A simple LC-MS method for the determination of iohexol and iothalamate in serum, using ioversol as an internal standard.

BACKGROUND: Chronic kidney disease (CKD) is diagnosed and explored through the determination of the glomerular filtration rate (GFR). Our goal was to develop a simple LC-MS method for the determination in serum of 2 popular GFR markers, contrast agents iohexol and iothalamate, for routine use and comparison studies between the two markers. A similar contrast agent, ioversol, was used as an internal standard and the method underwent a rigorous validation protocol based on ß-expectation tolerance intervals. METHODS: We adapted the HPLC-UV method from Cavalier et al. to our LC-MS system. Data treatment for the validation was performed using Multiquant 3.0 (Sciex, Framingham, MA, USA) and e.noval 3.0 software (Arlenda, Liège, Belgium). RESULTS: According to the validation results our method will give accurate and reliable results for concentrations ranging from 6.8 to 250µg/ml for iohexol and 6.15µg/ml to 250µg/ml for iothalamate. In our practice these intervals are sufficient to determine both compounds in most patient samples. Samples with higher detected concentrations can always be diluted into range. CONCLUSION: With its internal standard and extensive validation, our method is now ready for routine and clinical research use.

Renal safety in pediatric imaging: randomized, double-blind phase IV clinical trial of iobitridol 300 versus iodixanol 270 in multidetector CT.

BACKGROUND: It is debated whether iso-osmolar and low-osmolar contrast media are associated with different incidences of contrast medium-induced nephropathy (CIN) in patients with renal insufficiency. OBJECTIVE: To compare the incidence of CIN in children undergoing contrast-enhanced multidetector computer tomography (MDCT) with intravenous injection of low-osmolar (iobitridol, Xenetix® 300) or an iso-osmolar (iodixanol, Visipaque® 270) iodinated contrast medium. MATERIALS AND METHODS: One hundred forty-six children with normal renal function were included in this multicenter trial and underwent contrast-enhanced MDCT. The primary endpoint was the relative change in creatinine clearance from 48 h pre- to 72 h postcontrast medium administration using a noninferiority analysis in the intent-to-treat (ITT, n = 128) and per protocol (n = 68) populations. Secondary endpoints were incidence of CIN, global image quality, diagnostic efficacy and clinical safety. RESULTS: In the ITT population, the noninferiority of iobitridol over iodixanol was demonstrated. CIN incidence was 4.8% (three cases) with iobitridol and 10.6% (seven cases) with iodixanol (not significant). No statistically significant differences were observed for the secondary endpoints. CONCLUSION: Comparable satisfactory safety profiles were confirmed for both contrast media, with no significant difference in the incidence of CIN in children with normal renal function.

Assessing the effectiveness of X-ray contrast media for abdominal computed tomographic examinations: comparison of four low-osmolality agents.

The objective of this investigation was to assess the effectiveness of four iodinated X-ray contrast media for abdominal computed tomographic (CT) examinations. Fifty-three patients were prospectively randomized to receive iohexol 300 mgI/ml (100 ml, n = 17), ioversol 320 mgI/ml (100 ml, n = 13), iopromide 300 mgI/ml (75 ml, n = 12), or iopentol 300 mgI/ml (100 ml, n = 11) to perform a dynamic contrast-enhanced abdominal CT. Image-enhancement profiles for the liver, aorta, and vena cava were studied. The maximum liver enhancement, the time to maximum liver enhancement, and the area under the hepatic enhancement-time curve (AUC) were determined for each examination. Liver-enhancement profile showed significant differences between the four contrast agents, with lower values for iopromide towards the final part of the CT examination (P < 0.05). Hepatic peak values were attained earlier for iopromide, although these were lower than those produced by any other of the agents evaluated in this study. Iopentol produced fast and intense hepatic peaks. Consequently, high AUC values were obtained with iopentol, low values were obtained with iopromide (P < 0.05), although this can be explained by the lower amount of contrast medium contained in the commercial vial and administered to the patient (75 ml vs 100 ml). When normalized to a 100 ml dose, the AUC value for iopromide becomes even higher than the average of the other three agents (P = 0.05). Ioversol, although available and administered as a more concentrated solution (320 mg/ml), was comparable to the less concentrated iohexol and iopentol (300 mgI/ml).(ABSTRACT TRUNCATED AT 250 WORDS)