Search

Background When using iTLC-SG thin layer chromatography plates to measure radiochemical impurities in 99mTc medronate, falsely high values were obtained for 99mTc pertechnetate impurity. Preliminary investigations indicated that the mass of 99mTc medronate applied to the plate influences the value. Aim The goal of this study was to determine if the concentration of medronate influences the value obtained for 99mTc pertechnetate impurity. Experimental 99mTc medronate was prepared at two concentrations: 4 mg/mL and 0.2 mg/mL. Impurity levels were measured using three stationary phases: dried and undried iTLC-SG and 54SFC paper. Two mobile phases were used: methyl ethyl ketone to detect 99mTc pertechnetate and sodium acetate 136 g/L to detect hydrolysed and colloidal 99mTc. Sample spot drying and volume were also investigated. Results With 4 mg/mL samples, the three stationary phases measured similar impurity levels (p > 0.05). With the 0.2 mg/mL samples, higher levels of 99mTc pertechnetate were measured with iTLC-SG than with paper (p

Background: 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.

To determine if 99mTc-Nanocoll is affected by storage in a syringe, passage through an R-Lock or mixing with Patent Blue V dye.A Nanocoll kit was reconstituted at 280 MBq/5 ml. Samples of 0.5 ml were drawn into 3 ml Plastipak syringes. After 1 h and 6 h, adsorption of 99mTc on a syringe was measured and the following tests of quality were performed on samples from the kit and a syringe: 99mTc-pertechnetate impurity by thin-layer chromatography, the percentage of 99mTc on particles100 nm by Nuclepore filtration and particle size by photon correlation spectroscopy. These tests were also applied to samples that had been passed through an R-Lock or mixed with Patent Blue V. Each experiment was performed five times.In all samples, adsorption of 99mTc on syringes was1%, 99mTc-pertechnetate impurity was2%,95% of 99mTc was labelled to particles100 nm in diameter, the mean particle diameter was 6.6 nm and the particles had a diameter of12 nm. All tests showed no significant difference (P0.05, n = 5) between 99mTc-Nanocoll from the original kit and a syringe at either 1 h or 6 h. Similar results were obtained with samples that had been passed through an R-Lock or mixed with Patent Blue V.A capped 3 ml Plastipak syringe is a suitable container in which to supply 99mTc-Nanocoll. Neither passage through an R-Lock nor mixing with Patent Blue V affects the quality of 99mTc-Nanocoll.

Background: The European Pharmacopoeia specifies Instant Thin-Layer Chromatography Silica Gel (ITLC-SG) as the stationary phase for measuring radiochemical impurities in 99mTc Medronate. The Pall Corporation has stopped manufacturing ITLC-SG. Aim: To investigate chromatography papers as alternatives to ITLC-SG. Experimental: The resolution of the main 99mTc Medronate and impurity peaks were compared on five Whatman papers (1CHR, 31ET, 3MM, 4CHR and 54SFC) using the pharmacopoeial mobile phases: methyl ethyl ketone for detecting 99mTc pertechnetate impurity and sodium acetate solution (136 g/l) for detecting hydrolysed reduced and colloidal 99mTc impurities. The effects of three sample spot treatments (wet, hot dried and air dried) on the distribution of the radiochemical impurities were compared. The levels of radiochemical impurities measured in samples of 99mTc Medronate were compared. Results: The highest resolutions were obtained with 1CHR, 4CHR and 54SFC. Sample spot drying resulted in the measurement of artifactually high levels of 99mTc pertechnetate impurity. When analysing 99mTc Medronate, erroneously high levels of colloidal and 99mTc pertechnetate impurities were measured with 1CHR and 4CHR. Conclusions: 54SFC paper is a suitable alternative to ITLC-SG for measuring radiochemical impurities in 99mTc Medronate. The sample spot should be wet when the paper strip is placed in the chromatography tank. Copyright © 2009 John Wiley & Sons, Ltd.

Objective To determine the circumstances under which sodium chloride injection (SCI) that has been exposed to fluorescent light then used to prepare 99m Tc-MAG3 causes low radiochemical purity (RCP). Methods Two brands of SCI in plastic ampoules (Braun and Steri-Amp) and one in glass vials (Drytec) were exposed to light for up to 7 days then used to prepare 99m Tc-MAG3. RCP was measured by liquid chromatography. To study the effect on the labelling reaction, the reconstituted MAG3 kit was analysed before and after boiling and the formation of the 99m Tc-tartrate intermediate was investigated. Exposed water from plastic ampoules was analysed by mass spectrometry. Results After no exposure, each brand resulted in high RCP 99m Tc-MAG3 (>94%). Drytec SCI produced high RCP throughout (96.7 +/- 0.3%, n=5, 7 days). The RCP produced by Steri-Amp and Braun fell to 85.2 +/- 5.2% and 93.5 +/- 1.6% after exposure for 2 and 4 days, respectively. The chromatogram before boiling contained peaks corresponding to 99m Tc-tartrate and 99m Tc-pertechnetate. After boiling with unexposed SCI, these were minimal and a 99m Tc-MAG3 peak dominated. After boiling with exposed SCI, 99m Tc-pertechnetate and 99m Tc-MAG3 peaks were present. Measurements on tartrate showed a high level of 99m Tc-tartrate before and after boiling with unexposed SCI but a high level of 99m Tc-pertechnetate after boiling with exposed SCI. Mass spectrometry showed that compounds leach into the solution upon exposure to light. Conclusion Preparing 99m Tc-MAG3 using SCI from plastic ampoules that have been exposed to light causes reduced RCP. Exposure of plastic ampoules to light causes leaching of many compounds into the solution. An unknown leached compound destabilizes the 99m Tc-tartrate intermediate complex.