Monitoring of the degradation kinetics of diatrizoate sodium to its cytotoxic degradant using a stability-indicating high-performance liquid chromatographic method.

The X-ray diagnostic agent sodium diatrizoate (DTA) was studied for chemical degradation. The 3,5-diamino derivative was found to be the alkaline and acidic degradation product. The 3,5-diamino degradate is also the synthetic precursor of DTA and it is proved to have cytotoxic and mutagenic effects. A sensitive, selective and precise high-performance liquid chromatographic stability-indicating method for the determination of DTA in the presence of its acidic degradation product and in pharmaceutical formulation was developed and validated. Owing to the high toxicity of the degradation product, the kinetics of the acidic degradation process was monitored by the developed RP-HPLC method. The reaction was found to follow pseudo-first order kinetics. The kinetic parameters such as rate constant (K) and half-life (t½ ) were calculated under different temperatures and acid concentrations; activation energy was estimated from the Arrhenius plot. The developed RP-HPLC method depends on isocratic elution of a mobile phase composed of methanol-water (25:75 v/v; pH adjusted with phosphoric acid), and UV detection at 238 nm. The method showed good linearity over a concentration range of 2-100 µg/mL with mean percentage recovery of 100.04 ± 1.07. The selectivity of the proposed method was tested using laboratory-prepared mixtures. The proposed method has been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives and the results were statistically compared with the official USP method. Validation of the proposed method was performed according to International Conference on Harmonization guidelines.

A randomized comparison of the nephrotoxicity of iopamidol and diatrizoate in high risk patients undergoing cardiac angiography.

Three hundred seven high risk patients with renal impairment (serum creatinine greater than or equal to 1.5 mg/dl) were randomized in a double-blind manner to either iopamidol (a nonionic, low osmolar radiocontrast agent) or diatrizoate (a conventional radiocontrast agent) at cardiac angiography with subsequent follow-up study of renal function. Baseline clinical and angiographic variables were similar in the iopamidol (n = 155) and diatrizoate (n = 152) groups. Change in renal function after angiography was less pronounced with iopamidol compared with diatrizoate as measured by mean ( +/- SD) increase in 24 h serum creatinine (0.11 +/- 0.2 versus 0.22 +/- 0.26 mg/dl, p less than 0.001), mean maximal increase in serum creatinine (0.2 +/- 0.44 versus 0.38 +/- 0.73 mg/dl, p less than 0.0001) and percent of patients with a maximal increase in serum creatinine greater than 0.5 mg/dl (8% versus 19%, p less than 0.01). Such differences could not be documented in diabetic patients using insulin. There was no significant difference between agents in the number of patients developing clinically severe acute renal dysfunction. It is concluded that iopamidol is less nephrotoxic than diatrizoate in high risk patients at cardiac angiography. However, the difference in nephrotoxicity is small, of no major clinical significance in the majority of high risk patients and could not be documented in insulin-using diabetic patients. Iopamidol may be the preferred agent in certain patients with advanced renal impairment, but further study is warranted.

Functional and pathologic effects of multiple echocardiographic contrast injections on the myocardium, brain and kidney.

Myocardial contrast echocardiography can define in vivo the area at risk for necrosis after coronary occlusion. However, if this technique is to be used, it cannot be intrinsically toxic to the heart or other critical organs. To determine the functional and pathologic effects of contrast echocardiography, six intracoronary, six intrarenal and six intracarotid artery injections of 2 to 6 cc of a commonly employed contrast agent (agitated Renografin-saline solution) were performed in five dogs. A sixth dog served as a sham to assess any deleterious effects of the model preparation. Two-dimensional echocardiographic images and electrocardiograms were recorded during intracoronary injections, and heart rate, blood pressure, left ventricular end-diastolic pressure and rate of rise of left ventricular pressure (dP/dt) were continuously monitored. At 24 hours, echocardiographic and hemodynamic measurements were repeated, the dogs were killed and the heart, brain and kidneys were removed and prepared for light microscopic examination. Quantitative analysis of left ventricular wall motion was performed on control, peak contrast, post-contrast and 24 hour studies. With each intracoronary injection, there were transient decreases in blood pressure (p = 0.05 versus control) and increases in left ventricular end-diastolic pressure (p = 0.04 versus control). These were associated with depression of wall motion in contrast-enhanced regions (p = 0.01 versus control) and ST-T segment changes on the electrocardiogram. No significant change in heart rate or left ventricular dP/dt was noted. All variables normalized with the clearance of the contrast effect and remained normal to 24 hours. Light microscopic examination revealed no myocardial or cerebral changes attributable to the contrast agent injections.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study between three stability indicating spectrophotometric methods for the determination of diatrizoate sodium in presence of its cytotoxic degradation product based on two-wavelength selection.

Three sensitive, selective, and precise stability indicating spectrophotometric methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA) in the presence of its acidic degradation product (highly cytotoxic 3,5-diamino metabolite) and in pharmaceutical formulation, were developed and validated. The first method is ratio difference, the second one is the bivariate method, and the third one is the dual wavelength method. The calibration curves for the three proposed methods are linear over a concentration range of 2-24 µg/mL. The selectivity of the proposed methods was tested using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

Reversal of radiocontrast medium toxicity in human renal proximal tubular cells by white grape juice extract.

Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury. The pathophysiology of CIN is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. We have investigated the effect of a white grape (Vitis vinifera) juice extract (WGJe) on human renal proximal tubular (HK-2) cells treated with the radiocontrast medium (RCM) sodium diatrizoate. WGJe caused an increase in phosphorylation of the prosurvival kinases Akt and ERK1/2 in HK-2 cells. Treatment of HK-2 cells with 75 mgI/ml sodium diatrizoate for 2.5h and then further incubation (for 27.5h) after removal of the RCM caused a drastic decrease in cell viability. However, pre-treatment with WGJe, prior to incubation with diatrizoate, dramatically improved cell viability. Analysis of key signaling molecules by Western blotting showed that diatrizoate caused a drastic decrease in phosphorylation of Akt (Ser473), FOXO1 (Thr24) and FOXO3a (Thr32) during the initial 2.5h incubation period, and WGJe pre-treatment caused a reversal of these effects. Further analysis by Western blotting of samples from HK-2 cells cultured for longer periods of time (for up to 27.5h after an initial 2.5h exposure to diatrizoate with or without WGJe pre-treatment) showed that WGJe pre-treatment caused a negative effect on phosphorylation of p38, NF-κB (Ser276) and pERK1/2 whilst having a positive effect on the phosphorylation of Akt, FOXO1/FOXO3a and maintained levels of Pim-1 kinase. WGJe may alleviate RCM toxicity through modulation of signaling molecules that are known to be involved in cell death and cell survival and its possible beneficial effects should be further investigated.

Synergistic cytotoxicity of iodinated contrast agents and x-radiation.

The synergistic cytotoxicity of iodinated radiologic contrast agents and x-radiation is discussed. Experiments are described illustrating the phenomenon and lending support to the view that it is mediated by energetic photoelectrons. Some of its practical implications are indicated.

Contrast media-induced ventricular fibrillation. A comparison of Hypaque-76, Hexabrix, and Omnipaque.

Contrast media occasionally produce ventricular fibrillation during coronary angiography. We compared the fibrillatory propensity of the conventional ionic contrast medium, Hypaque-76 (H76) to the low osmolar ionic dimer Hexabrix (HB) and to the nonionic agent Omnipaque (OM) in 20 open chest anesthetized dogs. Intracoronary injection of 6 mL of contrast medium produced spontaneous ventricular fibrillation in four of ten dogs with H76, compared with two of ten with HB, and zero of ten with OM (P = .07). The induction of two premature beats by programmed stimulation of the myocardium during injection of 4 mL of contrast medium produced ventricular fibrillation in ten of ten dogs with H76, compared with three of ten with HB, and zero of ten with OM (P less than .001). Both H76 and HB produced ventricular fibrillation in ten of ten dogs when three premature beats were induced, compared with two of ten dogs with OM (P less than .001). Four mL H76 produced a 109 +/- 18 msec increase in the QT interval, compared with an 82 +/- 17 msec increase with HB, and a 45 +/- 12 msec increase with OM. We conclude that both low osmolar HB and OM are less fibrillatory than the conventional ionic medium H76, and that the nonionic medium OM is less fibrillatory than the ionic dimer contrast medium HB.

Do contrast media aggravate Fanconi's syndrome in rats? A comparison of diatrizoate, iohexol, and ioxilan.

Urine profiles (albumin, glucose, N-acetyl-beta-D-glucosaminidase [NAG], lactate dehydrogenase [LDH], L-gamma-glutamyltransferase [GGT], sodium, and phosphate) were followed for seven days after intravenous (IV) administration of either diatrizoate, iohexol, ioxilan, or saline in 24 Wistar rats with a tubular dysfunction induced by IV sodium maleate. Ioxilan and saline had a similar effect on albumin excretion, iohexol had an intermediate effect, and diatrizoate increased it significantly from day 2 to day 7. Glucosuria was significantly greater after diatrizoate than after the nonionic contrast media (CM) or saline. Diatrizoate delayed normalization of enzymuria, whereas iohexol and ioxilan did not. None of the CM affected urinary sodium or phosphate excretion. It is concluded that Fanconi's syndrome is significantly aggravated only by diatrizoate.

Effects of contrast media on the conducting system of the heart during coronary angiography. A comparison of Renografin-76 to Hypaque-76.

Electrocardiographic changes induced by ionic contrast media can cause complications during coronary angiography. A conduction delay through various parts of the heart is one factor in the genesis of asystole or ventricular fibrillation. Hypaque-76 (H76) and Renografin-76 (R76) are nearly identical ionic contrast media except that R76 binds more calcium than H76 because of the presence of sodium citrate and EDTA in R76. To determine whether the calcium binding additives in ionic contrast media contribute to the cardiac conduction abnormalities, we examined conduction time through the atrioventricular (AV) nodal tissue (via bipolar His bundle electrograms) and through the distal part of the conduction system (recording the QRS complex from the ECG) during coronary angiography. We injected 10 mL of H76 and R76 in 19 closed chest dogs in a blinded, randomized fashion during coronary angiography. The effects of H76 and R76 on heart rate, AH interval, HV interval, V interval and PR interval, and QRS complex duration were recorded. In 14 nonatrial pacing dogs, compared with H76, R76 produced a greater increase in the AV interval (32.9 +/- 6 milliseconds vs 12.4 +/- 2 milliseconds, P less than .01) and the PR interval (29.6 +/- 6 milliseconds vs 11.9 +/- 4 milliseconds, P less than .02). Additionally, the heart rate decreased 13.9 +/- 3.5 beats/minute from control with R76 compared with a decrease of 4.2 +/- 2.6 beats/minute from control with H76 (P less than .05). There was no significant difference between the prolongation of the HV interval and V interval, or QRS complex duration generated by R76 and H76.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of contrast media on prostaglandin synthesis in vivo.

Since systemic reactions to contrast media (CM) in patients often resemble pathophysiologic conditions associated with prostaglandin metabolites prostacyclin (PGI2), and thromboxane B2 (TXB2), plasma levels of these mediators are likely to provide an index of CM pathogenesis. In this study, patients undergoing peripheral arteriography were injected either with a hyperosmolal CM sodium diatrizoate or with a newer low osmolal CM, iohexol. Arterial blood samples were collected before and after the procedure. Prostacyclin and thromboxane were quantified as 6 ketoprostaglandin F1a (PGF1a) and TXB2 by using radioimmunoassay kits. Diatrizoate caused prostaglandin I2 (PGI2) release in 60% of patients, whereas 66% receiving iohexol also exhibited increased levels of PGI2 in their plasma. TXB2 concentration remained unchanged. No clinically adverse reactions were seen following the procedure. These results indicate that both high and low osmolality CM are capable of stimulating vascular endothelium, thereby causing prostacyclin release. Molecular mechanisms, however, remain to be determined.

Intravascular contrast media and the blood-brain barrier. Testing the new nonionic agent ioxilan.

The effects of diatrizoate, iohexol, and ioxilan on the blood-brain barrier (BBB) were investigated in normal and hypertensive rats. Anesthetized Wistar rats received 14C-inulin as an indicator for BBB disruption. Diatrizoate, iohexol, or ioxilan (350 and 175 mgI/mL) or normal saline was then injected into the carotid artery (2 mL in 30 seconds). Twenty minutes later, the cardiovascular system was flushed, the brain removed, and each hemisphere was digested. BBB disruption, expressed as counts/minute/mg protein, was compared for each hemisphere in each group by analysis of variance. BBB damage in the diatrizoate-350 group was significantly greater than that in all other groups. No significant BBB damage resulted from iohexol or ioxilan relative to normal saline.

The aggravating effect of dehydration on pulmonary edema induced by ionic and nonionic contrast media.

High intravenous doses of diatrizoate are known to induce a profound degree of pulmonary edema in the rat. In euhydrated rats, similar doses of iohexol do not induce significantly higher lung weights when compared with nontreated animals. However, for dehydrated rats, intravenous administration of equivalent doses of these agents results in significant pulmonary edema formation with iohexol, and enhanced edema with diatrizoate; the same magnitude of response is not seen in euhydrated rats. These results show that patients susceptible to severe contrast reactions should be well-hydrated and preferably given a nonionic agent when contrast material must be administered.

Urine profiles following intravenous diatrizoate, iohexol, or ioxilan in rats.

The effects of intravenous diatrizoate, iohexol, ioxilan, or saline on albumin, glucose, sodium and the enzymes N-acetyl-beta-D-glucosaminidase (NAG), lactate dehydrogenase (LDH), and L-gamma-glutamyltransferase (GGT) in the urine of 24 normal Wistar rats were followed for seven days. During the first two hours after administration of diatrizoate, all profile components changed markedly; the albumin excretion was significantly greater than following ioxilan and iohexol; glucose, LDH, and GGT excretions were significantly greater than following ioxilan. Iohexol and ioxilan caused a higher excretion of albumin, LDH, and GGT than saline. Iohexol also increased glucose and sodium levels. Glucose and GGT were significantly higher following iohexol than following ioxilan. Both high osmolar and low osmolar contrast media may cause temporary glomerular and tubular damage. Urine profile components are affected most by diatrizoate, less by iohexol, and least by ioxilan.

Cardiac and hemodynamic tolerability of iodinated contrast media in the anesthetized rat.

RATIONALE AND OBJECTIVES: The study was designed to compare the hemodynamic effects of 11 iodinated contrast media (CM), including ionic (diatrizoate, ioxaglate), nonionic monomeric (iohexol, iopromide, iopamidol, iopentol, ioversol, iomeprol, ZK 139129), and nonionic dimeric (iotrolan, iodixanol) compounds. METHODS: Following left ventricular bolus injection of 1.2 g I/kg body weight in anesthetized rats, cardiohemodynamic parameters were measured. RESULTS: Compared with the control group, except for blood pressure (BP), all CM showed a similar response regarding the direction of the cardiohemodynamic changes after CM injection. A biphasic change in BP was observed for diatrizoate and iodixanol, whereas all other CM showed a transient increase in BP being most pronounced for ioxaglate. No arrhythmias were detected. The increase in LVEDP was lowest for the isotonic dimeric CM iotrolan and iodixanol. CONCLUSIONS: Only mild transient side effects were observed. Low osmolar, especially isotonic, dimeric CM show a clear benefit regarding cardiovascular side effects.

Scanning electron microscopic (SEM) studies on the effect of x-ray contrast media on aortic endothelium in the rat.

A study comparing the effects of diatrizoate, ioxitalamate, metrizamide, ioxaglate, and a 22% sorbitol on aortic endothelia of the rat was performed. In each case 1 ml of the respective solution was injected in a single dose into the aorta. Endothelial damage was seen after injection of metrizamide, diatrizoate, and ioxitalamate. After injection of ioxaglate or sorbitol, only minor endothelial changes were observed.

Histologic effects of Amipaque (metrizamide) and various contrast media on mouse peritoneum.

The histologic effects of Amipaque and various commonly used contrast media on mouse peritoneum were studied by intraperitoneal injections of Amipaque 370 mg I/ml and 170 mg I/ml, Conray 300 mg I/ml, Conray Meglumine 282 mg I/ml, Urografin 60% and 76%, Gastrografin and barium sulfate. Amipaque and the other water-soluble media cause no deleterious effects, whereas barium sulfate evokes granulomatous inflammatory reaction. Amipaque is suitable for gastrointestinal studies when leakage into the peritoneal cavity is expected.

Contrast media induced pulmonary edema. Comparison of ionic and nonionic agents in an animal model.

High intravenous doses of diatrizoate are known to induce pulmonary edema in the rat. The newer generation of contrast media--nonionics and monovalent dimers--are considered less toxic than diatrizoate. In this study we evaluated the degree of pulmonary edema induced by a high dose (6 g I/kg) of these new agents and found that Ioxaglate produced higher lung weights than Renografin 60 and Iopamidol. Iohexol and Amipaque did not induce a significant degree of edema. The model used in this study demonstrates distinct differences in pulmonary toxicity among these new agents, when given in doses exceedingly higher than given in clinical practice.

Antiplatelet action of intravascular contrast media. Implications in diagnostic procedures.

The antiplatelet action of intravascular contrast media (CM) Renografin-76 (diatrizoate meglumine and diatrizoate sodium) was studied in vitro and in 21 patients undergoing radiodiagnostic procedures. In vitro studies suggested that in Renografin-76, meglumine was the chief constituent responsible for its antiplatelet action. In post-CM plasma from patients, clotting times were prolonged and platelet aggregation greatly impaired, albeit normal aggregation restored within 3 hours. Although changes in global clotting times and platelet aggregation were mostly transient, it is possible that CM usage in patients with thrombocytopenia, sickle cell phenomenon, and on anticoagulant-antiplatelet drugs may present a serious risk to their hemostatic integrity.

Investigation of a new arthrographic contrast agent: Iotrol.

A new nonionic dimer (Iotrol; Schering AG) and diatrizoate meglumine-diatrizoate sodium (Renografin-60; Squibb) were compared as arthrographic agents by injecting these substances into the knees of rabbits. Three experienced arthrographers judged the image quality produced by Iotrol to be superior to that of Renografin-60. Following animal sacrifice, histologic examination of the synovium revealed a significant difference in the inflammatory response evoked by the contrast agents: Iotrol caused less inflammation. In a second group of rabbits, methylprednisolone was subcutaneously injected 24 hours before the arthrographic studies. The methylprednisolone significantly reduced the inflammation in the Renografin-60 subgroup when compared with the nonmedicated counterparts. No significant effect was noted in a like comparison with Iotrol. In addition, the administration of methylprednisolone led to a deterioration of the radiographic images. Based upon our data, we believe Iotrol is superior to Renografin-60 as an arthrographic agent.

Experimental tissue damage after subcutaneous injection of water soluble contrast media.

Various water soluble contrast media (WSCM) were injected subcutaneously into 970 hind feet of 485 rats. Gross morphologic changes were seen after the injection and analyzed as a function of various physicochemical characteristics of WSCM. The WSCM of larger volume, higher osmolality, higher iodine content, and meglumine salts rather than sodium salts caused more severe tissue damage; younger rats showed more severe tissue damage by WSCM of high osmolality.