured from a I O t o 20 per cent alcoholic 1 Presented a t the 50th Meeting of the American Chemical Society, hTew Orleans, March 31 t o April 3, 1915.

solution, or from a 20 per cent paste mixture containing sugar of milk or calcium carbonate. The body of t h e tablet is usually either sugar of milk or a mixture of this with cane sugar. Since t h e tablets contain b u t a minute q u a n t i t y of nitroglycerin ( I / Z O O grain t o 1 / 2 0 grain each), yet are quite powerful in action, it is necessary t h a t t h e strength shall be accurately adjusted, a n d t h a t t h e tablets shall not change in strength on keeping. It has been found t h a t there is a decided loss of strength in manufacturing, a n d this loss is now allowed for, t h e final adjustment being made by assay on a preliminary sample of tablets. T h e ratio of loss is not constant, a n d i t is necessary t o test each lot during t h e process of manufacture. This is a matter of detail which is easily adjusted, a n d tablets of nitroglycerin need not vary materially from t h e stated strength when first made. T h e question of permanence, however, has not yet been decided. Until within four years a trustworthy method of estimating t h e minute q u a n t i t y of nitroglycerin in tablets was not known. And t h e question of deterioration can only be settled b y starting with tablets whose strength has been accurately determined. About 3l/* years ago a series of sample tablets, freshly made a n d tested, was set aside for observation. These represented t h e usual market, a n d were stored, some in bottles of amber glass, some in white, some in bottles well filled a n d some partially filled, so t h a t t h e varying conditions of light a n d air might be considered in t h e keeping qualities of t h e tablets. Table I shows t h e results. TABLEI-TESTS No.

CLASS

1 2 3 4 Triturate

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Triturate Triturate Hypodermic Hypodermic Triturate

~~~

Hypodermic Hypodermic Hypodermic Hypodermic Triturate Triturate Hypodermic Triturate Triturate Hypodermic

OF

TABLETS

Strength Grain Material 1 / 2 0 Paqte lj25 P a G 1/25 Paste 1/25 Paste 1/50 Paste 1/50 Paste 1/50 Solution 1/60 Solution 1/100 Paste 1., /IO0 Paqte - ..~ 1:lOO Paste 1/100 Solution 1/100 Solution 1/100 Solution 1/100 Solution 1/ 100 Solution 1/150 Paste 11150 Paste 1/'150 Solution 11200 Paste 11200 Solution 11200 Solution

OF N ITROGLYCERIN

TEST-PERCENT 'AGES

Date of When manufacture made Sept. 1911 95 Feb. 1911 80 100 M a y 1911 100 Nov. 1911 95 Sept. 1911 100 Dec. 1911 100 Sept. 1913 Dec. 1913 100 May 1910 95 100 June 1911 Oct. 1911 '105 Dec. 1912 105 100 Dec. 1910 100 Dec. 1910 105 Sept. 1911 io5 Feb. 1912 100 Oct. 1911 100 Oct. 1911 100 Sept. 1913 Dec. 1911 100 Nov. 1913 100 Nov. 1912 100

Jan. June June 1912 1912 1914 95 95 95 80 80 loo io0 100 100 , . . 100 95 95 95 . . . 100 100 '. . , ... 85 ... ... 80 90 95 95 100 100 100 105 105 105 .. . . . 90 80 80 50 40 35 .. . 70 . . . io0 85 95 85 50 100 80 50

._.

, , , ,

.. ... ...

,I.

65

...

.._

55

60 90 80

It will be noticed t h a t all tablets c o n t a i n i n g less t h a n l / l o ~ g r a i n each have deteriorated, and, also, all those m a d e f r o m solution of nitroglycerin, while tablets m a d e from the p a s t e , of 1 / 1 ~ g~r a i n or over, have m a i n tained their strength. Two explanations of this are possible : ( I ) T h e solution may yield a finer attenuation of t h e nitroglycerin, exposing more surface a n d favoring volatilization. T h e chemists a t t h e Bureau of Mines hold t o t h e idea t h a t nitroglycerin is slightly volatile a t or'dinary temperatures, and this view is largely accepted. T h e deterioration of t h e tablets containing less t h a n 1 / 1 ~ ~grain each bears out this view, since in such tablets t h e nitroglycerin must be more highly a t t e n u a t e d t h a n in t h e stronger, t o secure

Dec., 191;

T H E J O U R N A L O F I N D C S T R I A L A Y D ELVGILVEERILVGC H E M I S T R Y

uniform dosage. On t h e other hand, the amount of air-space in t h e containers does not appear t o be a n y factor in t h e deterioration, since some tablets t h a t showed a jo per cent deterioration were stored in securely stoppered tubes which allowed only a very small proportionate air-space, and freshly opened tubes showed the same deterioration a s had taken place in bottles furnishing a relatively large air-space. ( 2 ) A second possible explanation is found in the two forms in which nitroglycerin is known t o exist. Kast, in 1906,found t h a t solid nitroglycerin is capable of existing in two isomeric forms-a labile form melting at 2 . ~ oc. and a stable form melting a t 13. j o c. H . Hibbert, in a paper read a t the Eighth International Congress of Applied Chemistry, confirmed this, and found t h a t freshly prepared llitroglycerin usually crystallizes in t h e labile form; but t h a t on long standing, particularly after having been once frozen, it tends t o change t o t h e stable form; t h a t the stable form is also promoted b y mixing with wood pulp and sodium nitrate, accompanied b y a trace of moisture; t h a t rubbing x4th a glass rod also promotes t h e change in the cold; and that the labile isomeride melts a t 2.0' C. and the stable a t 1 3 . 2 ' C. ' The used in the above tab1ets was O n e lot of paste, purchased in October Igo8, and four lots Of solution, purchased in September 1910,July 1 9 1 1 , February 1 9 1 2 , and I I a r c h 1912. They were stored in a small, unheated, and isolated building, in which the temperature is always very t o that Of the O u t e r atmosphere. Thus t h e paste had passed through t W o Winters before being used in a n y of the series of tablets here reported, while the solutions had all passed through one! winter's storage. I n Detroit a temperature Of a feVv7degrees below 0' F. (--IS' C.) occurs in most winters a few times. Hibbert f o u n d that cooling t o -4O' c. stirring 17-ith a glass rod was necessary t o crystallize the liquid nitroglycerin, but when the liquid was "seeded" with a crystal of the form desired. a temperature of - j o C . Only IVas necessary. He shoWed a marked tento gradually change i n t o t h e dency Of stable form, but did not succeed in reversing the Process. He was unable t o change a stabilized form t o labile. He further showed t h a t liquid nitroglycerin is much more susceptible t o shock-decomposition t h a n the solid, but t h a t the stabile isomeride seems to persist in the liquid condition after i t had been formed, and t h a t slowly-frozen nitroglycerin differs in its properties from rapidly-frozen. Thus i n the paste form, We have in t h e condition most conductive t o forming the stable isomeride, e. g., the presence of a hard-crystalline body sugar) and Of a trace of moisture; IThile in the alcoholic solution t h e conditions may be unfavorable t o the formation of the stable form. Even t h e labile crystals do not form except in the presence of some sharp body and rubbing' Hibbert used ground glass and a glass rod t o obtain the crystals. Thus the nitroglycerin in those tablets which deteriorated may have been in t h e labile condition,

IOjj

with a greater tendency t o decomposition than the others. Several tests were made for nitrites in the deteriorated tablets, which might show decomposition, but none were found. But if decomposition occurs, i t is more likely t o be an oxidation process than a reduction, hence a failure t o find nitrites proves nothing. The work on t h e isomerides of nitroglycerin is too recent t o prove whether it is a factor in the deterioration Of nitroglycerin in tablets or not, but three facts are established. I-Tablets containing less than ' / ' I O O grain of nitroglycerin lose strength very markedly on keeping. 11-Tablets made from a n alcoholic solution of nitroglycerin are less stable t h a n those made from a paste, III-It is Probable t h a t a nitroglycerin which has been slowly frozen and slowly thawed is better for tablet use than one freshly made. LABORATORY OF P A R K E , DAVIS& C O > l P A N Y DETROIT.~ I I C H I G A N ~.

ON CONSTITUENTS OF OIL OF CASSIA' By FRANCIS D. DODGEA K D ALFREDE. SHERXDAL Received Ma$ 28, 1915

The essential oil of cassia, obtained i n China by steam distillation of the bark and leaves of Cinnamo?num cassia, is commercially one of the most important oils, yet its composition does not Seem t o have been thorougllly investigated, T h e chief constituentis t h e fi-ell-known cinnamic aldehyde, t h e amount of which, in per cent. pure oils, appears t o \-ary frorn 7 j t o the last f r a c t i o n s of the oil, a crystalliIle compound has, at times, been noted: i t was designated steroptene" by Rochleder who first observed i t , and \%,as later identified as t h e methyl ether of orthocoumaric aldehyde by Bertram and Kursten2 who also synthesized the compound by the condensation of methyl salicylic aldehyde Tvith acetaldehyde, In 1889, Schimmel and C o . isolated cinnamyl acetate as a constituent, and t h e presence of phenyl-propyl acetate indicated by the boiling point of the alcohols obtained by saponification of t h e esters present, Cinnamic acid also occurs in small a m o u n t s , undoubtedly resulting f r o m oxidation of the cinnamic aldehyde. In commercial oils, mineral oil and rosin are found, eTidence of t h e gross adulteration so long practiced, Apparently pure oils generally show a slight rot a t i o n , in t h e polarimeter, b u t to this is d u e , has not yet been ascertained,

In the course of a n examination of a sample of oil of cassia, it as found that lTvhen t h e alkaline solution obtained by shaking the oil dilute sodium hydroxide was acidified and distilled with steam, the distillate gave an intense purple coloration 7h-ithferric chloride, this reaction could n o t be due to any of the heretofore recognized constituents of t h e oil, t h e test was applied to' various samples of commercial oils, to determine if it were perhaps due to the presence of a n accidental impurity. Fifteen cc. of oil were per cent sodium shaken with an equal volume of Society' N e w l ~ ~ ~ n ~ ~: ~e ~&p a$ ~e ~c ~~ :the ~ ~ lAmerican ~ f 2 J . p y a k l . Chem., [21 61, 316.