Blood contamination of the pharmaceutical staff by irinotecan and its two major metabolites inside and outside a compounding unit.

BACKGROUND: Caregivers in healthcare settings are exposed to a risk of antineoplastic drug contamination which can lead to adverse health effects. Biological monitoring is necessary to estimate the actual level of exposure of these workers. This study was conducted with the aim of assessing blood contamination levels by irinotecan and its metabolites of pharmaceutical staff operating inside and outside a compounding unit. METHODS: The study took place within the pharmaceutical unit of a French comprehensive cancer centre. Blood samples were collected from the pharmacy workers operating inside and outside the compounding unit, and analysed by UHPLC-MS/MS. Plasma and red blood cell irinotecan and its metabolites (SN-38; APC) were determined with a validated analytical method detection test. RESULTS: A total of 17/78 (21.8%) plasma and red blood cell-based assays were found to be contaminated among staff. Overall, the total number of positive assays was significantly higher for staff members working outside the compounding unit than for workers working inside it (P = 0.022), with respectively 5/42 (11.9%) and 12/36 (33.3%) positive assays. For plasma dosages, the "outside" group had a significantly higher number of positive assays (P = 0.014). For red blood cell-based assays, no significant difference was found (P = 0.309). CONCLUSIONS: This study reveals that pharmaceutical staff serving in health care settings are exposed to a risk of antineoplastic drug contamination, not only inside the compounding room but also in adjacent rooms. The results would help to raise awareness and potentially establish protective measures for caregivers working in areas close to the compounding room as well.

The Antitumoral Effect of the S-Adenosylhomocysteine Hydrolase Inhibitor, 3-Deazaneplanocin A, is Independent of EZH2 but is Correlated with EGFR Downregulation in Chondrosarcomas.

BACKGROUND/AIMS: 3-Deazaneplanocin, DZNep, has been reported to inhibit the EZH2 histone methylase and to induce cell apoptosis in chondrosarcomas (CS). The present study aims to confirm the therapeutic potential of EZH2 inhibitors and investigate the molecular mechanisms of DZNep in chondrosarcomas. METHODS: CS cell lines and primary cultures were used. Apoptosis was investigated using PARP cleavage, caspase 3/7 activity, or Apo2.7 expression. S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM) were quantified by UHPLC-MS/MS. Differentially expressed genes in treated-chondrosarcomas and chondrocytes were researched by microarray analysis. RESULTS: DZNep induced apoptosis in chondrosarcomas both in vivo and in vitro. However, this effect was not correlated to EZH2 expression nor activity, and EZH2 knock-down by siRNA did not reduce CS viability. Additionally, the reduction of H3K27me3 induced by GSK126 or tazemetostat (EPZ-6438) did not provoke chondrosarcoma death. However, as expected, DZNep induced SAH accumulation and reduced SAM:SAH ratio. Further, microarray analysis suggests a key role of EGFR in antitumoral effect of DZNep, and pharmacological inhibition of EGFR reduced chondrosarcoma survival. CONCLUSION: EZH2 is not an adequate target for chondrosarcoma treatment. However, DZNep induces apoptosis in chondrosarcomas in vitro and in vivo, by a mechanism likely mediated though EGFR expression. Consequently, it would be worth initiating clinical trials to evaluating efficiency to S-adenosylhomocysteine hydrolase or EGFR inhibitors in patients with chondrosarcomas.

Oxy-PAHs: occurrence in the environment and potential genotoxic/mutagenic risk assessment for human health.

Structurally modified polycyclic aromatic hydrocarbons (PAHs) such as nitrated PAHs (nitro-PAHs) and oxygenated PAHs (oxy-PAHs) can be incriminated in the total toxicity of polycyclic aromatic compounds (PACs) fraction in the environment. Compared to nitro-PAHs, oxy-PAHs have been poorly studied. Oxy-PAHs covers compounds with different moieties such as polycyclic aromatic ketones (PAKs) and polycyclic aromatic quinones (PAQs). In this review, we have compiled exhaustively all the data available on the sources, the fate, and the occurrence of oxy-PAHs focusing on the most ubiquitous ones in the environment, ie PAKs and PAQs. Data concerning their genotoxicity, mutagenicity and tumor promotion potential for humans are also provided based on the mode-of-action analysis framework. Mutagenicity results based on the limited number of oxy-PAHs tested, are unequivocal on the concern they represent. Their omission in mutagenic/carcinogenic risk has caused a dramatic underestimation of cancer risk. On the basis of environmental and genotoxicological data, we suggest prioritized 4 major oxy-PAHs molecules in ecotoxicological and toxicological studies, namely 6 H-benzo[cd]pyren-6-one (BPO), 7,12-benz[a]anthracenequinone (BAQ), 5,12-naphthacenequinone (NCQ) and 11 H-benzo[b]fluoren-11-one (B[b]FO). We also propose to develop biomarkers of exposure and/or risk for these compounds, for example by quantification of DNA adducts.

Love Acoustic Wave-Based Devices and Molecularly-Imprinted Polymers as Versatile Sensors for Electronic Nose or Tongue for Cancer Monitoring.

Cancer is a leading cause of death worldwide and actual analytical techniques are restrictive in detecting it. Thus, there is still a challenge, as well as a need, for the development of quantitative non-invasive tools for the diagnosis of cancers and the follow-up care of patients. We introduce first the overall interest of electronic nose or tongue for such application of microsensors arrays with data processing in complex media, either gas (e.g., Volatile Organic Compounds or VOCs as biomarkers in breath) or liquid (e.g., modified nucleosides as urinary biomarkers). Then this is illustrated with a versatile acoustic wave transducer, functionalized with molecularly-imprinted polymers (MIP) synthesized for adenosine-5'-monophosphate (AMP) as a model for nucleosides. The device including the thin film coating is described, then static measurements with scanning electron microscopy (SEM) and electrical characterization after each step of the sensitive MIP process (deposit, removal of AMP template, capture of AMP target) demonstrate the thin film functionality. Dynamic measurements with a microfluidic setup and four targets are presented afterwards. They show a sensitivity of 5 Hz·ppm(-1) of the non-optimized microsensor for AMP detection, with a specificity of three times compared to PMPA, and almost nil sensitivity to 3'AMP and CMP, in accordance with previously published results on bulk MIP.

The use of enzyme-coupled magnetic nanoparticles for studying the spectra of unusual substrates of mushroom tyrosinase by direct surface-assisted laser desorption/ionisation and high-resolution electrospray ionisation quadrupole-quadrupole-time-of-flight mass spectrometry.

RATIONALE: Tyrosinase-coupled magnetic particles (EMPs) were used to demonstrate that resorcinol-containing tyrosinase inhibitors are oxidised by tyrosinase only in the presence of the enzyme's classic substrate. This shows the potential for the application of EMPs as a non-organic matrix for monitoring enzymatic conversion of a novel substrate family directly on-the-spot, principally due to minimal enzyme requirement per analysis. METHODS: Tyrosinase was covalently coupled to core-shell-type silica-coated iron oxide magnetic nanoparticles (EMPs) that were applied as non-organic SALDI matrix suitable for studying low-mass compounds using a classic matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometer. Because of the dual function of the EMPs - enzyme host and non-organic matrix - we describe this ionisation method as Enzyme-coupled Nanoparticles-Assisted LDI-MS (ENALDI-MS). Supplementary studies of the enzymatic conversion of glabridin and 3-(2,4-dihydroxyphenyl)propionic acid (DHPA) were conducted by high-resolution electrospray ionisation quadrupole-quadrupole-time-of-flight mass spectrometry (ESI-QqTOF-MS). RESULTS: The initial experiment involving EMPs as non-organic matrix (ENALDI-MS) showed enzymatic conversion of glabridin, a strong tyrosinase inhibitor, only in the presence of L-Tyr, the classic tyrosinase substrate. These findings were evaluated by ESI-QqTOF-MS proving that glabridin and DHPA are converted into the corresponding quinones by tyrosinase only in the presence of the auxiliary monophenol or o-diphenol substrates (L-Tyr and catechin, respectively) capable of regenerating the active site of tyrosinase. CONCLUSIONS: EMPs were shown to be useful as a non-organic matrix to monitor enzymatic conversion of the novel tyrosinase substrate family directly on-the-spot with a minimal enzyme consumption (6.5 pmol/spot). Results obtained by ENALDI-MS were fully confirmed by ESI-QqTOF-MS demonstrating that resorcinol-containing tyrosinase inhibitors may be oxidised by the enzyme in the presence of its classic substrates.

Evaluation of molecularly imprinted polymers using 2',3',5'-tri-O-acyluridines as templates for pyrimidine nucleoside recognition.

In this paper, we describe the synthesis and evaluation of molecularly imprinted polymers (MIPs), prepared using 2',3',5'-tri-O-acyluridines as 'dummy' templates, for the selective recognition of uridine nucleosides. The MIPs were synthesised using a non-covalent approach with 2,6-bis-acrylamidopyridine (BAAPy) acting as the binding monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent. The MIPs were evaluated in terms of capacity, selectivity and specificity by analytical and frontal liquid chromatography measurements. The results obtained in organic mobile phases suggest that the nucleosides are specifically bound to the polymer by the complementary hydrogen bonding motifs of the binding monomer and the nucleoside bases. The MIPs exhibited relatively high imprinting factors for 2',3',5'-tri-O-acyluridines, while they did not show any binding capacity for other nucleosides lacking the imide moiety on their base. Moreover, the presence of ester-COO groups in the EGDMA cross-linker may lead to the formation of additional hydrogen bonds with the 2',3' and/or 5'-OH of sugar part, allowing enhancement of the recognition of the uridine nucleosides. In aqueous media, results show that the binding is driven by hydrophobic interactions.

UHPLC-MS/MS method for the quantification of ultra-traces of irinotecan and its metabolites in red blood cells and plasma to detect caregivers' contamination.

The occupational exposure of caregivers to antineoplastic agents has been demonstrated since 1979. Since the early 1990s, numerous studies from several countries have demonstrated the contamination of care facilities by antineoplastic drugs. As it is easier to sample, most contamination measurements in workers are carried out in urine sample. The distribution and elimination half-lives of irinotecan suggest that blood can be considered as better than urine for the biomonitoring of a potential contamination of healthcare workers. We describe here the development and the validation of a UHPLC-MS/MS method to simultaneously quantify irinotecan, and two of its main metabolites, APC and SN-38, at ultra-trace levels in plasma and red blood cells (RBC). This method has been applied to blood samples collected from several healthcare services in a French comprehensive cancer center. The results demonstrate that the method is sensitive enough to identify a contamination of healthcare workers by irinotecan and SN-38 at very low concentrations. Moreover, the results show that analysis of RBC is of great interest and complementary to that of serum.

In vitro genotoxicity potential investigation of 7 oxy-PAHs.

Air pollutants include many compounds among them oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs). As they are suspected to generate DNA damage and mutagenicity, an understanding of their mode of action could highlight a carcinogenic potential risk in exposed population. In this article, a prospective study on seven oxy-PAHs selected in terms of occurrence in the environment was conducted on mutagenicity, genotoxicity, and cytotoxicity potentials using in vitro assays including Ames test on five strains, kinetic analysis of cytotoxicity and apoptosis, phosphorylation of histone H2AX, and p53 induction assays on human lung cell line BEAS-2B. Ames test demonstrated that mutagenicity pattern depended on the oxy-PAH tested. Except for BAQ, all oxy-PAHs tested gave mutagenic effect, in the absence and/or in the presence of metabolic activation (S9 fraction). At 24 h of exposure, the majority of oxy-PAHs induced γ-H2AX in BEAS-2B cells and/or phosphorylation of p53 at serine 15 and cell death at highest tested concentrations. Although 9,10-AQ and B[b]FO were mutagenic in bacteria, they failed to induce any of the other genotoxicity biomarkers. In comparison with the benzo[a]pyrene, all oxy-PAHs were less potent in terms of genotoxic potential at the same concentration. These results highlighted the genotoxic and mutagenic potential of these oxy-PAHs and provide preliminary information concerning their possible mechanism of action for toxicity, contributing to a better evaluation of the real associated health risks for human and environment.

Continuous-flow step gradient mass spectrometry based method for the determination of kinetic parameters of immobilized mushroom tyrosinase in equilibrating conditions: comparison with free enzyme.

A mass spectrometry (MS)-based methodology for enzymatic assay in equilibrium conditions was designed and evaluated. This on-line assay involves the introduction of a continuous-flow step gradient (CFSG) of a substrate solution in the column containing immobilized enzyme and the simultaneous tracking of the product formation. We showed that the constant concentration of substrate in the entire bioreactor for an appropriate duration ensures the equilibration of the studied enzyme (mushroom tyrosinase). Under these conditions, it was demonstrated also that the kinetic and enzymatic parameters (Michaelis-Menten constant, K(M) , the maximal specific activity, SA(max)) are independent of the flow rate of the mobile phase. The feasibility of the mentioned approach for inhibitory tests was also investigated. The coupling of the mass spectrometer to the bio-reactor allows the selective monitoring of the enzymatic reaction products and increases their detection level. Very high sensitivity, 500 pmol/min/column, and selective monitoring of the products of the enzymatic reaction are allowed by MS detection. The methodology developed here constitutes a sensitive analytical tool to study enzymes requiring long equilibration times.

Is the blood of a surgeon performing HIPEC contaminated by irinotecan, its major metabolites and platinum compounds?

OBJECTIVES: Hyperthermic intraperitoneal chemotherapy (HIPEC) is a beneficial surgical technique for patients, but the surgeons are being exposed to cytotoxic drugs. Few biomonitoring studies were led on blood samples in the context of HIPEC. This study aimed to evaluate the surgeon's plasmatic and red blood cell (RBC) contamination by irinotecan, two of its major metabolites and platinum compounds. METHODS: HIPEC procedures performed using the coliseum techniques were observed between September 2015 and April 2018 in a French comprehensive cancer center. Irinotecan and its metabolites SN-38 and APC were dosed by UHPLC with a limit of quantification determined at 50 pg/mL. Platinum compounds were dosed by inductively coupled plasma mass spectrometry with a limit of quantification determined at 16 pg/mL. RESULTS: Despite collective and personal protective equipment, 80% of plasma samples were contaminated by irinotecan and 33% by platinum compounds out of 21. The results showed that the surgeon was contaminated after HIPEC and even after a period of HIPEC inactivity. Nineteen percent of plasmatic samples and 45% of RBC samples were contaminated by SN-38, the active metabolite of irinotecan. APC was only found in some RBC samples (33%). CONCLUSIONS: Even if this study shows blood contamination by irinotecan, two of its major metabolites (including active SN-38) and platinum compounds both in the plasma and RBC of a surgeon performing the HIPEC procedures, further studies should be performed to confirm these results. Additional studies should be carried out to further investigate the contamination in the context of HIPEC and more broadly in the hospital.

Investigation by mass spectrometry and 32P post-labelling of DNA adducts formation from 1,2-naphthoquinone, an oxydated metabolite of naphthalene.

Naphthalene is the simplest representative of polycyclic aromatic hydrocarbons (PAHs). It is detected as major pollutant in the different compartments of the environment. This compound is considered by the international agency for research on cancer (IARC), the specialized cancer agency of the World Health Organisation (WHO), as a possible carcinogenic (group 2B) since 2002, mainly based on studies on chronic inhalation in rodent by the national toxicology program of the U.S. department of health and human services. In humans, its main metabolites correspond to derivatives substituted in position and 1 and 2 as 1,2-naphthoquinone (1,2-NphQ). Based on previous studies, 1,2-NphQ is supposed to react with DNA to form mostly depurinating adducts, a possible initiating step of carcinogenicity. To confirm this potentiality, adducts were synthetized by the reaction of 1,2-NphQ with 2'-deoxyguanosine (2'-dG) in N,N-dimethylformamide (DMF), water and calf thymus DNA. 2'-dG adducts were analyzed by 32P post-labelling, HPLC with ultra-violet detection and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). We found stable DNA adducts detected in DNA. We proposed a formation mechanism by a 1,4-Michael addition with 2'-dG. Adducts with 2'-deoxyxanthosine are formed after a spontaneous deamination of 2'-dG. These adducts are good candidates as biomarkers allowing evaluation of exposure to naphthalene and its derivatives in the development of pathologies such as cancer.

A validated UHPLC-MS/MS method for simultaneous quantification of 9 exocyclic DNA adducts induced by 8 aldehydes.

Human exposure to aldehydes is implicated in several diseases including cancer. These strong electrophilic compounds can react with nucleophilic sites in DNA to form reversible and irreversible modifications. These modifications, if not repaired, can contribute to pathogenesis. The aim of our study was to provide a mass spectrometry (MS)-based profiling method for identifying potential biomarkers of aldehydes exposure. We have developed and validated a highly sensitive method using ultra high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) for the simultaneous quantitation of 9 exocyclic DNA adducts derived from 8 main exogenous and endogenous aldehydes, namely formaldehyde, acetaldehyde, acrolein, crotonaldehyde, malondialdehyde, 4-hydroxy-2-nonenal, glyoxal and methylglyoxal. Finally, we applied the established method to quantify adducts in genomic DNA isolated from the blood of a smoker and a non-smoker blood samples in order to demonstrate its applicability.

Sensitivity improvement by using contactless conductivity rather than indirect UV detection for the determination of enantiomeric purity of amines by CE.

A capacitively coupled contactless conductivity detection (C4D) system for CE with a flexible detection cell was applied for the enantioseparation of small chiral underivatized amines using chiral crown ether or CD as chiral selector. Since these compounds are poorly UV-active, C4D was an alternative detection mode. The composition (ionic strength, pH, chiral selector) of the electrolyte was optimized in order to be suitable for C4D. (-)-(18-crown-6)-2,3,11,12-tetracarboxylic acid was required as chiral selector to resolve the enantiomers of small polar amines. However, trimethyl-beta-CD was suitable to separate amines possessing hydrophobic carbon chains. The performance of C4D was compared with indirect UV detection in terms of sensitivity, repeatability and accuracy. The linearity range of C4D was very large (1.5-1600 microg/mL) compared with the indirect UV linearity range (25-400 microg/mL) and allowed the determination of the enantiomeric purity of isopinocampheylamine up to 0.25%. The CE-C4D method has been fully validated by applying a novel strategy using accuracy profiles. All relative biases of the developed method were included within the +/-15% limits of acceptance. C4D is a good alternative to indirect UV detection for the enantioseparation of non-UV absorbing amines since the method development is fast and easy and, the sensitivity is improved by a factor of 100 compared with that of the indirect UV mode.

Simultaneous enantioselective determination of fenamiphos and its two metabolites in soil sample by CE.

The enantioseparation of fenamiphos and its two main metabolites (fenamiphos sulfoxide and fenamiphos sulfone) were simultaneously achieved by CE by using a dual CD system. A mixture of 25 mM carboxymethyl-beta-CD and 10 mM hydroxypropyl-alpha-CD was added to the acetic acid/ammonia (ionic strength=50 mM, pH 5) buffer and was suitable for the baseline resolution of all stereoisomers of analytes. A further addition of 5% methanol to the BGE increased significantly the resolution between the diastereoisomers of fenamiphos sulfoxide. An overimposed pressure (0.2 psi) was applied during the analysis in order to have better peak efficiencies and small run time. The composition of the sample solvent was found to be a crucial parameter. An amount of 15% MeOH added to the sample was a good alternative to ensure the total solubility of fenamiphos and the baseline separation of fenamiphos sulfoxide enantiomers. The extraction of pesticides from soil samples was also investigated. A methanolic extraction allowed recovering 50-75% of pesticides, which were detected by CE at the parts per million concentration level (3-100 mg/kg) with a good precision (5.1-13.2% RSD). This method was applied to soil samples and was found to be suitable to monitor the enantiomeric degradation of fenamiphos in environmental samples.

Molecular imprinting of AMP by an ionic-noncovalent dual approach.

In order to mimic recognition properties of adenylate kinase, molecularly imprinted polymers (MIPs) were prepared for adenosine 5'-monophosphate (AMP), a substrate of the enzyme. Different functional monomers interacting with the phosphate moiety were tested, and the MIP giving the best specific binding of AMP was composed with one equivalent of 2-(dimethylamino)ethyl methacrylate and ten equivalents of acrylamide compared to AMP. Packed into solid phase cartridge, this polymer showed similar characteristics than the enzyme, since it was specific for AMP toward other nucleotides.

Comparison of water, sediment, and plants for the monitoring of antibiotics: a case study on a river dedicated to fish farming.

Oxolinic acid, flumequine, oxytetracycline, and florfenicol are antibiotics commonly used in farming. Because an important percentage of these antibiotics given to fish and cattle ends up, directly or indirectly, in the freshwater environment, suitable tools for the monitoring of these antibiotics are needed. A French river was chosen because of the location of four fish farms and a sewage plant on its main course. First, a passive monitoring program involving water, sediment, and autochthonous bryophytes was performed at 25 sampling sites tested once every three months for one year. Second, an active monitoring method was performed using moss bags for a one-month exposure period, both upstream and downstream of each potential source of antibiotics. Sediment and bryophyte samples, but not water samples, were found to be useful for monitoring environmental contamination by oxolinic acid, flumequine, oxytetracycline, and florfenicol. Sediments and bryophytes also appeared to be complementary media for dating the river's contamination by antibiotics. Data collected by both active and passive monitoring methods confirmed contamination of the river, mainly by flumequine and oxytetracycline, attributable to fish farming but also to terrestrial animal farming and perhaps human pharmaceuticals.

Plasminogen Activator Inhibitor-1 (PAI-1) deficiency predisposes to depression and resistance to treatments.

Major depressive disorder (MDD) is one of the most frequent psychiatric illnesses, leading to reduced quality of life, ability to work and sociability, thus ranking among the major causes of disability and morbidity worldwide. To date, genetic and environmental determinants of MDD remain mostly unknown. Here, we investigated whether and how the Plasminogen Activator Inhibitor-1 (PAI-1) may contribute to MDD. We first examined the phenotype of PAI-1 knockout (PAI-1-/-) and wild-type (PAI-1+/+) male mice with a range of behavioral tests assessing depressive-like behaviors (n = 276). We next investigated the mechanisms relating PAI-1 to MDD using molecular, biochemical and pharmacological analyzes. We demonstrate here that PAI-1 plays a key role in depression by a mechanism independent of the tissue-type Plasminogen Activator (tPA) - Brain-Derived Neurotrophic Factor (BDNF) axis, but associated with impaired metabolisms of serotonin and dopamine. Our data also reveal that PAI-1 interferes with therapeutic responses to selective serotonin reuptake inhibitors (escitalopram, fluoxetine). We thus highlight a new genetic preclinical model of depression, with the lack of PAI-1 as a factor of predisposition to MDD. Altogether, these original data reveal that PAI-1 should be now considered as a key player of MDD and as a potential target for the development of new drugs to cure depressive patients resistant to current treatments.

Simultaneous determination of optical and chemical purities of a drug with two chiral centers by liquid chromatography-circular dichroism detection on a non-chiral stationary phase.

The need for a rapid and cheap chromatographic technique for the simultaneous determination of diastereoisomeric and chemical purities of a drug has led to develop a non-enantioselective HPLC method on a porous graphitic carbon (PGC) sorbent and by using circular dichroism (CD) detection. Among a lot of non-chiral chromatographic supports tested, PGC was the only one allowing the separation of all benzoxathiepin diastereoisomers. After optimization of the chromatographic conditions, a mobile phase composed of chloroform, acetonitrile and methanol was suitable to elute the diastereoisomers with their related chemical impurities in less than 20 min by gradient mode. CD detection was found to be compatible with elution gradient and both the UV, CD and g anisotropy factor signals were recorded without disturbance. The determination of chemical purity was achieved with UV detection (254 nm) whereas the diastereoisomeric purity was determined using CD detection (258 nm) by plotting the anisotropy factors (R,S-S,R and R,R-S,S) versus the enantiomeric excess of each couple of enantiomers. A mathematic model was developed in order to express the diastereoisomeric excess versus the enantiomeric excess of each couple of enantiomers. Hence, the HPLC-UV/CD method was convenient to give access simultaneously to the optical and chemical purities of a chiral drug.

Molecularly imprinted polymer of 5-methyluridine for solid-phase extraction of pyrimidine nucleoside cancer markers in urine.

Normal and modified urinary nucleosides represent potential biomarkers for cancer diagnosis. To selectively extract modified nucleosides, we developed a molecularly imprinted polymer (MIP) of 5-methyluridine as selective material for molecularly imprinted solid-phase extraction (MISPE). The MIPs were obtained from vinyl-phenylboronate ester derivative of the template, acrylamide and pentaerythritol triacrylate co-polymer, and were tested in batch and cartridge experiments with aqueous samples. Our results indicated that the imprinted polymer was selective for pyrimidine nucleosides with a K(d) and a B(max) of 46 microM and 18 micromol/g, respectively. Finally, a MISPE of the most common pyrimidine nucleoside cancer markers in urine sample was realized.

Chiral analysis of milnacipran by a nonchiral HPLC--circular dichroism: improvement of the linearity of dichroic response by temperature control.

The determination of the enantiomeric excess (e.e.) of a basic drug has been investigated in LC using a nonchiral stationary phase and a circular dichroism (CD) detector in order to avoid expensive chiral columns. The CD detector records both dichroic (Deltaepsilon) and UV (epsilon) signals at the same wavelength and calculates the anisotropy factor (g=Deltaepsilon/epsilon), which is linearly related to the e.e. The enantiomeric and chemical composition of a chiral drug can be simultaneously determined on a nonchiral HPLC support. However, the g factor from the CD signal is temperature dependent. Indeed, the temperature has an influence on the stability of the CD signal and the linear regression between g factor and the e.e. of 1R,2S-enantiomer. So, a decrease in temperature gives rise to an improvement of the above-mentioned linearity correlation. After optimization of chromatographic parameters (porous graphitic carbon-based column, methanol/ phosphate buffer as mobile phase) and selection of CD wavelength, a linear regression of g factor versus e.e. of 1R,2S-enantiomer was obtained at temperature-controlled CD detection and an LOQ of 94% was found. The enantiomeric composition of milnacipran was determined with good accuracy.