PREPARATION OF CORTICAL HORMONE 241 



suitable for parenteral administration is desirable. The follow- 

 ing procedure has been found by the author to give extracts 

 suitable for parenteral (subcutaneous, intraperitoneal, intra- 

 muscular, or intravenous) administration. 



The brownish resin obtained after eluting the charcoal hor- 

 mone combination with chloroform and removing the chloroform 

 is dissolved in the smallest possible amount of ethyl alcohol. 

 About 10 volumes of ethyl ether (free of peroxides) is now 

 slowly added and any precipitate which may form is discarded. 

 To the alcohol-ether solution is now added distilled water (1 

 cc. for each 50 grams of the original glands) and the ether and 

 alcohol removed by distillation in vacuo. The resulting aque- 

 ous solution is filtered and the water-insoluble precipitate 

 again treated in the same manner as was the original resin. 

 This repetition is necessary in order to remove the hormone 

 which is adsorbed on the lipoidal precipitate. If an abundant 

 precipitate is present repeated extraction and precipitation may 

 be necessary for the complete transferral of the hormone to 

 aqueous solution. The combined aqueous solutions are now 

 evaporated in vacuo at 45°C. The resinous material which 

 remains in the flask is again dissolved in the least amount of 

 ethyl alcohol and precipitated with an excess of ether as de- 

 scribed above. The hormone remains in the alcohol-ether 

 solution while the insoluble fraction is inert. After filtration 

 and evaporation of the solvents, this process is repeated. The 

 final resin is extracted with 1,4 dioxane which dissolves the 

 hormone leaving an inert residue. The dioxane solution is 

 displaced with physiological solution and filtered after thor- 

 ough cooling in the ice chest over night. The product thus 

 obtained after sterilization by filtration has been found suitable 

 for parenteral administration. 



The final aqueous solution obtained, as described above, 

 contains relatively little solid matter aside from the added 

 salt. Thus 10 kilograms of fresh beef adrenals gave 20 cubic 

 centimeters of a final extract which when assayed was found 

 to contain 500 rat units (as defined in the next chapter), and 



