[Previous Months][Date Index][Thread Index][Join - Register][Login]
  [Message Prev][Message Next][Thread Prev][Thread Next]

[IPp] Insulin - loss of potency

> In a message dated 4/30/2003 7:10:43 AM Pacific Daylight Time,
> email @ redacted writes:
> > In fact, the labelling says in bold type 
> > 
> > So that's why we change the insulin every two days.>>

This is from a letter I received from Eli Lilly and Co. Jan of 1998.
It was in response to a question about Humalog, but it is 
generally applicable to all insulin and insulin-analog products.
....While it is agreed that refrigeration should be employed whenever 
possible, we have found the loss of biological potency of insulin is 
such a slow and gradual process that if one is careful to protect 
insulin supplies from extremes of temperature, any decrease of 
potency probably will not interfere in any way with the control of 

All preparations of insulin are required by law to bear the 
instruction on the labels: "Keep in a cold place--avoid freezing." 
This is a requirement of the Food and Drug Administration (FDA) 
concerning the storage of insulin. As defined in the United States 
Pharmacopeia 23, cold specifies storage temperatures between 2 and 8 
degrees C (36 to 46 F).

The United States Pharmacopeia Dispensing Information, -Sixteenth 
Edition 1996 Advice for the Patient, Volume II has the following 
information on insulin storage. "An unopened bottle of insulin should 
be refrigerated until needed. It should never be frozen. Remove the 
insulin for the refrigerator and allow it to reach room temperature 
before injecting. An insulin bottle in use may be kept at room 
temperature for up to 1 month. Insulin that has been kept at room 
temperature for longer than a month should be thrown away." The USPNF 
23 specifications for thermostatically controlled room temperature is 
from 59 to 86 degrees F.

At elevated temperatures, insulin has been shown to lose potency. 
This loss of potency is accelerated as the temperature increases. For 
this reason, as stated earlier, and for reasons of consistent 
temperature exposure, it is recommended that refrigeration be 
employed whenever possible. As an example, a vial of insulin stored 
at 86 F will lose approximately 1.7% of its potency over 30 days. In 
contrast, insulin stored in a refrigerator will lose less than 0.1% 
of its potency over 30 days.

This last bit is what is of interest. Basically, get it hotter and it 
loses strength. Not all at once, but certainly a good percentage over 

email @ redacted
for HELP or to subscribe/unsubscribe, contact: