Determination of iohexol by capillary blood microsampling and UHPLC-MS/MS

Abstract

One of the most important tools used to evaluate kidney function in the context of chronic kidney disease or other renal function related pathologies is the exploration of glomerular filtration rate (GFR). Iohexol is up to this moment a good candidate molecule for the GFR assessment since it exhibits minimum protein binding rates and minimum extra-renal clearance, being neither secreted nor reabsorbed at the tubular level. This study proposes and evaluates a new LC-MS/MS method for the iohexol determination from capillary blood, prelevated using volumetric absorbative microsampling (VAMS) systems. As an alternative to VAMS, a brand new HemaPEN ® device for micro-prelevation was also tested. A new high throughput sample preparation protocol adapted for iohexol quantification from whole blood VAMS samples was developed. The medium term stability study of iohexol in dried whole blood VAMS samples that was conducted showed a good stability of this molecule for up to 12 days. By collecting only 10 μL of blood, iohexol can be analyzed from dried whole blood VAMS samples for concentration ranges between 1 and 250 μg/mL. Due to the analyte stability in VAMS for up to 12 days, this approach might be successfully applied for GFR assessment for clinical cases allowing minimum invasiveness and even delayed analysis.

Volumetric absorptive microsampling as alternative sampling technique for renal function assessment in the paediatric population using iohexol

“…(±SD) values of 104 (±12) and 107 (±3) %, at low and high QC level, respectively. These extraction recoveries are higher than those obtained using an Ostro-96® well plate (53.6 -65.7%) for the extraction of iohexol in VAMS [31]. Furthermore, similar extraction recoveries with Ostro® plates were obtained for the determination of iohexol in chicken plasma [40].…”

“…The best fit was obtained when applying a 1/x 2 weighting. The calibration range was in the same order of magnitude as reported by Ion et al (1-500 µg/mL) applying VAMS [31]. This calibration range comprises concentrations obtained after injection of the above mentioned iohexol doses to paediatric patients.…”

“…Nevertheless, haematocrit can still influence the recovery of the analyte and its effect should therefore always be checked during validation [30]. Currently, to the authors' knowledge, only a single literature report published by Ion et al is available describing a VAMS assay for iohexol [31].…”

“…The objective of the current study was to develop and validate an ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) assay for the quantification of iohexol using VAMS devices. In contrast to the recent paper published by Ion et al, in this paper special attention was paid to the long-term stability of the samples and the influence of haematocrit on the method accuracy [31]. Furthermore, a pilot study was designed to assess the suitability of this VAMS technology as alternative for the conventional quantification of iohexol in paediatric plasma.…”

UHPLC–MS/MS Method for Iohexol Determination in Human EDTA and Lithium-Heparin Plasma, Human Urine and in Goat- and Pig EDTA Plasma

“…Next to being cumbersome and difficult to perform in the clinic, inulin for parenteral administration is no longer available and is thus being replaced by alternative markers such as radiolabeled compounds or contrast media. Radiolabeled compounds have their obvious drawbacks and the nonionic contrast agent iohexol is currently the most widely used alternative marker for GFR measurement in humans due to its favorable safety profile, high concordance with urinary inulin clearance and ease of use, for example, iohexol in urine and plasma is stable at room temperature, 4, -20 and -80 • C [5][6][7]. In addition to the use of iohexol in clinical Bioanalysis (2020) 12 (14), 981-990 ISSN 1757-6180 981 10.4155/bio-2020-0122 C 2020 Newlands Press practice and clinical research, iohexol is also used to measure kidney function in animal models to evaluate the pathogenesis and treatment of kidney disease.…”