A method for detection and quantification of hydroxyethyl starch in plasma

issue due to increasing evidence that HES accumulates in plasma and various tissues and therefore leads to unfavourable outcome in critically ill patients [1,2]. No simple methods are available for monitoring HES plasma levels; present technologies to measure HES are based on gas chromatography-mass spectrometry, which are timeconsuming and need advanced equipment [3]. Here, we applied Lugol’s iodine solution (LUGOL; Sigma-Aldrich, Steinheim, Germany) to determinate HES concentrations in plasma and compare the results with those obtained by high-performance liquid chromatography (HPLC). Th e study was approved by the institutional ethical committee (Friedrich-Schiller-University, Jena) as well as by the animal welfare committee (Th üringer Landesamt für Lebensmittelsicherheit und Verbraucherschutz, Germany). Blood samples from healthy volunteers were diluted with balanced 6% HES 130/0.4 (Fresenius Kabi, Bad Homburg, Germany) to get concentrations up to 30 mg/ml. Samples were centrifuged (10 minutes, 4,700×g, 4°C), and plasma aliquots were mixed with 10% trichloroacetic acid and re-centrifuged (5 minutes, 4,700×g, 4°C). Th e supernatant was mixed (4:1) with LUGOL and optical density was measured at 530 nm. For in vivo experiments, 5 ml or 10 ml of 6% HES 130/0.4 was infused into wistar rats over 1 hour via a central venous catheter. Blood samples were obtained prior and up to 24 hours after infusion. Plasma samples were prepared as described. For HPLC analysis, plasma samples were diluted 1:10 with water, then mixed with 60% perchloric acid, heated at 90°C for 60 minutes, diluted again (1:50) and subjected to HPLC [4]. For correlation analysis the Pearson correlation coeffi cient was calculated. Using the LUGOL method, we found a linear correlation (r2 > 0.99) between calculated and measured