Am  jour.  Pharm.  i     The  Stability  of  Iodine  Ointments. 
Aug.  1917.  J 
341 
Three  were  found  to  be  pure,  the  fourth  was  low  in  iodine.  Ex- 
periments showed  that  iodine  ointment  deteriorates  rapidly ;  con- 
sequently, no  further  collections  of  samples  were  made. 
In  1 91 2  Pullen8  reported  that  he  had  prepared  two  specimens  of 
iodine  ointment  according  to  the  British  Pharmacopeia,  one  being 
from  new  lard  and  the  other  from  a  specimen  of  lard  at  least  two 
years  old.  Assays  for  free  iodine  were  carried  out  immediately 
after  the  preparations  were  made,  and  at  intervals  afterward  up  to 
four  months.    The  following  values  were  found  : 
Pullen  found  that  the  loss  in  free  iodine  could  be  accounted  for 
by  the  iodine  which  had  gone  into  combination  with  the  fats  of  the 
ointment  base. 
Pullen  also  found  that  if  the  potassium  iodide  and  glycerin  were 
omitted  in  the  preparation  of  the  ointment,  the  loss  in  free  iodine 
was  very  rapid,  the  preparation  containing  practically  no  free  iodine 
(only  y2o)  after  a  few  hours.  He  concludes  that  the  use  of  potas- 
sium iodide  and  glycerin  is  necessary  for  the  preservation  of  the 
ointment.  He  obtained  specimens  of  iodine  ointment  in  drug  stores, 
and  assayed  them  for  free  iodine.  It  is  to  be  presumed  that  the 
ages  of  the  several  specimens  were  not  known.  The  results  are 
found  in  the  following  table : 
Specimen  No.  1   2.74  per  cent. 
Specimen  No.  2    2.85  per  cent. 
Specimen  No.  3    2.62  per  cent. 
Specimen  No.  4    2.48  per  cent. 
Specimen  No.  5   2.53  per  cent. 
Specimen  No.  6    2.79  per  cent. 
8 Pharm.  Jour.,  89,  610  (1912). 
Iodine  introduced   
Iodine  found  immediate!}"  after  making 
Iodine  found  after  twenty-four  hours  . 
Iodine  found  on  the  third  day   
Iodine  found  on  the  seventh  day   
Iodine  found  on  the  fourteenth  day  .  . . 
Iodine  found  after  one  month   
Iodine  found  after  two  months   
Iodine  found  after  four  months   
Sample  I. 
Ointment  from  new 
lard,  Per  Cent. 
4-0 
3-95 
3-30 
3.18 
3-15 
3.00 
3.00 
2.90 
2.92 
Sample  II. 
Ointment  from  old 
lard,  Per  Cent. 
4.0 
