Am.  Jour.  Pharm.  \ 
April,  1900.  J 
Citrate  of  Magnesium. 
175 
EFFERVESCING  CITRATE  OF  MAGNESIUM. 
By  Wilbur  1^.  Scovihe. 
It  is  frequently  reported  in  pharmaceutical  literature  that  magne- 
sium sulphate  is  found  in  solution  of  magnesium  citrate  as  an  adulte- 
rant, but  rarely  does  any  one  call  attention  to  the  almost  universal 
existence  of  magnesium  sulphate  in  the  so-called  granular  effervescent 
citrate  of  magnesium.  Yet  true  citrate  of  magnesium  is  seldom 
obtained,  at  least  in  New  England,  under  this  title.  Nearly  all  of 
the  so-called  granular  effervescent  citrate  of  magnesium  consists  of  an 
effervescent  sulphate  of  magnesium  or  of  sodium.  The  United  States 
Pharmacopoeia  has  embalmed  the  title  and  kept  it  before  the  pro- 
fession, but  the  preparation  itself  has  been  defunct  for  more  than  a 
decade.  It  is  time  that  the  corpse  were  buried  and  the  thing  called 
by  its  right  name.  So  long  as  the  Pharmacopoeia  holds  this  title, 
it  will  appear  as  an  alias  upon  the  label  of  ambiguous  preparations, 
and  variable  will  be  its  forms.  The  true  article  can  be  secured  by 
dint  of  hard  emphasis  in  an  order,  a  willingness  to  delay  and  to 
remunerate  accordingly,  and  an  assertion  that  the  purchaser  knows 
what  he  wants  and  will  insist  upon  having  that  and  naught  else, 
but  in  the  ordinary  channels  of  trade,  and  ordered  in  the  usual  man- 
ner, another  article  will  be  sent,  in  the  writer's  opinion,  every  time. 
The  objections  to  the  official  preparation  are  threefold:  (1)  it  is 
not  as  nice  appearing  a  preparation  as  its  substitutes ;  (2)  it  costs 
several  times  as  much,  and  (3)  it  is  a  difficult  and  tedious  prepara- 
tion to  make. 
As  to  its  action,  Dr,  H.  A.  Hare  says :  "  Citrate  of  magnesium  is  a 
much  more  irritating  purge  than  the  sulphate,"  but  the  question  of 
therapeutics  I  will  not  attempt  to  consider. 
Probably  the  greatest  obstacles  to  its  practical  employment  are 
its  cost  and  the  difficulties  of  making  it.  In  its  manufacture,  acid 
citrate  of  magnesium  is  first  formed  by  reacting  upon  magnesium 
carbonate  with  citric  acid. 
In  this  reaction  sixteen  molecules  of  water  contained  in  the  mag- 
nesium carbonate  and  the  citric  acid  are  liberated,  and  water  must 
be  added  very  cautiously,  or  a  fluid  mass  will  result  instead  of  a 
paste.  The  mass  is  then  dried  and  powdered.  In  drying,  it  forms 
a  very  hard  and  tough  residue,  which  adheres  tenaciously  to  the 
plates  on  which  it  was  dried,  and  is  difficult  to  powder.  Greasing 
the  plates  only  partially  helps  the  sticking,  and  it  is  likely  to  give  a 
