Chromatography Forum

Can anybody give the hint about the extraction procedure of tolterodine from human plasma to analyze the drug using LC-MS/MS.

Here is a generic procedure useful for basic drugs with Oasis MCX sample preparation devices. It has been tested over and over again with many different compounds and results in a rather clean extract.

Sample preparation:
1. Acidify your plasma sample, filter or centrifuge, then add the internal standard that you choose.
2. Use an Oasis MCX cartridge or 96-well plate. The exact volume for any of the steps depends on the volume of the device that you select.
3. Activate the SPE device by adding methanol, followed by acidified water (use the same acid as used to acidify you sample).
4. Load the sample onto the SPE device
5. Wash the sample clean by using 1% formic acid in methanol.
6. Extract your analyte from the cartridge using at least 1% ammonia in methanol (if the recovery is not 100%, increase the ammonia concentration.

You can analyze tolterodine in plasma without sample preparation using our Primesep technology. Plasma proteins will repel from the surface (having the same charge as the stationary phase). Tolterodine will be charged too but is hydrophobic enough to retain by RP mechanism. You are using two mechanisms - ion-exchange to repel positively charge proteins and reverse phase to retain your hydrophobic compound (similar to the following applications)

http://www.allsep.com/Technology_Direct ... alysis.php

http://allsep.com/makeCmp.php?cmp=Cmp_113 (example on Primesep B column, Primesep D will perform the same way)

You can use formic acid instead of TFA, or ammonium formate/ammonium acetate.

Tolterodine is exist as salt normaly so by addition of little about sodium hydroxide you can have tolterodine base in a sample and if at all any interaction with the protin are there you are breaking it here.

Directly after converting to base you can extract in Hexane .

Direct extraction is very precise and accurate method.