THE  AMEEIOA]^ 
JOURNAL  OF  PHARMACY 
SEPTEMBER,  igii 
THE  PHARMACOPCEIAL  STANDARD  FOR  DESICCATED 
THYROID  GLANDS/ 
By  Reid  Hunt  and  Atherton  Seidell, 
[Division  of  Pharmacology,  Hygienic  Laboratory,  U.  S.  P.  H.  and  M.  H. 
Service,  Washington,  D.  C] 
During  the  past  few  years  a  great  many  experiments  have  been 
made  in  this  laboratory  upon  the  relation  between  the  physiological 
activity  of  thyroid  and  its  iodine  content.  These  experiments,  and 
practically  all  others  that  have  been  described  in  the  literature, 
defmonstrate  this  parallelism;  it  may  therefore  be  concluded  that  at 
present  the  most  satisfactory  way  to  standardize  thyroid  is  by 
means  of  the  determination  of  the  organically  combined  iodine  which 
it  contains.  From  the  standpoint  of  the  Pharmacopoeia  the  question 
resolves  itself  simply  into  the  selection  of  the  rnost  satisfactory 
method  for  the  iodine  estimation  and  the  adoption  of  the  most 
reasonable  percentage  content  of  iodine  as  the  standard. 
Of  the  methods  which  may  be  used  for  the  determination  of 
the  iodine  there  are  only  two  which  need  to  be  considered,  viz., 
the  older  Baumann  method  which  consists  of  fusion  with  caustic 
alkali,  liberating  the  iodine  by  suitable  means  from  the  aqueous 
solution  of  the  fused  residue,  extracting  it  with  an  immiscible 
solvent,  and  estimating  its  quantity  colorimetrically,  and  the  recently 
proposed  Hunter  method,  which  differs  from  the  above  in  sub- 
stituting alkali  carbonates  for  the  fusion,  conversion  of  the  iodine 
to  the  iodic  state,  and  estimating  its  amount  by  a  volumetric 
procedure.  O'f  these  two  methods  the  latter  has  been  found  by 
us  to  possess  advantages  both  in  reliability  of  the  results,  and 
*  Read  at  the  Boston  Meeting  of  the  American  Pharmacentical  Asso- 
ciation. August,  igii. 
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