By mary c. green on Wednesday, September 8, 1999 - 03:02 pm:

Never have done method development, thought this site would be a good place to start gathering information. Please give me a push don't want to use a radioactive assay.

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By brian paasch on Wednesday, September 8, 1999 - 03:20 pm:

From the massive tome, "HPLC methods for Pharmaceutical Analysis" by Lunn and Schmuff, ISBN 0-471-18176-5, starting on page 446 there are 17 different methods listed for cyclosporin in various sample matrices. There are no listings for your other two compounds. But, as you said, its a start.

-brian paasch
Genentech, Inc.

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By mary c. green on Monday, September 13, 1999 - 10:09 am:

Thanks Brian for your reference book title. Will update you here on my progress. Anyone else out there in the big world of chromatography with any suggestions?

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By V. Tkach on Wednesday, September 15, 1999 - 05:30 am:

Dear Mary, specify please, in what sample You want to determine ivermectin (drug, or tissue, or other)? The selection of a method depends on it.

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By mary c. green on Wednesday, September 15, 1999 - 01:58 pm:

V. Tkach,

I should have realized from the reading i have done that the sample matrix is important. Thanks for taking the time to ask for clarification. The experiment is concerned with the transport of the drug across a monolayer of cultured cells bathed in opti-MEM from GIBCO.

mary

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By V. Tkach. on Monday, September 20, 1999 - 05:07 am:

Mary, I do not have method just for your samples. Therefore I offer you for orientation any references to the method of determination ivermectin in plasma of blood. Probably, you should it slightly change.

1) Arzneim-Forsch/Drug Res. 43 (I), Nr.5 (1993) 609-611
Determination of Ivermectin in Human Plasma by High-performance Liquid Chromatography.
D.R.Krishna and U.Klotz.

2) Journal of Chromatography, 413 (1987) 326-331
Determination of 22,23-dihydroavermectin B1a in dog plasma using solid-phase extraction and high-performance liquid chromatography. Kenji Kojima, Kazumitsu Yamamoto, Yutaka Nakanishi and Hiromi Katae.

I shall be glad, if it will be useful.

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By Imre Molnar on Thursday, October 14, 1999 - 01:37 pm:

Cyclosporin can be done on a C8 or C18 columns with an acetonitrile gradient. You will observ at room temperature however a strong band broadening. To get an accepable sharp peak, you have to increase the temperature to 80°C. That is because CyA has many different structural variants, which all have a somewhat different hydrophobic contact surface area and consequently a slightly different retention time. At increased temp., the differences between the variants ar becoming less and less and the peaks will be more sharp.
s. also H.Wilms and I.Molnar, Chromatographia, 19, 472 (1984).
Don't be afraid to work at that high temperature, it is going to be fine.
Imre Molnar
Berlin, Germany

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By ALAN KNAGGS on Friday, October 22, 1999 - 08:17 am:

BETHANECHOL CHLORIDE HPLC ASSAY REQUIRED. ANYONE GOT ANY IDEAS.

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By walid on Thursday, March 25, 2004 - 07:52 am:

Dear
iam looking for method of extraction of cyclosporin A from plasma(human plasma)