Flow-injection fluorimetric determination of trimeprazine and trifluoperazine in pharmaceutical preparations

A flow-injection configuration for the fluorimetric determination of trimeprazine and trifluoperazine is proposed. The procedure is based on oxidation of the drugs by cerium(IV). The fluorescence of cerium(III) formed in the oxidation of trimeprazine or trifluoperazine is monitored. Lineal calibration graphs were obtained between 2 x 10(-7) and 1 x 10(-5)M for both trimeprazine and trifluoperazine with a sampling rate of 60 samples/hr. The relative standard deviations were over the ranges 0.78-1.16 and 0.84-0.97% for trimeprazine and trifluoperazine respectively. The applicability of the method to determination of trimeprazine and trifluoperazine was demonstrated by investigating the effect of potential interferences and by analysis of commercial pharmaceutical preparations.     

Enantioseparation of phenotiazines by affinity electrokinetic chromatography using human serum albumin as chiral selector: application to enantiomeric quality control in pharmaceutical formulations

Nowadays, there is a special interest within the pharmaceutical laboratories to develop single enantiomer formulations and consequently a need for analytical methods to determine the enantiomeric purity of drugs. The present paper deals with the enantiomeric separation of promethazine and trimeprazine enantiomers by affinity electrokinetic chromatography (AEKC)-partial filling technique using human serum albumin (HSA) as chiral selector. A multivariate optimization of the most critical experimental variables in enantioresolution, running pH, HSA concentration and plug length, is carried out to obtain enantioresolution of promethazine and trimeprazine. The estimated maximum and optimum resolution of trimeprazine and prometazine enantiomers (Rs = 1.74 and 2.01, respectively) corresponded to the following experimental conditions: pH 7.5; [HSA] 170 μM and plug length 190 s and pH 7.6; [HSA] 170 μM and plug length 170 s, for trimeprazine and prometazine, respectively. The developed methodologies were applied for the enantiomeric quality control of promethazine and trimeprazine enantiomers in commercially available pharmaceutical formulations. Resolution, accuracy, reproducibility, cost and sample throughput of the proposed methodologies make it suitable for quality control of the enantiomeric composition of promethazine and trimeprazine in pharmaceutical preparations.     

Sample stacking in laboratory-on-a-chip devices

In this study, enantioseparations of five phenothiazines, including promethazine, ethopropazine, trimeprazine, methotrimeprazine, and thioridazine, in cyclodextrin (CD)-modified capillary zone electrophoresis were investigated using a phosphate buffer (40 mM) at pH 3.0. We focussed on the separation of phenothiazines with the use of CDs at low concentrations. Three different CDs, including β-CD, hydroxypropyl-β-CD (HP-β-CD) and γ-CD, were chosen as chiral selectors. The results indicate that effective enantioseparation of phenothiazines, except for methotrimeprazine, is simultaneously achievable with addition of γ-CD at a concentration of 2.5–6.0 mM. The enantiomers of ethopropazine and trimeprazine are effectively separated with addition of HP-β-CD at low concentrations, in the range 0.4–6.0 mM, whereas those of promethazine and trimeprazine are baseline resolved with β-CD at much lower concentrations (0.02–3.0 mM) than with HP-β-CD. The results also confirm that the separation window is greatly enlarged at low CD concentrations. Moreover, the drastic variations of the electrophoretic mobility of phenothiazines as a function of CD concentration reveal that phenothiazines interact very strongly with CDs in the order γ-CD相似文献   

Determination of enantiomeric excess by chiral liquid chromatography without enantiomerically pure starting standards

A facile approach for the enantiomeric excess determination of enantiomeric mixtures without the necessity of pure enantiomer standards is presented. Promethazine and trimeprazine commercial nonracemic mixtures were used as cases study to probe the validity of the method. Chromatographic resolutions obtained with a chiral column AGP in reverse phase mode were 1.32–1.16 (promethazine) and 1.20–0.93 (trimeprazine) for the three detectors (circular dichroism, photometric and fluorimetric) in series. Results obtained showed that enantiomeric excess was 10.4, 8.71 and 8.58% for promethazine and 1.60, 1.23 and 1.80% for trimeprazine (medium values of 9.23 ± 1.01% and 1.54 ± 0.29%, respectively). Recovery assay over human serum samples, at three concentration levels, spiked with prometazine and submitted to solid‐phase extraction, gave values of 99.09–93.48% [S‐(?) enantiomer] and 98.51–91.89% [R‐(+)‐enantiomer]. Detection limits of promethazine enantiomers were between 0.02 µg (fluorimetric) and 1 µg (circular dichroism), and 0.02–1.1 µg for trimeprazine. Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluation of enantioselective binding of basic drugs to plasma by ACE

The present paper deals with the evaluation of the stereoselective binding of antihistamines (brompheniramine, chlorpheniramine, hydroxyzine, orphenadrine and phenindamine), phenothiazines (promethazine and trimeprazine) and a local anesthetic (bupivacaine) to human plasma proteins. Since all of them are drugs highly bound to proteins, a methodology to determine the bound fraction of each drug enantiomer was proposed. This methodology includes the incubation of samples containing plasma and racemic drug, ultrafiltration of the mixture and the chiral separation of enantiomers in the bound drug fraction using affinity EKC (AEKC)-partial filling technique and HSA as chiral selector. The results shown in this paper represent the first evidence of the enantioselective binding of some antihistamines such as brompheniramine, hydroxyzine, orphenadrine and phenindamine and the phenothiazines, promethazine and trimeprazine, to human plasma proteins. The binding of phenindamine to plasma presented the highest enantioselectivity (ES) (ES = 2.5) followed by trimeprazine (ES = 1.5) and promethazine (ES = 1.4).     

Sensitive determination of phenothiazines in body fluids by gas chromatography with surface ionization detection.

Fourteen phenothiazine derivatives were tested for their detection by gas chromatography (GC) with surface ionization detection (SID). The sensitivity of GC-SID was highest with trimeprazine and levomepromazine, which contain aliphatic tertiary amino side chains, and lowest with thiethylperazine and thioproperazine, which contain sulphur residues. Chlorpromazine, trimeprazine and promazine showed excellent linearity between the SID response and the drug amount in the range 0.25-3.0 pmol on-column. Their detection limits were as low as ca. 5-10 pg (15-30 fmol) on-column (250-500 pg per ml of body fluid). A detailed procedure for isolation of phenothiazines from human whole blood and urine using Sep-Pak C18 cartridges, before the GC with SID, is also presented. The recoveries of the drugs (100 pmol), which were added to 1 ml of whole blood or urine, were more than 79%. The baselines remained steady as the column temperature was increased.     

Drop-to-drop solvent microextraction coupled with gas chromatography/mass spectrometry for rapid determination of trimeprazine in urine and blood of rats: application to pharmacokinetic studies

A simple and rapid method based on drop-to-drop solvent microextraction (DDSME) coupled with gas chromatography/mass spectrometry (GC/MS) has been successfully applied for the pharmacokinetic studies of trimeprazine in 8 microL of urine and blood samples of rats. Several factors that influenced the extraction efficiency of DDSME, such as selection of organic solvent, extraction time, exposure volume of organic phase, addition of salt and pH, were optimized. Linearity was obtained over the concentration ranges of 0.2-10, 0.25-7.0 and 0.5-6.0 microg/mL with correlation coefficients of 0.998, 0.996 and 0.993 in deionized water, urine and blood samples of rats, respectively. The limits of detection (LODs) of trimeprazine were 0.05, 0.06 and 0.1 microg/mL in deionized water, urine and blood samples. The concentrations of trimeprazine obtained in urine and blood samples of rats were 0.21-1.25 and 2.72-0.22 microg/mL, respectively, after a single intravenous administration of this drug. The enrichment factors and LOD values obtained by DDSME coupled to GC/MS were compared with those of hollow fiber liquid-phase microextraction (HF-LPME) combined with GC/MS. We believe that this novel approach can be very useful in clinical application since only one microdrop of biological samples was required to perform the pharmacokinetic studies from rats, so the sample pretreatments for animal experiments can be very easy too.     

Gas chromatographic-mass spectrometric method for analysis of a pyrimido-s-triazine and some of its metabolites in dog urine.

3-Phenylpyrimido-[3,4-a]-s-triazines exhibit antiparasitic, antibacterial and antifungal activity. In order to study the metabolism of these heterocycles, 9,9-diethyl-3-phenyl-6,8-dioxo-2,3,4,5,6,7,8,9-octahydropyrimido[3 ,4-a]-s- triazine (TZ) was administered to dogs. Three potential metabolites were synthesized, and these models were identified and quantified with gas chromatography-mass spectrometry. The heterobicyclic compounds, TZ and its hydroxy derivative, underwent thermal degradation under chromatographic conditions. Dog urine spiked with the model metabolites was extracted, and the substances were quantified. The urine of dogs treated with TZ was studied, and two of the potential metabolites were recovered, identified and quantified.     

Computer assisted optimization of a flow-injection method for the assay of promethazine, chlorpromazine and trimeprazine in drug formulations

A simple, accurate and fast method for the determination of promethazine, chlorpromazine and trimeprazine neuroleptics in drug formulations by flow injection spectrophotometric detection was developed. The method was based on the oxidation of the drug with potassium dichromate in sulphuric acid media. Optimum conditions were obtained by using the modified simplex computer programme. A 110-mul sample volume was taken as reasonable for all the compounds. The optimum conditions reached were 76-cm coil length, 6.00 ml/min flow rate, 3.10M sulphuric acid and 0.00167M dichromate for promethazine; 94-cm coil length, 5.00 ml/min flow rate, 1.48M sulphuric acid and 0.00185M dichromate for chlorpromethazine and 80-cm coil length, 6.00 ml/min flow rate, 3.44M sulphuric acid and 0.000500M dichromate for trimeprazine. High sample throughput of at least 200 samples per hour was obtained for all compounds. Acceptable relative standard deviations in the range +/-0.4-0.9%, and good accuracy in the range 99.5-99.9% were attained when the method was statistically compared with the BP method and when applied to proprietary drugs, without suffering interferences.     

Metabolism of methyltestosterone in the greyhound

Gas chromatography/mass spectrometry and selective derivatisation techniques have been used to identify urinary metabolites of methyltestosterone following oral administration to the greyhound. Several metabolites were identified including reduced, mono‐, di‐ and trihydroxylated steroids. The major metabolites observed were 17α‐methyl‐5β‐androstane‐3α‐17β‐diol, 17α‐methyl‐5β‐androstane‐3α,16α,17β‐triol, and a further compound tentatively identified as 17α‐methyl‐5z‐androstane‐6z,17β‐triol. The most abundant of these was the 17α‐methyl‐5β‐androstane‐3α,16α,17β‐triol. This metabolite was identified by comparison with a reference standard synthesised using a Grignard procedure and characterised using trimethylsilyl (TMS) and acetonide‐TMS derivatisation techniques. There did not appear to be any evidence for 16β‐hydroxylation as a phase I metabolic transformation in the greyhound. However, significant quantities of 16α‐hydroxy metabolites were detected. Selective enzymatic hydrolysis procedures indicated that the major metabolites identified were excreted as glucuronic acid conjugates. Metabolic transformations observed in the greyhound have been compared with those of other mammalian species and are discussed here. Copyright © 2009 John Wiley & Sons, Ltd.     

Characterization of Metabolites in Plasma,Urine and Feces of Healthy Participants after Taking Brahmi Essence for Twelve Weeks Using LC-ESI-QTOF-MS Metabolomic Approach

Brahmi essence, developed from Bacopa monnieri (L.) Wettst. standardized extract and mulberry juice, was proven to improve the memory speed of healthy participants aged 55–80 years old, following a 12-week dietary program. However, the metabolites have not yet been reported. Our objective was to characterize the altered metabolites in the plasma, urine, and feces of healthy volunteers after consumption of Brahmi essence for 12 weeks, using the LC-MS metabolomics approach. The altered metabolites were selected from OPLS-DA S-plots; 15 metabolites in the plasma, 7 in the urine, and 17 in the feces samples were tentatively identified by comparison with an online database and literature. The metabolites in the plasma samples were in the classes of amino acids, acylcarnitine, and phospholipids. Benzeneactamide-4-O-sulphate and 3-hydroxyhippuric acid were found in urine samples. The metabolites in the class of amino acids, together with jujubogenin and pseudojujubogenin, were identified in the fecal samples. The aminoacyl-tRNA, aromatic amino acids, and branched-chain amino acid biosynthetic pathways were mainly related to the identified metabolites in all three samples. It could be implied that those metabolites and their pathways might be linked with the effect of Brahmi essence on memory speed.     

Metabolism of 14C-miloxacin in rats--metabolites in urine, bile and feces (author's transl)

Isolation and characterization of metabolites of miloxacin, a new antimicrobial agent, were undertaken with rats. 14C-Miloxacin was orally administered to Sprague-Dawley rats at a dose of 50 mg/kg, and urine, bile and feces were collected. The metabolites extracted from the biological samples were isolated by column and thin-layer chromatographies. Characterization of the isolated metabolites was carried out by comparison with the authentic materials in various physicochemical analyses. Eight metabolites together with intact miloxacin were identified; containing the metabolites of N-demethoxy (M-1), catechol (M-3) and 6-methoxy (M-2 and M-4) types and their conjugates with glucuronic acid.     

Male-specific metabolism of simvastatin by rat liver microsomes

Simvastatin was more effectively metabolized by the liver microsomes of male rats than females. The sex difference appeared in the composition of the metabolites. Two male-specific metabolites were identified by NMR and mass spectrometry as 3'-hydroxy and 3',3'-dihydroxy-delta 4',5' derivatives of simvastatin.     

UHPLC–Q-TOF–MS/MS-based metabolite profiling of duvelisib and establishment of its metabolism mechanisms

Duvelisib is a dual inhibitor of phosphoinositide 3 kinase that received global approval by the US Food and Drug Administration in 2018 to treat follicular lymphoma after at least two prior systemic therapies. An extensive literature search revealed that, to date, metabolites of duvelisib have not been characterized and information on them is not available in any of the literature. Moreover, the metabolism pathway is yet to be established. This study aimed to investigate and characterize the metabolites of duvelisib generated in microsomes and S9 fractions. In this study, five duvelisib metabolites were identified using UHPLC–Q-TOF–MS/MS analysis technique. The structural characterization of the metabolites was performed by comparing the fragmentation pattern of duvelisib and its metabolites through an accurate mass measurement technique. Three metabolites were generated through phase I hydroxylation and dechlorination reactions. The other two metabolites were generated through a phase II glucuronidation reaction. The metabolism mechanism established through this study can be useful to improve the safety profile of drugs of similar categories in the future after establishment of the toxicity profile of the identified metabolites.     

Structural identification of mouse fecal metabolites of theaflavin 3,3'-digallate using liquid chromatography tandem mass spectrometry

Black tea consumption has been associated with many health benefits including the prevention of cancer and heart disease. Theaflavins are the major bioactive polyphenols present in black tea. Unfortunately, limited information is available on their biotransformation. In the present study, we investigated the metabolic fate of theaflavin 3,3'-digallate (TFDG), one of the most abundant and bioactive theaflavins, in mouse fecal samples using liquid chromatography/electrospray ionization tandem mass spectrometry by analyzing the MS(n) (n=1-3) spectra. Four metabolites theaflavin, theaflavin 3-gallate, theaflavin 3'-gallate, and gallic acid were identified as the major mouse fecal metabolites of TFDG. Glucuronidated and sulfated, instead of methylated metabolites of theaflavin 3-gallate, theaflavin 3'-gallate, and TFDG were detected and identified as the minor mouse fecal metabolites of TFDG. Our results indicate that TFDG can be degraded in mice. Further studies on the formation of those metabolites in TFDG-treated mice in germ-free conditions are warranted. To our knowledge, this is the first report on the biotransformation of TFDG in mice.     

Microbial transformation of (+)-adrenosterone

The microbial transformation of (+)-adrenosterone (1) by Cephalosporium aphidicola afforded three metabolites identified as androsta-1,4-diene-3,11,17-trione (2), 17beta-hydroxyandrost-4-ene-3,11-dione (3) and 17beta-hydroxyandrosta-1,4-diene-3,11-dione (4). The fermentation of 1 with Fusarium lini also produced metabolites 2 and 4, while the fermentation with Trichothecium roseum afforded metabolite 3. The structures of transformed products were determined by spectroscopic methods.     

Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors

In this study, enantioseparations of five phenothiazines, including promethazine, ethopropazine, trimeprazine, methotrimeprazine, and thioridazine, in CD-modified CZE using dual CD systems consisting of randomly sulfate-substituted CD (MI-S-beta-CD) and a neutral CD as chiral selectors in a citrate buffer (100 mM) at pH 3.0 were investigated. The results indicate that MI-S-beta-CD is an excellent chiral selector for enantioseparation of ethopropazine. The enantiomers of promethazine can also be baseline-resolved with MI-S-beta-CD at concentrations in the range of 0.5-1.0% w/v. On the other hand, thioridazine and trimeprazine interact strongly with neutral CDs. As a result, the enantioselectivity of these two phenothiazines is remarkably and synergistically enhanced with increasing the concentration of neutral CDs in the presence of MI-S-beta-CD and simultaneous enantioseparations of these phenothiazines, except for methotrimeprazine, could favorably be achieved with the use of dual CD systems. Moreover, by varying the concentration of beta-CD or gamma-CD at a fixed concentration of MI-S-beta-CD (0.75% w/v) reversal of the enantiomer migration order of promethazine occurred. This may be attributable to the opposite effects of charged and neutral CDs on the mobility of the enantiomers of promethazine.     

Metabolic profile of glyburide in human liver microsomes using LC‐DAD‐Q‐TRAP‐MS/MS

The sulfonylurea urea drug glyburide (glibenclamide) is widely used for the treatment of diabetes milletus and gestational diabetes. In previous studies monohydroxylated metabolites were identified and characterized for glyburide in different species, but the metabolite owing to the loss of cyclohexyl ring was identified only in mouse. Glyburide upon incubation with hepatic microsomes resulted in 10 metabolites for human. The current study identifies new metabolites of glyburide along with the hydroxylated metabolites that were reported earlier. The newly identified drug metabolites are dihydroxylated metabolites, a metabolite owing to the loss of cyclohexyl ring and one owing to hydroxylation with dehydrogenation. Among the 10 identified metabolites, there were six monohydroxylated metabolites, one dihydroxylated metabolite, two metabolites owing to hydroxylation and dehydrogenation, and one metabolite owing to the loss of cyclohexyl ring. New metabolites of glyburide were identified and characterized using liquid chromatography–diode array detector–quadruple‐ion trap–mass spectrometry/mass spectrometry (LC‐DAD‐Q‐TRAP‐MS/MS). An enhanced mass scan–enhanced product ion scan with information‐dependent acquisition mode in a Q‐TRAP‐MS/MS system was used to characterize the metabolites. Liquid chromatography with diode array detection was used as a complimentary technique to confirm and identify the metabolites. Metabolites formed in higher amounts were detected in both diode array detection and mass spectrometry detection. Copyright © 2012 John Wiley & Sons, Ltd.     

Syntheses of potential metabolites of a potent kappa-opioid receptor agonist, TRK-820

Chemical syntheses of three kinds of potential metabolites of TRK-820, a potent kappa-opioid receptor agonist, were described. One of the potential metabolites 2, 17-N-dealkylated TRK-820, was synthesized starting from noroxycodone through 8 steps in 21% total yield. Glucuronidation of intermediate 10 and compound 1, the free base of TRK-820, was carried out stereoselectively to give 3-O-beta-D-glucuronides 15 and 16 in good yields, respectively. Syntheses of potential conjugated metabolites 3 and 4 were accomplished through 10 steps and 2 steps in 11% and 43% total yields, respectively. Among the potential metabolites of TRK-820, compounds 2 and 4 were identified as metabolites in human hepatocytes. The results of pharmacological studies of compounds 2, 3, and 4 are described.     

Exploring the In Vivo Existence Forms (23 Original Constituents and 147 Metabolites) of Astragali Radix Total Flavonoids and Their Distributions in Rats Using HPLC-DAD-ESI-IT-TOF-MSn

Astragali Radix total flavonoids (ARTF) is one of the main bioactive components of Astragali Radix (AR), and has many pharmacological effects. However, its metabolism and effective forms remains unclear. The HPLC-DAD-ESI-IT-TOF-MSⁿ technique was used to screen and tentatively identify the in vivo original constituents and metabolites of ARTF and to clarify their distribution in rats after oral administration. In addition, modern chromatographic methods were used to isolate the main metabolites from rat urine and NMR spectroscopy was used to elucidate their structures. As a result, 170 compounds (23 original constituents and 147 metabolites) were tentatively identified as forms existing in vivo, 13 of which have the same pharmacological effect with ARTF. Among 170 compounds, three were newly detected original constituents in vivo and 89 were new metabolites of ARTF, from which 12 metabolites were regarded as new compounds. Nineteen original constituents and 65 metabolites were detected in 10 organs. Four metabolites were isolated and identified from rat urine, including a new compound (calycoisn-3’-O-glucuronide methyl ester), a firstly-isolated metabolite (astraisoflavan-7-O-glucoside-2’-O-glucuronide), and two known metabolites (daidzein-7-O-sulfate and calycosin-3’-O-glucuronide). The original constituents and metabolites existing in vivo may be material basis for ARTF efficacy, and these findings are helpful for further clarifying the effective forms of ARTF.