Sonochemical synthesis of iron-graphene oxide/honeycomb-like ZnO ternary nanohybrids for sensitive electrochemical detection of antipsychotic drug chlorpromazine.

We report a novel electrochemical sensor for the sensitive and selective determination of the antipsychotic drug chlorpromazine (CPZ) based on the iron (Fe) nanoparticles-loaded graphene oxide (GO-Fe)/three dimensional (3D) honeycomb-like zinc oxide (ZnO) nanohybrid modified screen printed carbon electrode (SPCE). The 3D hierarchical honeycomb-like ZnO was synthesized using a novel aqueous hydrothermal method and the GO-Fe/ZnO nanohybrid was prepared based on an inexpensive and fast sonochemical method using a high-intensity ultrasonic bath (Delta DC200H, 200 W, 40 KHz). Characterizations including scanning electron microscopy, elemental mapping, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy were carried out as part of this work. The electrocatalytic oxidation behavior of CPZ at various electrodes was investigated using the cyclic voltammetry technique, through which the GO-Fe/ZnO modified SPCE was identified as the best performing electrode. The quantitative determination of CPZ was then performed using the differential pulse voltammetry technique. The as-prepared GO-Fe/ZnO/SPCE sensor exhibited a quick and sensitive response towards the oxidation of CPZ with linear concentration ranges from 0.02 to 172.74 µM and 222.48 to 1047.74 µM. The modified SPCE sensor displayed a low detection limit (LOD) of 0.02 µM and a high sensitivity of 7.56 µA µM-1 cm-2. The proposed sensor also showed remarkable operational and storage stability, reproducibility, and repeatability. Furthermore, the practicability of the GO-Fe/ZnO/SPCE sensor has been verified with real sample analysis using commercial antipsychotic CPZ tablets and human urine samples, and adequate recovery has been achieved.

Magnetic micro-solid-phase extraction based on magnetite-MCM-41 with gas chromatography-mass spectrometry for the determination of antidepressant drugs in biological fluids.

A new facile magnetic micro-solid-phase extraction coupled to gas chromatography and mass spectrometry detection was developed for the extraction and determination of selected antidepressant drugs in biological fluids using magnetite-MCM-41 as adsorbent. The synthesized sorbent was characterized by several spectroscopic techniques. The maximum extraction efficiency for extraction of 500 µg/L antidepressant drugs from aqueous solution was obtained with 15 mg of magnetite-MCM-41 at pH 12. The analyte was desorbed using 100 µL of acetonitrile prior to gas chromatography determination. This method was rapid in which the adsorption procedure was completed in 60 s. Under the optimized conditions using 15 mL of antidepressant drugs sample, the calibration curve showed good linearity in the range of 0.05-500 µg/L (r2  = 0.996-0.999). Good limits of detection (0.008-0.010 µg/L) were obtained for the analytes with good relative standard deviations of <8.0% (n = 5) for the determination of 0.1, 5.0, and 500.0 µg/L of antidepressant drugs. This method was successfully applied to the determination of amitriptyline and chlorpromazine in plasma and urine samples. The recoveries of spiked plasma and urine samples were in the range of 86.1-115.4%. Results indicate that magnetite micro-solid-phase extraction with gas chromatography and mass spectrometry is a convenient, fast, and economical method for the extraction and determination of amitriptyline and chlorpromazine in biological samples.

Sequential injection chromatography for separation and quantification of chlorpromazine in human urine and pharmaceutical formulations.

Sequential injection chromatography (SIC) is a recent, simple, and inexpensive green miniaturized separation technique. In the current study, SIC was exploited for the first time for biochemical analysis. A new SIC method for the separation and quantification of chlorpromazine in human urine, as well as pharmaceutical formulations, was developed and validated. Clozapine was used as an internal standard. Chlorpromazine was successfully separated on a C18 monolithic column (25x4.6 mm id). The UV detection was carried out at 250 nm using miniaturized fiber optic spectrometric devices. The optimum mobile phase composition was 30 mmol/L phosphate-acetonitrile-methanol (55.0 + 31.5 + 13.5, v/v/v) at pH 3.0. The sample volume was 40 microL and flow rate was 40 microL/s. Acceptable chromatographic results were obtained. The resolution was 2.7, peak symmetry was 1.1, and number of theoretical plates was more than 1 x 10(6). Good linearity (r = 0.9997) in the range of 25-100 microg/mL was also obtained. The method offered acceptable recovery for both human urine (89.6-93.1%) and pharmaceutical formulations (96.9-98.5%), which was sensitive enough to detect chlorpromazine. The LOD and LOQ in human urine were 61 and 204 ng/mL, respectively. The method was rapid and reagent-saving, and hence safe for the environment. The sample throughput was 26.3 samples/h and the total volume of consumed reagents was 4.0 mL.

[Simultaneous determination of chlorpromazine and promethazine and their main metabolites by capillary electrophoresis with electrochemiluminescence].

Based on the phenomenon that each of chlorpromazine (CPZ), promethazine (PMZ), chlorpromazine sulfoxide (CPZSO) and promethazine sulfoxide (PMZSO) could enhance the electrochemiluminescence (ECL) intensity of tris(2,2'-bipyridyl) ruthenium, a novel and sensitive method was proposed for the simultaneous determination of CPZ, PMZ and their main metabolites using capillary electrophoresis (CE) coupled with ECL detection. The influences of several experimental parameters were explored. The optimum experimental conditions were as follows: detection potential of 1. 20 V (Ag/AgCl), 40 mmol/L of phosphate buffer solution (pH 6.5) containing 5 mmol/L tris(2,2'-bipyridyl) ruthenium in ECL detection cell, running buffer solution of 18 mmol/L (pH 4.8), sample injection of 8 s at 11 kV, and separation voltage of 13.5 kV. The detection limits (3sigma) of this method were 8.3 x 10(-7) g/L for CPZ, 7.2 x 10(-6) g/L for PMZ, 1.9 x 10(-5) g/L for CPZSO and 3.7 x 10(-6) g/L for PMZSO. The linear ranges of ECL intensity versus mass concentration of medicaments were 7. 1 x 10(-6) - 6. 3 x 10(-3) g/L for CPZ, 7.5 x 10(-5) - 4.6 x 10(-3) g/L for PMZ, 9.7 x 10(-5) - 3.6 x 10(-3) g/L for CPZSO and 8.1 x 10(-5) - 7.7 x 10(-3) g/L for PMZSO. The relative standard deviations (RSDs) of the four target compounds were not more than 3% for ECL intensity and 1% for migration time. This method has the merits of simplicity, speediness, sensitivity, small sample injection, and free from interference. This method was successfully utilized to directly and simultaneously detect CPZ, PMZ, CPZSO and PMZSO in urine samples of pet dogs.

Dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of clozapine and chlorpromazine in urine.

A simple method has been proposed for the determination of clozapine (CLZ) and chlorpromazine (CPZ) in human urine by dispersive liquid-liquid microextraction (DLLME) in combination with high-performance liquid chromatography-ultraviolet detector (HPLC-UV). All important variables influencing the extraction efficiency, such as pH, types of the extraction solvent and the disperser solvent and their volume, ionic strength and centrifugation time were investigated and optimized. Under the optimal conditions, the limit of detection (LODs) and quantification (LOQs) of the method were 13 and 39 ng/mL for CLZ, and 2 and 6 ng/mL for CPZ, respectively. The relative standard deviations (RSDs) of the targets were less than 5.1% (C=0.100 µg/mL, n=9). Good linear behaviors over the tested concentration ranges were obtained with the values of R (2)>0.999 for the targets. The absolute extraction efficiencies of CLZ and CPZ from the spiked blank urine samples were 98.3% and 97.8%, respectively. The applicability of the technique was validated by analyzing urine samples and the mean recoveries for spiked urine samples ranged from 93.3% to 105.0%. The method was successfully applied for the determination of CLZ and CPZ in real human urine.

False negative result for amphetamines on the Triage Drug of Abuse panel? The cause of the unusual phenomenon with experimental analyses.

On-site drug screening devices are widely used today for their simple test procedures and instantaneous results. Among other devices, a Triage Drug of Abuse panel is considered to be highly reliable for its high specificity and sensitivity of abused drugs. Although it is known that a false positive amphetamine (AMP) result may be obtained from the urine samples containing putrefactive amines or ephedrine-related compounds, no clinical false negative methamphetamine results have been reported to date. However, a false negative Triage result was obtained from the urine of a fatal methamphetamine poisoning victim taking Vegetamine tablets. Further experimental analyses revealed that the cross-reactivity of methamphetamine and chlorpromazine metabolites, including nor-2-chlorpromazine sulfoxide, was the cause for a false negative Triage reaction for AMP. Forensic scientists and clinicians must be aware of the limitations of on-site drug testing devices and the need for the confirmatory laboratory tests for the precise identification and quantification of drugs in suspicious intoxication cases, as also recommended by the manufacturers.

Implementation and performance evaluation of a database of chemical formulas for the screening of pharmaco/toxicologically relevant compounds in biological samples using electrospray ionization-time-of-flight mass spectrometry.

Electrospray ionization (ESI)-time-of-flight (TOF) MS enables searching a wide number of pharmaco/toxicologically relevant compounds (PTRC) in biosamples. However, the number of identifiable PTRC depends on extension of reference database of chemical formulas/compound names. Previous approaches proposed in-house or commercial databases with limitations either in PTRC number or content (e.g., few metabolites, presence of non-PTRC). In the frame of development of a ESI-TOF PTRC screening procedure, a subset of PubChem Compound as reference database is proposed. Features of this database (approximately 50,500 compounds) are illustrated, and its performance evaluated through analysis by capillary electrophoresis (CE)-ESI-TOF of hair/blood/urine collected from subjects under treatment with known drugs or by comparison with reference standards. The database is rich in parent compounds of pharmaceutical and illicit drugs, pesticides, and poisons and contains many metabolites (including about 6000 phase I metabolites and 180 glucuronides) and related substances (e.g., impurities, esters). The average number of hits with identical chemical formula is 1.82 +/- 2.27 (median = 1, range 1-39). Minor deficiencies, redundancies, and errors have been detected that do not limit the potential of the database in identifying unknown PTRC. The database allows a much broader search for PTRC than other commercial/in-house databases of chemical formulas/compound names previously proposed. However, the probability that a search retrieves different PTRC having identical chemical formula is higher than with smaller databases, and additional information (anamnestic/circumstantial data, concomitant presence of parent drug and metabolite, selective sample preparation, liquid chromatographic retention, and CE migration behavior) must be used in order to focus the search more tightly.

Extraction and determination of trace amounts of chlorpromazine in biological fluids using hollow fiber liquid phase microextraction followed by high-performance liquid chromatography.

In the present work, hollow fiber liquid phase microextraction (HF-LPME) in conjunction with reversed-phase HPLC/UV was developed for extraction and determination of trace amounts of chlorpromazine in biological fluids. The drug was extracted from an 11 ml aqueous sample (source phase; SP) into an organic phase impregnated in the pores of the hollow fiber (membrane phase; MP) followed by the back-extraction into a second aqueous solution (receiving phase; RP) located in the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, compositions of SP and RP solutions, extraction time, ionic strength and stirring rate on the extraction efficiency of the drug were examined and optimized. Under the optimal conditions, enrichment factor of 250, dynamic linear range of 1-500 microgl(-1), and limit of detection of 0.5 microgl(-1) were obtained for the drug. The percent relative intra-day and inter-day standard deviation (R.S.D.%) based on three replicate determinations were 6.7 and 10.3%, respectively. The method was applied to drug level monitoring in the biological fluids and satisfactory results were obtained.

Investigating the post-chemiluminescence behavior of phenothiazine medications in the luminol-potassium ferricyanide system: molecular imprinting-post-chemiluminescence method for the determination of chlorpromazine hydrochloride.

A new post-chemiluminescence (PCL) phenomenon was observed when phenothiazine medications were injected into the reaction mixture after the chemiluminescence (CL) reaction of luminol and potassium ferricyanide had finished. A possible reaction mechanism was proposed based on studies of the kinetic characteristics of the CL, CL spectra, fluorescence spectra, and on other experiments. The feasibility of determining various phenothiazine medications by utilizing these PCL reactions was examined. A molecular imprinting-post-chemiluminescence (MI-PCL) method was established for the determination of chlorpromazine hydrochloride using a chlorpromazine hydrochloride-imprinted polymer (MIP) as the recognition material. The method displayed high selectivity and high sensitivity. The linear range of the method was 1.0 x 10(-8) approximately 1.0 x 10(-6), with a linear correlation coefficient of 0.9985. The detection limit was 3 x 10(-9) g/ml chlorpromazine hydrochloride, and the relative standard deviation for a 1.0 x 10(-7) g/ml chlorpromazine hydrochloride solution was 4.0% (n = 11). The method has been applied to the determination of chlorpromazine hydrochloride in urine and animal drinking water with satisfactory results.

Ion-pair complex-based solvent extraction combined with chemiluminescence determination of chlorpromazine hydrochloride with luminol in reverse micelles.

A new chemiluminescence (CL) method is proposed for the determination of chlorpromazine hydrochloride, which is based on the dichloromethane solvent extraction of ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride and luminol chemiluminescence detection in a reversed micellar medium formed by the cation surfactant cetyltrimethylammonium bromide in a dichloromethane-cyclohexane (1:1 V/V)-water (0.3 mol/L Na2CO3 buffer solution with the pH of 11.5). The ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. In the optimum conditions, CL intensities are proportional to concentrations of the studied drug over the range 0.05 approximately 10 microg/mL with a detection limit (DL) of 6 ng/mL. The relative standard deviation (R.S.D.) is 2.6% for 1.25 microg/mL chlorpromazine hydrochloride (n = 11). R.S.D. (precision) of inter-day and intra-day is less than 6%, and accuracy of inter-day and intra-day is satisfactory. The method has been applied to the determination of studied drug in pharmaceutical preparations and biological fluids with satisfactory results.

Quinidine inhibits the 7-hydroxylation of chlorpromazine in extensive metabolisers of debrisoquine.

Quindine is a potent inhibitor of CYP2D6 (debrisoquine 4-hydroxylase). Its effect on the disposition of chlorpromazine was investigated in ten healthy volunteers using a randomised crossover design with two phases. A single oral dose of chlorpromazine hydrochloride (100 mg) was given with and without prior administration of quinidine bisulphate (250 mg). Chlorpromazine and seven of its metabolites were quantified in the 0- to 12-h urine while plasma concentrations of chlorpromazine and 7-hydroxychlorpromazine were measured over 48 h. All volunteers were phenotyped as extensive metabolisers with respect to CYP2D6 using the methoxyphenamine/O-desmethyl-methoxyphenamine metabolic ratio. Quinidine significantly decreased the urinary excretion of 7-hydroxylchlorpromazine 2.2-fold. Moreover the urinary excretion of this metabolite correlated inversely (rs = -0.80) with the metabolic ratio. The urinary recoveries of chlorpromazine, chlorpromazine N-oxide, 7-hydroxy-N-desmethylchlorpromazine, N-desmethyl-chlorpromazine sulphoxide and the total of all eight analytes were unaltered by quinidine. However, quinidine administration caused significant increases in the urinary excretions of chlorpromazine sulphoxide, N-desmethylchlorpromazine and N, N-didesmethylchlorpromazine sulphoxide, which indicated that compensatory increase in these metabolic routes of chlorpromazine might have been responsible for the lack of change observed in the urinary recovery of the parent drug. Quinidine administration produced modest decreases (1.2- to 1.3-fold) in the mean peak plasma concentrations and mean areas under the plasma concentration-time curves of 7-hydroxychlorpromazine and increases (1.3- to 1.4-fold) in these parameters for the parent drug chlorpromazine, but none of these changes reached statistical significance. Based on ANOVA the sample sizes required to detect these differences as significant (alpha = 0.5) with a probability of 0.8 were determined to vary between 15 and 42. These data suggest that CYP2D6 is involved in the metabolism of chlorpromazine to 7-hydroxychlorpromazine. However, genetic polymorphism in this metabolic process did not play a dominant role in accounting for the extremely large interindividual variations in plasma concentrations encountered with this drug.

A liquid chromatographic method for the determination of promethazine enantiomers in human urine and serum using solid-phase extraction and fluorescence detection.

A LC method was developed for the concurrent assay of R(+) and S(-) promethazine from human urine and serum. The method involves the use of solid-phase extraction for sample clean-up. Chromatographic resolution of the enantiomers was performed under isocratic conditions using a mobile phase of hexane-1,2-dichlorethane-absolute ethanol-trifluoroacetic acid (400:150:100:1, v/v/v/v) at a flow rate of 1 ml min-1 on a brush-type column KK-CARNU. The enantiomers were detected by fluorescence using an excitation wavelength of 250 nm and a 280 nm emission cutoff filter. Chlorpromazine was used as the internal standard for urine analysis. Standard addition was used for promethazine analysis from serum. Drug to internal standard ratios were linear from 0.25 to 10 micrograms ml-1 in urine. Serum levels were linear from 2 to 10 ng ml-1.

The metabolites of chlorpromazine N-oxide in rat bile.

1. The metabolism of chlorpromazine N-oxide was studied in female rats after a 20 mg/kg single i.p. dose. 2. Metabolites identified in urine and faeces were chlorpromazine, 7-hydroxychlorpromazine, chlorpromazine sulphoxide, N-desmethylchlorpromazine and N-desmethylchlorpromazine sulphoxide. As these same five metabolites were previously shown to be present after oral administration this indicates that reduction of chlorpromazine N-oxide occurs not only in the gastrointestinal tract but also at other sites. 3. The metabolism of chlorpromazine N-oxide was studied following its administration by either i.p., i.v. or oral routes to female rats in which the bile duct was cannulated. 4. There were no qualitative differences between the three routes of administration with respect to the metabolites identified. With the exception of the absence of N-desmethylchlorpromazine and N-desmethylchlorpromazine sulphoxide, all metabolites previously identified in urine and faeces were also present in bile. 5. Additionally there were three compounds present in rat bile which were not identified in urine or faeces. These were chlorpromazine N-oxide, chlorpromazine N,S-dioxide and 7-hydroxychlorpromazine O-glucuronide. This is the first unequivocal evidence for the identification of intact 7-hydroxychlorpromazine O-glucuronide in any species. 6. The inability to detect chlorpromazine N-oxide and chlorpromazine N,S-dioxide in the faeces of rats is likely to be due to the reduction of the N-oxide group on the passage of these biliary metabolites down the intestinal tract.

Quantitative analysis of chlorpromazine by electron spin resonance (ESR) spectroscopy.

A simple and sensitive method is described for quantitative analysis of chlorpromazine in blood, serum, urine and tissue homogenate. The chlorpromazine cation radical produced by adding perchloric acid and 2,3-dichloro-5,6-dicyano-p-benzoquinone to the sample can be detected by the ESR method at room temperature. The sensitivity limit is 10 ng, that is, 20 microliters of the solution containing 0.5 microgram chlorpromazine/ml. The time needed for the measurement is within 10 min. The chlorpromazine radical thus produced is very stable; for example, 95% of the radical was observed after 24 h. The advantage of this method is discussed by comparing with the ordinary spectrophotometry which requires the purification of the sample.

The metabolism of chlorpromazine N-oxide in man and dog.

1. The metabolism of chlorpromazine N-oxide was studied in female dogs and adult male humans after a single oral dose. 2. There was extensive metabolism in both species in that between four and seven metabolites were separately identified in urine and faeces. Apart from chlorpromazine N-oxide, chlorpromazine N,S-dioxide was the only isolated metabolite which retained the N-oxide group. The other identified metabolites were chlorpromazine and its 7-hydroxy, sulphoxide, N-desmethyl, 7-hydroxy-N-desmethyl and N-desmethylsulphoxide derivatives. 3. With dog samples, metabolites were separated by h.p.l.c. and individually collected prior to mass spectrometric analysis. With human samples, metabolites were directly subjected to h.p.l.c.-mass spectrometric determination. With all metabolites their structures were confirmed by direct comparison of their mass spectra and chromatographic behaviours with those of authentic samples. 4. The metabolites identified in urine and faeces were for the most part the same in both species, with the exceptions that chlorpromazine N-oxide was identified in the faeces of dog only and 7-hydroxy-N-desmethylchlorpromazine was identified in the urine of man only. 5. The observation of N-oxide compounds in the excreta of both man and dog contrasted with that for the previously studied rat, where no such compounds were detected.

Simultaneous determination of chlorpromazine and levomepromazine in human plasma and urine by high-performance liquid chromatography using electrochemical detection.

A rapid, selective and sensitive method for the simultaneous determination of chlorpromazine and levomepromazine in human plasma and urine has been developed using high-performance liquid chromatography with electrochemical detection. The unchanged drugs and internal standard extracted from plasma and urine were separated by reversed-phase high-performance liquid chromatography. The influence of acetonitrile concentration and of the pH of the mobile phase were investigated. The detection limits were 100 pg for chlorpromazine and for levomepromazine. In comparison with three other detection systems this was found to be the most sensitive method. This method was successfully applied to the simultaneous determination of chlorpromazine and levomepromazine in human plasma and urine for pharmacokinetic studies.