An evaluation of GMCP‐SA as a replacement for ITLC‐SG when measuring the levels of radiochemical impurities in 99mTc radiopharmaceuticals by thin‐layer chromatography

Abstract

AbstractBackground: The European Pharmacopoeia and radiopharmaceutical manufacturers specify Instant Thin‐Layer Chromatography Silica Gel impregnated glass fibre (ITLC‐SG) as the stationary phase for measuring the radiochemical purity (RCP) of most technetium‐99m (99mTc) radiopharmaceuticals. During 2008, The Pall Corporation stopped manufacturing ITLC‐SG. A replacement is required. Aim: To evaluate Varian's Glass Microfibre Chromatography Paper impregnated with salicic acid (GMCP‐SA) as a replacement. Experimental: Samples of six 99mTc radiopharmaceuticals (albumin nanocolloid, colloidal tin, exametazime, medronate, pentetate and succimer) were prepared containing levels of radiochemical impurities between 0 and 10%. Samples were tested using ITLC‐SG and GMCP‐SA with the mobile phase specified in the pharmacopoeia or by the manufacturer. Analysis was performed by thin‐layer radiochromatogram scanning. Results: For measuring the RCP of albumin nanocolloid, colloidal tin, exametazime and succimer, GMCP‐SA is a suitable replacement for ITLC‐SG. For medronate, GMCP‐SA is suitable for measuring colloidal 99mTc impurity despite producing slightly higher values than ITLC‐SG, but unsuitable for measuring 99mTc pertechnetate impurity due to significant over‐estimation. For pentetate, GMCP‐SA is suitable for measuring colloidal 99mTc impurity but gives slightly higher values for 99mTc pertechnetate impurity than ITLC‐SG. Conclusion: GMCP‐SA is a suitable alternative to ITLC‐SG for analysing some 99mTc radiopharmaceuticals but is not a universal replacement. Copyright © 2009 John Wiley & Sons, Ltd.