Direct Plasma Sample Injection in Multiple-Component LC−MS−MS Assays for High-Throughput Pharmacokinetic Screening

Abstract

The simultaneous dosing of numerous compounds followed by multiple-component analysis using LC-MS-MS (the N-in-1 approach) has significantly improved the throughput of the drug-screening process. However, plasma samples still need to be extracted before LC-MS-MS analysis, which frequently limits the throughput of the assay. In this work, a high-throughput on-line extraction technique has been developed for multiple-component LC-MS-MS assays using a high-flow column-switching technique. In N-in-1 LC-MS-MS assays, high sensitivity is required since the dose level is generally reduced to minimize drug-drug interactions. In addition, good chromatographic separation is essential to minimize interference and suppression effects. The direct plasma sample injection method developed in this work has successfully met the two requirements for multiple-component LC-MS-MS assays in high-throughput pharmacokinetic screening. Plasma samples containing a large number of potential drug candidates were directly injected onto an extraction column operated under a flow rate sufficiently high to exhibit a turbulent-flow profile. The extracted analytes were then eluted onto an analytical column via column switching for LC-MS-MS analysis. The use of turbulent flow resulted in a faster and more rugged extraction with reduced carryover compared with results obtained under laminar-flow conditions. Meanwhile, the use of a column-switching method maintained the chromatographic resolving power and high sensitivity of the LC-MS-MS assay. Separation efficiency, dynamic range, accuracy, and precision comparable with those of solid-phase extraction have been achieved with the turbulent-flow column-switching technique. As a result, this technique has been successfully and routinely used for high-throughput pharmacokinetic screening.

Methylcellulose-immobilized Reversed-phase Precolumn for Direct Analysis of Drugs in Plasma by HPLC

“…27,28 In this study, we tried to modify the ODS silica particles with a hydrophilic polymer such as MC, hexadimethrine, polyvinylalcohol, polyvinylpyrrolidone, certain dextran derivatives and alginic acid in various solvents (mixture of water and organic solvents, and aqueous solutions at various pHs). Unfortunately, the prepared material did not show satisfactory RAM function.…”

Results from a bench marking survey on cassette dosing practices in the pharmaceutical industry

“…This practice, made possible by the extraordinary specificity of tandem MS detection, is seen as a way to maximize the utilization of expensive LC/MS/MS instrumentation and to minimize the number of animals used. Since the initial reporting of N-in-one dosing by Berman and co-workers in 1997 [1], several reports have appeared in the literature [2][3][4][5]. Interested readers are also referred to a seminal article by White and Manitpisitkul on the pharmacokinetic implications of CD [6].…”

Current Developments in LC-MS for Pharmaceutical Analysis

“…The principles, operation procedures and applications of these methods have been described. [58][59][60][61][62][63][64][65][66][67][68] In these methods, a robotic liquid handling system is used to handle and process samples automatically, thus eliminating the time consuming manual steps in sample preparation.…”

“…Fast-flow on-line extraction methods based on the column switching technique have been described. [72][73][74][75][76] Biological samples, e.g. plasma, are injected directly into the LC-MS system without prior sample preparation.…”