i84 
Medicated  Gauges. 
/Am.  Jour.  Pharni. 
1       April,  1911. 
Picric  Acid  Gauze,  2  Per  Cent.,  Dry. 
Picric  acid  . 
Water   
Acetone  .... 
Sterile  gauze 
2  Gm. 
.50  c.c. 
50  c.c. 
TOO  Gill. 
Dissolve  the  picric  acid  in  the  acetone  and  water  and  proceed 
as  under  iodoform  gauze,  dry. 
Dissolve  the  picric  acid  in  the  glycerin,  water  and  acetone  and 
proceed  as  for  phenolated  gauze,  moist.  ■ 
All  gauzes  for  medication  should  be  sterilized  just  before  being 
used.  This  should  be  preferably,  by  dry  heat  at  a  temperature  of 
I20°-I50°  C.  for  one  half-hour,  as  many  of  the  moistening  liquids 
cannot  be  satisfactorily  applied  to  any  but  dry  material. 
The  amount  of  solution  required  for  the  impregnation  of  a  given 
amount  of  gauze  will  vary  slightly  according  to  the  number  of 
threads  to  a  given  unit  and  the  tightness  of  twist  of  the  fabric. 
Glycerin  and  acetone  are  not  miscible,  except  upon  the  addition 
of  water.  Hence,  it  will  be  noted  that  gauzes  prepared  with  ma- 
terial insoluble  in  water  are  moistened,  where  required,  with 
glycerin  solutions  after  impregnation.  ' 
In  working  out  these  formulas  the  question  as  to  method  of 
figuring  the  percentages  arose.  It  will  be  noted  that  the  percentage 
of  medicament  is  based  in  each  case  upon  the  amount  added  to  100 
parts  of  dry  gauze.  It  is  obvious  that  this  furnishes  the  most 
convenient  and  most  satisfactory  means  of  figuring.  The  generally 
adopted  method  of  parts  in  100  parts  of  finished  product,  would 
be  uncertain  because  of  the  variability  of  the  moisture  content 
through  sterilization.  Then,  too,  the  weight  of  gauze  taken  is 
never  exactly  that  given  in  a  formula,  but,  in  the  nature  of  the  case 
must  be  either  a  fraction  or  a  multiple  of  the  same  and,  often,  an 
exceedingly  inconvenient  figure  for  calculation.   For  instance,  work- 
PicRic  Acid  Gauze,  2  Per  Cent.,  ^Ioist. 
Picric  acid  . 
Glycerin  .  .  .  , 
Water   
Acetone  .... 
Sterile  gauze 
2  Gm. 
5  Gm. 
50  c.c. 
50  c.c. 
100  Gm. 
