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Dear all:
We are having some troubles in the translation and consequently
understanding of a phrase belonging to the FDA guideline relating
Biowaver from August 2000. When the concept of Solubility is defined it
says: "A drug substance is considered highly soluble when the highest
strength is soluble in 250 ml or less of aqueous media over the pH range
of 1-7.5."
The trouble regards to "over the pH range of 1-7.5":
Some of us understands that it means "all" over the pH range of 1-7.5.
In other words, has the drug to be soluble "along the whole pH range"
of 1 to 7.5? or does the drug to be soluble only in some of the
pHs between 1 and 7.5?
Thanks for your kind attention, Silvia Giarcovich
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The following message was posted to: PharmPK
At 11:24 AM 5/29/01 -0500, you wrote:
>Some of us understands that it means "all" over the pH range of 1-7.5.
>In other words, has the drug to be soluble "along the whole pH range"
>of 1 to 7.5? or does the drug to be soluble only in some of the
>pHs between 1 and 7.5?
The requirement is across the entire range. So if you determine you
have an acid with a pKa of 4, for example, you would want to test at
pH 1, because that is where the lowest solubility would be.
Walt Woltosz
Chairman & CEO
Simulations Plus, Inc. (SIMU)
1220 W. Avenue J
Lancaster, CA 93534-2902
U.S.A.
http://www.simulations-plus.com
Phone: (661) 723-7723
FAX: (661) 723-5524
E-mail: walt.aaa.simulations-plus.com
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The following message was posted to: PharmPK
This phrase means in ALL the pH values within the range so stated,
not just some.
Chuck Collins
--
Charles C. Collins, Ph.D.
Associate Professor of Pharmaceutics
Duquesne University Mylan School of Pharmacy
President - Duquesne University Faculty Senate
collinsc.aaa.duq.edu
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Hello,
Please see the section III-A (entitled 'Determining Drug Substance
Solubility Class') of the "Waiver of In Vivo Bioavailability and
Bioequivalence Studies for Immediate-Release Solid Oral Dosage Forms
Based on a Biopharmaceutics Classification System" guidance to the
industry. This section should provide an answer to your question.
Regards,
Joga Gobburu
Pharmacometrics,
CDER, FDA
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The following message was posted to: PharmPK
Dear all,
As I under stand and we have applied Biowaver, any pH value between 1 and
7.5 the drug dose should be soluble. solubility should be done at extremes,
i.e and at points in between.
Sami Qassim
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