538 
Economy  of  Time  in  Percolation. 
( Am.  Jour.  Pharm. 
I     August,  1921. 
upon  the  duration  of  the  period  of  contact  of  the  menstruum  with 
the  drug.  Evidence  in  support  of  this  is  afforded  by  the  results  of 
an  experiment  carried  out  in  this  laboratory  some  years  ago.  One 
thousand  grammes  of  powdered  digitalis  were  percolated  with  ten 
liters  of  the  menstruum  directed  by  the  U.  S.  Ph.,  VIII,  during  a 
period  of  about  three  months  with  periods  of  maceration.  The  last 
portion  of  about  3000  cc.  of  percolate  represented  the  activity  of 
about  two  grammes  of  the  powder. 
It  is  difficult  to  understand  what  advantage  can  result  from  the 
maceration  of  the  drug  for  a  period  of  twenty-four  hours  after  the 
menstruum  begins  to  drop  from  the  percolator  if  the  menstruum  had 
penetrated  thoroughly  into  the  cells  of  the  drug  previous  to  its  being 
packed  tightly  into  the  percolator.  The  higher  the  percentage  of 
the  active  principles  present  in  the  drug  the  more  rapidly  will  they 
pass  into  solution  in  the  menstruum  up  to  the  point  of  saturation, 
and  conversely,  the  lower  the  percentage  present  the  more  slowly 
will  they  pass  into  solution. 
From  this  it  follows  that  if  maceration  is  required  at  any 
time  (after  the  preliminary  period  before  the  drug  is  packed)  it 
will  be  toward  the  end  of  the  percolation  when  the  powder  is  nearly 
exhausted.  If  percolation  is  not  too  rapid  the  drug  will  be  practically 
exhausted  by  a  suitable  menstruum  without  this  period  of  macera- 
tion. 
SUMMARY. 
Tinctures  of  aconite,  nux  vomica  and  strophanthus  were  pre- 
pared without  macerating  the  drugs  after  the  liquid  began  to  drop 
from  the  percolator. 
The  tinctures  prepared  in  this  way  represent  the  activity  of  the 
drug  almost  completely. 
The  first  portion  of  the  percolate  is  much  more  active  than  the 
last  portion ;  the  first  portion  of  the  percolate  of  aconite  was  at  least 
eighteen  times  as  active  as  the  last  portion. 
3  There  is  some  evidence  that  alcohol  is  not  the  best  menstruum  for  mak- 
ing tincture  of  strophanthus.  A  tincture  of  strophanthus  was  prepared  with 
a  menstruum  of  65  per  cent,  alcohol  in  this  laboratory  several  years  ago,  at 
which  t'me  the  several  fractions  of  the  percolate  were  tested  for  their  activity. 
It  was  found  that  the  first  portion  of  percolate,  representing  one-tenth  of  the 
volume  of  the  finished  tincture,  contained  65  per  cent,  of  the  active  principles, 
and  the  second  portion  of  equal  volume  contained  more  than  75  per  cent,  of 
the  balance,  the  remainder  of  the  percolate  containing  about  10  per  cent. 
