AmApriir'i9u rm' }    Sterilisation  of  Adrenalin  Solutions.  147 
These  results  show  that  ampoules  of  Adrenalin  Chloride  Solu- 
tion can  be  sterilized  a  number  of  times  (in  this  series  7  times) 
without  any  deterioration,  and  after  that  the  loss  of  activity  is 
gradual. 
Third  Series. 
The  next  experiments  give  a  comparison  of  the  stability  of 
Adrenalin  Chloride  Solution  1  in  1000  with  that  of  an  analogous 
synthetic  substance  of  equal  physiologic  activity.  The  latter  was 
made  by  treating  the  crystals  with  dilute  hydrochloric  acid  and 
diluting  1  in  1000.  The  Adrenalin  Chloride  Solution  used  was  made 
from  C.  P.  Adrenalin  crystals  and  contained  no  preservative  other 
than  a  slight  excess  of  hydrochloric  acid.  This  solution  was  tested 
and  found  to  possess  standard  activity. 
Three  different  procedures  were  followed  in  sterilizing  the 
solutions  but  the  conditions  were  duplicated  for  each  solution  in 
order  to  obtain  a  direct  comparison.  The  conditions  to  which  the 
solutions  were  subjected  will  be  briefly  stated  and  the  results  placed 
in  the  form  of  a  table  so  as  to  give  a  better  opportunity  for  com- 
parison. 
In  the  first  method  of  this  series  10  c.c.  of  the  1  in  1000  solu- 
tion to  be  sterilized  was  placed  in  a  graduated  cylinder  which  was 
then  plugged  with  cotton,  and  gradually  heated  in  a  water  bath  to 
the  temperature  of  boiling  water.  This  temperature  was  main- 
tained for  15  minutes  and  at  the  end  of  that  time  the  solution  was 
cooled,  made  up  to  its  original  volume  if  any  loss  due  to  evaporation 
had  occurred,  and  one  cubic  centimeter  removed  for  testing.  This 
process  was  repeated  four  times. 
In  the  second  method  25  c.c.  of  the  solution  to  be  sterilized 
was  placed  in  a  tightly  corked  bottle  which  was  then  partially  im- 
mersed in  boiling  water  for  periods  of  15  minutes  each.  Under 
these  conditions  there  was  no  loss  by  evaporation.  Each  solution 
was  submitted  to  four  periods  of  sterilization  and  a  test  of  its 
activity  made  after  each  period. 
In  the  third  method  of  this  series  20  c.c.  of  the  solution  to 
be  tested  was  placed  in  a  small  open  flask  and  boiled  over  a  flame 
for  5  minutes.  After  each  period  of  boiling  the  loss  due  to  evapora- 
tion, which  was  considerable,  was  made  up  with  distilled  water  and 
the  activity  of  the  solution  then  determined. 
