418 
Lanolin  in  Pharmacy. 
f  Am.  Jour.  Pharm. 
X      August,  1889. 
SOME  SUGGESTIONS  FOR  THE  USE  OF  LANOLIN  IN 
PHARMACY. 
By  A.  Ball. 
Lanolin,  the  purified  fat  of  sheep's  wool,  discovered  for  use  com- 
mercially by  Liebreich,  is  now  so  well  known  that  little  need  be  said 
about  its  composition.  Its  consistence  is  somewhat  elastic  and  sticky, 
and  in  order  to  make  it  more  pliable  it  is  necessary  to  dilute  it  with  a 
substance  which  will  not  detract  from  its  penetrating  power.  What 
is  to  be  used  ?  is  frequently  asked  in  dispensing.  The  fact  that  lano- 
lin will  take  up  twice  its  own  weight  of  an  alkaline  solution  should 
not  be  lost  sight  of.  In  the  preparation  of  ung.  potassii  iodidi  B.  P. 
with  lard,  it  is  first  necessary  to  saponify  the  lard  with  potassii  carbo- 
nas,  when  the  soap  will  take  up  the  iodide,  which  is  subsequently 
decomposed  again  by  the  soap,  iodine  being  set  free,  as  indicated  by 
the  decoloration.  With  lanolin  the  case  is  different,  as  the  solution  is 
perfectly  absorbed  by  the  fat.  I  recently  made  some  experiments 
with  the  ointment,  prepared  with  three  different  bases.  No.  1  with 
equal  parts  lard  and  lanolin.  No.  2  with  equal  parts  vaselin 
and  lanolin.  No.  3  lanolin  with  30  per  cent,  added  distilled 
water. 
These  ointments  were  severally  spread  on  pieces  of  membrane,  pre- 
viously tested  as  to  permeability  by  dialysing  1  oz.  of  cochineal  solu- 
tion. After  standing  twelve  hours  on  the  septum  no  difference  in 
color  could  be  discerned ;  the  membranes  were  then  washed,  and  the 
ointments  evenly  spread  over  the  surface,  to  within  an  inch  of  the  out- 
side. After  dialysing  for  twenty-four  hours  at  50°  F,  No.  3  only 
gave  the  iodine  reaction.  I  then  kept  them  in  a  temperature  of  80° 
F.  for  twenty-four  hours,  when  I  found  No.  3  gave  a  copious  pre- 
cipitate, No.  2  less,  and  No.  1  still  less,  when  tested  with  nitrate  of 
silver  solution,  showing  that  most  iodide  had  passed  through  the  mem- 
brane in  the  case  of  the  lanolin  base.  Fat  had  also  passed  through 
in  each  case.  I  reasoned  that  if  the  ointment  would  pass  through  a 
dead  membrane  it  would  most  certainly  pass  through  a  living  one, 
osmosis  being  the  same  in  each  case.  Osmotic  action  has  doubtless  to 
perform  a  most  important  part  in  the  absorption  of  medicinal  agents 
when  applied  as  ointments. 
Oleates  are  especially  adapted  for  mixing  with  lanolin.  Dr.  Shoe- 
maker very  clearly  proved  the  peculiar  penetrating  properties  of  the 
