Lot consistency is a major concern in pharmaceutics. Constant testing of batches of tablets and capsules as they emerge from the production line ensures that patients receive a regular dosage that falls with-in a standard deviation of 5 percent.High-performance liquid chromatography has been the traditional tool for assessing blend uniformity; however, this process is somewhat lengthy, requiring the sample to be dissolved in solution.Merck & Co. is experimenting with the new PharmaLibs system from Pharma Laser that competes with both wet chemistry and near-infrared spectroscopy for determining sample content. The test can be performed in less than a minute.Laser-induced breakdown spectroscopy could enable in-line pharmaceutical analysis. Merck is evaluating the PharmaLibs system for measuring uniformity and excipients in tablets and capsules in pharmaceutical manufacturing. The inset (bottom) shows the laser-induced plasma. PharmaLibs uses the laser-induced breakdown spectroscopy process, in which pulses from an Nd:YAG laser at 1064 nm cause a photochemical and photothermal breakdown in the sample, generating a plasma. The plasma excites excipient atoms in the sample, and the light they emit is transferred via a fiber optic bundle to a gated CCD camera. The emission line intensities provide information about the presence and concentration of active ingredients, lubricants, disintegrants, binders and other ingredients that affect the performance of drugs.Mark Mowery, a senior research chemist at Merck, said that PharmaLibs rapidly measures uniformity and excipient assays in-line. Although he doesn't believe that the high-performance liquid chromatography technique for composite assay and degradate testing will go away anytime soon, he said laser-induced breakdown spectroscopy has potential for in-line analysis."We are evaluating whether it can replace some existing techniques," Mowery said. "It definitely has its uses."He also said that the system is straightforward and doesn't take a lot of time to get up and running.The primary disadvantage of laser-induced breakdown spectroscopy is that, because it relies on atomic emission, the sample species of interest must contain an element that is unique to the sample matrix.