THE  AMERICAN 
JOURNAL  OF  PH4MIACY 
H  2  1B99  S 
JUNE,  iSgg.    \.f*A  r£Nr  0^°"'' 
HYDRASTINE  HEXIODIDE,  AND  ASSAY  OF  HYDRAS- 
TIS CANADENSIS  BY  MEANS  OF  STANDARD  IODINE 
FOR  HYDRASTINE  AND  OF  STANDARD  POTASSIUM 
IODIDE  FOR  BERBERINE. 
By  H.  M.  Gordin  and  A.  B.  Prescott. 
In  the  work  of  Research  Committee  D.,  Section  II,  Revision  aud  Publica- 
tion of  the  Pharmacopoeia  of  the  United  States. 
When  a  solution  of  iodine  in  potassium  iodine  is  added  to  a  solu- 
tion of  a  salt  of  hydrastine  a  dense  precipitate  falls  out,  of  a  color 
varying  from  light  brown  to  very  dark  brown.  In  this  order  of 
mixing  the  alkaloidal  solution  with  the  iodine  solution,  a  mixture 
of  different  periodides  seems  to  be  formed,  no  matter  whether  the 
addition  of  iodine  is  stopped  while  the  alkaloid  is  yet  in  excess  or 
carried  till  the  iodine  is  in  excess.  Even  in  the  first  case,  that  is,, 
when  the. addition  of  iodine  is  stopped  long  before  all  the  alkaloid 
is  precipitated,  the  body  formed  only  approaches  a  triiodide  in  com- 
position, but  does  not  correspond  to  a  triiodide  exactly.  As  will  be 
seen  from  the  accompanying  analysis,  the  total  iodine  of  the  per- 
iodide  formed  under  these  circumstances  agrees  quite  well  with  the 
theoretical  amount  required  by  hydrastine  triiodide,  but  the  additive 
iodine  is  considerably  below  the  amount  required  by  that  body.  It 
will  be  noticed  that  there  is  a  decided  difference  in  this  respect  be- 
tween hydrastine,  on  the  one  hand,  and  strychnine,  brucine  and  some 
other  alkaloids  on  the  other.  The  latter  always  form  triiodides 
when  iodine  is  added  to  an  excess  of  a  solution  of  their  salt.1 
1  Ftoc.  Am.Phar.  Assoc.,  1898,  Vol.  46,  p.  35S.  Abstract,  this  Journal, 
Vol.  70,  p.  439. 
(257) 
