Wavelength dependency and photosensitizer effects in UV-LED photodegradation of iohexol

Iodinated X-ray contrast media (ICM) are ubiquitously present in water sources and challenging to eliminate using conventional processes, posing a significant risk to aquatic ecosystems. Ultraviolet light-emitting diodes (UV-LED) emerge as a promising technology for transforming micropollutants in water, boasting advantages such as diverse wavelengths, elimination of chemical additives, and no induction of microorganisms' resistance to disinfectants. The research reveals that iohexol (IOX) degradation escalates as UV wavelength decreases, attributed to enhanced photon utilization efficiency. Pseudo-first-order rate constants (kobs) were determined as 3.70, 2.60, 1.31 and 0.65 cm2 J-1 at UV-LED wavelengths of 255, 265, 275 and 285 nm, respectively. The optical properties of dissolved organic matter (DOM) and anions undeniably influence the UV-LED photolysis process through photon competition and the generation of reactive substances. The influence of Cl- on IOX degradation was insignificant at UV-LED 255, but it promoted IOX degradation at 265, 275 and 285 nm. IOX degradation was accelerated by ClO2-, NO3-and HA due to the formation of various reactive species. In the presence of NO3-, the kobs of IOX followed the order: 265 > 255 > 275 > 285 nm. Photosensitizers altered the spectral dependence of IOX, and the intermediate photoactivity products were detected using electron spin resonance. The transformation pathways of IOX were determined through density functional theory calculations and experiments. Disinfection by-products (DBPs) yields of IOX during UV-LED irradiation decreased as the wavelength increased: 255 > 265 > 275 > 285 nm. The cytotoxicity index value decreased as the UV-LED wavelength increased from 255 to 285 nm. These findings are crucial for selecting the most efficient wavelength for UV-LED degradation of ICM and will benefit future water purification design.

Photocatalytic activation of sulfite by maghemite (γ-Fe2O3) for iohexol degradation and alleviation effect of HCO3- on water acidification

Photo-catalyzing sulfite (S(IV)) for the generation of sulfate radical (SO4•-) has emerged as a novel advanced oxidation process (AOP) recently. However, both the potential of soil minerals as effective photocatalysts and the process of water acidification due to S(IV) oxidation have been overlooked. Herein, maghemite (γ-Fe2O3), a typical soil iron oxide with excellent photocatalytic reactivity like hematite and magnetic-collectible property like magnetite, was successfully used to activate S(IV) for iohexol degradation under visible light irradiation. As a result, 91.3% of iohexol was eliminated within 15 min at 0.1 g/L maghemite and 0.5 mM S(IV) under neutral conditions. The influencing factors, including initial pH, catalyst dosage, S(IV) amount, co-existing substances and water matrix, were systematically investigated. The maghemite/S(IV)/vis system exhibited superior performance in iohexol degradation at a wide pH range (3-10). It was found that the released proton via S(IV) oxidation led to severe water acidification. Interestingly, a low dose of HCO3- could evidently resist water acidification with little influence on iohexol elimination. Radical quenching experiments and electron spin resonance (ESR) analysis confirmed that SO4•-, •OH and •O2- were involved in iohexol abatement with SO4•- being the dominant reactive species. Compared with hydrogen peroxide, persulfate and peroxymonosulfate, the established maghemite/S(IV)/vis system achieved much more remarkable degradation performance. Furthermore, the reactivity of the catalyst was not obviously reduced even after 10 runs of reaction. This study expands the application of soil iron oxide mineral in S(IV) activation in water treatment and proposes an approach to regulate water acidification in S(IV)-based AOP.

Overcoming slow removal efficiency-induced highly toxic I-DBPs in water by oxygen vacancies enriched invasive plant biochar catalyst: Experimental and theoretical studies

Developing effective and safe catalysts operated in the in-depth removal of iodinated X-ray contrast media is important for overcoming slow removal efficiency-induced highly toxic iodine-replaced disinfection byproducts (I-DBPs). In this study, a novel oxygen vacancies enriched heterogeneous biochar catalyst (Mo-Co-ECM) from the invasive plant was synthesized by a facile one-step hydrothermal carbonization method and used for the in-depth removal of iohexol (IOH) by the activation of peroxymonosulfate (PMS). The results indicated that after adding PMS for 3 min, the removal efficiency of IOH in Mo-Co-ECM/PMS system reached 100% and exhibited a superior degradation efficiency compared to Co-ECM/PMS and ECM/PMS system. Only nine I-DBPs were found during the degradation, which were dominated by small molecules compounds (MW<400). The in-depth degradation suppresses the formation of the toxic intermediates. The density functional theory and electron spin resonance showed that due to the existence of Mo and oxygen vacancies, the electron transfer ability was improved, which accelerated the cycle of Co3+/Co2+, so as to enhance the catalytic activity of Mo-Co-ECM/PMS system. This study is expected to provide a general way for decreasing the production of toxic intermediates during the advanced oxidation of contaminants, meanwhile recovering resources.

Contrast-induced ischemic colitis following coronary angiography: A case report

BACKGROUND

Ischemic colitis (IC) is common, rising in incidence and associated with high mortality. Its presentation, disease behavior and severity vary widely, and there is significant heterogeneity in therapeutic strategies and prognosis. The common causes of IC include thromboembolism, hemodynamic insufficiency, iatrogenic factors and drug-induced. However, contrast-induced IC, especially isolated right colon ischemia is rarely reported.

CASE SUMMARY

A 52-year-old man was admitted to the hospital due to intermittent chest distress accompanied by palpitation. Coronary angiography was performed using 60 mL of the iodinated contrast agent iohexol (Omnipaque 300), and revealed moderate stenosis of the left anterior descending artery and right coronary artery. At 3 h post-procedure, he complained of epigastric pain without fever, diarrhea and vomiting. Vital signs remained normal. An iodixanol-enhanced abdominal computed tomography (CT) scan revealed thickening, edema of the ascending and right transverse colonic wall and inflammatory exudate, without thrombus in mesenteric arteries and veins. Following 4 days of treatment with antibiotic and supportive management, the patient had a quick and excellent recovery with disappearance of abdominal pain, normalization of leucocyte count and a significant decrease in C reactive protein. There was no recurrence of abdominal pain during the patient's two-year follow-up.

CONCLUSION

This case emphasizes that contrast-induced IC should be considered in the differential diagnosis of unexplained abdominal pain after a cardiovascular interventional procedure with the administration of contrast media. Timely imaging evaluation by CT and early diagnosis help to improve the prognosis of IC.

Facilitated encapsulation of a nonionic contrast agent for X-ray computed tomography into lipid vesicles by the multiple emulsification-solvent evaporation method

We studied the encapsulation of iohexol (Ihex), a nonionic contrast agent used for X-ray computational tomography, into lipid vesicles using the multiple emulsification-solvent evaporation method to formulate a nanosized contrast agent. This lipid vesicle preparation method consists of three steps: (1) primary emulsification for producing water-in-oil (W/O) emulsions containing fine water droplets that will be converted to the internal water phase of the lipid vesicles, (2) secondary emulsification for formulating multiple water-in-oil-in-water (W/O/W) emulsions encapsulating the fine water droplets containing Ihex, and (3) solvent evaporation to remove the oil phase solvent (n-hexane) and to form lipid bilayers surrounding the fine inner droplets, resulting in the formation of lipid vesicles encapsulating Ihex. As the diameter and Ihex concentration of the primary W/O emulsion droplets decreased, a higher Ihex encapsulation yield was obtained for the final lipid vesicles. The entrapment yield of Ihex in the final lipid vesicles varied significantly with the emulsifier (Pluronic® F-68) concentration in the external water phase of W/O/W emulsion, and the highest yield (65%) was obtained when the emulsifier concentration was 0.1 wt%. We also investigated the powderization of lipid vesicles encapsulating Ihex via lyophilization. The powderized vesicles were dispersed in water after rehydration and maintained their controlled diameters. The entrapment yield of Ihex in powderized lipid vesicles was maintained for over 1 month at 25 ˚C, while significant leakage of Ihex was observed in the lipid vesicles suspended in the aqueous phase.

Multiple CEST contrast imaging of nose-to-brain drug delivery using iohexol liposomes at 3T MRI

Image guided nose-to-brain drug delivery provides a non-invasive way to monitor drug delivered to the brain, and the intranasal administration could increase effective dose via bypassing Blood Brain Barrier (BBB). Here, we investigated the imaging of liposome-based drug delivery to the brain via intranasal administration, in which the liposome could penetrate mucus and could be detected by chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) at 3T field strength. Liposomes were loaded with a computed tomography (CT) contrast agent, iohexol (Ioh-Lipo), which has specific amide protons exchanging at 4.3 ppm of Z-spectrum (or CEST spectrum). Ioh-Lipo generated CEST contrasts of 35.4% at 4.3 ppm, 1.8% at -3.4 ppm and 20.6% at 1.2 ppm in vitro. After intranasal administration, these specific CEST contrasts were observed in both olfactory bulb (OB) and frontal lobe (FL) in the case of 10% polyethylene glycol (PEG) Ioh-Lipo. We observed obvious increases in CEST contrast in OB half an hour after the injection of 10% PEG Ioh-Lipo, with a percentage increase of 62.0% at 4.3 ppm, 10.9% at -3.4 ppm and 25.7% at 1.2 ppm. Interestingly, the CEST map at 4.3 ppm was distinctive from that at -3.4 pm and 1.2 ppm. The highest contrast of 4.3 ppm was at the external plexiform layer (EPL) and the region between left and right OB (LROB), while the CEST contrast at -3.4 ppm had no significant difference among all investigated regions with slightly higher signal in olfactory limbus (OL, between OB and FL) and FL, as validated with histology. While no substantial increase of CEST contrast at 4.3 ppm, -3.4 ppm or 1.2 ppm was observed in OB and FL when 1% PEG Ioh-Lipo was administered. We demonstrated for the first time the feasibility of non-invasively detecting the nose-to-brain delivery of liposomes using CEST MRI. This multiple-contrast approach is necessary to image the specific distribution of iohexol and liposome simultaneously and independently, especially when designing drug carriers for nose-to-brain drug delivery.

Metrics-driven successful strategy by emergency and radiology driven task force to mitigate global CT contrast media shortage in a safety net hospital

Iodinated contrast media (ICM) shortages and secondary supply chain problems due to Coronavirus Disease lockdowns in China significantly impacted radiology operations nationwide. The lack of ICM necessitated operational workflow changes designed to ration contrast use, particularly in the hospital setting. In this manuscript, we share our strategic methods with advanced process/outcome metrics to monitor the effectiveness of our strategy under a coordinated multidisciplinary team effort. Alternate studies such as substituting magnetic resonance angiography for computed tomographic angiography for emergency department patients were studied to measure the suitability of these examinations for specific diagnoses. This article presents readers with a comprehensive crisis management strategy deployed at our institution, emphasizing various options with a limited ICM supply, and minimizing the impact on clinical care.

Glomerular filtration rate in critically ill neonates and children: creatinine-based estimations versus iohexol-based measurements

BACKGROUND

Acute kidney injury (AKI) and augmented renal clearance (ARC), both alterations of the glomerular filtration rate (GFR), are prevalent in critically ill children and neonates. AKI and ARC prevalence estimates are based on estimation of GFR (eGFR) using serum creatinine (SCr), which is known to be inaccurate. We aimed to test our hypothesis that AKI prevalence will be higher and ARC prevalence will be lower in critically ill children when using iohexol-based measured GFR (mGFR), rather than using eGFR. Additionally, we aimed to investigate the performance of different SCr-based eGFR methods.

METHODS

In this single-center prospective study, critically ill term-born neonates and children were included. mGFR was calculated using a plasma disappearance curve after parenteral administration of iohexol. AKI diagnosis was based on the KDIGO criteria, SCr-based eGFR, and creatinine clearance (CrCL). Differences between eGFR and mGFR were determined using Wilcoxon signed-rank tests and by calculating bias and accuracy (percentage of eGFR values within 30% of mGFR values).

RESULTS

One hundred five children, including 43 neonates, were included. AKI prevalence was higher based on mGFR (48%), than with KDIGO or eGFR (11-40%). ARC prevalence was lower with mGFR (24%) compared to eGFR (38-51%). eGFR equations significantly overestimated mGFR (60-71 versus 41 ml/min/1.73 m², p < 0.001-0.002). Accuracy was highest with eGFR equations based on age- and sex-dependent equations (up to 59%).

CONCLUSION

Iohexol-based AKI prevalence was higher and ARC prevalence lower compared to standard SCr-based eGFR methods. Age- and sex-dependent equations for eGFR (eGFR-Smeets for neonates and eGFR-Pierce for children) best approached measured GFR and should preferably be used to optimize diagnosis of AKI and ARC in this population. A higher resolution version of the Graphical abstract is available as Supplementary information.

Comparing the efficiency of six clearing methods in developing seeds of Arabidopsis thaliana

ClearSee alpha and FAST9 were optimized for imaging Arabidopsis seeds up to the torpedo stages. The methods preserve the fluorescence of reporter proteins and seed shape, allowing phenotyping embryos in intact seeds. Tissue clearing methods eliminate the need for sectioning, thereby helping better understand the 3D organization of tissues and organs. In the past fifteen years, clearing methods have been developed to preserve endogenous fluorescent protein tags. Some of these methods (ClearSee, TDE, PEA-Clarity, etc.) were adapted to clear various plant species, with the focus on roots, leaves, shoot apical meristems, and floral parts. However, these methods have not been used in developing seeds beyond the early globular stage. Tissue clearing is problematic in post-globular seeds due to various apoplastic barriers and secondary metabolites. In this study, we compared six methods for their efficiency in clearing Arabidopsis thaliana seeds at post-globular embryonic stages. Three methods (TDE, ClearSee, and ClearSee alpha) have already been reported in plants, whereas the others (fsDISCO, FAST9, and CHAPS clear) are used in this context for the first time. These methods were assessed for seed morphological changes, clearing capacity, removal of tannins, and spectral properties. We tested each method in seeds from globular to mature stages. The pros and cons of each method are listed herein. ClearSee alpha appears to be the method of choice as it preserves seed morphology and prevents tannin oxidation. However, FAST9 with 60% iohexol as a mounting medium is faster, clears better, and appears suitable for embryonic shape imaging. Our results may guide plant researchers to choose a suitable method for imaging fluorescent protein-labeled embryos in intact Arabidopsis seeds.

Iohexol plasma and urinary concentrations in cirrhotic patients: A pilot study

BACKGROUND

Renal failure is an independent prognostic factor for survival in patients with cirrhosis. Equations to calculate serum creatinine significantly overestimate the glomerular filtration rate (GFR). Plasma clearance of direct biomarkers has been used to improve the accuracy of evaluations of GFR in this population, but no study has simultaneously measured plasma and urinary clearance, which is the gold standard.

AIM

To study calculated plasma and urinary concentrations of iohexol, based on the kinetics of samples collected over 24 h from cirrhotic patients with three different grades of ascites.

METHODS

One dose of iohexol (5 mL) was injected intravenously and plasma concentrations were measured 11 times over 24 h in nine cirrhotic patients. The urinary concentration of iohexol was also measured, in urine collected at 4, 8, 12 and 24 h.

RESULTS

The plasma and urinary curves of iohexol were similar; however, incomplete urinary excretion was detected at 24 h. Within the estimated GFR limits of our population (> 30 and < 120 mL/min/1.73 m²), the median measured GFR (mGFR) was 63.7 mL/min/1.73 m² (range: 41.3–111.3 mL/min/1.73 m²), which was an accurate reflection of the actual GFR. Creatinine-based formulas for estimating GFR showed significant bias and imprecision, while the Brochner–Mortensen (BM) equation accurately estimated the mGFR (r = 0.93).

CONCLUSION

Plasma clearance of iohexol seems useful for determining GFR regardless of the ascites grade. We will secondly devise a pharmacokinetics model requiring fewer samples andvalidate the BM equation.

A comparative study on adsorption behavior of iodinated X-ray contrast media iohexol and amidotrizoic acid by magnetic-activated carbon

As persistent and ubiquitous contaminants in water, iodinated X-ray contrast media (ICM) pose a non-negligible risk to the environment and human health. In this study, we investigated the adsorption behavior of two typical ICM compounds, iohexol (IOH) and amidotrizoic acid (DTZ), on magnetic activated carbon. Theoretical investigations, using density functional theory, identified the molecule structures and calculated the molecular diameters of IOH (1.68 nm) and DTZ (1.16 nm), which revealed that ICM could be adsorbed by mesopores and larger micropores. Therefore, magnetic activated carbon with a porous structure was prepared by the co-precipitation method to investigate the adsorption mechanism of IOH and DTZ. MAC--5 (magnetic activated carbon with a theoretical iron oxide content of 37%) showed the best adsorption ability for both IOH and DTZ, with maximum adsorption capacities of 86.05 and 43.00 mg g^-1, respectively. Adsorption kinetics and isotherm models were applied to explore the mechanisms involved, and the effects of solution pH, initial concentration, temperature, ionic strength, and natural organic matter were also investigated. The pore filling effect, π-π stacking, hydrogen bonding, and electrostatic interaction, were found to be the main adsorption mechanisms. The co-adsorption data showed that competition may occur in ICM coexisting environments. Interestingly, the used MAC--5 could be successfully regenerated and its adsorption efficiency did not decrease significantly after five cycles, indicating that it is a promising adsorbent for ICM. The results from this study provide some new insights for the treatment of water containing ICM.

Fatal multiorgan dysfunction following repeated iodinated radiocontrast injection in a patient on low dose oral methotrexate

Background

Methotrexate is an antimetabolite drug that blocks the dihydrofolate reductase enzyme and impairs cell DNA synthesis. Administration of intravenous iodinated radiocontrast agents can precipitate life-threatening toxicity in patients receiving methotrexate.

Case

A 60-year-old female patient, a known case of rheumatoid arthritis, underwent craniotomy and clipping of distal anterior cerebral artery aneurysm. The patient was on low dose oral methotrexate for the past 5 years that was interrupted 2 days prior to surgery. The patient received the first intravenous contrast injection (Iohexol) during diagnostic cerebral angiography , one day prior to surgery (50 ml) and the second contrast dose on the first postoperative day (60 ml). The patient developed severe methotrexate toxicity leading to fatal multiorgan failure and death following repeated contrast imaging with intravenous Iohexol.

Conclusions

Even though oral low methotrexate has a minor adverse effect, life-threatening toxicity can get precipitated in the presence of iodinated contrast agents.

Estimation of cefepime, piperacillin, and tazobactam clearance with iohexol-based glomerular filtration rate in paediatric patients

PURPOSE

Estimated glomerular filtration rate (eGFR) equations reflect kidney function imprecisely. We aimed to describe whether iohexol-based GFR or eGFRs predict clearance of cefepime, piperacillin, and tazobactam in pharmacokinetic (PK) models in this population and its clinical significance.

METHODS

Hospitalized patients (0.5-25 years) with haemato-oncological disease and infection receiving cefepime or piperacillin/tazobactam were included. PK samples were collected at a steady state concomitantly with samples for iohexol-based GFR. PK models were developed in NONMEM. Weight, postmenstrual age, iohexol-based GFR, different eGFR equations (Schwartz updated, Lund-Malmö revised, CKD-EPI, Bouvet, Schwartz cystatin C-based) were tested as covariates. Probabilities of neurotoxic/therapeutic concentrations were assessed by simulations.

RESULTS

Fifteen patients receiving cefepime and 17 piperacillin/tazobactam were included (median (range) age 16.2 (1.9-26.0) and 10.5 (0.8-25.6) years, iohexol-based GFR 102 (68-140) and 116 (74-137) mL/min/1.73 m², respectively). Two-compartment model provided the best fit for all drugs. Weight was covariate for central and peripheral compartment, clearance and intercompartmental clearance (only tazobactam), and postmenstrual age for clearance (excluding cefepime). Iohexol-based GFR was the best predictor of clearance. The model of cefepime without vs with iohexol-based GFR underestimated the probability of neurotoxic concentrations (28.3-28.6% vs 52.1-69.3%) and overestimated the probability of therapeutic concentrations (> 90% vs 81.9-87.1%) in the case of iohexol-based GFR 70-80 and 130-140 mL/min/1.73 m², respectively.

CONCLUSION

Iohexol-based GFR can predict better than eGFRs the clearance of cefepime, piperacillin, and tazobactam in children and young adults with haemato-oncological disease and infection, warranting further investigation as an indicator of renal function to improve targeting of therapeutic window.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

EudraCT 2015-000,631-32, EudraCT 2016-003,374-40 (24.10.2016).

Enhanced degradation of iohexol in water by CuFe2O4 activated peroxymonosulfate: Efficiency, mechanism and degradation pathway

Iohexol as an iodinated X-ray contrast agent is widely used, and it is the potential precursor for toxic iodinated disinfection by-products in the disinfection process. In this study, a series of CuFe₂O₄ catalysts were prepared by sol-gel method with different molar ratios of total metal cations to citric acid ([Meⁿ⁺]_T/CA) and employed as heterogeneous catalysts to activate peroxymonosulfate (PMS) for the removal of iohexol. The catalysts were characterized by various technologies, and the effect of [Meⁿ⁺]_T/CA molar ratio on the catalysts' properties was explored. The CuFe₂O₄ synthesized with [Meⁿ⁺]_T/CA molar ratio of 1:1 showed the best catalytic activity to PMS, and 95.0% of 1.0 mg/L iohexol was removed within 15 min by using 50 mg/L CuFe₂O₄ and 20 mg/L PMS. The quenching experiment and electron spin resonance (ESR) spectra indicated the generation of SO₄^- and OH in the CuFe₂O₄/PMS system, and the quantity experiments revealed that the generation concentration of SO₄^- was ten times higher than that of OH. The generation mechanism of SO₄^- and ·OH were investigated by ATR-FTIR and X-ray photoelectron spectroscopy (XPS) spectra. The effects of catalyst dosage, PMS and iohexol concentration on the removal of iohexol were studied, and various water matrix factors including solution pH, natural organic matter (NOM) concentration and inorganic ions were also considered. Based on the twelve intermediate products of iohexol detected by UPLC-QTOF/MS, the degradation pathway was proposed. The high catalytic activity and reusability of CuFe₂O₄ indicated that CuFe₂O₄ activating PMS is an effective and sustainable way for the treatment of iohexol.

Comparative study of plasma clearance of iohexol at different injection doses

BACKGROUND

Our goal was to compare the metabolic curves of plasma clearance of iohexol (Cl_IOH) at standard dose (5 ml) and contrast-level dose (50 ml).

METHODS

The concentration of iohexol was measured at fasting state and at nine different time periods after a single bolus of iohexol injection. The interval between the injection of the two doses was longer than 24 hrs. Using a multi-point method and a dual-sample method, Cl_IOH-M and Cl_IOH-D were calculated, and the correlation and consistency of Cl_IOH between the two doses were compared.

RESULTS

The metabolic curves of iohexol at the 5 ml and 50 ml injection were substantially identical. The correlation of Cl_IOH-M between the two doses was 0.930, the mean deviation was 1.3 ± 6.9 ml/min/1.73 m². Taking Cl_IOH-5ml-M as the standard, the Cl_IOH-50ml-D at 2 h and 4 h had a correlation coefficient of 0.975, a mean deviation of 0.1 ± 5.3 ml/min/1.73 m², and the concordances were 100% corresponding to P₃₀, 88.9% corresponding to P₁₀, and 77.8% corresponding to P₅.

CONCLUSION

When a regular dose of iohexol is used for enhanced CT, Cl_IOH can be used for the measurement of GFR, and a proper time for blood collection can be 2 h and 4 h.

Does the cardiovascular drug levosimendan prevent iodinated contrast medium nephrotoxicity with glycerol aggravation in rats?

Background

We investigated whether levosimendan prevents contrast medium nephrotoxicity with glycerol aggravation in rats.

Methods

Forty-eight Wistar albino rats were assigned to eight groups (n = 6 × 8). No medication was administered to group I (controls); glycerol (intramuscular injection of 25% glycerol, 10 mL/kg) group II; intravenous iohexol 10 mL/kg to group III; glycerol and iohexol to group IV; iohexol and intraperitoneal levosimendan 0.25 mg/kg to group V; glycerol, iohexol, and levosimendan 0.25 mg/kg to group VI; iohexol and levosimendan 0.5 mg/kg to group VII; and glycerol, iohexol, and levosimendan 0.5 mg/kg to group VIII. One-day water withdrawal and glycerol injection prompted renal damage; iohexol encouraged nephrotoxicity; levosimendan was administered 30 min after glycerol injection and continued on days 2, 3, and 4. The experiment was completed on day 5. Serum blood urea nitrogen (BUN) and creatinine levels, superoxide dismutase (SOD) activity, glutathione (GSH), malondialdehyde (MDA) levels, tumour necrosis factor-α (TNF-α), nuclear factor kappa ß (NFK-ß), interleukin 6 (IL-6), and histopathological marks were assessed. One-way analysis of variance and Duncan’s multiple comparison tests were used.

Results

Levosimendan changed serum BUN (p = 0.012) and creatinine (p = 0.018), SOD (p = 0.026), GSH (p = 0.012), and MDA (p = 0.011). Levosimendan significantly downregulated TNF-α (p = 0.022), NFK-ß (p = 0.008), and IL-6 (p = 0.033). Histopathological marks of hyaline and haemorrhagic cast were improved in levosimendan-injected groups.

Conclusion

Levosimendan showed nephroprotective properties due to its vasodilator, oxidative distress decreasing and inflammatory cytokine preventing belongings.

3-Aminophenylboronic acid-mediated aggregation of gold nanoparticles for colorimetric sensing of iohexol in environmental and biological samples

Iohexol (IHO), as one of iodinated X-ray contrast, is often used as not only a chemical marker for tracking wastewater contamination in aquatic environment, but also an ideal glomerular filtration rate marker for explorating kidney disease. To these aims, it is important to establish reliable, fast, and cheap methods to detect IHO in environmental and biological samples. This work describes for the first time the development of a selective, sensitive and reliable colorimetric sensing assay for the fast determination of IHO in environmental and biological samples based on 3-aminophenylboronic acid (3-APBA) mediated aggregation of gold nanoparticles (AuNPs). In this approach, 3-APBA can assemble on the AuNPs surface through electrostatic interaction between its amino groups with the negatively charged citrate stabilizer of AuNPs to form AuNP@3-APBA. Subsequently, the aggregation and visual color change of the assembled AuNP@3-APBA are induced by the covalent reaction between boronic acid ligands of 3-APBA and cis-diols of IHO. The developed assay presented a very simple operating procedure and a rapid analysis time of around 10 min. The developed assay also exhibited good selectivity and a low limit of detection (LOD) of 0.005 mM for detecting IHO. Moreover, the developed assay showed comparable accuracy and precision to the high-performance liquid chromatography-diode array detector (HPLC-DAD) method when used for the rapid determination of IHO in river water and human urine samples. The recoveries of IHO at three spiking levels were in the range of 91.5-106.3% with relative standard deviation (RSD) values below 6.39%.

The correlation between kidney volume and measured glomerular filtration rate in an Asian ADPKD population: a prospective cohort study

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disorder that leads to end stage renal disease (ESRD). Cyst expansion in ADPKD is strongly associated with the decline in renal function. However, the correlation between total kidney volume (TKV) and glomerular filtration rate (GFR) at an early stage has not been well demonstrated. There is growing evidence that utilization of estimated GFR (eGFR) may induce misleading information in a population with near normal renal function. Therefore, a more accurate method is essential.

Methods

A prospective cohort of ADPKD patients was conducted with clinical data and laboratory collection. Measured GFR (mGFR) was assessed by iohexol plasma clearance method using ultra performance liquid chromatography. eGFR was calculated using the CKD-EPI equation. Kidney volumes were evaluated using MRI imaging protocol.

Results

Thirty two patients completed the study. The mean age was 56 years old. The mean initial mGFR was 83.8 mL/min/1.73m². The mean change in mGFR per year was –2.99 mL/min/1.73m²/year. The mean initial height-adjusted TKV (htTKV) was 681.0 mL/m. The mean percentage change in htTKV per year (%ΔhtTKV/y) was 4.77 %/year. mGFR had a better association with clinical parameters than eGFR. Initial mGFR was significantly and inversely correlated with initial htTKV and age. The percentage change in mGFR per year was significantly and inversely correlated with the %ΔhtTKV/y and 24-hr urine albumin. The %ΔhtTKV/y was significantly correlated with initial htTKV.

Conclusions

Our studies demonstrated that mGFR using iohexol is a more reliable and accurate method than eGFR for evaluating GFR changes in the early stages of ADPKD patients. There is a strong inverse correlation between kidney volume and mGFR in an Asian ADPKD population. The initial htTKV is a good predictor of kidney volume progression. The %ΔhtTKV/y is a good early surrogate marker for the decline in renal function. 24-hr urine albumin is also a good indicator for renal progression.

Microfluidic-assisted synthesis of multifunctional iodinated contrast agent polymeric nanoplatforms

Contrast Induced Nephropathy is the most severe side-effect arising after non-ionic iodinated contrast agents (CAs) intravenous administration. The use of antioxidants (i.e., N-Acetylcysteine; NAC) is one of the attempted prevention approaches. Herein, we describe the microfluidic-assisted synthesis of iodinated polymeric nanoparticles (NPs) as new multifunctional blood pool CA. The aim of this research is to co-encapsulate Iohexol (IOX; iodinated CA) and NAC (preventive agent) into poly-D,L-lactide-co-glycolide (PLGA) and PEGylated-PLGA (PLGA-PEG) NPs to exploit CA diagnostic proprieties and NAC preventing antioxidant activity. A microfluidic-assisted nanoprecipitation protocol has been set-up for PLGA and PLGA-PEG NPs, evaluating the effect of formulation and microfluidic parameters by analysing the size, PDI and IOX and NAC encapsulation efficiency. The optimized NPs (PLGA-PEG, L:G 50:50, 5% PEG, Mw 90 kDa) formulated with a size of 67 ± 2.8 nm with PDI < 0.2, spherical shape, and an IOX and NAC encapsulation efficiency of 38% and 20%, respectively. The IOX and NAC encapsulation was confirmed by FTIR and DSC. In vitro release study showed an IOX retention into the polymeric matrix and NAC sustained release up to 24-48 h stating microfluidics as powerful tool for the formulation of multifunctional nanoplatforms. Finally, the protective effect of NPs and NAC were preliminary assessed on human kidney cells.

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

The glomerular filtration rate (GFR) is considered the best overall index for the renal function. Currently, one of the most promising exogenous markers for GFR assessment is iohexol. In this study, the suitability of volumetric absorptive microsampling (VAMS) as alternative for the conventional blood sampling and quantification of iohexol in paediatric plasma was assessed. Therefore, a new, fully validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed. Subsequently, the clinical suitability was evaluated in 20 paediatric patients by comparing plasma iohexol concentrations and associated GFR values obtained by the VAMS method with those obtained by conventional blood sampling and quantification of iohexol in plasma. The developed, simple and cost-effective LC-MS/MS-method fulfilled all pre-set validation acceptance criteria. Iohexol could be accurately quantified within a haematocrit range of 20-60% and long-term stability of iohexol in VAMS was demonstrated up to 245 days under different storage temperatures. Both iohexol plasma concentrations (r = 0.98, mean bias: -4.20%) and derived GFR values (r = 0.99; mean bias: 1.31%), obtained by a conventional plasma and the VAMS method, demonstrated good correlation and acceptable bias. The agreement between the two methods was especially good for GFR values higher than 60 mL/min/1.73 m². Nevertheless, for GFR values <60 mL/min/1.73 m² the accuracy compared to the plasma method was lower. However, small adjustments to the sampling protocol could probably solve this problem.

Aorta, liver, and portal vein CT contrast enhancement during the portal venous phase are positively associated with abdominal fat percentage in dogs

Contrast-enhanced computed tomography (CT) is increasingly being used as a standard diagnostic test for dogs with suspected abdominal pathology. The iodinated contrast dose is commonly calculated based on linear increases in total body weight. However, body fat is not metabolically active and contributes little to dispersing or diluting the contrast medium in the blood. The aim of this retrospective single-center analytic study was to investigate the possible correlation between abdominal organ and vessel enhancement, and abdominal fat percentage in dogs. We hypothesized that, when dosing intravenous iodinated contrast according to total body weight, there would be a positive association between the degree of contrast enhancement of selected organs and vessels with increasing abdominal fat percentage. Vascular and parenchymal attenuation data were collected from 62 multiphasic abdominal CECT scans performed on dogs over a 5-year period at U-Vet Werribee Animal Hospital between February 2014 and February 2019. Findings based on a linear regression model showed a positive association of aorta (P = .005), liver (P = .045), and portal vein (P = .001) enhancement to abdominal fat percentage during the portal venous phase. Authors recommend that other body size parameters, such as lean body weight, should be considered when calculating iodine dose for abdominal contrast-enhanced CT in dogs.

MRGPRX2 mediates immediate-type pseudo-allergic reactions induced by iodine-containing iohexol

BACKGROUND

Iohexol is a typical iodinated radiocontrast medium and widely used in clinical angiography. Hypersensitivity reactions induced by iohexol are common side effects known to increase the risk for patients. Iodine is the main functional group of iohexol, and it can induce delayed anaphylaxis. However, iohexol also induces immediate-type allergies, but the underlying mechanism is still not clear. MRGPRX2 is a key receptor present on mast cells, which mediates pseudo-allergic reactions induced by various drugs.

METHODS

We aimed to verify the relationship between iohexol-induced anaphylactic reactions and MRGPRX2. MRGPRX2-mediated pseudo-allergic reactions induced by iohexol were investigated in vivo and in vitro using a mouse model of local and systemic anaphylaxis and mast cell degranulation assays, respectively.

RESULTS

Iohexol caused pseudo-allergic reactions in wild-type (WT) mice by activating mast cells to release histamine and cytokines. However, it did not induce a similar phenomenon in Kit^W-sh/W-sh (MUT) mice. Iohexol stimulated intracellular calcium ion (Ca²⁺) influx in MRGPRX2-HEK293, MrgprB2-HEK293, and LAD2 cells but not in NC-HEK293 cells. After knockdown of MRGPRX2 expression in LAD2 cells, the degree of iohexol-induced degranulation was reduced. In addition, after structural modification of iohexol by removal of iodine, a reduction in iohexol-induced effects, such as local and systemic anaphylaxis in mice and degranulation of LAD2 cells, could be observed. Iohexol was shown to induce immediate-type pseudo-allergic reactions via MRGPRX2, which was dependent on the presence of iodine.

CONCLUSIONS

Conclusively, inhibition of MRGPRX2-mediated mast cell degranulation and cytokine release is important to prevent iohexol-induced immediate-type pseudo-allergic reactions.

Catalytic ozonation of iohexol with α-Fe0.9Mn0.1OOH in water: Efficiency, degradation mechanism and toxicity evaluation

Iohexol, a widely used iodinated X-ray contrast media, is difficult to completely degrade with the traditional water treatment process. Catalytic ozonation with synthesized α-Fe_0.9Mn_0.1OOH as the catalyst can significantly promote the degradation of iohexol relative to that with ozonation alone. Hydroxyl radicals play a predominant role during the degradation of iohexol. The effect of various factors, including catalyst dose, ozone dose, iohexol concentration and water matrix factors, on the catalytic performance were investigated. The presence of α-Fe_0.9Mn_0.1OOH in the catalytic system can significantly promote the removal of iohexol and mineralization of the dissolved organic carbon in real water samples. The intermediate products were determined by high-resolution liquid chromatography, and the reaction site was predicted by frontier electron density (FED) calculations. The degradation mechanism of iohexol followed the processes of H-abstraction, amide hydrolysis, amide oxidation, and ·OH substitution. Higher exposure concentrations of iohexol had a negative effect on the survival and hatching rates in the development of zebrafish embryos. The autonomic movement process and heartbeat rate of the zebrafish larvae showed significant differences as the exposure concentration of iohexol increased. The catalytic ozonation process with α-Fe_0.9Mn_0.1OOH can decrease the toxicity of iohexol containing water.

Minimal risk of contrast-induced kidney injury in a randomly selected cohort with mildly reduced GFR

OBJECTIVES

Previous large studies of contrast-induced or post-contrast acute kidney injury (CI-AKI/PC-AKI) have been observational, and mostly retrospective, often with patients undergoing non-enhanced CT as controls. This carries risk of inclusion bias that makes the true incidence of PC-AKI hard to interpret. Our aim was to determine the incidence of PC-AKI in a large, randomly selected cohort, comparing the serum creatinine (Scr) changes after contrast medium exposure with the normal intraindividual fluctuation in Scr.

METHODS

In this prospective study of 1009 participants (age 50-65 years, 48% females) in the Swedish CArdioPulmonary bioImage Study (SCAPIS), with estimated glomerular filtration rate (eGFR) ≥ 50 mL/min, all received standard dose intravenous iohexol at coronary CT angiography (CCTA). Two separate pre-CCTA Scr samples and a follow-up sample 2-4 days post-CCTA were obtained. Change in Scr was statistically analyzed and stratification was used in the search of possible risk factors.

RESULTS

Median increase of Scr post-CCTA was 0-2 μmol/L. PC-AKI was observed in 12/1009 individuals (1.2%) according to the old ESUR criteria (> 25% or > 44 μmol/L Scr increase) and 2 individuals (0.2%) when using the updated ESUR criteria (≥ 50% or ≥ 27 μmol/L Scr increase). Possible risk factors (e.g., diabetes, age, eGFR, NSAID use) did not show increased risk of developing PC-AKI. The mean effect of contrast media on Scr did not exceed the intraindividual Scr fluctuation.

CONCLUSIONS

Iohexol administration to a randomly selected cohort with mildly reduced eGFR is safe, and PC-AKI is very rare, occurring in only 0.2% when applying the updated ESUR criteria.

KEY POINTS

• Iohexol administration to a randomly selected cohort, 50-65 years old with mildly reduced eGFR, is safe and PC-AKI is very rare. • Applying the updated ESUR PC-AKI criteria resulted in fewer cases, 0.2% compared to 1.2% using the old ESUR criteria in this cohort with predominantly mild reduction of renal function. • The mean effect of CM on Scr did not exceed the intraindividual background fluctuation of Scr, regardless of potential risk factors, such as diabetes or NSAID use in our cohort of 1009 individuals.

Evaluation of the pharmacokinetic drug-drug interaction potential of iohexol, a renal filtration marker

PURPOSE

Carboplatin dose is calculated based on kidney function, commonly estimated with imperfect creatinine-based formulae. Iohexol is used to measure glomerular filtration rate (GFR) and allows calculation of a more appropriate carboplatin dose. To address potential concerns that iohexol administered during a course of chemotherapy impacts that therapy, we performed in vitro and in vivo pharmacokinetic drug-drug interaction evaluations of iohexol.

METHODS

Carboplatin was administered IV to female mice at 60 mg/kg with or without iohexol at 300 mg/kg. Plasma ultrafiltrate, kidney and bone marrow platinum was quantitated by atomic absorption spectrophotometry. Paclitaxel microsomal and gemcitabine cytosolic metabolism as well as metabolism of CYP and UGT probes was assessed with and without iohexol at 300 µg/mL by LC-MS/MS.

RESULTS

In vivo carboplatin exposure was not significantly affected by iohexol co-administration (platinum AUC combination vs alone: plasma ultrafiltrate 1,791 vs 1920 µg/mL min; kidney 8367 vs 9757 µg/g min; bone marrow 12.7 vs 12.7 µg/mg-protein min). Paclitaxel microsomal metabolism was not impacted (combination vs alone: 6-α-OH-paclitaxel 38.3 versus 39.4 ng/mL/60 min; 3-p-OH-paclitaxel 26.2 versus 27.7 ng/mL/60 min). Gemcitabine human cytosolic elimination was not impacted (AUC combination vs gemcitabine alone: dFdU 24.1 versus 23.7 µg/mL/30 min). Iohexol displayed no relevant inhibition of the CYP and UGT enzymes in human liver microsomes.

CONCLUSIONS

Iohexol is unlikely to affect the clinical pharmacokinetics of carboplatin, paclitaxel, gemcitabine, or other agents used in combination with carboplatin treatment. Measuring GFR with iohexol to better dose carboplatin is unlikely to alter the safety or efficacy of chemotherapy through pharmacokinetic drug-drug interactions.

Highly efficient degradation of iohexol on a heterostructured graphene-analogue boron nitride coupled Bi2MoO6 photocatalyst under simulated sunlight

Iohexol (IOH), as a typical iodinated X-ray contrast media (ICMs) with potential threat to human health, is difficult to be removed with the conventional wastewater treatment methods. In this work, new boron nitride coupled Bi₂MoO₆ layered microspheres (BN/Bi₂MoO₆) composites were applied to remove IOH from water via photocatalytic degradation. The degradation constant k_app of IOH over 3.5 wt% BN/Bi₂MoO₆ was 0.016 min^-1, which was 3.2 times that of Bi₂MoO₆ (0.005 min^-1). The degradation rate of IOH on 3.5 wt% BN/Bi₂MoO₆ reached 92% in 150 min. The enhanced photocatalytic activity of BN/Bi₂MoO₆ can be attributed to the heterojunction between BN and Bi₂MoO₆. The matched type-I band alignment heterojunction of two semiconductors prominently improved the charge separation. Based on the trapping experiments, holes and superoxide radicals were proved to be the main active species for photocatalytic IOH degradation. Besides, the degradation products of IOH were analyzed by LC-HRMS and the possible degradation mechanism of IOH was also proposed in this work.

Bismuth chelate as a contrast agent for X-ray computed tomography

Backgrounds

Due to the unexpected side effects of the iodinated contrast agents, novel contrast agents for X-ray computed tomography (CT) imaging are urgently needed. Nanoparticles made by heavy metal elements are often employed, such as gold and bismuth. These nanoparticles have the advantages of long in vivo circulation time and tumor targeted ability. However, due to the long residence time in vivo, these nanoparticles may bring unexpected toxicity and, the preparation methods of these nanoparticles are complicated and time—consuming.

Methods

In this investigation, a small molecular bismuth chelate using diethylenetriaminepentaacetic acid (DPTA) as the chelating agent was proposed to be an ideal CT contrast agent.

Results

The preparation method is easy and cost—effective. Moreover, the bismuth agent show better CT imaging for kidney than iohexol in the aspect of improved CT values. Up to 500 µM, the bismuth agent show negligible toxicity to L02 cells and negligible hemolysis. And, the bismuth agent did not induce detectable morphology changes to the main organs of the mice after intravenously repeated administration at a high dose of 250 mg/kg. The pharmacokinetics of the bismuth agent follows the first—order elimination kinetics and, it has a short half—life time of 0.602 h. The rapid clearance from the body promised its excellent biocompatibility.

Conclusions

This bismuth agent may serve as a potential candidate for developing novel contrast agent for CT imaging in clinical applications.

Quantitation of iohexol, a glomerular filtration marker, in human plasma by LC-MS/MS

We developed a high-performance liquid chromatography mass spectrometry method for quantitating iohexol in 50 μL human plasma. After acetonitrile protein precipitation, chromatographic separation was achieved with a Shodex Asahipak NH2P-50 2D (5 μm, 2 × 150 mm) column and a gradient of 0.1 % formic acid in acetonitrile and 0.1 % formic acid in water over a 10 min run time. Mass spectrometric detection was performed on a Micromass Quatromicro triple-stage bench-top mass spectrometer with electrospray, positive-mode ionization. The assay was linear from 1 to 500 μg/mL for iohexol, proved to be accurate (101.3-102.1 %) and precise (<3.4 %CV), and fulfilled Food and Drug Administration (FDA) criteria for bioanalytical method validation. Recovery from plasma was 53.1-64.2 % and matrix effect was trivial (-3.4 to -1.3 %). Plasma freeze thaw stability (97.4-99.4 %), stability for 5 months at -80 °C (95.5-103.3 %), and stability for 4 h at room temperature (100.6-103.3 %) were all acceptable. This validated assay using a deuterated internal standard will be an important tool in measuring iohexol clearance and determining glomerular filtration rate (GFR) in patients.

Activation of sulfite autoxidation with CuFe2O4 prepared by MOF-templated method for abatement of organic contaminants

Copper ferrite (denoted as CuFe₂O_4MOF), prepared via a complexation reaction to obtain bimetal-organic frameworks (Cu/Fe bi-MOFs), followed by a combustion process to remove the MOF template, is employed as a heterogeneous activator to promote sulfite autoxidation for the removal of organic contaminants. At pH 8.0, more than 80% of the recalcitrant organic contaminant iohexol (10 μM) can be removed within 2 min by the activation of sulfite (500 μM) with CuFe₂O_4MOF (0.1 g L^-1). CuFe₂O_4MOF exhibits more pronounced catalytic activity in accelerating sulfite autoxidation for iohexol abatement compared to that fabricated by hydrothermal and sol-gel combustion methods. Radical quenching studies suggest that the sulfate radical (SO₄^•-) is the main reactive species responsible for iohexol abatement. The performance of CuFe₂O_4MOF/sulfite for iohexol abatement can be affected by several critical influencing factors, including the solution pH and the presence of humic acid, Cl^-, and HCO₃^-. The effect of the ionic strength and the results of the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis indicate that sulfite autoxidation in the presence of CuFe₂O_4MOF involves an inner-sphere interaction with the surface Cu(II) sites of CuFe₂O_4MOF. X-ray photoelectron spectroscopy (XPS) characterization suggests that the surface Cu(II)-Cu(I)-Cu(II) redox cycle is responsible for efficient SO₄^•- production from sulfite. Overall, CuFe₂O_4MOF can be considered an alternative activator for sulfite autoxidation for potential application in the treatment of organic-contaminated water.

Efficient activation of sulfite autoxidation process with copper oxides for iohexol degradation under mild conditions

Sulfite has been recently emerging as an appealing sulfate radical (SO₄^•-) precursor for efficient treatment of organic contaminants. Due to the negligible autoxidation of sulfite, activators are often introduced to accelerate sulfite autoxidation and the concomitant generation of SO₄^•-. Present heterogeneous activators are mostly not very effective under mild conditions (pH 7.0-8.0). In this work, efficient activation of sulfite with copper oxides including Cu₂O and CuO for iohexol degradation under mild pH conditions is proposed. In a comparison of iohexol degradation efficiency by sulfite autoxidation activated with different metal oxides (Co₃O₄, CoO, α-Fe₂O₃, γ-Fe₂O₃, CuO and Cu₂O), CuO and Cu₂O with lower toxicity are efficient activators and removal efficiencies of ~95% can be obtained at pH 8.0. SO₄^•- is identified to be the major species contributing to the removal of iohexol by electron paramagnetic resonance (EPR) spectroscopy and quenching experiment. Based on the effect of ionic strength and copper leaching, sulfite is proposed to interact with copper oxides via inner-sphere coordination. Effect of critical influencing parameters and efficacy of copper oxides in real water matrixes are investigated. The results suggest that using copper oxides as activators is a new alternative to promote sulfite autoxidation process for rapid contaminants degradation.

Diagnostic potential of simplified methods for measuring glomerular filtration rate to detect chronic kidney disease in dogs

Background

Glomerular filtration rate (GFR) is the most sensitive indicator of initial renal function decline during chronic kidney disease (CKD), but conventional protocols for measuring GFR are labor‐intensive and stressful for the dog.

Objectives

To assess the diagnostic potential for detecting CKD with simplified GFR protocols based on iohexol plasma clearance.

Animals

Seventeen CKD‐positive and 23 CKD‐negative dogs of different breeds and sex.

Methods

Prospective nonrandomized study. Plasma iohexol was measured 5, 15, 60, 90, and 180 minutes after injection. Glomerular filtration rate was calculated using 5 samples (GFR₅) or simplified protocols based on 1, 2, or 3 samples. The GFR₅ and simplified GFR were compared by Bland‐Altmann and concordance correlation coefficient (CCC) analysis, and diagnostic accuracy for CKD by receiver operating characteristic curves. A gray zone for each protocol was bounded by the fourth quartile of the CKD‐positive population (lower cutoff) and the first quartile of the CKD‐negative population (upper cutoff).

Results

All simplified protocols gave reliable GFR measurements, comparable to reference GFR₅ (CCC >0.92). Simplified protocols which included the 180‐minutes sampling granted the best GFR measure (CCC: 0.98), with strong diagnostic potential for CKD (area under the receiver operating characteristic curve ± SE: 0.98 ± 0.01). A double cutoff including a zone of CKD uncertainty guaranteed reliable diagnosis outside the gray area and identified borderline dogs inside it.

Conclusions

The simplified GFR protocols offer an accurate, hands‐on tool for CKD diagnosis in dogs. The gray zone might help decision‐making in the management of early kidney dysfunction.

Efficient abatement of an iodinated X-ray contrast media iohexol by Co(II) or Cu(II) activated sulfite autoxidation process

Efficient abatement of an iodinated X-ray contrast media iohexol by an emerging sulfite autoxidation advanced oxidation process is demonstrated, which is based on transition metal ion-catalyzed autoxidation of sulfite to form active oxidizing species. The efficacy of the combination of sulfite and transition metal ions (Ag(I), Mn(II), Co(II), Fe(II), Cu(II), Fe(III), or Ce(III)) was tested for iohexol abatement. Co(II) and Cu(II) are proven to show more pronounced catalytic activity than other metals at pH 8.0. According to the quenching studies, sulfate radical (SO₄^•-) is identified to be the primary species for oxidation of iohexol. Increasing dosages of metal ion or sulfite and higher pH values are favorable for iohexol abatement. Inhibition of iohexol abatement is observed in the absence of dissolved oxygen, which is vital for the production of SO₅^•- and subsequent formation of SO₄^•-. Overall, activation of sulfite to produce reactive radicals with extremely low Co(II) or Cu(II) concentrations (in the range of μg L^-1) in circumneutral conditions is confirmed, which offers a potential SO₄^•--based advanced oxidation process in treatment of aquatic organic contaminants.

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

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.

•

Successful VAMS-based bioanalytical method for iohexol analysis in whole human blood.

•

Proven medium term stability of iohexol in VAMS samples.

•

HemaPens as a promising alternative for iohexol analysis using only 2.74 μL of blood.

Myasthenic crisis following iodinated contrast material (iohexol) aspiration: a case report

Background

The number of contrast media-related procedures is ever increasing due to the widespread availability of theoretically safe, low osmolar iodinated contrast material. Although intravenously administered contrast is known to precipitate myasthenic crisis, oral contrast aspiration as a causative factor is not yet documented as such.

Case summary

A 48-year-old Sinhalese man diagnosed as having myasthenia gravis, was evaluated for progressive dysphagia with an upper gastrointestinal contrast study. Iodinated contrast material (iohexol) was used as the contrast medium and there was direct evidence of contrast aspiration during the study. Several minutes after the procedure, severe respiratory distress with evidence of myasthenic crisis requiring intubation and intensive care admission was noted. Treatment with intravenous immunoglobulin, high-dose steroids, and broad-spectrum intravenously administered antibiotics led to an uneventful recovery, although the latter part of the clinical course was complicated with total left lung collapse.

Summary

Myasthenic crisis can be precipitated by various factors and a successful recovery requires mechanical respiratory support with immunomodulatory and steroid therapy. This is the first reported case that describes the development of myasthenic crisis following iohexol-associated aspiration pneumonitis.

Comparison of inert and non-inert cathode in cathode/Fe3+/Peroxymonosulfate processes on iohexol degradation

To investigate the effect of cathode materials on organics degradation in a cathode/Fe³⁺/PMS process, different cathode materials (platinum, copper and iron) were selected and their performances were compared with iohexol as target organics. The optimal conditions were found to be different for different cathode/Fe³⁺/PMS processes. With a relatively high cathodic current input (2.0 mA/cm²), similar results were found for all the three cathode/Fe³⁺/PMS processes. With a small cathodic current input (not higher than 1.0 mA/cm²), the iohexol removal followed the order of Fe-cathode/Fe³⁺/PMS > Cu-cathode/Fe³⁺/PMS > Pt-cathode/Fe³⁺/PMS, due to the corrosion of Cu-cathode and Fe-cathode and the more serious corrosion of Fe-cathode than Cu-cathode. The corrosion of non-inert cathode materials (Cu-cathode and Fe-cathode) meant that these cathodes not only transmitted electrons but also participated in aqueous reactions, which complicated the mechanisms of cathode/Fe³⁺/PMS processes. The radical identification experiments indicated that SO₄^- was more important than OH for iohexol degradation in Cu-cathode/Fe³⁺/PMS process, while OH played a major role in Pt-cathode/Fe³⁺/PMS and Fe-cathode/Fe³⁺/PMS processes. The different reaction mechanisms resulted in different iohexol transformation pathways in cathode/Fe³⁺/PMS processes with different cathode materials.

Development and validation of an ultra-high performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of iohexol, p-aminohippuric acid and creatinine in porcine and broiler chicken plasma

In order to study the renal function, in terms of glomerular filtration and effective renal plasma flow, in broiler chickens and pigs, an ultra-high performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of iohexol, p-aminohippuric acid (PAH) and exogenously administered creatinine in plasma was developed and validated. Sample preparation consisted of a deproteinization step using methanol for porcine plasma and an Ostro™ Protein Precipitation & Phospholipid Removal Plate was used for broiler chicken plasma. Chromatographic separation was achieved on a Hypersil Gold aQ column using 0.1% formic acid in water and 0.1% formic acid in methanol as mobile phases. The total run time was limited to 10 min. Matrix-matched calibration curves for iohexol and PAH were prepared and good linearity (r ≥ 0.9973; gof ≤ 6.17%) was achieved over the concentration range tested (0.25-90 μg/mL). Limits of quantification were 0.25 μg/mL for iohexol and PAH. Water was used as surrogate matrix for analysis of creatinine in plasma. This surrogate calibration curve showed good linearity over the concentration range tested (0.25-90 μg/mL) (r ≥ 0.9979; gof ≤ 5.66%). For creatinine, the relative lower limit of quantification was 201.03 ± 49.20% and 60.14 ± 7.64% for chicken and porcine plasma, respectively. The results for within-day and between-day precision and accuracy fell within the specified ranges. This straightforward, cost-effective and rapid method, determining iohexol, PAH and creatinine within one single chromatographic run, has been successfully used for the analysis in porcine and broiler chicken plasma samples in order to determine the renal function of these species.

Performance of Cu-cathode/Fe3+/peroxymonosulfate process on iohexol degradation

Copper was used as a non-inert cathode material in a Cathode/Fe³⁺/peroxymonosulfate(PMS) system, and the performance of this novel Cu-cathode/Fe³⁺/PMS system was tested with a typical iodinated X-ray contrast media (iohexol) as target organics. The reaction mechanisms and the iohexol degradation pathways were investigated. The operational conditions of Cu-cathode/Fe³⁺/PMS process on iohexol degradation were optimized to be 1.0 mM Fe³⁺ dosage, 3.0 mM PMS dosage and 0.50 mA/cm² of current input. The much lower current applied in the present study than previous reports would help to save energy and be more economical. Compared with typical inert cathode (Pt-cathode), the Cu-cathode/Fe³⁺/PMS process has better performance on both iohexol removal and deiodination, due to that Cu-cathode participated in Fe²⁺ regeneration and PMS activation via surface Cu°-Cu⁺(s)-Cu²⁺-Cu° redox cycle. Fe²⁺ could be produced via reactions between Fe³⁺ and Cu/Cu⁺(s) as well as cathodic reduction of Fe³⁺. SO₄^- was generated from PMS activation by Fe²⁺, Cu/Cu⁺(s) and cathodic reduction. OH was also generated in this process but SO₄^- played a dominant role in iohexol degradation. The intermediate products of iohexol and its transformation pathways were complex due to the varied reaction mechanisms involving both oxidation and reduction in Cu-cathode/Fe³⁺/PMS process.

Iohexol-measured glomerular filtration rate in children and adolescents with chronic kidney disease: a pilot study comparing venous and finger stick methods

BACKGROUND

Measurement of glomerular filtration rate by iohexol disappearance (iGFR) has become a gold standard in the pediatric chronic kidney disease (CKD) population. The need for serial phlebotomy can be difficult and minimizing venipunctures would be beneficial. Furthermore, finger stick collection for dried blood spot (DBS) may be more tolerable in the pediatric population, and equivalence between these two methods may further simplify the process.

METHODS

This was a cross-sectional study in children and adolescents 1 to 21 years with stages I-IV CKD. Iohexol was infused and blood drawn 10, 30, 120, and 300 min later. Blood spots on filter paper were collected by finger stick after each of the latter two blood draws. The rate of iohexol plasma disappearance was used to calculate GFR. Pearson's correlation coefficient and bias, Students t test, and Bland-Altman graphical representations were used to compare methods.

RESULTS

Forty-one patients were recruited. The mean creatinine was 1.13 mg/dL (SD 0.45), the mean 4-point iGFR was 73.2 ml/min/1.73m² (SD 27.5) and the mean 2-point iGFR was 75.6 ml/min/1.73m² (SD 27.3). Correlation between 2-point and 4-point venous GFR was r = 0.97; p < 0.001. The correlation between the DBS and the 2-point venous GFR was r = 0.95; p < 0.001, with no significant bias. Ninety-four percent of the 2-point GFR's were within 10% of the 4-point GFR's and 80% of DBS-GFRs were within 10% of the 2-point GFR's.

CONCLUSIONS

The 2-point iGFR was highly correlated and agreed well with the 4-point iGFR. The same was true for the DBS method and the 2-point venous method. DBS sampling by finger stick sampling at 2 time points after iohexol infusion gave an acceptably accurate measurement of GFR.

Lack of impact of iodinated contrast media on kidney cell-cycle arrest biomarkers in critically ill patients

Background

Iodinated contrast media may contribute to acute kidney injury. However, several recent works suggest that this toxicity is minimal in the clinical setting. Recently, urinary G1 cell-cycle arrest proteins tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin like growth factor binding protein 7 (IGFBP-7) were identified as highly sensitive and specific biomarkers for early detection of kidney aggression. The impact of contrast administration on those biomarkers has not been specifically evaluated but could provide clues about the toxicity of contrast media. This study aimed at measuring changes in TIMP-2 and IGFBP-7 urinary concentrations before and after a contrast-enhanced computed tomography in critically ill patients.

Methods

77 patients were included in a prospective observational cohort study. Urinary [TIMP -2]·[IGFBP-7] was measured before, 6 and 24 h after contrast infusion. Urine output and serum creatinine were followed 3 days.

Results

Median [TIMP-2]·[IGFBP-7] was 0.06 [interquartile range 0.04;0.26], 0.07 [0.03;0.34] and 0.10 [0.04;0.37] (ng/mL)²/1000 respectively before, 6 and 24 h after contrast infusion. Individual changes from baseline were − 0.01 [− 0.11;0.11] and 0.00 [− 0.10;0.09] (ng/ml)²/1000 at 6 and 24 h. These changes were not higher among the patients increasing their Kidney Disease Improving Global Outcome (KDIGO) classification within 3 days after contrast infusion (n = 14 [18%] based on creatinine criterion only, n = 42 [55%] based on creatinine and urine output).

Conclusions

Changes in [TIMP-2]·[IGFBP-7] urinary concentration after contrast-enhanced computed tomography were insignificant, suggesting minimal kidney aggression by modern iodinated contrast media.

Bedside Iohexol Ventriculography for Patients with Obstructive Colloid Cysts: A Protocol to Identify Auto-Fenestration of the Septum Pellucidum

OBJECTIVE

Patients with hydrocephalus secondary to third ventricular colloid cysts can require bilateral external ventricular drain (EVD) placement while awaiting surgery. However, some patients could develop auto-fenestration of the septum pellucidum (AFSP) and only require 1 EVD. We evaluated our experience with bedside iohexol ventriculography and staged EVD placement for patients with obstructive hydrocephalus.

METHODS

We retrospectively identified 34 patients who had been treated for third ventricular colloid cysts (2013-2016). The preoperative and postoperative data, including age, sex, colloid cyst size, preoperative hydrocephalus, preoperative EVD placement, preoperative iohexol ventriculography, operative approach, intraoperative findings, and postoperative ventriculoperitoneal shunt requirements, were reviewed.

RESULTS

Hydrocephalus was found in 23 patients (68%) on initial presentation. Nine patients (26%) had EVDs placed before surgery. Six patients (18%) underwent iohexol ventriculography after insertion of a right-sided EVD. Five patients (15%) demonstrated no evidence of ventricular communication. Four patients (67%) required left-sided EVD placement. One patient (17%) had robust communication between the lateral ventricles after intraventricular iohexol injection, which was managed with a single EVD. AFSP was observed during surgical resection of this patient's colloid cyst. One other patient who did not undergo preoperative EVD placement was noted to have AFSP intraoperatively, resulting in 2 of 34 patients (6%) with AFSP in our series.

CONCLUSIONS

A subset of patients with obstruction at the foramina of Monro can develop AFSP. Iohexol ventriculography after unilateral EVD placement allows clinicians to assess for the presence of AFSP and identify patients who can be treated with a single EVD before surgery.

Accuracy of iohexol plasma clearance for GFR-determination: a comparison between single and dual sampling

Background

Current guidelines regarding plasma-sampling techniques for glomerular filtration rate (GFR) determination are inconsistent. Single-sample methods are commonly believed not to be precise enough to meet clinical demands. The present study compared the agreement between single- and dual- plasma sampling methods with a three-point plasma clearance of iohexol.

Methods

A total of 46 healthy volunteers and 124 chronic kidney disease (CKD) patients with varying degrees of renal dysfunction received 5 ml iohexol (300 mgI/ml) i.v. and plasma samples were drawn at 2-, 3- and 4-h post-injection. Plasma-iodine concentrations were detected by high-performance liquid chromatography (HPLC).

Results

Bias was similar among single-plasma sampling methods (SPSM) and dual-plasma sampling methods (DPSM). The best correlation was obtained from the 2- and 4-h DPSM (concordance correlation coefficient [CCC]: 0.9988) with none of the estimates differed by more than 30% from the reference GFR and only one (0.06%) estimate differed by more than 10% (P₃₀, 100%; P₁₀, 99.4%). SPSM using samples around 3- or 4-h demonstrated acceptable accuracy at a GFR level of ≥60 ml/min/1.73m² (P₃₀ = 100% and P₁₀ > 75% for both measurements).

Conclusion

4-h SPSM is advantageous in clinical practice in subjects with GFR ≥ 60 ml/min/1.73m². For patients with an expected GFR < 60 ml/min/1.73m², a prolonged sampling time is more reliable.

Cytotoxicity of radiocontrast dyes in human umbilical cord mesenchymal stem cells

Radiocontrast dyes are used for a wide range of diagnostic procedures for enhancing the image of anatomical structures, pain targets, and vascular uptake. While some of these dyes show toxicity to primary cells, their effect on stem cells, particularly mesenchymal stem cells (MSCs), is unknown. This study investigates the cytotoxic effects of two clinically used radiocontrast dyes, iohexol and iopamidol, on bone marrow and human umbilical cord MSCs. Exposure to these dyes significantly affected morphology of MSCs from both sources, as treated cells appeared transparent and no longer fibroblastoid. Cell viability decreased as determined by trypan blue and Annexin-V/PI staining, in a dose dependent manner with simultaneous loss of CD90 and CD105 concurrent with spontaneous differentiation in MSCs treated with iohexol and iopamidol. In addition, significantly higher cell death was observed in MSCs exposed to iopamidol than iohexol. At a concentration of 1:1, iohexol and iopamidol induced apoptosis in 19% and 92% (<.01) of MSCs, respectively. Global transcriptome analysis of treated MSCs revealed 139 and 384 differentially expressed genes in iohexol vs control and iopamidol vs control at p ≤ .01 and 1.5-fold, respectively. This suggested that iopamidol had more significant effect on the transcription of MSCs. Based on these results a molecular mechanism of radiocontast dye induced cell death via intrinsic apoptosis pathway mediated by p53 was proposed. Since iopamidol was significantly more toxic than iohexol in human MSCs, a more careful examination of safety of radiocontrast dyes for clinical use is warranted.

Coating and Pharmacokinetic Evaluation of Air Spray Coated Drug Coated Balloons

Drug coated balloons (DCB) are becoming the standard-care treatment for peripheral arterial disease (PAD). DCB use excipients to transfer and retain anti-proliferative drugs, such as paclitaxel. Excipients thus play a vital role in the design and function of DCB, however methods to coat balloons with excipients and anti-proliferative drugs remain unknown. The goal of this study was to thus develop an approach to coat and evaluate DCB for various excipients. An air sprayer method was developed to deposit paclitaxel and various excipients onto non-coated commercially available angioplasty balloons. The coating of the angioplasty balloons was evaluated for drug deposition and coating efficiency using high performance liquid chromatography tandem mass spectrometry. Drug transfer and retention of the coated angioplasty balloons into arterial segments were evaluated ex vivo using harvested pig arteries in a pulsatile flow bioreactor. The air sprayer method successfully delivered varying excipients including bovine serum albumin (BSA), urea and iohexol. The air spray method was configured to coat four angioplasty balloons simultaneously with paclitaxel and iohexol with an average paclitaxel load of 4.0 ± 0.70 µg/mm². The intra-day (within) and inter-day (between) coating precisions, defined as relative standard deviation (RSD), was 17.2 and 15.5%, respectively. Ex vivo deployment of iohexol-paclitaxel DCB yielded an arterial paclitaxel concentration of 123.4 ± 44.68 ng/mg (n = 3) at 1 h, 126.7 ± 25.27 ng/mg (n = 3) at 1 day, and 12.9 ± 12.88 ng/mg (n = 3) at 7 days. This work provides proof-of-concept of a quick, inexpensive approach to coat commercially available angioplasty balloons with paclitaxel and various excipients.

Challenges in Measuring Glomerular Filtration Rate: A Clinical Laboratory Perspective

The assessment of kidney function is a cornerstone in the clinical management and health of the patient. Although the kidneys perform many physiologic functions and are essential for maintaining homeostasis, kidney function is typically evaluated, quantitated, and understood using the glomerular filtration rate (GFR). Although GFR can be directly measured using a variety of externally administered glomerular filtration markers, in general practice, the GFR is usually estimated (eGFR) using endogenous markers that are cleared primarily by kidney filtration. Common situations exist where the GFR needs to be measured (mGFR) in order to proceed with care. This manuscript will review laboratory challenges in the assessment of GFR. Key points to consider when implementing a mGFR testing protocol are the following: marker selection, clearance methodology (urinary vs solely plasma measurements of filtration marker), sample collection, number of samples to collect, staff required, and analytical measurement technology for the filtration marker selected. We suggest those wanting to implement mGFR testing examine site-specific institutional resources along with patient population and proceed with the approaches best suited for their clinical needs and laboratory resources available.

Measured GFR in Routine Clinical Practice-The Promise of Dried Blood Spots

Accurate determination of glomerular filtration rate (GFR) is crucial for the diagnosis of kidney disease. Estimated GFR (eGFR) calculated by serum creatinine and/or cystatin C is a mainstay in clinical practice and epidemiologic research but lacks precision and accuracy until GFR <60 mL/min/1.73 m². Furthermore, eGFR may not precisely and accurately represent changes in GFR longitudinally. The lack of precision and accuracy is of concern in populations at high risk for kidney disease, as the dissociation between changes in eGFR and GFR may lead to missed diagnoses of early kidney disease. Therefore, improved methods to quantify GFR are needed. Whereas direct measures of GFR have been too cumbersome for screening and ambulatory care, a practical method of measuring GFR by iohexol clearance using dried capillary blood spots exists. In this review, we examine the current literature and data addressing GFR measurements by dried capillary blood spots and its potential application in high-risk groups.

[The combination of percutaneous iohexol-ethanol injection with radiofrequency ablation for the treatment of primary liver cancer in high-risk locations]

Objective: To investigate the safety and efficacy of radiofrequency ablation (RFA) with percutaneous iohexol-ethanol injection (PIEI), compared with RFA plus transcatheter arterial chemoembolization (TACE) for patients with primary liver cancer(PLC)in high-risk locations. Methods: From January 2012 to December 2014, 54 patients with PLC in high-risk locations were enrolled. They were divided into Group A (RFA combined with PIEI) and Group B (RFA plus TACE). The efficacy and adverse events were assessed. Results: 54 patients had 74 lesions in high-risk locations. There were 26 cases with 40 lesions in Group A, and 28 cases with 34 lesions in Group B. The complete ablation rate of Group A was significantly higher than that of Group B (92.5% vs 70.6%, P=0.014). The two-year local tumor progressionrateand two-year overall survival rate were similar between these two groups (Group A 20.0% vs Group B 38.2%, P=0.083; 90.3% vs 84.3%, P=0.523). Furthermore, the surgery-related severe adverse events of Group A (7.1%, one case of liver abscess and one case ofhematobilia) were more common than that of Group B (0%, P=0.491). No significant differences were found in common adverse events including fever, pain, elevation of aminotransferase and bilirubin. Conclusions: Compared with RFA plus TACE, RFA plus PIEI resulted inbetter complete ablation rate in patients with primary liver cancer in high risk locations. Prospective, randomized, controlled trials are warranted for further evaluation.

Workflow sensitivity of post-processing methods in renal DCE-MRI

OBJECTIVE

Estimation of renal filtration using dynamic contrast-enhanced imaging (DCE-MRI) requires a series of analysis steps. The possible number of distinct post-processing chains is large and grows rapidly with increasing number of processing steps or options. In this study we introduce a framework for systematic evaluation of the post-processing chains. The framework is later used to highlight the workflow processing chain sensitivity towards accuracy in estimation of glomerular filtration rate (GFR).

METHODS

Twenty healthy volunteers underwent DCE-MRI examinations as well as iohexol clearance for reference GFR measurements. In total, 692 different combinations of post-processing steps were explored for analysis, including options for kidney segmentation, B1 inhomogeneity correction, placement of arterial input function, gadolinium concentration estimation as well as handling of motion-corrupted volumes and breathing motion. The evaluation of various processing chains is presented using a classification tree framework and random forest ensemble learning.

RESULTS

Among the processing steps subject to testing, methods for calculating the gadolinium concentration as well as B1 inhomogeneity correction had the largest impact on accuracy of GFR estimations. Different segmentation methods did not play an important role in the post-processing of the MR data except from one processing chain where the automated segmentation outperformed the manual segmentation.

CONCLUSION

The proposed classification trees were efficiently used as a statistical tool for visualization and communication of results to distinguish between important and less influential processing steps in renal DCE-MRI. We also identified several crucial factors in the processing chain.

Standardization of a Videofluoroscopic Swallow Study Protocol to Investigate Dysphagia in Dogs

Background

Videofluoroscopic swallow study (VFSS) is the gold standard for diagnosis of dysphagia in veterinary medicine but lacks standardized protocols that emulate physiologic feeding practices. Age impacts swallow function in humans but has not been evaluated by VFSS in dogs.

Hypothesis/Objectives

To develop a protocol with custom kennels designed to allow free‐feeding of 3 optimized formulations of contrast media and diets that address limitations of current VFSS protocols. We hypothesized that dogs evaluated by a free‐feeding VFSS protocol would show differences in objective swallow metrics based on age.

Animals

Healthy juvenile, adult, and geriatric dogs (n = 24).

Methods

Prospective, experimental study. Custom kennels were developed to maintain natural feeding behaviors during VFSS. Three food consistencies (thin liquid, pureed food, and dry kibble) were formulated with either iohexol or barium to maximize palatability and voluntary prehension. Dogs were evaluated by 16 swallow metrics and compared across age groups.

Results

Development of a standardized VFSS protocol resulted in successful collection of swallow data in healthy dogs. No significant differences in swallow metrics were observed among age groups. Substantial variability was observed in healthy dogs when evaluated under these physiologic conditions. Features typically attributed to pathologic states, such as gastric reflux, were seen in healthy dogs.

Conclusions and Clinical Importance

Development of a VFSS protocol that reflects natural feeding practices may allow emulation of physiology resulting in clinical signs of dysphagia. Age did not result in significant changes in swallow metrics, but additional studies are needed, particularly in light of substantial normal variation.

Automated thin-film microextraction coupled to a flow-through cell: somewhere in between passive and active sampling

A prototype for the automated thin-film microextraction of pharmaceuticals from aqueous solutions has been developed and is presented here for the first time. With a software-controlled setup, extraction methods for ivermectin and iohexol have been developed. The widely used antiparasitic agent ivermectin is non-polar and has a high tendency to sorb to surfaces. In contrast to this, the nonionic but polar iodinated X-ray contrast agent iohexol is freely water soluble. With these two substances, a wide range of polarity is covered. Sorption kinetics and thermodynamics of ivermectin and iohexol were studied. With the presented passive sampling approach, it was possible to extract up to 96.2% ivermectin with a C₁₈-phase within 1 h and up to 74.6% of iohexol with a PS-DVB phase within 36 h out of water. Using abamectin as internal standard, it was possible to quantitatively follow dissipation of ivermectin in a simulated surface water experiment. Predominantly, the newly developed prototype can be used for automated and time-resolved extraction of xenobiotics from waterbodies under field conditions, for the extraction of substances under laboratory conditions as an alternative to the elaborate solid-phase extraction, and for the automated control of chemical reaction kinetics.