Microparallel Liquid Chromatography
Nanostream (www.nanostream.com) has developed a high-throughput, parallel-format, microfluidic liquid chromatography system. The key to this technology is the Brio cartridge, consisting of 24 columns packed with stationary-phase material for reversed-phase separations. Three different cartridges are available with more in development.
The company offers three productsthe original CL system for high-throughput chemical analysis, the LD system for assay detection, and the CX system for chromatographic sample preparation. One benefit of our systems is that we are using a flow rate of 240 microliters/minute and dividing that among 24 different separations, explains Surekha Vajjhala, vp, marketing. Sample sizes are usually 0.5 microliters up to 5 microliters.
The LD system obtains quantitative information about hits while offering additional information on compound purity and solubility. Historically, HPLC has been used to develop biochemical assays. With the emphasis on higher throughput and larger compound libraries, researchers moved away from HPLC. Now they are turning back to separation-based assays because they want a generic screening platform that can be used for assays that are otherwise difficult to do, states Vajjhala.
The CX system is for chromatographic sample preparation for drug metabolism and pharmacokinetic profiling. It also has UV absorbance detection and a time-triggered parallel fraction collector.
Analysis software for all three systems provides real-time visualization of chromatograms from sets of 24 samples as they are separated.
Eksigent Technologies’(www.eksigent.com) product line for drug discovery includes the Express LC-100 and the Express LC-800. Both use special small-scale columns, called ChromXP, and reportedly provide high-resolution and high-speed separations that can’t be achieved with conventional HPLC. The Express LC-100 is a single-channel HPLC that runs assays five-times faster, says the company, and is optimized for 300-µm internal diameter columns and flow rates of 0.20 to 30 microliters/minute. Inline flow meters actively measure actual flow in each mobile phase and provide adjustments to deliver accurate and consistent gradient.
The Express LC-800 is a parallel HPLC with eight channels that the company says runs ten-times faster than conventional HPLC. It allows the user to try eight different separation methods simultaneously. High-throughput applications include AMDETox, analytical method development, and peptide separations.
In addition, the company is developing a system in partnership with two pharmaceutical companies for chiral analysis, says Phillip DeLand, senior product marketing manager. This uses molecule confirmation to differentiate two compounds.
You often find an ingredient with two structuresone is biologically active and the other is inert, or worse-case scenario, toxic, DeLand explains. The company anticipates a launch date for the chiral system in the third quarter of 2006.