III. INDUSTRIAL PREPARATION 417 



nitrate to the nutrient medium in which vitamin B12 is produced l)y fer- 

 mentation. A product of a specific activity of ~ 67 mc per miUigram was 

 obtained. It has also been possible to label the cyanide group ^- of cyano- 

 cobalamin by treating vitamin Bi2b with HC'**N. 



Direct neutron irradiation of vitamin B12 resulted in formation of the 

 radioactive form containing cobalt 60.®* The crystals were not visibly 

 altered by irradiation, and the microbiological activity was retained. 



III. Industrial Preparation 



H. M. WUEST 



The industrial history of vitamin B12 is nearly as dramatic as its isolation 

 and early clinical use. As the compound was found in an industrial labora- 

 tory and proved to be of clinical value from the very beginning, it was only 

 natural that it was practically available to the medical profession a short 

 time after its isolation ; four months after the first publication of the group 

 around Karl Folkers (Rickes et al, April, 1948^,) Merck & Co., Inc., an- 

 nounced at the meeting of the Hematological Society in Buffalo that 

 crystalline vitamin B12 was available for therapeutic purposes (August, 

 1948). 



Today vitamin B12 plays an important role not only in the pharmaceutical 

 industry but also in agriculture. The following forms are important: 



a. Low concentrates, up to 15 mg. of B12 per pound = 0.0033 %, with- 

 out or with antibiotics. 



b. Aledium and high concentrates, up to 1000 7 per gram = 0.1 % B12. 



c. Crystals, U.S. P. 95 % pure. 



Form a is used only for the preparation of animal feed, b serves for oral 

 therapeutic use, mainly for pan-vitamin mixtures, whereas c is the starting 

 material for ampuled solutions (with 15 or 30 7 per miUihter). 



Compared with the enormous scientific and clinical literature on B12, the 

 technical literature of its preparation is rather modest. However, consider- 

 able information can be collected from the patent descriptions. 



Three sources of raw material maj' be considered as a starting point for 

 the isolation of B12 as such or in the form of concentrates: 



1. The mother liquors of the microbial formation of antibiotics like 



" G. E. Bo.xer, J. C. Rickards, C. Rosenblum, and D. T. Woodbury, Arch. Biochem. 



30, 470 (1951). 

 «3 R. C. Anderson and Y. Delabarre, J. Am. Chem. Soc. 73, 4051 (1951). 

 1 E. L. Rickes, N. G. Brink, F. R. Koniuszy, T. R. Wood, and K. Folkers, Science 

 107, 396 (1948). 



