Am.  Jour.  Pharm.  \ 
October.  1906.  J 
Some  Alkaloidal  Assays. 
463 
EXTRACTUM  PHYSOSTIGMAT1S. 
Having  found  the  pharmacopceial  method  rather  complicated  I 
have  used  the  following  method  which  is  short  and  exact : 
Dissolve  2  grammes  of  the  solid  extract  placed  in  a  small  evapo- 
rating dish  in  about  io  c.c.  of  cold  water  acidulated  with  5  drops  of 
dilute  acetic  acid  (U.S.P.)  and  transfer  the  turbid  liquid  to  a  25  c.c. 
measuring  flask.  Wash  the  dish  with  small  quantities  of  water  and 
make  up  the  liquid  to  25  c.c.  Filter  through  a  dry  filter  and  by 
means  of  a  pipette  transfer  12-5  c.c.  of  the  filtrate  to  separating 
funnel  No.  1.  To  the  contents  of  the  funnel  add  10  c.c.  of  a  satu- 
rated solution  of  sodium  bicarbonate  and  100  c.c.  of  a  mixture  of 
one  volume  of  petroleum  ether  and  three  volumes  of  ether.  Shake 
thoroughly  for  a  minute  or  so,  draw  off  the  alkaline  aqueous  liquid 
and  throw  it  away,  then  filter  the  ethereal  solution  into  separating 
funnel  No.  2  through  a  plain  double  filter  of  ordinary  paper  having 
four  folds  on  each  side.  Wash  the  first  separating  funnel  and  the 
filter  repeatedly  with  more  of  the  immiscible  solvent  and  concentrate 
the  ethereal  liquid  to  about  one-half.  Cool,  dilute  with  ether  and 
shake  out  first  with  excess  of  standard  acid  and  then  twice  with 
water.  Titrate  excess  of  acid  with  standard  alkali,  using  hematoxylin 
as  indicator.  The  acid  liquid  is  perfectly  colorless  and  the  end  reac- 
tion is  exceptionally  sharp. 
A  higher  yield  of  alkaloid  can  be  obtained  by  substituting  chloro- 
form for  the  petroleum  ether  in  the  above  immiscible  solvent.  In 
this  case,  too,  the  method  works  well  and  the  end  reaction  is  very 
sharp.  But  neither  method  gives  the  amount  of  all  the  alkaloids 
in  the  drug,  which  could  only  be  obtained  by  repeated  extraction 
with  chloroform.  As  this  is  inconvenient  the  results  obtained  by 
either  of  the  above  methods  could  be  adopted  as  official  standard. 
A  sample  obtained  from  P.  D.  &  Co.  gave  the  following  results: 
The  apparatus  described  in  this  paper  as  well  as  the  one  de- 
scribed in  this  Journal,  1905,  p.  463,  can  be  obtained  from  E.  H. 
Sargent  &  Co.,  Chicago,  111. 
Northwestern  University  School  of  Pharmacy. 
Per  cent. 
Stated  strength  . 
By  first  method  . 
By  second  method 
5-00 
4-20 
4-91 
