8o 
Abstracts  of  Papers. 
J  Am.  Jour.  Pliarm. 
t   February,  1913. 
The  Determination  of  Glycerin  in  Suppositories. 
By  Chas.  E.  Vanderkleed  and  Fritz  Heidlberg. 
In  determining  the  amount  of  glycerin  in  suppositories  the 
authors  adopted  a  method  which  is  based  upon  Hehner's  bichromate 
method  for  the  estimation  of  glycerin : 
Half  of  a  suppository — about  2  grains — is  dissolved  in  a  separa- 
tor with  hot  water  acidified  with  sulphuric  acid  and  shaken  out  with 
ether,  thereby  separating  the  stearic  acid.  The  aqueous  solution  is 
evaporated  to  a  small  volume  which  drives  off  all  the  ether ;  the  solu- 
tion is  then  transferred  to  a  250  c.c.  volumetric  flask  and  filled  to 
the  mark  with  water. 
Twenty-five  c.c.  of  the  filtered  solution  is  measured  into  a  250  c.c. 
volumetric  flask,  35  c.c.  of  potassium  bichromate  solution  is  added, 
and  lastly  25  c.c.  of  strong  sulphuric  acid  is  added  slowly  with 
constant  rotation  to  avoid  ebullition.  The  flask  is  then  transferred 
to  a  boiling  water-bath  for  20  minutes,  cooled,  and  filled  to  the  mark. 
In  25  c.c.  of  this  solution  the  excess  of  bichromate  is  determined  by 
adding  20  c.c.  of  potassium  iodide  T.  S.  and  titrating  against 
approximately  N-10  sodium  thiosulphate  solution,  the  factor  of 
which  toward  the  potassium  bichromate  solution  has  been  deter- 
mined previously.  Calculate  the  amount  of  potassium  bichromate 
which  has  been  used  to  oxidize  the  glycerin  to  C02.  One  c.c.  of 
potassium  bichromate  is  equivalent  to  0.01  glycerin. 
The  bichromate  solution  is  made  by  dissolving  74.615  grams 
recrystallized  potassium  bichromate  in  distilled  water,  adding  150  c.c. 
sulphuric  acid  and  making  up  the  volume  to  1000  c.c.  at  200  C. 
With  some  modification  the  same  method  was  used  to  determine 
glycerin  in  a  mixture  of  potassium  chlorate,  chalk,  phenol,  soap,  and 
essential  oils,  as  they  occurred  in  a  toothpaste. 
From  Proc.  Perm.  Pharm.  Assoc. 
Aqua  Caryophylli. 
By  Milton  Dunn. 
The  author  states  that  the  Elixir  Digestivum  Compositum,  and 
various  elixirs  of  lactated  pepsin  on  the  market,  are  used  principally 
as  vehicles  and  as  such  are  not  satisfactory,  notwithstanding  all 
that  has  been  done  to  make  them  popular  with  physicians. 
