^"^  Mar'ch^^92'S:!        Pepsiu  AdsoYptiofi  by  CkarcoaL  i6i 
Since  powdered  charcoal  is  a  very  good  adsorbent,  we  will  start 
our  attack  upon  it  and  its  common  accomplice,  in  the  medical  pro- 
fession. Charcoal  and  pepsin  is  a  very  frequent  combination  dis- 
pensed by  prescriptionists,  as  well  as  put  up  in  tablet  and  capsule 
form  by  w^holesalers.  While  it  is  advised  therapeutically  that  pep- 
sin be  given  alone  and  not  in  combinations  for  fear  of  its  chemical 
incompatibility;  in  this  instance  no  chemical  reaction  occurs,  but 
an  adsorption  of  pepsin  by  the  charcoal  as  soon  as  the  two  substances 
are  moistened. 
To  prove  this  adsorption,  two  samples  of  pepsin,  a  powdered  and 
a  granular  grade,  were  first  tested  by  the  U.  S.  P.  method  of  assay 
and  found  to  be  of  i  :  3000  strength  or  U.  S.  P.  As  our  present 
day  pepsin  is  an  enzyme  in  combination  with  albumin  (mostly 
albumin)  it  wiU  readily  give  an  albumin  test,  when  the  top  layer  of 
an  acid  solution  is  heated  in  a  test  tube  over  a  flame.  (Same  as  heat 
test  for  albumin  in  urine.)  By  filtering  this  acid  solution,  which  is  of 
pepsin  and  acid  strength  according  to  U.  S.  P.  assay,  through  char- 
coal, the  filtrate  will  be  free  from  albumin.  This  charcoal-filtered 
solution  was  tested  on  freshly-coagulated  albumin  according  to 
U.  S.  P.  assay  and  found  to  assay  i  :  300.  This  value,  I  believe, 
could  be  lowered  considerably,  by  better  filtration  as  only  ordinary 
filter  paper  was  used. 
Next  a  group  of  tests  were  made  with  0.5  Gm.  of  charcoal  in 
100  Mils,  of  the  U.  S.  P.  test  solution.  This  charcoal-containing 
solution  assayed  to  about  i  :  500  as  near  as  could  be  estimated; 
the  charcoal  making  the  end  reaction  indistinct.  This  group  of 
tests  was  made  to  ascertain  what  action  might  be  expected  to  occur 
in  the  stomach,  when  about  the  same  proportions  of  each  drug  are 
dispensed  in  tablet  form. 
Since  this  adsorption  by  charcoal  is  a  very  rapid  process,  it  can 
be  readily  seen  that  pepsin-charcoal  combinations,  in  tablet  or 
capsule  form,  will  as  soon  as  moistened  (in  the  process  of  dissolving) 
begin  the  adsorption  reaction.  An  easy  example  of  this  can  be 
shown  by  dissolving  a  few  charcoal  and  pepsin  tablets  in  0.2  per 
cent,  hydrochloric  acid,  filtering  the  solution,  and  testing  filtrate 
for  albumin;  this  will  prove  the  albuminous  enzyme  is  absent. 
From  these  experiments  and  deductions  it  can  be  readily  seen 
that  all  our  former  therapeutics  concerning  these  two  drugs,  when 
used  together,  has  been  at  fault. 
While  on  this  subject  of  adsorption,  it  might  be  well  to  state  some 
