PharmPK Discussion - Inteference presence

PharmPK Discussion List Archive Index page

On 24 Jun 1998 at 10:16:53, Fabio MACCHI (fabio.macchi.aaa.zambongroup.com) sent the message


Hallo:

I've an analytical problem due to the presence of an interferent peak at
the retention time of the analyte.
The HPLC indicate that the area of the interferent is about 8% of the LOQ
of the analyte.
How i should tret the "blank" sample in order to quantify the analyte?

Reguards

Dr. Fabio Macchi
Pharmacokinetics Lab.-ZambonGroup S.p.A.
fabio.macchi.-a-.zambongroup.com

Back to the Top

On 25 Jun 1998 at 08:52:54, David_Bourne (david.aaa.pharm.cpb.uokhsc.edu) sent the message

[Another topic with two replies today - db]

Date: Thu, 25 Jun 1998 07:49:09 +0200
From: "PharmaContract - dbrandt" 
Organization: Swiss Pharma Contract
MIME-Version: 1.0
To: PharmPK.at.pharm.cpb.uokhsc.edu
Subject: Re: PharmPK inteference presence

Dear Fabio,

instead of treating yout "blank" sample you should better change you
HPLC method. Have you tried serveral columns such as RP-18, Sulfonic
etc. or have you tried to change the pH of the buffer solution. May be
this would make more sense than manipulations with the blank sample.

Regards Derek
--
Swiss Pharma Contract
Derek K. Brandt
PO-BOX
4002 Basel Switzerland
e-mail: dbrandt.aaa.pharmacontract.ch

---

Date: Thu, 25 Jun 1998 10:49:44 +0200
From: "Dr. Bernhard Ladstetter" 
Reply-To: Lstetter.-a-.merck.de
Organization: merck.de
MIME-Version: 1.0
To: PharmPK.aaa.pharm.cpb.uokhsc.edu
Subject: Re: PharmPK inteference presence

Provided the signal of the interference is reproduceable and you use the
same matrix for calibration and quality controls as for the unknowns I
would treat that signal as background and would substract it from the
analyte signal.

Regards,

Bernhard J. Ladstetter, PhD
Institute of Pharmacokinetics and Metabolism
Merck KGaA, Germany

Back to the Top

On 24 Aug 1998 at 11:25:08, sriram (ksriram.-at-.ufl.edu) sent the message


Welcome to the contamination club!!!!
I have been working on developing an assay for a glucocorticoid  and I
have been finding blank plasma peaks for over 3 months now. my search
for the source of contamination seems to be an eternal one.
Please find out if your problem is only a contamination !!!

regards
Sriram
Dept of Pharmaceutics
University of Florida

Back to the Top

On 25 Aug 1998 at 10:37:43, "Tata, Prasad" (PrasadT.-at-.MOCR.OAPI.COM) sent the message


This is a standard problem when you are attempting to quantitative
endogenous substances or near endogenous substances. best strategy of
countering this problem

a) is to use standard addition technique  or
b) use a blank matrix (plasma) pretreated with activated charcoal (to remove
the interfering component) and using thus treated plasma for preparing the
standards and Qcs.

Hope this helps.

Prasad Tata
Otsuka America Pharmaceutical,Inc.

Back to the Top

Want to post a follow-up message on this topic? If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "Inteference presence" as the subject

PharmPK Discussion List Archive Index page