jS^e^^gio^^^""^  }    Stability  of  Digitalis  Leaf  Extracts.  395 
then  manufactures  the  unassayed  infusion,  usually  in  liter  quanti- 
ties as  prescribed  in  the  pharmacopceia.  He  does  well  if  he  produces 
a  preparation  equal  in  value  to  those  made  in  the  earlier  times 
when  the  clinician's  report  to  the  pharmacist  constituted  something 
of  a  pharmacological  opinion  on  the  drug  used. 
While  it  is  true  that  the  pharmacopoeia  wisely  directs  that  the 
infusion  must  be  freshly  prepared  from  the  leaves,  the  fact  is  that 
the  quantities  outlined  in  the  text,  which  produce  one  liter  of  the 
preparation,  leads  most  pharmacists  in  practice  to  overstock  this 
galenical. 
Our  results  upon  the  stability  of  the  infusion  proved  of  great 
interest.  When  this  subject  is  studied  using  the  one-hour  frog 
method,  we  find  that  the  infusion  stored  at  low  temperatures  will 
lose  about  20  per  cent,  of  its  activity  in  6-7  days;  while  in  warmer 
weather,  the  velocity  of  the  change  is  greater  and  the  same  stage  of 
decomposition  results  in  3-5  days.  It  would  appear  reasonable 
therefore  to  limit  the  production  of  the  infusion  to  small  quantities. 
An  excellent  system  of  digitalis  administration  which  is  widely  used 
in  this  country  consists  in  giving  3-8  grains  daily  for  several  days 
until  the  desired  therapeutic  effect  is  obtained,  with  subsequent 
diminution  to  1-3  grains  per  day.  If  we  adopt  this,  it  is  evident 
that  since  one  teaspoonful  (4  Cc.)  of  the  infusion  is  equivalent  to 
I  grain  (0.06  Gm.)  of  the  drug  that  a  four  ounce  (120  Cc.)  quantity 
constitutes  a  very  desirable  quantity  of  the  infusion  for  prescription 
work.  This  amount  of  infusion  contains  about  31  grains  (2.00  Gm.) 
of  the  drug  and  this  supplies  a  quantity  usually  considered  necessary 
during  a  5  to  7-day  course. 
Our  conclusions  are  based  upon  the  deterioration  rate  as  deter- 
mined by  the  one-hour  frog  method.  Hatcher  and  Eggleston,^ 
using  the  cat  method  have  reported  results  that  lead  to  the  conclu- 
sion that  "the  infusion  is  fairly  stable  when  prepared  and  kept  with 
ordinary  care,  no  important  change  then  occurring  within  a  week." 
They  report  stability  of  an  order  never  observed  by  ourselves.  Thus 
for  example,  they  found  an  official  infusion  that  had  been  kept 
stoppered  at  70°  F.  for  19  days  to  test  the  same  as  at  the  beginning. 
In  another  case,  a  specimen  made  by  the  official  process  and  kept 
in  the  ice  box  for  four  weeks  retained  its  activity  unchanged.  An 
aqueous  infusion  after  28  days  in  the  ice  box  retained  about  80  per 
cent,  of  its  activity.    It  is  necessary  to  refer  the  reader  to  the  original 
^  J.  A.  M.  A.,  65:  1902,  1915. 
