STABILITY 



54. American Cyanamid Co., U.S. P. 2335605 ; Lederie Labs., Inc., 



U.S.P. 2336067. 



55. A. Galat, /. Amer. Chem. Soc, 1945, 67, 1414. 



56. Nopco Chemical Co., B.P. 627816. 



57. F. Hofifmann-La Roche & Co., B.P. 551990. 



4. PROPERTIES OF PANTOTHENIC ACID 



D-Pantothenic acid has not been obtained in the free state, and 

 is usually supplied in the form of its sodium or calcium salt. The 

 sodium salt is a white, very hygroscopic solid, crystallising in colourless 

 needles, m.p. 122 to 124° C, with a specific rotation of [a]i^° = + 29° 

 or [a]|^° = + 27° in water, the concentration of the solution being 

 1-9. According to H. C. Parke and E. J. Lawson,^ it is macb less 

 hygroscopic after crystallisation from absolute ethyl or isopropyl 

 alcohol. The calcium salt is a white powder, less hygroscopic than 

 the sodium salt. It was obtained crystalline by Levy et al.,^ and by 

 J. H. Ford,^ who recorded a m.p. of 170 to 172° C. 



Quinine D-pantothenate has m.p. 136° C. and optical rotation 

 [a]i^° = — 95°, whilst quinine L-pantothenate has m.p. 183-5° C. 

 and optical rotation [a]i^° = — 121°, both rotations being measured 

 in water.* Cinchonidine D-pantothenate has m.p. 178 to 179° C. 

 and optical rotation [a]i®° = — 62-8° in water.^ 



Ethyl D-pantothenate is a coloiurless oil with an optical rotation 

 of [oCff' = -f 36-8° in absolute alcohol. 



References to Section 4 



1. H. C. Parke and E. J. Lawson, /. Amer. Chem. Soc, 1941, 63, 2869. 



2. H. Levy, J. Weijlard and E. T. Stiller, ibid., 2846. 



3. J. H. Ford, ibid., 1946, 68, 1666. 



4. A. Griissner, H. Gatzi-Fichter and T. Reichstein, Helv. Chim. Acta, 



1940, 23, 1276. 



5. R. Kuhn and T. Wieland, Ber., 1941, 74, 218. 



5. STABILITY OF PANTOTHENIC ACID 



Pantothenic acid is one of the more heat-stable members of the 

 vitamin B complex, but the _/>H of its solutions must be kept approxi- 

 mately neutral, as it is readily hydrolysed under acidic or alkaline 

 conditions. The substance has maximiun stability over the _/>H range 

 5-5 to 7-0.1 



Reference to Section 5 



I. D. V. Frost, Ind. Eng. Chem., Anal. Ed., 1943, 16, 306. 



359 



