A sensitive postcolumn derivatization/UV detection system for HPLC determination of antitumor divalent and quadrivalent platinum complexes

The Dark Side of Platinum Based Cytostatic Drugs: From Detection to Removal

The uncontrolled release of pharmaceutical drugs into the environment raised serious concerns in the last decades as they can potentially exert adverse effects on living organisms even at the low concentrations at which they are typically found. Among them, platinum based cytostatic drugs (Pt CDs) are among the most used drugs in cancer treatments which are administered via intravenous infusion and released partially intact or as transformation products. In this review, the studies on environmental occurrence, transformation, potential ecotoxicity, and possible treatment for the removal of platinum cytostatic compounds are revised. The analysis of the literature highlighted the generally low total platinum concentration values (from a few tens of ng L−1 to a few hundred μg L−1) found in hospital effluents. Additionally, several studies highlighted how hospitals are sources of a minor fraction of the total Pt CDs found in the environment due to the slow excretion rate which is longer than the usual treatment durations. Only some data about the impact of the exposure to low levels of Pt CDs on the health of flora and fauna are present in literature. In some cases, adverse effects have been shown to occur in living organisms, even at low concentrations. Further ecotoxicity data are needed to support or exclude their chronic effects on the ecosystem. Finally, fundamental understanding is required on the platinum drugs removal by MBR, AOPs, technologies, and adsorption.

Anti-mitochondrial autoantibodies in systemic lupus erythematosus and their association with disease manifestations

Mitochondria are organelles that govern energy supply and control cell death. Mitochondria also express bacterial features, such as the presence of inner membrane cardiolipin and a circular genome rich in hypomethylated CpG motifs. While mitochondrial extrusion by damaged organs or activated cells is thought to trigger innate immunity, it is unclear whether extracellular mitochondria also stimulate an adaptive immune response. We describe the development of novel assays to detect autoantibodies specific to two distinct components of the mitochondrion: the mitochondrial outer membrane and mitochondrial DNA. Antibodies to these two mitochondrial constituents were increased in both human and murine systemic lupus erythematosus (SLE), compared to controls, and were present at higher levels than in patients with antiphospholipid syndrome or primary biliary cirrhosis. In both bi- and multi-variate regression models, antibodies to mitochondrial DNA, but not whole mitochondria, were associated with increased anti-dsDNA antibodies and lupus nephritis. This study describes new and optimized methods for the assessment of anti-mitochondrial antibodies, and demonstrates their presence in both human and murine SLE. These findings suggest that different mitochondrial components are immunogenic in SLE, and support the concept that extracellular mitochondria may provide an important source of circulating autoantigens in SLE.

Development and Validation of a Simple and Sensitive Spectrometric Method for Estimation of Cisplatin Hydrochloride in Tablet Dosage Forms: Application to Dissolution Studies

Cisplatin hydrochloride is an important chemotherapeutic drug for cancer treatment. It has a low molar absorptivity in the UV region and has no fluorescence. Therefore, a selective derivatizing reaction is required for its detection in bulk and pharmaceutical dosage form if detection by UV spectrophotometry is sought. In view of this, a simple, accurate, rapid, and cost-effective spectrophotometric method for its estimation has been developed by the complexation of the drug with ortho-phenylene diamine and monitoring the absorbance of formed green color at 706 nm. The method has been validated and successfully applied for the assay and dissolution studies of cisplatin hydrochloride tablets. The method demonstrated good linearity over the range from 0.4 to 1.4 μg/mL with a correlation coefficient of 0.9999. The accuracy of the method was 99.98%. The precision demonstrated relative standard deviation of less than 2.5%. The developed method was successfully applied for dissolution studies of sustained release tablets of cisplatin with a cumulative release of 86.7% in 12 hours. The proposed method can be applied in routine quality control in the pharmaceutical industries since it is precise, accurate, simple, and economic.

Analytical methodologies for the determination of cisplatin

cis-Diamminedichloroplatinum(II) (cisplatin) is a important chemotherapeutic drug for cancer treatment since 1978. Unfortunately, because of the severe side-effects like nephrotoxicity, ototoxicity, etc., they are administered in small doses at low concentration establishing the maximum limit dosage to 100 mg/m(2) (21 days). A variety of analytical methods have been proposed for the determination of cisplatin in biological fluids and tissues that permit the accurate determination at or below the part per billion level in the native sample. The purpose of the current review is to provide a systematic survey of the latest analytical techniques for the determination of cisplatin in biological samples.

Determination of chloroplatinates by CE coupled to inductively coupled plasma sector field MS

In the present work the degradation of chloroplatinates emitted into the aquatic environment has been investigated in model studies. CE coupled to inductively coupled plasma sector field MS (ICP-SFMS) was employed as an analytical method of measurement. The CE-ICP-MS interface utilized the functional make-up flow design with a microconcentric nebulizer. [Pt(Cl(4))](2-) and [Pt(Cl(6))](2-) were separated within 5 min. During a measurement period of 6 h an excellent reproducibility of migration times (RSD 2.3%) could be achieved. The high sensitivity of ICP-SFMS resulted in an LOD of 80 ng/L platinum for the two compounds. External calibration using rhenium as internal standard was linear over three orders of magnitude. However, with external calibration a long-term drift of signal intensity was observed. In order to reduce the uncertainty of the obtained results, quantification of [PtCl(6)](2-) was performed for the first time by species-specific on-line isotope dilution MS using (194)[PtCl(6)](2-) as spike. The two different quantification strategies were compared in terms of their total combined uncertainty of measurement according to the EURACHEM guideline. The method was employed for monitoring the time-dependent degradation of [Pt(Cl(4))](2-) and [Pt(Cl(6))](2-) in water containing 0 and 2.8 mmol/L Cl(-) and river water. [Pt(Cl(6))](2-) was stable whereas [Pt(Cl(4))](2-) showed rapid degradation following pseudo first-order kinetics.

A high-performance liquid chromatographic assay for determination of cisplatin in plasma, cancer cell, and tumor samples

A method for determination of cis-diaminedichloroplatinum (II) (cisplatin) in ultrafiltered plasma, cell, and tumour samples is described. Cisplatin separation was carried out on a reversed-phase column using methanol-acetonitrile-water as the mobile phase. The flow rate was maintained constant at 1.6 mL/min and analysis was performed at 23 degrees C. Detection was carried out by absorbance at 254 nm. The method was linear in the range of 0.2-10 microg/mL, and the coefficients of variation were <10%. Using this technique, we measured the intracellular accumulation of cisplatin in cancer cells and in tumours of mice receiving treatment with cisplatin and evaluated the pharmacokinetics of cisplatin in nu/nu mice after intraperitoneal (i.p.) administration. The method proved to be adequate for measuring cisplatin both in vitro and in vivo and could be suitable for studies of cisplatin pharmacokinetics in animal models.

Platinum group elements in the environment and their health risk

Accumulation of platinum group elements (PGEs) in the environment has been increased over the time. Catalytic converters of modern vehicles are considered to be the main sources of PGE pollution, since the correlation is between the Pt:Rh ratios in various environmental compartments and in converter units. The present literature survey shows that the concentration of these metals has increased significantly in the last decades in diverse environmental matrices; like airborne particulate matter, soil, roadside dust and vegetation, river, coastal and oceanic environment. Generally, PGEs are referred to behave in an inert manner and to be immobile. However, there is an evidence of spread and bioaccumulation of these elements in the environment. Platinum content of road dusts can be soluble, consequently, it enters the waters, sediments, soil and finally, the food chain. The effect of chronic occupational exposure to Pt compounds is well-documented, and certain Pt species are known to exhibit allergenic potential. However, the toxicity of biologically available anthropogenic Pt is not clear. Hence, there is a need to study the effect on human health of long-term chronic exposure to low levels of Pt compounds.

Electrospray ionization mass spectrometry coupled to liquid chromatography for detection of cisplatin and its hydrated complexes

Electrospray ionization mass spectrometry (ESI-MS) coupled to liquid chromatography (LC) has been applied to investigate cisplatin and its hydrated complexes. Three hydrolysis products were identified following incubation of cisplatin in aqueous solution: monohydrated species, dihydrated species and the hydroxo-bridged dimer, each of which exhibited characteristic mass spectrometric behavior. The technique was employed to investigate the time- and pH-dependent hydrolysis of cisplatin in aqueous solution. The results have demonstrated that LC/ESI-MS is a powerful technique for the analysis of Pt(II) complexes and for monitoring their hydrolysis reactions.

Validation of a LC method for the analysis of oxaliplatin in a pharmaceutical formulation using an experimental design

A rapid and sensitive RP-HPLC method with UV detection for routine control of oxaliplatin in a pharmaceutical formulation (Eloxatin) was developed. Quantitation was accomplished with the internal standard method. The procedure was validated by linearity (correlation coefficient=0.999948), accuracy, robustness and intermediate precision. Experimental design was used during validation to calculate method robustness and intermediate precision. For robustness test three factors were considered: percentage v/v of acetonitrile, flow rate and temperature; an increase in the flow rate results in a decrease of the drug found concentration, while the percentage of organic modifier and temperature have no important effect on the response. For intermediate precision measure the considered variables were: analyst, equipment and days. The RSD value (2.27%, n=24) indicated a good precision of the analytical method.

Simultaneous determination of intact cisplatin and its metabolite monohydrated cisplatin in human plasma

Cisplatin is a cytotoxic platinum compound, used in the treatment of several solid tumors. Cisplatin and to a greater extent its hydrolysis product monohydrated cisplatin are responsible for side-effects like nephrotoxicity. A sensitive, accurate and precise method was developed to simultaneously determine cisplatin and monohydrated cisplatin in plasma. The compounds were separated by high-performance liquid chromatography and quantified by off-line furnace atomic absorption spectrophotometry. The linear ranges for cisplatin and monohydrated cisplatin in deproteinized plasma were 60-600 and 87.5-700 nM, respectively. From plasma, the mean recovery of cisplatin was 83.2% and that of monohydrated cisplatin 79.1%. The lower limits of quantification of cisplatin and monohydrated cisplatin in deproteinized plasma were 60 and 87.5 nM, respectively. Over the whole calibration range, the within- and between-day accuracy of intact cisplatin ranged from 100.7 to 111.4 and 94.8-102.0%, respectively. The within- and between-day accuracy of monohydrated cisplatin ranged from 107.1 to 113.3 and 101.4-104.9%, respectively. The within-day and between-day precision of cisplatin ranged from 3.4 to 11.5 and 7.3-10.3%, respectively. For monohydrated cisplatin, the within-day and between-day precision ranged from 3.7 to 6.2 and 5.6-7.9%, respectively. Currently, the developed assay has been implemented in pharmacokinetic studies of patients treated with cisplatin alone or in combination with other drugs.

Anti-tumor effect of intraperitoneal administration of cisplatin-loaded microspheres to human tumor xenografted nude mice

This study evaluates the anti-tumor effect of cisplatin-loaded microspheres (CDDP-MS) against peritoneal carcinomatosis using human tumor xenografts. The incorporated CDDP was released from CDDP-MS for 3 weeks in vivo as well as in vitro. CDDP-MS at a dose of 35 mg/kg (at maximal tolerable dose (MTD)) showed effective anti-tumor activity (tumor growth inhibition rate (IR)=70.3%) against Li-7 (human liver cancer) xenografts transplanted into the peritoneal cavity. This procedure also resulted in increased life span (ILS (%)=47.2%), whereas CDDP dissolved in saline solution (CDDP-SOL) at a dose of 8 mg/kg (at MTD) was ineffective (IR=15.7%, ILS=2.6%). Likewise, CDDP-MS (35 mg/kg) significantly prolonged the mean survival time (ILS=50.8%) compared with a CDDP-SOL group (8 mg/kg) (ILS=13.1%) in the mice with Li-7 xenografts transplanted into the spleen. Furthermore, CDDP-MS showed markedly effective anti-tumor activity (IR=82.2%) against H-154 (human stomach cancer) xenografts, in which CDDP-SOL was effective (IR=69.5%) at the MTDs. The suppressive effect of CDDP-MS on accumulation of malignant ascites was intimately related to unchanged CDDP concentration in ascites. These results demonstrated that the administration of CDDP-MS resulted in an unchanged CDDP concentration in ascites, and induced a sustained tumor growth inhibition along with a prolonged survival time.

Simple and rapid determination of carboplatin in plasma by high-performance liquid chromatography. Error pattern and application to clinical pharmacokinetic studies

Carboplatin is an antitumor agent widely employed in cancer chemotherapy. A specific and selective method for the determination of carboplatin in human plasma and its applications to pharmacokinetic investigations is described. One ultrafiltration step, through a Centrifree micropartition system (Amicon) at 2000 g for 10 min, is the only requirement as sample treatment. The resulting solution is injected into an Inertsil ODS-2 (5 microm, 25 cm x 4.6 mm I.D.) analytical column. The mobile phase consisted of 0.1 M potassium dihydrogenphosphate with 1 mM dipotassium edetate adjusted to a pH between 3 and 3.5. The limit of quantitation was 1 mg/l. The method showed good recovery (100.68+/-5.49%) and precision: the within-day relative standard deviation (RSD) for carboplatin (3-350 mg/l) was 2.07% and the between-day RSD for carboplatin, in the previously described range, was 1.31%. We determined the assay error pattern for proper weighting of serum level data in pharmacokinetic models. The selectivity (discrimination between the parent drug and platinum-containing species such as carboplatin metabolites), simplicity and speed of this assay for free carboplatin quantitation should facilitate pharmacokinetic investigations and therapeutic drug monitoring.

Pharmacokinetic behaviour of cisplatin in peritoneal fluid after intraperitoneal administration of cisplatin-loaded microspheres

The objective of this study was to establish a pharmacokinetic model for the estimation of unchanged cis-dichlorodiammine-platinum (II) (CDDP) concentration in peritoneal fluid after intraperitoneal administration of cisplatin-loaded microspheres (CDDP-MS) and to elucidate the accuracy of this model by comparisons between actual and simulated values after intraperitoneal administration of CDDP-MS. We developed a method enabling the precise and quick assessment of the drug concentration in the peritoneal cavity. The pharmacokinetic parameters obtained after intravenous bolus injection at a dose of 2 mg kg(-1) were total body clearance (1026 mL h(-1) kg(-1)), elimination rate constant (3.24 h(-1)) and distribution volume of systemic circulation (316.7 mL kg(-1)). After an intraperitoneal bolus injection at a dose of 5 mg kg(-1), the absorption rate constant from the peritoneal cavity (3.64 h(-1)) and the distribution volume of the peritoneal cavity (13.5 mL kg(-1)) were determined. The protein-binding rate constant in ascites was 0.58 h(-1). Using these pharmacokinetic parameters, we established a pharmacokinetic model consisting of two compartments. Administration of CDDP-MS at a dose of 10 mg kg(-1), which released CDDP over 7 days in-vitro, yielded sustained concentrations of unchanged CDDP (1-2 mg mL(-1)) in the peritoneal cavity that persisted for 7 days, and that were predictable by applying the in-vitro dissolution profile to the pharmacokinetic model. The findings obtained from this study are useful for understanding the basic pharmacokinetic characteristics of unchanged CDDP in the peritoneal cavity and may also be important in the development of optimized CDDP-MS formulations.

Validation of high-performance liquid chromatographic assay methods for the analysis of carboplatin in plasma ultrafiltrate

Validation of two HPLC assays for the quantitation of carboplatin in human plasma ultrafiltrate is described. Both assay methods employed a YMC ODS-AQ 3.9 x 150 mm (3 microm) column for the chromatographic separation. The first method utilized direct UV detection, the second method utilized UV detection following post-column derivatization with sodium bisulfite. Structural analogues of carboplatin were synthesized and used as internal standards for the assays. With direct UV detection, sample clean-up using solid-phase extraction on amino cartridges was required prior to injection, with extraction recoveries ranging from 80 to 90%. This extraction procedure was not necessary with the post-column reaction method, which employed a more selective analytical wavelength. Unfortunately, instability of the post-column reagent was a problem and led to greater variability in predicted concentration values. For standard curves, a weighted (1/y2) regression approach was used for plots of peak area or peak height ratio (carboplatin/internal standard) vs. carboplatin concentration. The limit of detection of both assays was 0.025 microg/ml and both were validated for carboplatin concentrations from 0.05 to 40 microg/ml. Accuracy and precision data were generated using three batches of validation samples, each batch consisting of a standard curve and five sets of quality control samples. Stability of carboplatin in blood, plasma, plasma ultrafiltrate, and reconstituted extracts was evaluated. The assay methods were employed for the pharmacokinetic analysis of blood samples drawn from a pediatric patient that received a 400 mg/m2 dose of carboplatin.

Determination of platinum (II,IV) and palladium(II) as thiocyanate complexes by capillary zone electrophoresis analysis of carboplatin and similar drugs

The thiocyanate complexes of Pd(II), Pt(II) and Pt(IV) were studied by capillary zone electrophoresis. Pd(II) can be detected in the form of the thiocyanate complex at 305 nm with higher sensitivity than in the form of its chloro complex (absorption maximum 214 nm). A detection limit equal to 5 ppb for Pd has been finally achieved. The possibility of simultaneous determination of Pd(II) and Pt(IV) in the form of thiocyanate complexes has also been demonstrated. When the method optimized for the determination of Pt(II) was applied to the drugs Cykloplatin and Ribocarbo (containing carboplatin) and Platidiam (containing cisplatin), good agreement of the platinum content with the declared value was obtained. Samples of vehicle exhaust particulates (National Institute for Environmental Studies, Japan, No. 8 reference material) were also analyzed.

European hospitals as a source for platinum in the environment in comparison with other sources

The concentration of platinum in the sewage of five European hospitals originating from excreted antineoplastic drugs, cisplatin and carboplatin, was analyzed in a short term study to provide an order of magnitude of Pt emissions from hospitals into aquatic environments. These emissions were compared with a rough estimation of emissions by cars. The average daily concentrations in the hospital effluents were approximately < 10-601 ng l-1 Pt (20-3580 ng l-1 in 2-h mixed samples). As expected from consumption data, the daily average concentrations should range from < 10-710 ng l-1 Pt. Platinum emitted by hospitals is 3.3-12.3% (1.3-14.3 kg per year) the estimated amount emitted by cars equipped with catalytic converters in the different European countries. Compared to platinum emissions from other sources, the effluents of hospitals are a minor source of platinum in municipal sewage, but they should not to be disregarded. Other possible sources for the emission of platinum into the environment should be considered in further investigations.

Recent applications of high-performance liquid chromatography to the analysis of metal complexes

Interest in metal complexes in modern inorganic chemistry has resulted in increasing demands for the analysis of these compounds. This paper reviews the most recent applications of high-performance liquid chromatography (HPLC) to the analysis of metal complexes. The review centres on the use of the technique in metal complex syntheses, reactions, characterizations and complexations and retention behaviour of these compounds, as reported in the literature since 1994.