560 
Official  Lead  Preparations. 
( Am.  Jour.  Pharm. 
1  November,  1897. 
LIQUOR  PLUMBI  SUBACETATIS.  - 
If  it  were  possible  to  realize  the  idea  of  an  international  Pharma- 
copoeia, this  preparation  deserves  attention  among  the  first  to  secure 
uniformity  in  method  of  preparation  as  well  as  in  the  proportion  of 
basic  salt. 
It  is  unnecessary  to  point  out  the  respective  variations  in  different 
pharmacopoeias,  and  only  sufficient  to  call  attention  to  varying 
degrees  of  specific  gravity,  volumetric  strength  and  method  of  prepa- 
ration. 
Even  in  the  Pharmacopoeia  of  the  United  States  the  two  last 
revisions  have  been  productive  of  deviation  in  strength  from  the  pre- 
vious editions. 
The  subject  of  Goulard's  extract  may  be  treated  under  the  follow- 
ing heads,  viz.:  preparation,  specific  gravity  and  volumetric  strength. 
PREPARATION. 
The  following  are  the  full  pharmacopceial  directions : 
Grammes. 
Lead  acetate  170 
Lead  oxide   100 
Distilled  water  to  make  1,000 
Dissolve  the  lead  acetate  in  800  grammes  of  boiling  distilled 
water,  in  a  glass  or  porcelain  vessel.  Then  add  the  lead  oxide,  pre- 
viously passed  through  a  fine  sieve,  and  boil  for  half  an  hour,  occa- 
sionally adding  hot  distilled  water  to  make  up  the  loss  by  evapora- 
tion. Remove  the  heat,  allow  the  liquid  to  cool  and  add  enough 
distilled  water,  previously  boiled  and  cooled,  to  make  the  product 
weigh  1,000  grammes. 
Finally  filter  the  liquid  in  a  closely  covered  funnel. 
In  these  directions  the  amount  of  insoluble  basic  lead  subacetate 
is  included  in  the  final  weight,  and  the  solution  is  directed  to  be 
filtered  therefrom. 
The  filtrate  weighs,  according  to  the  National  Dispensatory, 
approximately  950  grammes. 
An  inquiry  among  a  number  of  pharmacists  revealed  that  the 
pharmacopceial  directions  are  interpreted  by  several  to  read  to 
make  the  filtrate  weigh  1,000  grammes.  This  would  result  in  a 
preparation  approximately  5  per  cent,  weaker  in  strength. 
The  basis  for  this  opinion  is  furnished  by  the  official  direction  of 
boiling  the  oxide  in  800  grammes  of  distilled  water,  in  which  the 
