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Dear all,
I would like to know about the what kind of column should be use
for the stability studies in artificial gastric juice at pH 1.2 and 3.0. We
tried with Inertsil ODS 3V (250 X 4.6 mm) but it is not with standing
especially at PH 1.2. Kindly help us regarding this.
Thanking you and Regards
Gopinadh Bhyrapuneni
Research Assistant
Drug Metabolism & Pharmacokinetics
Suven Life Sciences Ltd
18/b, IDA, Phase-3, Jeedimetla
Hyderabad - 500 055
Phone : 9140 3092 1690 Ext: 331
Fax : 9140 2319 3541
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The following message was posted to: PharmPK
Hi
I think that Waters (www2.waters.com) claims that xTerra columns withstand
extreme pH, although I am not sure about pH below 2...
Hope it helps.
Facundo Garcia Bournissen.
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Dear Gopinadh,
If you choose to work with acidic buffers in reversed phase HPLC, I
beleive stablebond SB columns are ideal for robust and reproducible
results. While SB-C18 offer you to work in pH ranges 1-8 and at exhaustive
temperature ranges upto 80*C, they are suitable for separation of acidic,
basic and neutral compounds at low pH. Having been experimented SB columns
at a low pH RP-HPLC on my hands, I can recommend you to use with
confidence. Agilent supplies Zorbax SB C18 columns at your convenience
along with other manufacturer and the choice is solely yours.
Apart XTERRA columns from Waters can also be tried since they are stable
over widened pH ranges if you chose to work with LC-MS/MS ( pH 1-12). If
the attempt still doesn't work you to overcome bad chromatography then you
may have to take a closer look at your experimental design. Even acidic
buffer that is being used for stability studies may cause poor peak shape
if it is not compatible with your mobile phase. In such cases you can
evaporate and reconstitute with your mobile phase. Also use the right
buffers based on pKa of your compound and buffers for better
chromatography. If the buffer that is being employed doesn't have any
buffering capacity at your working pH for ionizable analytes then you may
end up with poor peak shape.
Hope this helps.
Regards,
Syed Mustafa S,
Orchid Research and Development centre,
Plot No: 476/14,
Old Mahabalipuram Road,
Sholinganallur,
Chennai-600119.
syedmustafa.-at-.orchidpharma.com
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The following message was posted to: PharmPK
>... I would like to know about the what kind of column should be use
for the stability studies in artificial gastric juice at pH 1.2 and 3.0. We
tried with Inertsil ODS 3V (250 X 4.6 mm) but it is not with standing
especially at PH 1.2. ...
The new Gemini series from Phenomenex is created to work pH 1 =>
12. Their Web site provides useful info on this. Let me know if you need
more data; good luck.
Martin Risk
martinrisk.aaa.earthlink.net
650/281-9399; fax: 707/313-0955
555 Bryant St., #506
Palo Alto, CA 94301-1704
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The following message was posted to: PharmPK
Dear Gopinadh,
I am not sure whether I do understand you (and previous replies from other
list members) correctly ;-)
Although your sampling media from the dissolution test is of a low pH, it
does not mean that you have to run your HPLC at low pH.
Generally it should be possible to run the method at e.g. pH 4-6, where the
introduction of a small sample volume (let's say 10 ul) of a lower pH
should not interfer with the separation.
If your separation gets too much disturbed (if you experience negative
peaks, or retention time changes if you are using a counterion), you may
consider bringing the sample to a higher pH first.
best regards
Helmut
--
Helmut Sch=FCtz
BEBAC
Consultancy Services for Bioequivalence and Bioavailability Studies
Neubaugasse 36/11
1070 Vienna/Austria
tel/fax +43 1 2311746
http://BEBAC.at
Bioequivalence/Bioavailability Forum at http://forum.bebac.at
http://www.goldmark.org/netrants/no-word/attach.html
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The following message was posted to: PharmPK
Dear Gopinadh,
I agree with Helmut, namely that you don't have to run the HPLC
system at the pH of your sample, and if necessary, the sample pH
could be increased prior to injection. Most silica bonded phases are
stable only to about pH 2 because the Si-0-Si bond hydrolyzes. You
might try one of the polymer reversed phase columns (e.g., PRP from
Hamilton) or the zirconia polybutadiene column (Zirchrom PBD), which
should be immune to pH problems; however, you may not get the same
selectivity that you would get on a silica based column.
Best regards,
Lori Payne, Ph.D.
Laboratory Director
BASi Northwest Laboratory
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Have a look of Phenomenex Gemini column which is stable from pH1 -12.
http://www.phenomenex.com/Phen/products/gemini/index.htm
Xiaowei Teng "Shirley"
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)