Association of Urine Platinum With Acute Kidney Injury in Children Treated With Cisplatin for Cancer

Cisplatin is a chemotherapeutic agent highly excreted in urine and known to cause acute kidney injury (AKI). As AKI diagnosis by serum creatinine (SCr) is usually delayed, endeavors for finding early AKI biomarkers continue. This study aims to determine if urine platinum (UP) concentration 24 hours after cisplatin infusion is associated with AKI, and to evaluate the association between urine platinum and tubular damage biomarkers: neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Children treated with cisplatin in 12 Canadian centers (April 2013 to December 2017) were included. Urine from the morning after the first cisplatin infusion of the first or second cisplatin cycle was measured for urine platinum, NGAL, and KIM-1. SCr and serum electrolytes were used to detect AKI by either SCr elevation or urinary electrolyte wasting (potassium, magnesium, phosphate). The associations of urine platinum with AKI, NGAL, and KIM-1 were assessed. A total of 115 participants (54% boys, median age, 8.5 years; interquartile range, 4.0-13.4) were included, of which 29 (25%) and 105 (91%) developed AKI defined by SCr and electrolyte criteria, respectively. Higher urine platinum was associated with higher cisplatin dose (Spearman rho, 0.21) and with younger age (Spearman rho, -0.33). Urine platinum was not associated with postinfusion AKIor KIM-1, but was weakly associated with NGAL, particularly in participants without SCr AKI (Pearson's r, 0.22). Urine platinum may be a marker of mild tubular injury but is not likely to be a useful biomarker of clinically evident AKI.

Silicone implants--a possible confounder for urinary platinum background concentrations?

INTRODUCTION

Urinary platinum excretion from occupationally unexposed population is very low. Up to now, in Germany, dental noble metal alloys and a platinum based chemotherapy have been identified as reason for elevated urine concentrations. As fabrication of silicone involves platinum as catalyst, this study examines the potential release of platinum from silicone breast implants by quantifying urinary platinum concentration.

METHODS AND RESULTS

Platinum release from three different types of silicone implants into saline solution was measured in a laboratory experiment. It showed a strong increase of platinum concentration during the first 30 min and high platinum concentrations even after 60 h. In the following field study urinary platinum concentrations were determined from 30 women with dental gold alloy restorations and 28 women without such dental inlays. Median platinum concentrations were 5.2 ng/l urine (21.2 ng/g creatinine) for the women with dental gold inlays and 6.0 ng/l urine (5.4 ng/g creatinine) for those without. Compared with the urinary platinum concentrations provided by the German Environmental Survey (GerES) for the general female population the urinary platinum levels of women with silicone implants of the presented study were significantly higher, both for the study groups with and without dental gold alloy inlays.

CONCLUSIONS

Silicone breast implants must be considered as a new confounder and as a further contributor to elevated urinary platinum concentrations in human platinum background reference values of women.

Flow injection analysis with electrochemical detection for rapid identification of platinum-based cytostatics and platinum chlorides in water

Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED). Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer) and potential changes (1,000, 1,100 and 1,200 mV) offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

Speciation of platinum in blood plasma and urine by micelle-mediated extraction and graphite furnace atomic absorption spectrometry

A highly sensitive and selective technique for the speciation of platinum by cloud point extraction prior to determination by graphite furnace atomic absorption spectrometry (GFAAS) was described. The separation of Pt(II) from Pt(IV) was performed in the presence of 4-(p-chlorophenyl)-1-(pyridin-2-yl)thiosemicarbazide (HCPTS) as chelating agent and Triton X-114 as a non-ionic surfactant. The extraction of Pt(II)-HCPTS complex needs temperature higher than the cloud point temperature of Triton X-114 and pH = 7, while Pt(IV) remains in the aqueous phase. The Pt(II) in the surfactant phase was analyzed by GFAAS, and the concentration of Pt(IV) was calculated by subtraction of Pt(II) from total platinum which was directly determined by GFAAS. The effect of pH, concentration of chelating agent, surfactant, and equilibration temperature were investigated. An enrichment factor of 42 was obtained for the preconcentration of Pt(II) with 50 mL solution. Under the optimum experimental conditions, the calibration curve was linear up to 30 μgL(-1) with detection limit of 0.08 μgL(-1) and the relative standard deviation was 1.8%. No considerable interference was observed due to the presence of coexisting anions and cations. The accuracy of the results was verified by analyzing different spiked samples (tap water, blood plasma and urine). The proposed method was applied to the speciation analysis of Pt in blood plasma and urine with satisfactory results.

Determination of Rh, Pd and Pt in urine samples using a pre-concentration sequential injection analysis system coupled to a quadrupole-inductively coupled plasma-mass spectrometer

The proposed flow system was developed in order to minimize the drawbacks related to the PGEs determination by quadrupole-inductively coupled plasma-mass spectrometry (Q-ICP-MS). It was intended not only to lower the limits of detection (LODs) but also to eliminate the interferences originating from some atomic and molecular ions produced in the argon plasma. This was accomplished by means of an on-line sample clean-up/pre-concentration step, using a chelating resin (Metalfixtrade mark Chelaminetrade mark) in which Rh, Pd and Pt were preferably retained when compared with the interfering species. The results obtained by using the developed flow system in the analysis of urine samples are presented. With a sampling rate of 9 samples h(-1) (i.e., 27 determinations) and a sample consumption of ca. 10 mL, the developed flow system allowed linear calibration plots up to 100 ngL(-1) with detection limits of 1.2 ngL(-1) (Rh), 0.4 ngL(-1) (Pd) and 0.9 ngL(-1) (Pt). Repeatability studies showed good precision (R.S.D.%, n=5): 3.7% (Rh); 2.6% (Pd) and 2.4% (Pt), for 10 ngL(-1); 2.4% (Rh); 1.4% (Pd) and 1.9% (Pt), for 50 ngL(-1); and 1.3% (Rh); 0.58% (Pd) and 0.62% (Pt), for 100 ngL(-1). By spiking human urine samples, recovery tests were performed, and the values obtained ranged between 89% and 105% (Rh); 90% and 104% (Pd); and 93% and 105% (Pt).

Biomonitoring of tram drivers exposed to airborne platinum, rhodium and palladium

OBJECT

The aim of this study was to evaluate urinary levels of Pt, Rh and Pd in occupationally exposed subjects.

METHODS

A total of 122 healthy male subjects of Rome (Italy) were studied; 64 were municipal tram drivers and 58 control subjects. Metal quantification in the urine samples was carried out by sector field inductively coupled plasma mass spectrometry.

RESULTS

There were statistically significant differences between urinary Pt and Rh levels of the workers and the control group (Pt median: 1.23 versus 1.03 ng/g creatinine; Rh median: 19.16 versus 11.18 ng/g creatinine), while no difference in Pd levels was observed (Pd median: 11.47 versus 8.75 ng/g creatinine).

CONCLUSIONS

Urinary Pt and Rh could be useful biomarkers for monitoring population groups occupationally exposed to these elements. Urinary concentration of Pt and Rh, though still low, could be of some concern in workers heavily exposed to urban car traffic.

Comments on total platinum concentration and platinum oxidation states in body fluids, tissue, and explants from women exposed to silicone and saline breast implants by IC-ICPMS

The paper by Lykissa and Maharaj (Lykissa, E. D.; Maharaj, S. V. M Anal. Chem. 2006, 78, 2925-2933) purports to provide evidence that the urine of women with silicone breast implants contain 60 to over 1700 times more platinum in their urine that the urine of people with no known exposure to platinum. Further, they purport to show evidence that the platinum used in the manufacture of breast implants (Pt0) is converted by a unknown process to yield highly oxidized platinum species, stable in biological matrixes, up to and including Pt6+. This correspondence poses three questions associated with the work and directs the reader's attention to the data, which clearly show that the blood and urine platinum levels in implanted women and their healthy control group were not significantly different from one another.

Comments on Total Platinum Concentration and Platinum Oxidation States in Body Fluids, Tissue, and Explants from Women Exposed to Silicone and Saline Breast Implants by IC−ICPMS

The paper by Lykissa and Maharaj (Lykissa, E. D.; Maharaj, S. V. M. Anal. Chem. 2006, 78, 2925-2933) comes to two main conclusions: platinum is found at elevated levels in women who have received breast implants, and the platinum is present in unusual oxidation states. The authors make clear their view that these are very surprising and disturbing results, both because of the quantity of platinum found and the association between higher oxidation states of platinum and toxicity of various types (sensitization-contact dermatitis, carcinogencity, among others). However, the conclusions arrived at by the authors are unsupported by the Experimental Section of the paper and the data that are reported there, and contravene the well-established chemistry of platinum.

Simultaneous Determination of Palladium, Platinum and Rhodium by On-Line Column Enrichment and HPLC with 5-(2,4-Dihydroxyphenylazo)-Rhodanine as Pre-Column Derivatization Reagent

In this paper, a new method for the simultaneous determination of palladium, platinum and rhodium ions was developed using a rapid column high performance liquid chromatography equipped with on-line enrichment technique. The palladium, platinum and rhodium ions were pre-column derivatized with DHAR to form colored chelates. The Pb-DHAR, Pt-DHAR and Rh-DHAR chelates could be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column [ZORBAX Stable Bound, 4.6 x 10 mm, 1.8 microm] with a 0.05 mol L(-1) of phosphoric acid solution as mobile phase. After enrichment, and by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and traveling towards the analytical column. The separation of these chelates on the analytical column [ZORBAX Stable Bound, 4.6 x 50 mm, 1.8 microm] was satisfactory with 54% acetonitrile (containing 0.05 mol L(-1) of phosphoric acid and 0.1% of tritonX-100) as mobile phase. Palladium, platinum and rhodium were separated completely within 2 min. By on-line enrichment technique, the enrichment factor of 100 was achieved, and the detection limits (S/N = 3) of palladium, platinum and rhodium reaches 1.4 ng L(-1), 1.6 ng L(-1) and 2.0 ng L(-1), respectively. This method was applied to the determination of palladium, platinum and rhodium in water, urine and soil samples with good results.

Simultaneous determination of palladium, platinum, rhodium and gold by on-line solid phase extraction and high performance liquid chromatography with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine as pre-column derivatization regents

In this paper, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A new method for the simultaneous determination of palladium, platinum, rhodium and gold ions as metal-HNATR chelates was developed using a rapid analysis column high performance liquid chromatography equipped with on-line solid phase extraction technique. The samples (Water, human urine, geological samples and soil) were digested by microwave acid-digestion. The palladium, platinum, rhodium and gold ions in the digested samples were pre-column derivatized with HNATR to form colored chelates. The Pd-HNATR, Pt-HNATR, Rh-HNATR and Au-HNATR chelates can be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column [Zorbax Stable Bound, 10 mm x 4.6 mm, 1.8 microm] with a buffer solution of 0.05 mol L(-1) phosphoric acid as mobile phase. After the enrichment had finished, by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and travelling towards the analytical column. These chelates separation on the analytical column [Zorbax Stable Bound, 10 mm x 4.6 mm, 1.8 microm] was satisfactory with 72% acetonitrile (containing 0.05 mol L(-1) of phosphoric acid and 0.1% of Triton X-100) as mobile phase. The palladium, platinum, rhodium and gold chelates were separated completely within 2.5 min. Compared to the routine chromatographic method, more then 80% of separation time was shortened. By on-line solid phase extraction system, a large volume of sample (10 mL) can be injected, and the sensitivity of the method was greatly improved. The detection limits (S/N=3, the sample injection volume is 10 mL) of palladium, platinum, rhodium and gold in the original samples reaches 1.4, 1.8, 2.0 and 1.2 ng L(-1), respectively. The relative standard deviations for five replicate samples were 2.4-3.6%. The standard recoveries were 88-95%. This method was applied to the determination of palladium, platinum, rhodium and gold in human urine, water and geological samples with good results.

High performance liquid chromatographic determination of platinum in blood and urine samples of cancer patients after administration of cisplatin drug using solvent extraction and N,N'-bis(salicylidene)-1,2-propanediamine as complexation reagent

A high performance liquid chromatographic (HPLC) procedure has been developed for the determination of cisplatin, based on the pre-column derivation of platinum(II) with reagent N,N'-bis(salicylidene)-1,2-propanediamine (H2SA2pn). The neutral platinum complex was extracted, concentrated in an organic solvent and then injected (5 microl) on a reverse phase HPLC column, Varian Micro-Pak SP C-18, 5 microm (150 mm x 4.0 mm i.d.). The complex was eluted isocratically using a ternary mixture of methanol/acetonitrile/water (40/30/30, v/v/v) at a flow rate of 1.0 ml/min and was determined by a UV detector set at 254 nm after elution. A detection limit was found to be 4.0 ng per injection. The amounts of platinum in blood serum and urine of cancer patients after administration of cisplatin were observed in a range of 221-298 ng/ml and 43-97 ng/ml with relative standard deviation (R.S.D.) of 3.6-4.6% and 3.5-4.8%, respectively. Preliminary metabolism profiles of Pt concentrations in blood and urine from the patients were established.

Single-dose pharmacokinetics of a novel oral platinum cytostatic drug ([OC-6-43]-bis[acetato][1-adamantylamine]amminedichloroplatinum [IV]) in pigs

The pharmacokinetics of total platinum (Pt) were investigated after a single oral dose of (OC-6-43-bis(acetato)(1-adamantylamine)amminedichloroplatinum (IV) (LA-12). A dose of 3 mg/kg (n = 3) and 30 mg/kg (n = 3) was given to two parallel groups of pigs (n = three each). Pt was measured in the blood, urine and feces by atomic absorption spectrometry. Blood was sampled at specified times until 240 h, urine was obtained through a catheter at 1-h intervals until 6 h, and feces were collected until 240 h after administration. LA-12 was rapidly absorbed, as indicated by a T(max) of total Pt within 0.5-1.5 h after administration. The mean (SEM) values for maximum plasma concentration (0.060 +/- 0.025 and 0.39 +/- 0.08 mg/l) and the area under the plasma concentration vs. time curve (12.6 +/- 5.6 and 36.3 +/- 2.0 mg.h/l) increased less than proportionally to the increase in the dose. The mean (SEM) Pt urinary excretion determined over a 6-h postdose period achieved only 1.9% and 0.8% of the administered doses, respectively. Within 2 h after dosing, the renal clearance of total Pt was approximately 2-fold higher than that of creatinine (CL(cr)). Thereafter, it steadily dropped and in the last collection interval (5-6 h postdose) its value was 50% less than CL(cr). Platinum recoveries in feces over 10 days after dosing reached 0.4% and 2.6% of the administered dose, respectively. This finding indicates that the extent of absorption of both doses was high. There were no changes in results of hematology and clinical biochemistry tests.

Comparison of inductively coupled plasma mass spectrometry techniques in the determination of platinum in urine: quadrupole vs. sector field

In recent years the increasing use of platinum (Pt) both in medical and in industrial applications has caused its growing anthropogenic emission and spread in the environment. Pt is released into the atmosphere by exhaust catalytic converters, and Pt compounds are often used in antitumour therapies. As a consequence, significant amounts of Pt can be detected in hospital wastewaters. This can lead to an increase in the exposure levels to Pt, especially in urban areas. It is therefore necessary to determine Pt reference values in the general population, by using suitable procedures able to achieve adequate analytical performances. Several measurements of Pt in biological fluids have been reported, but the analytical methods used for the determination of Pt often lack information about the uncertainty of the results, especially for low concentrations of urinary Pt in non-occupationally exposed subjects. The present paper considers the measurement of urinary Pt levels in a general population group from central Italy, by both quadrupole (Q) and sector field (SF) inductively coupled plasma mass spectrometry (ICP-MS). The two procedures were validated and their expanded uncertainties were evaluated. The limits of detection (LODs), calculated taking into account dilution factors, were 0.18 and 0.05 ng L(-1) of Pt for the Q and SF procedures, respectively. The median value observed was 4.13 ng L(-1) of Pt in urine, while the relative combined uncertainty at 5 ng L(-1) was below 20% with both ICP-MS techniques. These data are in good agreement with those reported in the literature for similar studies.

Biomonitoring of titanium, mercury, platinum, rhodium and palladium in dental health care workers

BACKGROUND

In dentistry, titanium, mercury, platinum, rhodium and palladium are used to produce dental fillings. Therefore, dental workers who apply such materials may be exposed to these metals.

METHODS

The study concerned 40 healthy subjects-20 controls and 20 dental health care workers-to determine serum and urinary levels of the aforementioned metals by inductively coupled plasma mass spectrometry.

RESULTS

Mean urinary and serum titanium did not reveal statistically significant differences in the two groups. The very low urinary and serum levels of mercury, platinum, rhodium and palladium prevented us from making a statistical evaluation between the two groups.

CONCLUSIONS

We did not find a significant increase in serum and urinary titanium levels in dental health care workers. Measurement of mercury, platinum, rhodium and palladium in urine and serum was not useful in determining occupational exposure.

Early onset of cisplatin-induced nephrotoxicity in streptozotocin-diabetic rats treated with insulin

Mechanism of protection against cisplatin nephrotoxicity in streptozotocin-diabetic rats is unclear but is associated with decreased renal platinum accumulation. This study was designed to determine whether normalization of hyperglycaemia by insulin treatment to six week streptozotocin-diabetic rats reversed protection against cisplatin nephrotoxicity. Male Sprague-Dawley rats divided into 3 groups (n=10/group) (1) non-diabetic (2) untreated streptozotocin-diabetic and (3) insulin-treated streptozotocin-diabetic groups were rendered diabetic using streptozotocin (65 mg/kg body weight, intravenous). At the end of 6 weeks, Group 3 animals were treated with insulin (subcutaneously) for 21 days to normalize glucose. After 21 days of insulin treatment, the mean +/- S.D. plasma glucose (mg%) in Group 3 animals at 144.8 +/- 22.03, was significantly lower than Group 2 animals (412 +/- 24.69) and comparable to age-matched non-diabetic (Group 1) animals. Blood urea nitrogen at 24 hr after intraperitoneal administration of cisplatin (5 mg/kg body weight) increased by a factor 2.5 in Group 3 compared to 1.1 and 1.3 in Group 1 and Group 2 animals respectively. In the same animals, at 96 hr the blood area nitrogen increased by a factor of 3.2 and 2.9 in Group 1 and Group 3 respectively compared to 1.14 for Group 2 animals. Renal platinum levels in Group 1, Group 2 and Group 3 after 96 hr after cisplatin administration were 6.92 +/- 0.83, 3.46 +/- 0.77 & 6.20 +/- 0.64 (microg/g wet weight of tissue) respectively. Results indicate that 21 day insulin treatment to streptozotocin-diabetic animal reverses protection against cisplatin toxicity. Moreover, insulin treatment increased the susceptibility of streptozotocin-diabetic rats to cisplatin-induced renal toxicity.

Biomonitoring of traffic police officers exposed to airborne platinum

BACKGROUND

Over the past two decades there has been a substantial increase in environmental levels of palladium, platinum, and rhodium, the platinum group elements (PGEs), due to the widespread use of catalytic converters for automotive traction.

AIM

To evaluate urinary platinum levels in occupationally exposed subjects.

METHODS

A total of 161 employees from the Rome City Police Force were studied; 103 were traffic police involved in controlling streets with an average flow of vehicles, while the remaining 58 were control subjects engaged only in office work. Platinum quantification in the urine samples of these subjects was carried out by sector field inductively coupled plasma mass spectrometry.

RESULTS

There were no statistically significant differences between platinum levels in the group of subjects engaged in traffic control and the control group (4.45 (2.42) ng/l v 4.56 (2.84) ng/l, respectively).

CONCLUSIONS

Urinary levels were found to be higher than those reported for other urban populations, thus showing a progressive increase in human exposure to Pt.

Platinum determination by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) in different matrices relevant to human biomonitoring

The analytical challenges of Pt determination by ICP-SFMS posed by different human tissues and fluids have been critically assessed. Investigated samples were (1) urine, (2) serum of cancer patients sampled during chemotherapy with carboplatin, (3) microdialysates (20 micro L sample volume) collected from tumor and non-tumor tissue, and, finally-for the first time-(4) human lung tissue to study background concentrations of inhaled platinum. Sample preparation involved microwave digestion and open vessel treatment or simple dilution (microdialysates). Depending on the sample preparation and introduction systems used (microconcentric nebulization, ultrasonic nebulization with and without membrane desolvation) excellent procedural detection limits (3s criterion) of 0.35 pg g(-1) for urine, 420 pg g(-1) for serum, 400 pg g(-1) for lung tissue and 13 pg g(-1) for microdialysates could be obtained. Ultratrace concentrations of 1-40 pg g(-1), and 1000-3000 pg g(-1) were measured in urine and human lung tissue, respectively, as typical for samples in environmental studies. Quantification was carried out by IDMS and standard addition in the case of urine samples. Internal standardization could not correct for non-spectral interferences in external calibration. In the serum and microdialysates of patients during chemotherapy with carboplatin, elevated Pt levels ranging between 0.01 and 10 micro g g(-1) were determined by external calibration ((195)Pt isotope). For all investigated samples spectral interferences could be excluded by following different strategies. High-resolution control measurements ((194)Pt, (195)Pt) were performed in the case of elevated Pt levels, i.e. for microdialysates and serum samples. An Hf/Pt ratio of 0.4 was determined in human lung samples. An HfO formation ratio of 0.2% was assessed for standard solutions at the present experimental conditions, revealing that the contribution of (179)Hf(16)O, (178)Hf(17)O, (177)Hf(18)O to the (195)Pt isotope signal used for quantification was not significant.

Pharmacokinetics of satraplatin (JM216), an oral platinum (IV) complex under daily oral administration for 5 or 14 days

BACKGROUND

Satraplatin (JM216; bis-acetatoammine-dichlorocyclohexylamine platinum (IV)) is a platinum (Pt) complex developed in an attempt to circumvent tumour resistance and which can be administered by the oral route. The fate of platinum delivered by this oral formulation administered at various doses under the 5 or 14 days schedule, has been studied to a limited extent.

PATIENTS AND METHODS

Total (Ptot) and ultrafilterable (PtUF) platinum were determined in 19 patients enrolled in phase I (PI) and II (PII) studies (PI, n = 14, advanced cancer; PII, n = 5, untreated small cell lung carcinoma). JM216 doses were 10 to 50 mg m-2 day-1 x 14 d (days) (dose escalation in PI) and 120 mg m-2 day-1 x 5d (fixed dose in PII), administered to fasted patients in a standardized way. Ptot and PtUF levels were determined by atomic absorption spectrometry on d1 and d14, followed over 28 days in PI; and on d1, followed over 5 days in PII. Pharmacokinetic parameters were derived by a noncompartmental approach.

RESULTS

JM216 is rapidly absorbed with a Tmax obtained within 2.5-3 hours and 1-2 hours for Ptot and PtUF, respectively. The pharmacokinetics of JM216 was linear across the tested doses in PI, with the exposure of Ptot on d14 being better correlated with dose per BSA (Body surface area) (r = 0.91) than that of PtUF (r = 0.61). In PI, Cmax on d1 increased proportionally to the dose (r = 0.82 and r = 0.72 for Ptot and PtUF, respectively). Apparent clearances in PI were 1.1 +/- 0.5 L h-1 and 37.0 +/- 33 L h-1 for Ptot and PtUF, respectively. Prolonged terminal half-lives were observed after the last JM216 administration with mean values of 216 +/- 37 hours and 107 +/- 89 hours, for Ptot and PtUF respectively. The accumulation ratio (Cmaxd14/Cmaxd1) indicated a higher accumulation of Ptot (3.5 +/- 1.6) than of PtUF (1.8 +/- 1) under multiple dose regimen. The apparent volumes of distribution (terminal phase) were similar in the PI and PII studies: 326 +/- 112 L and 3094 +/- 1493 L, and 557 +/- 267 L and 4154 +/- 2147 L, for Ptot and PtUF, respectively. In PI, the nadir of thrombocytopenia was related both to the cumulated dose of JM216 (r = 0.81) and to the AUC of Ptot on d14 (r = 0.77), whereas the AUC of PtUF was not predictive (r = 0.48). The Cmax of Ptot and PtUF on d1 was related to neutropenia (r = 0.61 and r = 0.65, respectively) and to thrombocytopenia (r = 0.77 and r = 0.74, respectively). No relationships were found between leukocytes or neutrophils percent decrease and the AUCs or total, dose of JM216.

CONCLUSION

JM216 is an orally bioavailable platinum-containing chemotherapeutic agent yielding predictable total levels of platinum which appears to accumulate in plasma after multiple administration over 14 days. These results should be set in relation to clinical efficacy and tolerance, to optimise the dose regimen of JM216 in further studies.

Allergic reaction to platinum in silicone breast implants

Platinum is used as a catalyst in the manufacture of silicone breast implants. Because platinum is recognized as a potent sensitizer in certain circumstances, some have expressed concern that women with silicone breast implants are exposed to platinum, which is causing allergic reactions. We searched the literature for information on the level of platinum in breast implants and reports of sensitization that clearly related to platinum in women with breast implants. We found no published report with convincing evidence that platinum causes allergic reactions in women with breast implants or that women with breast implants are any more likely to have allergic reactions than women without breast implants.

Biological monitoring of hospital personnel occupationally exposed to antineoplastic agents

To detect trace amounts of urinary cyclophosphamide (CP), ifosfamide (IF) and methotrexate (MTX), sensitive and specific high-performance liquid chromatography/ tandem mass spectrometry (HPLC-MS/MS) procedures, incorporating either liquid-liquid (for CP and IF), or solid-phase, extraction (for MTX) have been developed. Urinary platinum (Pt) was also detected using inductively coupled plasma-mass spectrometry (ICP-MS). These methods showed acceptable imprecision and inaccuracy. The limit of detection (LOD) was 50 ng/l for CP and IF, 200 ng/l for MTX and 1 ng/l for Pt. Biomonitoring was performed on two consecutive days on nine subjects preparing, and seven administering, antineoplastic drugs. Urine was collected at the beginning, at the end and during the work shift. Eighteen urine samples were positive for CP (range: 50-10031 ng/l), whereas IF was detected in one subject only (153 ng/l). LOD was never exceeded for MTX. In urine samples from nurses and pharmacy technicians, Pt was detected in three subjects (range 920-1300 ng/l). These findings were compared with the results from a previous survey carried out in the same hospital when different work practices were in use. The proposed methods are simple, fast and reliable and can be used to identify exposure of hospital personnel handling antineoplastic drugs.

Pharmacokinetics of oxaliplatin (NSC 266046) alone and in combination with paclitaxel in cancer patients

Oxaliplatin (OPT), a third-generation platinating agent, is currently being evaluated in a phase II clinical trial in head and neck cancer patients and in a phase I clinical trial in combination with paclitaxel (TXL).

PURPOSE

The aim of this study was to investigate the pharmacokinetics and biological correlates of OPT alone as well as the potential pharmacokinetic interaction between OPT and TXL.

METHODS

In the phase II study, OPT was given alone as a 2-h i.v. infusion at 60 mg/m(2) weekly for 4 weeks with the cycle repeated after a 2-week rest. In the concurrent phase I combination trial OPT was also given as a 2-h i.v. infusion, but followed by a 1-h i.v. infusion of TXL, weekly for 4 weeks with the cycle repeated after a 2-week rest. The clinical pharmacokinetics of OPT alone and in combination with TXL were investigated in the first cycle of each treatment protocol. The platinum levels in plasma, plasma ultrafiltrate (PUF) and urine were measured by a fully validated inductively coupled plasma mass spectrometry (ICPMS) method.

RESULTS

In the ten patients receiving OPT alone, the concentration-time profiles of total platinum exhibited a biexponential decline both in plasma and in PUF. The peak levels of platinum were 2.72+/-0.41 microg/ml in plasma and 1.36+/-0.42 microg/ml in PUF at the end of the OPT infusion, and the platinum levels were still detectable at >10 ng/ml 94 h after the OPT infusion. The mean terminal t(1/2) values of total platinum in plasma and in PUF were 58.9 h and 22.8 h, respectively. The AUC of ultrafilterable platinum represented about 10% of that of the total plasma platinum. The platinum levels in the DNA fraction of peripheral white blood cells (WBC) correlated with the platinum levels in PUF ( r=0.77, P<0.01). In the phase I combination study, the dose level of OPT was escalated from 35 mg/m(2) to 60 mg/m(2). The concentration-time profiles of platinum in the combination trial also showed biexponential decay in plasma and in PUF as exhibited by OPT alone. However, the terminal elimination rate constant (beta) of total plasma platinum increased at all dose levels of OPT when combined with TXL at 45 mg/m(2) ( P<0.05). A concomitant increase in clearance (CL) of total plasma platinum was observed at the OPT dose level of 45 mg/m(2) in combination with TXL at 45 mg/m(2). No statistically significant difference in the 24-h urinary elimination of total platinum was detected between the combination groups and the single-agent group. The AUC values of total platinum in PUF were proportional to OPT doses ranging from 35 to 60 mg/m(2), whether OPT was given alone or in combination with TXL.

CONCLUSIONS

OPT clearance may be enhanced by TXL when the two agents are used in combination in patients. The Pt-DNA adduct level in peripheral WBC was found to be a good indicator for oxaliplatin exposure in patients, and should be further exploited for potential tumor drug exposure.

Atypical pharmacokinetics and excretion of new platinum analogues in rodents

PURPOSE

Two new series of platinum complexes with cytotoxic activity in vivo are [Pt(NRCH2)2L2], (R=polyfluorophenyl, L=pyridine or substituted pyridine) and [Pt(NRCH2CH2NR'2)2L(X)], (R, L as before; R'=Me or Et, X=halogen). The aim of this study was to determine the pharmacokinetics and excretion in mice and in isolated perfused rat livers of a representative compound from each class, respectively: Pt103 (R=p-HC6F4, L=pyridine) and Pt109 (R, L as for Pt103, R'=Et, X=I).

METHODS

Mice were given intraperitoneal injections of active doses of Pt103, Pt109, or cisplatin in a variety of vehicles. Blood was sampled at several times to 48 h. Some mice were placed in metabolic cages where urine and feces were collected. In isolated, perfused rat livers, perfusate and bile were collected following a dose of Pt103, cisplatin or carboplatin. Platinum was measured in blood, urine, feces, or perfusate by atomic absorption spectroscopy. Three vehicles used were peanut oil, dimethyl sulphoxide, and saline/Tween 20.

RESULTS

In contrast to renal excretion of over 70% for cisplatin in saline, urinary excretion of platinum was less than 24% of a dose of Pt109 in peanut oil, less than 21% of P103 in DMSO, and only 4% for Pt103 in peanut oil. Over 60% of Pt103 was eliminated in mouse feces, and 57% was excreted in bile from rat liver. Plasma protein binding of Pt109 was greater than 90% at 6 h following administration in mice.

CONCLUSION

In contrast to cisplatin and carboplatin, representatives of two new classes of platinum anticancer agents undergo minimal renal elimination, but are excreted mainly in the bile and feces. If a platinum complex with a similar excretion profile was introduced into the clinic, there might be a therapeutic advantage in terms of drug toxicity and combination therapy with other cytotoxics.

Gamma-glutamyl transpeptidase-deficient mice are resistant to the nephrotoxic effects of cisplatin

We have proposed that the nephrotoxicity of cisplatin, a widely used chemotherapy drug, is the result of the binding of cisplatin to glutathione and the subsequent metabolism of the cisplatin-glutathione complex via a gamma-glutamyl transpeptidase (GGT)-dependent pathway in the proximal tubules. To test the hypothesis that GGT activity is essential for the nephrotoxicity of cisplatin, the effects of cisplatin were examined in wild-type and GGT-deficient mice. Mice were treated with 15 mg cisplatin/kg. Five days after treatment, renal histopathology, blood urea nitrogen levels, serum creatinine, platinum excretion, and platinum accumulation in the kidney were examined. Half the mice were supplemented with N-acetylcysteine, which has been shown to correct low levels of tissue glutathione in GGT-deficient mice. The data show that cisplatin was nephrotoxic in wild-type mice but not in GGT-deficient mice. The wild-type mice, with and without N-acetylcysteine supplementation, had significantly elevated levels of blood urea nitrogen, serum creatinine, and renal tubular necrosis. There was no evidence of nephrotoxicity in the GGT-deficient mice regardless of N-acetyl cysteine supplementation. No differences in platinum excretion were seen comparing wild-type and GGT-deficient mice, nor was there any significant difference in renal platinum accumulation. These data suggest that renal cisplatin toxicity is dependent on GGT activity, and is not correlated with uptake. The results support our hypothesis that the nephrotoxicity of cisplatin is the result of the metabolism of the drug through a GGT-dependent pathway.

Urinary platinum levels associated with dental gold alloys

Platinum concentrations were determined in 50 urine and 20 saliva samples obtained from 50 subjects who had gold dental restorations. In addition, 42 urine and 35 saliva samples were collected from subjects who did not have gold dental restorations. Subjects with gold alloys had significantly (p < .001) higher urinary platinum excretion (mean = 11.9 +/- 8.5 ng/gm creatinine, range = 1.9-45.8 ng/gm creatinine) than controls (mean = 6.2 +/- 3.2 ng/gm, range = 1.9-14.4 ng/gm creatinine). Mean saliva concentrations were significantly higher in subjects with dental gold alloys (526 pg/gm vs. 8.5 pg/gm; p < .001). A laboratory test with 5 commercially available dental gold/platinum alloys showed that 0.1% sodium chloride mobilized platinum within 1 hr (i.e., 1-18 pg/ml) of its introduction. In conclusion, dental gold/platinum alloys appear to be the main source for urinary platinum excretion from the occupationally unexposed population.

Urinary excretion of platinum in chemotherapy-treated long-term survivors of testicular cancer

As the majority of patients with metastatic testicular cancer are cured by cisplatin-based chemotherapy and can expect an additional life span of around 50 years, late toxicity is of particular relevance. Urine and serum concentrations of platinum were determined by voltammetry in 37 patients at 5.3 to 16.8 years after cisplatin-based chemotherapy. Urinary excretion and serum levels of platinum were 100 to 1000 times higher in patients than in unexposed controls. There may be an association between platinum storage and endocrinologic and metabolic late sequelae, as well as a risk of second cancer. However, further research is necessary to clarify the biological relevance of long-term storage of platinum.

Reduction of cisplatin nephrotoxicity by procainamide: does the formation of a cisplatin-procainamide complex play a role?

Procainamide protects mice bearing P388 leukemic cells against the toxicity of cisplatin without diminishing antitumor activity. The mechanism of action of procainamide protection was investigated both in vitro and in vivo. HPLC studies showed that procainamide forms a complex with cisplatin in vitro that has a UV spectrum similar to that of DPR, a triamine platinum complex that contains procaine as ligand. We report here the effect of the reaction product of cisplatin and procainamide on both cisplatin-induced DNA interstrand cross-links (ISCLs) and on the total DNA platination of isolated DNA. Total DNA platination in vitro of isolated DNA was increased by 113% (P <.01) and 17% (P <.05) after incubation times of 1.75 and 6 h, respectively, compared with products from the reaction of cisplatin with water. Furthermore, the reaction product of cisplatin and procainamide was bound to DNA to a significantly greater extent than was cisplatin itself. ISCLs were decreased by 41% when this drug combination was incubated with DNA for 1.75 h, but no changes were observed after incubation for 6 h. We also examined the influence of the time interval between administration of cisplatin and procainamide on normal kidney injury, the renal distribution and urinary excretion of platinum, and the formation of cisplatin-DNA adducts in renal tissue of Sprague-Dawley rats after i.p. administration of 7.5 mg/kg cisplatin either with or without procainamide. The plasma concentrations of urea and creatinine and kidney histology demonstrated that procainamide provided effective protection in vivo in the rat when administered either simultaneously or at 0.5 and 1 h before or after cisplatin. The protection was accompanied by both higher renal levels of platinum and cisplatin-DNA adducts and by an increase in the formation of ISCLs. Moreover, a dose-dependent reduction of urinary excretion and concentration of platinum was also observed. We propose that procainamide, after accumulation in the kidney, may coordinate with cisplatin to form a less toxic DPR-like complex that renders rats less susceptible to cisplatin-induced toxicity.

Pharmacokinetics and pharmacodynamics of lobaplatin (D-19466) in patients with advanced solid tumors, including patients with impaired renal of liver function

The purpose of this study was to determine the influence of impaired renal and liver function on the pharmacokinetics and pharmacodynamics of lobaplatin in cancer patients. A total of 25 patients with advanced solid tumors not amenable for standard treatment entered the study. Patients had normal organ function or an impaired liver or renal function (two levels). The starting dose of lobaplatin was 50 mg/m2 i.v. given every 3 weeks. The blood and urine of all patients were sampled for the determination of (ultrafilterable) platinum, intact lobaplatin, creatinine, and blood cell counts. No objective responses were recorded. Five patients experienced no change and received 4-10 cycles (median, 6 cycles) of lobaplatin. The extent and duration of hematological toxicity were worse in patients with impaired renal function. Thrombocytopenia was most prominent; grade 4 toxicity was observed in 15 patients in the first two cycles of treatment. The concentration-time curves of ultrafilterable platinum and intact lobaplatin revealed almost identical patterns. The elimination of ultrafilterable platinum [final half-life (t1/2 final) = 131+/-15 min; clearance (Cl) = 125+/-14 ml/min/1.73 m2] was much faster than that of total platinum (t1/2 final = 6.8+/-4.3 days, CI = 34+/-11 ml/min/1.73 m2). No pharmacokinetic differences were observed between patients with normal organ function and those with an impaired liver function within the investigated range. An impaired renal function resulted in an increase of the t1/2 final due to a decrease of the total body Cl that resulted in a higher exposure of the body to the drug. The calculated creatinine Cl was linearly correlated with the total body clearance of ultrafilterable platinum (r = 0.91), which resulted in the dosage formula D = AUCinfinity (1.1 Cl(CrU) + 16), in which D represents dose, AUC represents area concentration-time curve, and Cl(CrU) represents creatinine Cl. The thrombocyte surviving fraction correlated well with the AUC value of ultrafilterable platinum (r = 0.72). It can be concluded that the hematological toxicity and the pharmacokinetics of lobaplatin are strongly affected by renal function. The total body Cl of ultrafilterable platinum correlated well with the creatinine Cl and the thrombocyte surviving fraction. In patients with renal function, represented by a creatinine clearance > or =30 ml/min/1.73 m2, the derived dosage formula will enable us to calculate the dose that is expected to lead to an acceptable extent of thrombocytopenia in a patient with a given renal function. Prospective studies with larger groups of patients are needed to prove the value of this dosage formula.

Internal platinum, palladium, and gold exposure in environmentally and occupationally exposed persons

In a pilot study the urinary platinum (Pt), palladium (Pd), and gold (Au) excretion was analyzed in 27 dental technicians, 17 road construction workers and 17 school-leavers using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Detection limits in urine were 0.24 ng/l for Pt and Au and 0.17 ng/l regarding Pd. A standardized questionnaire was used to assess information about kind and degree of contact to these metals, the physical condition of the volunteers and confounding factors. Significant differences between the three study groups were found. The mean Pt, Pd, and Au excretions of the dental technicians were significantly higher than those of the road construction workers and school-leavers. This indicates that the occupational treatment of dental alloys leads to an internal exposure to these metals which is distinctly higher than that from automobile exhaust exposure. Significant differences between Monday morning (pre-shift) and Thursday afternoon (post-shift) urine samples of the dental technicians were not found. The Pt excretion of road construction workers working near a much traveled highway was comparable with that of school-leavers being less (only environmentally) exposed to automobile exhaust. Regarding Pd and Au the road construction workers showed a tendency to higher levels in urine when compared with the school-leavers, but statistically significant differences were not found. The tendency to higher urinary Pd and Au levels in the road-construction workers may be explained by their slightly greater number of noble metal containing artificial dentures, which may cause an additional exposure. A statistically significant effect of age on the urinary noble metal excretion was not detectable.

Platinum concentrations in urban road dust and soil, and in blood and urine in the United Kingdom

Increasing Pt concentrations from vehicle catalysts have been reported from a number of countries. Analysis of Pt and Pd in soils and road dusts taken from areas of high and low traffic flows in SE England show concentrations of Pt in the range < 0.30-40.1 ng g-1 and Pd in the range < 2.1-57.9 ng g-1. Higher concentrations of Pt are associated with high traffic densities. Samples taken from streets of lower traffic flows were found to contain the lower concentrations of the ranges. Pilot studies of Pt concentrations in blood and urine using ICP-MS have been carried out. Platinum concentrations in whole blood were: precious metal workers, 780-2170, mean 1263 pmol l-1 (0.152-0.423, mean 0.246 microgram l-1); motorway maintenance workers, 645-810, mean 744 pmol l-1 (0.126-0.158, mean 0.145 microgram l-1); Imperial College staff, 590-713, mean 660 pmol l-1 (0.115-0.139, mean 0.129 microgram l-1). Platinum concentrations in urine in pmol Pt per mmol creatinine were: precious metal workers, 122-682, mean 273 [0.21-1.18, mean 0.47 microgram Pt (g creatinine)-1]; motorway maintenance workers, 13-78, mean 33.7 [0.022-0.135, mean 0.058 microgram Pt (g creatinine)-1]; Imperial College staff, 28-130, mean 65.6 [0.048-0.224, mean 0.113 microgram Pt (g creatinine)-1]. Detection limits were 0.03 microgram l-1 for both blood and urine. The possible health effects of increasing Pt in the environment are discussed. Platinum provides an excellent example of the significance of speciation in metal toxicity. Platinum allergy is confined to a small group of charged compounds that contain reactive ligand systems, the most effective of which are chloride ligand systems. Metallic Pt is considered to be biologically inert and non allergenic and since the emitted Pt is probably in the metallic or oxide form, the sensitising potential is probably very low. Platinum from road dusts, however, can be solubilised, and enter waters, sediments, soils and the food chain. There is at present no evidence for any adverse health effects from Pt in the general environment, particularly allergic reactions.

Urinary excretion of platinum from platinum industry workers

OBJECTIVES

Assessment of level of exposure to platinum and platinum concentration in urine from platinum industry workers to evaluate internal exposures and excretion kinetics.

METHODS

Platinum concentrations in urine samples from 34 workers were measured by adsorptive voltammetry after UV-photolysis. Morning and evening samples were taken two to six times during six months. Individual exposures were assessed by personal air sampling. Also, two male volunteers were exposed to platinum dust for four hours at a typical platinum refinery workplace.

RESULTS

Urinary platinum excretion after a shift in platinum industry workers was found to be up to 6270 ng/g creatinine--that is, 1000 times above the median value of unexposed people. Urinary excretion reached the maximum nearly 10 hours after inhalative exposure to dust containing platinum. Elimination corresponded to a first half life of about 50 (95% confidence interval (95% CI) 36 to 66) hours, but there were indications that a part of the incorporated platinum is stored longer. The amount of urinary platinum excretion showed a close correlation with the exposure level monitored by personal air sampling.

CONCLUSIONS

A newly developed analytical method enabled the detection of even natural background concentrations of platinum. Thus, increased urinary platinum concentrations could be detected early, which is important to avoid damaging health of exposed workers.

Cisplatin pharmacokinetics in children with cancer

Cisplatin is an important drug in the treatment of a number of paediatric cancers yet, despite widespread use, there are only very limited data on the pharmacokinetics of the drug in children. Cisplatin pharmacokinetics were studied in 21 patients following a 24 h infusion of 50-120 mg/m2 cisplatin. Total and free platinum (Pt) levels in plasma and Pt in urine, were measured by atomic absorption spectrophotometry. Pharmacokinetic parameters were determined by non-compartmental and compartmental analyses. There was 3-fold interpatient variability in free drug exposure (area under the plasma concentration versus time curve--AUC) for a given surface area-based dose of cisplatin. The mean (+/- SD) pharmacokinetic parameters for free Pt were: AUC 0.47 +/- 0.13 mg/ml.min/100 mg/m2, Vdss 12.5 +/- 2.7 l/m2, t1/2 39 +/- 9 min, Ke 0.019 +/- 0.006 min-1, Clrenal 62 ml/min/m2, Cltotal 233 +/- 455 ml/min/m2, Cpss 0.31 +/- 0.09 microgram/ml. The total free Pt clearance was 1.5-5.8-fold higher (3.4 +/- 1.0) than the glomerular filtration rate (GFR). The renal clearance of cisplatin was not related to GFR and cisplatin was subject to only limited urinary excretion (27% administered dose 0-48 h), indicating that there are other important pathways of clearance beside renal elimination. Patient and treatment heterogeneity precluded the investigation of pharmacokinetic-pharmacodynamic relationships; however, the degree of interpatient pharmacokinetic variability observed suggests that body surface area-based dosing of cisplatin in children is not satisfactory.

Determination of platinum in workroom air and in blood and urine from nursing staff attending patients receiving cisplatin chemotherapy

OBJECTIVES

The use of anti-neoplastic drugs is increasing and nursing staff are evidently concerned about the risk of hazardous exposure. General methods are available for measuring exposure to carcinogens. These methods, however, lack specificity. One group of anti-neoplastic drugs, based on cisplatin derivatives, contain platinum, which can be analysed at low concentrations with the use of adsorptive voltammetry. The aim of this study was to employ this technique for assessment of occupational exposure by selective determination of platinum in workroom air and in blood and urine samples from medical staff nursing cancer patients.

METHODS

The voltammetric method for determination of platinum has been further developed for analysis of blood, urine and air samples. The effects of different materials in crucibles and different acids for sample pre-treatment, and of the ashing temperature programme were investigated for optimum conditions for analysis of blood, urine and filter samples. Occupational exposure to cisplatin derivatives was also investigated among medical staff. Air sampling in the workroom, as well as analysis of blood and urine samples from the exposed subjects, was carried out during the process of drug preparation and administration and when attending treated patients.

RESULTS

After development of the experimental method by the introduction of synthetic quartz crucibles and the optimization of acid composition, and of the temperature programme for sample pre-treatment, the recovery has been improved and the method has proved to be adequate for determination of platinum (Pt) in blood, urine and air-filter samples. Increased Pt blood levels were found in both graduate (2.2 +/- 1.7 ng ml-1) and staff nurses (3.8 +/- 4.0 ng ml-1), but not in pharmacists (0.47 +/- 0.31 ng ml-1), in comparison with unexposed subjects (1.2 +/- 0.69 ng ml-1). The variation was, however, high with CV > 50% for all groups. From the median values it can be seen that a few subjects with high values had a large impact on the mean values. The mean Pt level in urine samples was 126 +/- 92 ng l-1, which was found to be close to the pooled reference urine (110 ng l-1). No increased Pt air levels were found in any of the measurements. Moreover, the results showed difference in mean Pt blood level between staff at the investigated hospitals. The staff at hospital A had 1.2 +/- 0.53 ng ml-1, at hospital B 3.8 +/- 4.3 ng ml-1 and at hospital C 2.0 +/- 2.1 ng ml-1.

CONCLUSIONS

The method has proved to be adequate for determination of platinum in blood, urine and air-filter samples. No increased airborne Pt levels were found. However, increased Pt blood levels were found. Staff nurses had a higher mean level than graduate nurses, which indicates that possible exposure occurs while attending treated patients rather than during the preparation and administration of drugs. There was a noticeable variations in the mean blood level for the investigated groups as a whole. This variation might reflect an actual difference in the exposure situation, but more probably depends on differences in skill and experience between the subjects. Routines and facilities for handling anti-neoplastic drugs vary between the clinics and this also probably has an impact on exposure.

The determination of metals (antimony, bismuth, lead, cadmium, mercury, palladium, platinum, tellurium, thallium, tin and tungsten) in urine samples by inductively coupled plasma-mass spectrometry

OBJECTIVE

An analytical method has been established to determine the concentration of antimony (Sb), bismuth (Bi), lead (Pb), cadmium (Cd), mercury (Hg), Palladium (Pd), platinum (Pt), tellurium (Te), tin (Sn), thallium (Tl) and tungsten (W) in urine. The aim was to develop a method which is equally suitable for the determination of environmentally as well as occupationally caused metal excretion.

METHODS

Inductively coupled plasma-mass spectroscopy (ICP-MS) was used for the determination of metals. Calibration was done using aqueous solutions and standard addition respectively.

RESULTS

Urine samples of 14 persons occupationally non-exposed to metals were analysed. With the exception of Pt and Bi all the metals were found in these urine samples. The detection limits for these metals lie between 5 and 50 ng/l.

CONCLUSIONS

For some metals, which are important from an occupational as well as an environmental viewpoint, ICP-MS is more sensitive than atomic absorption spectrometry (AAS). ICP-MS, moreover, is welcome as a reference method for AAS with the additional advantage of multi-element measurement.

The effect of methylprednisolone on platinum kinetics and urinary enzyme excretion following intravenous cisplatin in vivo and on the growth inhibition of LLC-PK1 cells by cisplatin in vitro

In order to evaluate the mechanism of the protective action of methylprednisolone against cisplatin-induced nephrotoxicity, platinum kinetics and urinary enzyme excretion following intravenous cisplatin, with or without methylprednisolone, were studied in vivo. The growth inhibition of LLC-PK1 cells by cisplatin in the presence or absence of methylprednisolone was studied in vitro. Rats intravenously injected with cisplatin combined with subcutaneous methylprednisolone 4 h prior to the cisplatin injection excreted more platinum in urine than rats treated with cisplatin alone. Both plasma and kidney platinum concentrations in rats injected with both cisplatin and methylprednisolone were significantly lower than those in rats given cisplatin alone at 4 h after cisplatin injection. However, there was no significant difference in urinary excretion of lactate dehydrogenase, gamma-glutamyl transpeptidase or N-acetyl-beta-D-glucosaminidase between methylprednisolone-treated rats and control rats. Methylprednisolone did not affect the inhibitory effects of cisplatin on the cell growth of LLC-PK1. These findings indicate that methylprednisolone-induced increase in urinary platinum excretion, accompanied by a decrease in plasma and kidney platinum concentrations following cisplatin injection in rats, may be one of the mechanisms responsible for the protective action of methylprednisolone.

Cisplatin based chemotherapy in testicular cancer patients: long term platinum excretion and clinical effects

Patients with advanced testicular cancer (TC) have a very good long-term prognosis owing to cisplatin-based polychemotherapy. Platinum is believed to be excreted at a rapid rate via urine within weeks after chemotherapy. As a new, highly sensitive method has become available detecting even natural background platinum levels in body fluids, this study was set up to analyze urinary and serum platinum levels in long-term survivors of testicular neoplasm after cisplatin based polychemotherapy and to correlate clinical data with urinary and serum platinum levels. Urinary platinum concentrations were measured in 64 healthy controls (C) and 22 male patients (TC) 150 to 3022 days after the last application of i.v. cisplatin using voltammetry after UV-photolysis. In the latter group (TC), serum platinum levels were measured as well. Clinical data were analysed as to long-term organ toxicity. Mean urinary platinum levels were 2700 times higher in the patient group (TC) than natural background noise (p < 0.0001). There was a decline of urinary and serum platinum levels over time, being significantly above normal even 8 years after cisplatin exposure. The only significant variables related to the urine platinum concentration were a) the interval between the last i.v. cisplatin application and time of study and b) the total dose given. Not significant were the number of chemotherapy cycles, pre-therapy renal disease, patient age, tumour resection before/after chemotherapy, site of pre/post therapy resection, clinical staging, histological subtypes or tumour markers. Post-therapy renal disease or peripheral nerve damage were not significantly associated with urinary platinum levels. Our data indicate that even 8 years after cisplatin based chemotherapy 500 times elevated urinary and serum platinum levels can be measured in testicular cancer patients. No organ toxicity related to long-term platinum excretion could be detected. This may be due to our small sample size.

Cisplatin nephrotoxicity: inhibition of gamma-glutamyl transpeptidase blocks the nephrotoxicity of cisplatin without reducing platinum concentrations in the kidney

OBJECTIVE

Inhibition of gamma-glutamyl transpeptidase activity by acivicin or a large bolus of intravenous glutathione blocks the nephrotoxicity of cisplatin. The purpose of this study was to determine whether these compounds inhibit nephrotoxicity by reducing the amount of platinum retained by the kidney.

STUDY DESIGN

The platinum concentration in urine and kidney of cisplatin-treated rats was determined by graphite furnace atomic absorption spectroscopy. Tissues from three experimental groups of rats were analyzed. The first group was treated with a nephrotoxic dose of cisplatin. The second group was treated with acivicin before cisplatin. The third group received a bolus of glutathione before cisplatin. Urine collected for 3 hours after the injection of cisplatin and kidney tissue from animals 5 days after treatment were analyzed for platinum content.

RESULTS

Urine from animals pretreated with acivicin had the same concentration of platinum as that of control animals treated with cisplatin alone. Analysis of kidney tissue, blood urea nitrogen and serum creatinine 5 days after treatment showed that pretreatment with acivicin or glutathione blocked the nephrotoxicity of cisplatin. However, these agents did not alter the concentration of platinum in the kidney.

CONCLUSIONS

The data in this study reveal that pretreatment with acivicin or glutathione does not block the uptake of platinum into the kidney nor do these agents reduce the concentration of platinum retained by the kidney. The mechanism by which these agents may inhibit the nephrotoxicity of cisplatin is discussed.

Toxicity and excretion of cisplatin in the avian kidney

Cisplatin is a widely applied antineoplastic drug with significant nephrotoxic potential. The purpose of this study was to define the toxic effect and excretion of cisplatin in the chicken, a species widely applied to the study of tubular transport mechanisms but little used for toxicology studies. Toxicity was assessed by the relative effect of cisplatin on renal clearances of the standard reference substrates inulin and p-aminohippurate (PAH) and by morphologic assessment of the kidneys of cisplatin-treated chickens. The data clearly support close similarities in the pattern of tubular cell damage produced in the chicken versus that reported for rats and human patients. It was further demonstrated that administration of an organic cation reduced Pt accumulation in the kidney and mitigated the toxicity as has been reported for rats. Excretion studies were carried out during unilateral renal portal infusion of cisplatin, and the results indicated that cisplatin does not undergo net tubular secretion as occurs in the rat and human. It can be concluded that, while the pattern of cisplatin-induced nephrotoxicity closely parallels that seen in mammals, the avian kidney exhibits a different pattern of urinary Pt excretion than does the mammalian kidney after cisplatin administration.

Long-term platinum excretion in patients treated with cisplatin

The purpose of this study was to determine long-term renal platinum excretion after chemotherapy with cisplatin. We examined urinary platinum concentrations in 23 men at 150-3022 days after anticancer treatment for testicular neoplasm. Spot urine samples were analyzed by voltammetry. This new, subtle method with a detection limit of 2 pg platinum allows determination of even the natural background level. Urinary platinum concentrations in our patients ranged between 0.74 and 77.24 micrograms/g creatinine, depending on the total delivered dose and follow-up period. Regression analysis of the data showed two phases of long-term renal platinum excretion, one occurring at between 150 and 900 days of follow-up and the other with an onset at 900 days after cisplatin administration (r1(2) = 0.82, r2(2) = 0.88). Two biological half-lives of 160 and 720 days were calculated. Our results show that urinary platinum concentrations determined at 8 years after cisplatin therapy are 40 times higher than the background level (up to 0.02 micrograms/g creatinine). Our findings on the long-term pharmacokinetics of this anticancer agent may facilitate further studies on sites of platinum storage in the human body as well as clinical studies on the late adverse effects of cisplatin.

[The protective effects of two hydration protocols against cisplatin nephrotoxicity]

A comparative study was performed in 37 patients with breast cancer who received high doses of cisplatin (100 mg/m2, I.V. drip) accompanied by two different hydration protocols. The new hydration protocol is based on the study of relationship between the pharmacokinetic parameters of plasma and urinary platinum concentration and the cisplatin-induced nephrotoxicity. In the new hydration protocol the diuretic drugs were given twice- amid and twelve hours after the cisplatin infusion instead of giving once--immediately after the cisplatin infusion, and 1,000ml drinking water was given by p.o. before taking cisplatin. Because of the increase in urinary volume the peak levels of urinary platinum were decreased from 47.34 micrograms/ml to 13.49 micrograms/ml, so that the rate of the nephrotoxicity was reduced from 36.8% (7/19) to 5.6% (1/18). The results suggest that the new hydration protocol is more effective than that previously used to protect against cisplatin nephrotoxicity.

High doses of intrapleural cisplatin in a case of malignant pleural mesothelioma. Clinical observations and pharmacokinetic analyses

BACKGROUND

The authors report a feasibility study of intrapleural cisplatin in a patient with inoperable malignant pleural mesothelioma.

METHODS

Total and filterable platinum in pleural effusion and in plasma were monitored for two intrapleural courses of 120 mg/m2 cisplatin, and a weekly schedule was adopted. Platinum concentrations in pleural effusion, plasma, and urine were determined by flameless atomic absorption spectroscopy.

RESULTS

A lower peak of filterable platinum in plasma, a decrease in systemic filterable platinum exposure (AUC [area under the concentration-time curve]), and a greater pleural exposure to filterable platinum were observed after Course 2 compared with Course 1. After the second cycle of intrapleural treatment, the systemic AUC for filterable platinum was reduced by 40%.

CONCLUSIONS

The authors' findings may have some implications for the clinical use of intrapleural chemotherapy with high doses of cisplatin. Both infusions of cisplatin were generally well tolerated by the patient and were associated with the local pharmacologic advantage of sustained exposure to cisplatin of the pleural cavity. No sign of myelosuppression, neuropathy, or ototoxicity was observed, and acute toxicity consisted of mild nausea, vomiting, and prolonged anorexia. A transient presence of granular casts was the only observed nephrotoxic effect of cisplatin. Excellent local control of the disease with absence of recurrence of the effusion was observed.

Massive cisplatin overdose by accidental substitution for carboplatin. Toxicity and management

BACKGROUND

Unlike the related drug carboplatin, cisplatin is highly nephrotoxic and must be given with vigorous intravenous hydration at a much lower dose. As the result of an accidental substitution of cisplatin for carboplatin, a 68-year-old woman received a massive overdose of cisplatin without intravenous hydration.

METHODS

Laboratory documentation included measurements of platinum concentrations by atomic absorption spectroscopy and of xeroderma pigmentosum group E (XPE) binding factor, a protein that is involved in the recognition step of DNA repair.

RESULTS

Toxicities included severe emesis, myelosuppression, renal failure, and deafness, which are well known. Other toxicities were seizures, hallucinations, loss of vision, and hepatic toxicity, which were unusual and may have been caused by the magnitude of the overdose. As late as day 19, there was a continued cellular response from cisplatin, as evidenced by decreased levels of XPE binding factor in extracts from the patient's peripheral blood lymphocytes. Plasmapheresis was effective in lowering the platinum concentration from greater than 2900 ng/ml to 200 ng/ml and appeared to be of clinical benefit. Even after the onset of renal failure, hydration to increase urine volume resulted in increased urinary excretion of platinum. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was used to ameliorate myelosuppression. The patient received a transplanted kidney from her monozygotic twin sister and survived with no clinically significant deficit except for deafness.

CONCLUSION

No previous reports exist of survival after such a high dose of cisplatin without intravenous hydration. In the future, patients may benefit from similar management and heightened awareness of the possibility of accidental substitution.

Determination of platinum in urine, ultrafiltrate, and whole plasma by isotope dilution gas chromatography-mass spectrometry compared to electrothermal atomic absorption spectrometry

Isotope dilution gas chromatography-mass spectrometry (GC-MS) and electrothermal atomic absorption spectrometry (EAAS) are compared for platinum (Pt) determination in urine, plasma ultrafiltrate, and plasma samples from a patient undergoing cisplatin therapy. The isotope dilution GC-MS method is based on the use of lithium bis(trifluoroethyl)dithiocarbamate as a chelating agent and enriched 192Pt as an internal standard. Pt isotope ratios were measured using a Finnigan MAT 8230 organic mass spectrometer, and Pt concentrations were calculated from different sets of isotope ratios in the molecular ion of the Pt-chelate. In the EAAS method, Pt concentrations were determined using three different approaches. These were: (i) calibration curve based on aqueous standards containing Pt in 10% HCl, (ii) standard addition, and (iii) matrix digestion followed by standard addition. Good agreement was obtained for Pt concentrations determined by GC-MS and EAAS in urine samples while there were significant differences in Pt concentrations of ultrafiltrate and whole plasma samples by the two methods. Discussion of possible reasons for these differences emphasizes the need for future critical evaluation of these methods.

[Relationship between plasma and urinary platinum pharmacokinetics with cisplatin nephrotoxicity in breast cancer patients]

In 25 cycles of 20 breast cancer patients who received 26 cycles of high-dose cisplatin (100 mg/m2, iv drip), the urinary Alb, IgG and NAG values were elevated above normal. These patients were divided into low-nephrotoxicity and high-nephrotoxicity groups by the degree of renal dysfunction. Of these patients 35% showed high-nephrotoxicity. They had significantly higher plasma and/or urinary Pt peak levels during cisplatin infusion than did those with low-nephrotoxicity. And 70-80% of the patients developed significant nephrotoxicity when the urinary Pt level rose up to greater than 40 micrograms/ml or plasma Pt level greater than 4 micrograms/ml. It is very important to keep the urinary and plasma Pt level below 40 micrograms/ml and 4 micrograms/ml respectively in order to reduce the nephrotoxicity. It is suggested that the urine output be maintained over 300 ml/hr for 2 hours before and after the completion of infusion and greater than 100 ml/hr in the following 3 days. This helps keep the cisplatin-induced nephrotoxicity in less severe and the function of kidney easy to recover.

Effect of time of cisplatin administration on its toxicity and pharmacokinetics in dogs

Cisplatin (90 mg/m2) was administered in a 5-minute bolus IV infusion to dogs at 8 AM (n = 6) or 4 PM (n = 6). Blood and urine samples were collected over a 4-hour period for statistical moment pharmacokinetic analysis. Mean urinary excretion rate of total platinum was increased, whereas mean plasma residence time of ultrafilterable platinum was decreased, in the group treated at 4 PM (PM group), compared with those treated at 8 AM (AM group). Over a 2-week postinfusion-monitoring period, both groups of dogs developed decreases in creatinine clearance, urine/serum osmolality ratio (UOsm/SOsm), specific gravity, and increase in BUN, serum creatinine concentration, urine gamma-glutamyltranspeptidase/urine creatinine ratio (UGGT/UCr), fractional excretion of magnesium, and fractional excretion of phosphate. Urine specific gravity and UOsm/SOsm were significantly decreased, whereas UGGT/UCr and BUN were significantly increased in the AM group, compared with the PM group. The time of administration had a significant effect on the pharmacokinetics of cisplatin, which resulted in significant differences in cisplatin-induced renal toxicosis.

Disposition and tumour concentrations of platinum in hypoalbuminaemic patients after treatment with cisplatin for cancer of the head and neck

1 Platinum concentrations in the tumour reached a peak of 3.8 +/- 1.5 micrograms g-1 wet weight tissue at the end of an 8 h intravenous infusion of cisplatin. The tumour concentrations of platinum were higher than the corresponding plasma concentrations (2.5 +/- 0.9 micrograms ml-1) and declined more slowly. 2 Patients with squamous carcinoma of the head and neck had a significantly shorter median survival time if they had low plasma albumin concentrations (less than 40 g l(-1) compared with patients in the normal range, 133 days and 768 days respectively (P less than 0.05) after treatment with cisplatin. 3 No changes in the pharmacokinetics of platinum were detected to account for this poor response of hypoalbuminaemic patients, but plasma albumin concentration was found to be negatively correlated with the first order elimination rate constant. 4 The cumulative urinary excretion of platinum in the first 24 h was not altered by lowered plasma albumin. 5 The concentration of platinum in the tumour did not correlate with the survival time of the patient, but was found to be correlated with the volume of distribution in the post-distributive phase.

Trace element analysis in body fluids by glow discharge mass spectrometry: a study of lead mobilization by the drug cis-platin

A method is described, using glow discharge mass spectrometry, to measure lead and platinum levels at the p.p.b. level in the urine of patients receiving cancer chemotherapy with the drug cis-platin. Using bismuth added as an internal standard, the method is found to compare very favourably with other quantitative techniques, and requires relatively little sample preparation. The data obtained support the idea that normally stored body lead is displaced by the platinum complexed in the drug, but only to a small extent.

Toxicity after self-poisoning by ingestion of potassium chloroplatinite

A 31 year-old man ingested 10 mL of a photographic toning solution containing 600 mg of potassium chloroplatinite in a suicide attempt. Subsequent toxic effects included acute oliguric renal failure, metabolic acidosis, fever, muscle cramps, gastroenteritis and rhabdomyolysis. Laboratory abnormalities included mildly elevated liver enzymes and elevated peripheral blood neutrophil and eosinophil counts. All symptoms and signs of toxicity resolved over a six day hospital stay with supportive medical management only; thereafter he was lost to medical follow-up. A spot serum platinum concentration was 245 mcg/dL and a spot urine platinum concentration was 4200 mcg/L.