Journal of Optics, 200S, Vol.34. No.4 Page 181-192 LASER INDUCED BREAKDOWN SPECTROSCOPY FOR QUALITY CONTROL IN PHARMACEUTICALS INDUSTRY Bansi Lal*, Fang- Yu Yueh** and Jagdish P Singh** *Centre for Laser Technology, Indian Institute of Technology Kanpur, Kanpur-2080 16, India E-mail: bansi@iitk.ac.in **Diagnostic Instrumentation & Analysis Laboratory Mississippi State University 205 Research Bulevaro, Starkvile, MS 39759-7704, USA (Received March 26, 2004 and Revised July 14,2005) A description of the basic principal and experimental approach of the laser induced . breakdown spectroscopy (UBS), afast emerging optical diagnostic tool, isfollowed by the evaluations of this technique for the quality control in pharmaceutical industry. Four popular antacid products available in tablet form have been investigated for quantitative analysis of the active/inactive. ingredients as well as for impurities. The calibration curves prepared show a good linearity.. Elements not listed in the product labels have been identified and quantified. Also potential of LIBS to monitor intra- batch uniformity has been investigated. 1.INTRODUCfION Laser induced breakdown .spectroscopy (LIBS) is almost an ideal optical tectmique for in situ monitoring of the elemental composition of almost any material, even under hazardous conditions and in situations inaccessible otherwise. In lhis technique a high energy laser pulse focused on a sample produces a micro-plasma which is characteristic of the sample material. Temporal and spectral resolved analysis of the emission from the micro-plasma is used to monitor the elemental composition. The main advantages of this technique are : (i) fast analysis; one measurement per pulse in principle (ii) several elements can be monitored simultaneously, (Hi) potential of stand-off analysis and (iv) minimal sample preparation is required. LIBS since its discovery'-4 has been applied to monitor the elemental composition of metalsS, glass6, soil7, industrial bumers and furnaces!, biomaterials9, wood preservers 10, paintingsll etc. with reasonable success. The technique has also been used to analyse the gunshot residuel2, liquid/gas sampleSfor pollutants 13-14 (at ppb level) and human hair for toxic mineral analysisIS. The application ofLIBS for quality assurance in steel industry has been reported by Noll el aJl6whileSinghel al.17usedLIDSto determinecholorpheniramine maleate and magnesium stearate in tablets..Recentlyt8.19, LIBS_has been investigated to monitor the coating thickness and uniformity of pharmaceutical tablets. It has been re- ported that change in the coating thickness of the order of 2 wt% (weight percentage) is detectable withLIBS. The present paper after briefly reviewingthe principle and experimen- tal approaches of the LIBS technique, repQrts the application of LIDS for total quality control in pharmaceuticals industry for on-line monitoring of the concentration of the active/inactive ingredients as well as that of the impurities .inpharmaceutical prOducts.The investigation has been carried on the actual pharmaceutical products. The most popular Keywords: Laser induced breakdown spectroScopy;Quality control; Pharmaceutical in- dustry; Quantita~ve analysis; antacid tablets. . .