Am.  Jour.  Pharm. 
June,  1920. 
Stability  of  Digitalis  Leaf  Extracts. 
399 
kept  in  an  ice  chest  at  a  constant  temperature  of  io°  C.  The 
infusion  was  prepared  and  maintained  under  sterile  conditions  as 
above.    Drug  F2190: 
Date.  Time. 
9-16-19   At  once 
After 
After 
9-22-19   After 
9-24-19  After 
9-29-19   After 
10-  8-19   After 
10-18-19  After 
10-  23-19   After 
11-  10-19   After 
1 2-  1 7-1 9   After 
Activity,  %.   %  Deterioration. 
30  hours 
54  hours 
6  days 
8  days 
13  days 
22  days 
32  days 
37  days 
53  days 
92  days 
1-26-20   After  132  days 
The  above  work  was  repeated  at  room  temperature. 
105 
0 
95 
10 
95 
10 
85 
19 
85 
19 
80 
24 
70 
33 
65 
38 
60 
43 
55 
48 
45 
57 
40 
61 
Date. 
Time. 
10-14-19   After   24  hours 
10-17-19   After     4  days 
10-  23-19   After    10  days 
11-  11-19   After   28  days 
1 2-  1 7-1 9   After   64  days 
1-28-20   After  106  days 
Activity, 
105 
90 
80 
72 
60 
40 
%  Deterioration , 
O 
24 
31 
43 
61 
Plotting  these  curves  over  to  100  per  cent,  basis  as  a  starting 
point  in  each  case. 
110     Rate  of  Deterioration  of  Infusions  of  Digitalis 
90 
Q 
tt  80 
Q 
(0  fco 
540 
u 
O  JO 
0: 
20 
62)  WHICH  MOLDED  IN  ABOUT  2.^  DAYS  (ROOMTfMpJ 
ROOM  TEMP      STER/LE    WAR  n  WEATHER 
(.C)  IO°C  STERILE 
(d)  ROOM  TEt^FERATURE.   COOL  VYEATHER 
t*^)  15%  infusion:  cool  weather. 
\0       l^       14        Ife       16      20      ?Z      2A  28      iO      i,2      34     .it  ^8 
Time   in  Days 
