May, 1918 



C. U. C. P. ALUMNI JOURNAL 



83 



Solubility of Salicylic Acid. — T. K. 



E., New York, in compounding a pre- 

 scription calling for salicylic acid, so- 

 dium phosphate and ferric pyrophos- 

 phate, U. S. P. Vlli, noted the ease with 

 which the sparingly soluble organic acid 

 dissolved in an aqueous solution of so- 

 dium phosphate and desires to know why 

 this is so. In the tirst place, this prop- 

 erty of dissolving certain compounds that 

 are only sparingly soluble in water is 

 possessed by a number of salts such as 

 citrates, tartrates and phosphates. This 

 explains the preparation of the scale salts 

 of iron, for it is well known that the 

 definite chemicals ferric phosphate and 

 ferric pyrophosphate are insoluble in wa- 

 ter but when ferric citrate is made to 

 interact with sodium phosphate or so- 

 dium pyrophosphate, the medicinal wa- 

 ter-soluble scale salts are obtained. In the 

 case of salicylic acid, it is to be borne in 

 mind that official sodium phosphate is 

 alkaline in reaction and this is likely to 

 explain why it causes the acid to dissolve. 

 The chemical composition of the iron 

 compounds are not so easy to explain, 

 the only explanation that we have found 

 is that of Stevens, {Proc. A. Ph. A., 55, 

 1907. 155) who states that ferric chlo- 

 ride combines with potassium citrate in 

 the proportion of two molecules of the 

 ferric salt with three molecules of the 

 potassium compound, giving six mole- 

 cules of potassium chloride and a doul le 

 salt KaCgH.O, -I- 2 Fe C«H,0,. 



The Pharmacopoeia states that oil of 

 lemon should have a rotation of from 57° 

 to 64° at 25° C. and our problem there- 

 fore is to transcribe our querist's figures 

 given above from 15° C. to 25° C. In 

 Gildemeister, Hoffman and Kremers' 

 "The Volatile Oils," it is stated that for 

 converting the rotation of oil of lemon 

 from 15° C. to 20° C, one must add 9' 

 for each degree centigrade and from 20° 

 C. to 25° C, one must add 8.2' for each 

 degree centigrade. This done in the 

 present case, we find that the calculation 

 is 51° 50' -\- 45' -f- 41' or 53° 16', 

 w^hich is lower than the minimum re- 

 quirement of the Pharmacopoeia. 



Druggist's Sterilizer. — H. H. B., 

 New York, desires information as to a 

 cheap form of sterilizer for rendering 

 citrate of magnesia bottles aseptic. The 

 New York Department of Health has 

 gotten up a home-made sterilizer for re- 

 tail druggists, while, at the 1917 meeting 

 of the New York State Pharmaceutical 

 Association, J. Leon Lascoff recom- 

 mended the "Pressure Cooker" which is 

 made in Denver and which sells for 

 $15.00. For details see the Proceedings 

 of the Association for 1917, page 221. 



Rotation of Oil of Lemon. — H. D. 

 A., New York, has a sample of oil of 

 lemon which has the optical rotation 57° 

 50' at 15° C. He wishes to know how 

 this agrees with the requirements of U. 

 S. P. IX. 



Legal Queries. — During the month, 

 we have answered a number of queries 

 relating to pharmacy laws, local, state, 

 and national, emphasizing each time that 

 the information given was merely the 

 personal opinion of a layman. For this 

 reason we do not print such answers, 

 since in serious legal matters a lawyer 

 should be consulted. 



