Am.  Jour.  Pharm. 
July,  1886. 
Paraffin  as  an  Excipient. 
337 
PARAFFIN  AS  AN  EXCIPIENT  FOR  DEOXIDIZABLE 
SUBSTANCES. 
By  Geo.  Smith,  f.c.s. 
In  a  former  paper  published  in  this  Journal  (Am.  Jour.  Phar.,  1884, 
p.  436),  an  account  was  given  of  some  estimation  of  permanganate  of 
potassium,  which  had  been  made  into  pills  containing  2  grains  each  of  the 
salt  with  3  grains  of  an  excipient  composed  of  vaseline  2  parts,  paraffin 
wax  1  part,  and  kaolin  3  parts.  These  pills  were  coated  with  a  solution 
of  sandarac  resin  in  absolute  alcohol  and  had  been  kept  a  little  over 
seventeen  months  before  estimation.  The  results  then  obtained  by 
treating  them  and  their  resinous  coating  with  distilled  water  till  all 
permanganate  was  removed,  and  estimating  with  a  standardized  solu- 
tion of  oxalic  acid,  gave  a  reduction  equal  to  70  per  cent.,  but  on  care- 
fully scraping  off  the  sandarac  coating  a  reduction  equal  only  to  about 
47  per  cent,  was  observed.  The  presence  of  the  organic  coating  alone 
was  thus  proved  to  have  exercised  a  reducing  influence  equal  to  23  per 
cent.  It  was,  therefore,  considered  desirable  to  pursue  the  investiga- 
tion further  on  a  pill-mass  per  se  made  according  to  the  above  formula. 
The  best  white  vaseline  and  washed  kaolin  were  used  in  prepar- 
ing the  excipient.  The  mass  was  made  September  28,  1884,  and 
examined  July  6,  1885,  consequently  it  had  been  kept  a  little  over 
nine  months  (two  hundred  and  eighty-one  days).  The  oxalic  acid 
method  was  again  adopted  in  the  estimation  of  the  permanganate,  but 
the  solution  used  differed  from  the  former  one  in  the  mode  of  its  ti- 
tration. This  was  done  by  dissolving  6'3  gm.  of  dry  oxalic  acid  in  a 
litre  of  distilled  water,  and  ascertaining  the  exact  permanganate  value 
of  each  c.c.  by  titration  with  an  aqueous  litre  solution  containing  3*14 
gm.  of  a  sample  of  the  salt  (K2Mn2Og)  from  which  the  pills  were 
made.  A  mean  of  three  carefully  conducted  estimations  made  on 
10,  20  and  30  c.c,  gave  an  average  value  of  '00332  gm.  K2Mn208  for 
each  c.c.  of  oxalic  acid  solution.  The  pill-mass  used  in  the  estimation 
weighed  7-* 7 4  gm.  This,  according  to  the  formula,  originally  con- 
tained two-fifths  of  its  weight  of  potassium  permanganate,  therefore,, 
the  salt  theoretically  present  weighed  3'096  gm.  The  mass  was  care- 
fully rubbed  down  in  a  clean  glass  mortar  with  distilled  water  at  the 
ordinary  laboratory  temperature,  and  the  solution  filtered  through  glass 
wool  into  a  litre  flask  till  the  washings  were  colorless.  It  was  then 
diluted  to  1000  c.c.  with  distilled  water,  and  three  estimations  of  the 
unreduced  permanganate  were  made  as  follows : 
22 
