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Dear All,
I am facing matrix effect problem in method development of Olmesartan.
There is a drug enhancement problem in all the extraction methods.
(A) Protein precipitation method by using Acetonitrile:
(1)Procesing volume 0.1 mL 10%FA buffer(50micro litre) IS D4(50 micro litre) and ACN 1.0mL, further
evaporated to 50 degree celcius at evaporator for 20 min and reconstituted with 400 microlitre with
MP(0.1%FA:ACN:: 30:70)
(2) Procesing volume 0.1 mL, IS D4(50 micro litre) and ACN 1.0mL, further evaporated to 50 degree
celcius at evaporator for 20 min and reconstituted with 400 microlitre with MP(0.1%FA:ACN:: 30:70)
Calculation for Recovery: 400 microlitre of MP contains 1.0 microlitre drug and 25 microlitre of
IS.
(B) LLE Method by using ETHYL ACETATE AND TBME:
(1) Procesing volume 0.1 mL 10%FA buffer(50micro litre) IS D4(50 micro litre) and ETHYL
ACETATE/TBME 2.0 mL, Supernatant 1.8mL, further evaporated to 50 degree celcius at evaporator for 15
min and reconstituted with 400 microlitre with MP(0.1%FA:ACN:: 30:70).
(2) Procesing volume 0.1 mL, IS D4(50 micro litre) and ETHYL ACETATE/TBME 2.0 mL, Supernatant 1.8mL,
further evaporated to 50 degree celcius at evaporator for 15 min and reconstituted with 400
microlitre with MP(0.1%FA:ACN:: 30:70).
Calculation for Recovery: 400 microlitre of MP contains 1.8 microlitre drug and 40 microlitre of
IS.
(C) SPE Method by using SRATA CATRIDGE:
Procesing volume 0.5 mL and 0.5mL of 0.2%FA, IS D4(50 micro litre) and conditioning with 1.0 mL
methanol and 1.0 ml of 1% FA, and loaded the sample washed with 1.0ml of 1.0% FA, 1.0ml of Water
finally eluted with 1%ammonia in ACN with 0.5ml Twice, further evaporated to 50 degree celcius at
evaporator for 15 min and reconstituted with 400 microlitre with MP(0.1%FA:ACN:: 30:70).
Calculation for Recovery: 500 microlitre of MP contains 10 microlitre drug and 50 microlitre of IS.
The above said methods were applied in matrix effect experiment and also for P&A batch.
In all the above experiments what I have observed is that the responses in extracted sample is 20
times greater than aqueous recovery sample.
As per my concern is, it may be matrix effect as Drug enhancement but IS response is not affected
as Drug response affected.
Kindly suggest me how Can I reduce or stop drug enhancement or matrix effect.
It will very helpfull if you all help me in developing the method for Olmesartan by decreasing
matrix effect.
Thanks & Regards,
MUTHU SWAMY.C,
GROUP LEADER, BIOANALYTICAL DEPT.
QUEST LIFE SCIENCES PVT. LTD.,
CHENNAI
INDIA
Email :muthuswamy_23.aaa.yahoo.co.in
muthuswamy.aaa.questlifesciences.com
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Dear muthu,
You just try more aqs in mobile phase or try to develop gradient method,Which can separate
Co-eluting materials.
Or
you can optimize washing step in SPE to wash the impurities.
Regards,
Dipak S harwani
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Dear Sir,
Thank you very much for kind reply.
Yes, I am doing gradient method only in 70:30 ratio of ACN:0.1%FA.
I had optimised various steps in washing as well as in eluting step also.
But I am unable to stop the drug enhancement.
muthu.
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the method of extraction is very important to get ride of matrix effect (if you extract your drug
from plasma)
and some time the parameter that used is very important .give more details about your method to
clarify more reason for this proplem
thanks
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Dear Muthu,
I had two suggestions for your problem
One is change the source to APCI
Secondly try with chromatographic modifications.
Regards,
Sreekanth Dittakavi
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Dear mutthuswami;
I have done some work in this class of molecule based on my experience
I would suggest you few change in your lle method
1) use low strength hcl solution in extraction in stead of adding formic acid
2) and also try plain tbme instead of mixture with ethyl acetate
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Dear Muthu
In my opinion, you can do more changes like
1. Try select different daughter ion and check for enhancement and recovery
2. Try with longer column and 5ยต particle size column and try to retain more and see the effects
3. Try and include daugter Ion 180/180 in your MRM and see you can get any peak at the same time as
your main peak retention
4. Try to use pseudo MRM and check for enhancement
5. Try to reduce collision energy and increase DP and check.
6. Check you run without adding IS sometimes IS causes enhancement
7. Change your columns or put new column and check
I wish this helps
Regards
Karthikeyan Kandaswamy
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Dear sir,
Thank you very much for valuable suggestion.
Now i got rectifying my problems. Its working well now. Actually there was a problem with the
working standard.We have tried with another fresh working standard, its working well with 60% of
recovery.
Thank you one and all for your valubale suggestion and support.
Regards,
MUTHU SWAMY.C,
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