Its a colloidal solution.  It is more stable in the lower pH of D5W.   It is
also more stable when protected from sunlight.  I don't know the actual
stability, and it depends on the concentration, but my guess is at a week
out, you probably do not have enough concentration remaining active to meet
reasonable standards.  I may be wrong. I suggest measuring the active
concentration at time initial, and at given intervals throughout a week or
so.  Of course also in a light protected container.

We have been asked to do this same compound, and the patient needs 50mg
ampho qs with sterile water irrigation or injection to 500ml and uses 20 ml
as nasal irrigant twice daily. We dispense in amber poly bottle, with
refrigerate sticker. This technically is a 12.5 days supply, but my patient
has often not come back for 3-4 weeks.  Suggestions?

I'm not sure about D5W nasally, as one responder suggested. Would that
promote overgrowth of something else? Or just sticky nares?

Brad

----- Original Message -----
From: "Dr. Wayne Simon" <ariess@bellsouth.net>
Newsgroups: sci.med.pharmacy
Sent: Saturday, April 30, 2005 2:15 AM
Subject: Re: Stability Ampho in water