THE  AMEEICAN 
JOURNAL  OF  PHARMACY 
The  following  communication  contains  an  account  of  certain 
experiments  designed  to  furnish  knowledge  of  the  behavior  of  cal- 
cium glycerophosphate  in  solution  and  the  effect  upon  the  salt  of 
those  substances  which  are  commonly  associated  with  it  in  pharma- 
ceutical mixtures.  In  a  consideration  of  this  substance  one  must 
always  remember  that  the  commercial  salt  is  a  mixture  of  two 
isomeric  compounds  in  varying  proportions  depending  upon  the 
details  of  manufacture ;  the  isomerism  being  essentially  that  of  sub- 
stituted propyl  and  isopropyl  groups.  This  fact  in  itself  lends  so 
much  uncertainty  to  the  chemical  that  no  one  would  be  justified  in 
presenting  the  results  of  experiments  in  which  the  mixture  had  been 
used  without  a  statement  of  the  relative  proportions  of  the  isomers 
if  the  last  Pharmacopoeia  did  not  recognize  the  mixture  as  the 
official  substance.  I  have  not  been  able  to  find  a  reliable  method  for 
the  separation  of  the  isomers  and  cannot,  therefore,  state  the  com- 
position of  the  salt  used  in  these  determinations.  Analysis,  however, 
showed  that  it  easily  conformed  to  the  tests  of  the  Pharmacopoeia. 
In  this  investigation  the  first  step  was  the  compounding  of  the 
two  preparations  in  the  National  Formulary  which  contain  calcium 
glycerophosphate  (if  we  are  to  have  abbreviations  why  not 
"glycphos  "  instead  of  the  longer  official  term?).  It  was  found  that 
the  amount  of  calcium  glycerophosphate  directed  was  not  com- 
pletely soluble  in  either  of  the  official  menstrua,  the  consequence  of 
which  is  that  its  proportion  in  the  finished  elixir  will  vary  with  the 
skill  of  the  pharmacist,  the  temperature  of  the  laboratory  and  the 
composition  of  the  salt  he  employs.  By  directing  the  addition  of 
purified  talc  to  the  compound  elixir  and  immediate  filtration  the 
By  James  F.  Couch,  Washington,  D.  C. 
(243) 
