340  Lactic  Acid  Ester  of  Santalol,  etc.     { '^"'•.,f,?v%9u*"°' 
theory  of  their  activity  is  based  on  the  supposition  that  the  alkalinity 
of  the  duodenum  breaks  them  up,  liberating  nascent  santalol.  The 
therapeutic  dose,  however,  has  to  be  somewhat  increased  according 
to  the  molecular  weight  of  the  ester.  These  compounds  of  santalol 
are  known  under  various  trade  names  and  need  not  enter  into 
discussion  here. 
In  considering  a  compound  of  santalol  for  medicinal  use,  wc 
should  look  for  one  which  will  not  interfere  with  the  gastrointestinal 
digestive  processes  and  which  will  be  finally  eliminated  during 
metabolic  changes,  as  santalol,  Coo  and  HoO.  This  I  think  is  best 
realized  in  the  lactic  acid  ester  of  santalol  (CH3CHOHCOO, 
C15H05),  which  represents  69.74  per  cent,  of  pure  santalol.  It  has 
the  advantage  of  being  more  agreeable  to  the  taste  than  sandalwood 
oil  or  santalol,  it  is  well  tolerated  and  can  be  administered  in  the 
form  of  capsules.  Like  other  lactates,  the  lactic  radical  is  com- 
pletely consumed  in  the  economy.  It  renders  the  urine  somewhat 
alkaline,  diminishes  the  overstimulation  of  the  renal  parenchyma 
and  does  not  occasion  the  pain  in  the  back  so  often  complained  of 
by  patients  to  whom  sandalwood  oil  is  administered. 
While  lactic  acid  does  not  react  directly  with  santalol,  its  primary 
and  secondary  anhydrides,  the  so-called  lactid,  do  so  under  certain 
conditions,  and  a  patent  has  been  granted  for  the  process  of  manu- 
facture of  the  santalol  lactate  in  the  United  States  and  England  and 
is  pending  in  Germany  and  France.  In  practice,  this  is  obtained  by 
driving  ofif  from  syrupy  lactic  acid  25  per  cent,  of  the  compound 
with  water,  leaving  the  primary  and  secondary  anhydrides,  the 
dilactic  anhydride  of  Pelouse,  or  lactid,  which  is  solid  to  25°  C. 
It  is  an  advantage  to  use  a  slight  excess  of  the  lactid  over  and 
above  the  theoretical  combining  molecular  weights  and  this  leads  to 
som.e  difficulty  in  the  purification  of  the  final  product,  which  is  one 
of  the  essential  points  of  the  patent,  for  it  is  exceedingly  bitter  and 
disagreeable  to  the  taste  and  can  only  be  removed  from  the  santalol 
lactate  with  difficulty.  Primary  and  secondary  lactic  anhydrides, 
therefore,  are  placed  in  contact  with  the  santalol,  in  the  molecular 
proportions  necessary  for  chemical  combination  and  heated  in  a 
partial  vacuum  to  a  temperature  not  exceeding  130°  C. 
For  therapeutic  use,  and  for  reasons  of  economy,  it  is  considered 
unnecessary  to  obtain  an  absolutely  pure  santalol  lactate,  and  in  its 
manufacture,  U.S. P.  sandalwood  oil  containing  at  least  90%  santalol 
was  used,  rather  than  pure  santalol. 
