Zopiclone Research Articles

Rapid enantiomeric analysis of zopiclone in serum by supercritical fluid chromatography-tandem mass spectrometry.

Zopiclone (ZOP) is a hypnotic drug prescribed to treat insomnia. Due to the chiral nature of ZOP, the psychologically active S-form and inactive R-form need to be determined enantiomerically in a forensic drug analysis. In the present study, a supercritical fluid chromatography (SFC) method was designed with a faster analysis ability than that of previously reported techniques. The SFC-tandem mass spectrometry (SFC-MS/MS) method was optimized using a column with a chiral polysaccharide stationary phase (Trefoil CEL2). ZOP was extracted from pooled human serum using solid-phase extraction (Oasis HLB) and analyzed. The developed SFC-MS/MS method achieved the baseline separation of S-ZOP and R-ZOP within 2 min. The fit-for-purpose method validation indicated that the optimized solid-phase extraction achieved near complete recovery and approximately 70% of the matrix effect. Both the retention time and peak area showed sufficient precision. The lower and upper limits of quantification (LOQ) were 5.7 × 10-2 ng/mL and 25 ng/mL for R-ZOP, and 5.2 × 10-2 ng/mL and 25 ng/mL for S-ZOP. The calibration line was linear in the range from lower LOQ to upper LOQ. The stability test indicated that ZOP in serum stored in a refrigerator (4°C) degraded and about 55% remained in 31 days. The quick analysis of the SFC-MS/MS method makes it a valid option for the enantiomeric analysis of ZOP.

Orexin dual receptor antagonists, zolpidem, zopiclone, eszopiclone, and cognitive research: A comprehensive dose-response meta-analysis.

About one-third of adults have trouble sleeping, ranging from occasional difficulty to chronic insomnia, along with difficulty maintaining sleep. Many studies reported that the long-term use of hypnotics can cause brain dysfunction and damage cognition. The objective of the study is to evaluate whether low, medium, and high doses of orexin dual receptor antagonists (DORA), zopiclone (ZOP), eszopiclone (ESZ), and zolpidem (ZST) can impair cognition. From the beginning through September 20, 2022, PubMed, Embase, Scopus, the Cochrane Library, and Google Scholar were searched. Randomized controlled trials (RCTs) assessing the therapeutic effects of DORA, eszopiclone, and zopiclone for sleep and cognitive function were included. The primary outcomes were indices related to the cognitive profile, including memory, alertness, execution and control function, and attention and orientation. The secondary outcomes were indices related to sleep and adverse events. The standard mean difference (SMD) was generated for continuous variables. Certain data were captured from figures by GetData 2.26 and analyzed using RStudio 4.2. Finally, a total of 8,702 subjects were included in 29 studies. Compared with the placebo, the DSST (Digit Symbol Substitution Test) scores of low, medium, and high doses of DORA were SMD = 0.77; 95% CI: 0.33-1.20; SMD = 1.58; 95% CI: 1.11-2.05; and SMD = 0.85; 95% CI: 0.33-1.36, respectively. The DSST scores of zolpidem at low, medium, and high doses were SMD = -0.39; 95% CI: 0.85-0.07; SMD = -0.88, 95% CI: -2.34-0.58; and SMD = -0.12, 95% CI: -0.85-0.60, respectively. Zopiclone's DSST scale score was SMD = -0.18; 95% CI: -0.54-0.18. In addition, the total sleep time (TST) of low, medium, and high doses of DORA was SMD = 0.28, 95% CI: -0.15-0.70; SMD = 1.36, 95% CI: 0.87-1.86; and SMD = 2.59, 95% CI: 1.89-3.30, respectively. The TST of zolpidem with low, medium, and high doses was SMD = 1.01, 95% CI: 0.18-1.83; SMD = 1.94, 95% CI: 0.46-3.43; and SMD = 1.71, 95% CI: 0.86-2.56, respectively. The TST of low, medium, and high doses of eszopiclone was relatively SMD = 2.03, 95% CI: -0.21-4.27; SMD = 2.38, 95% CI: 1.35-3.42; and SMD = 1.71, 95% CI: 0.60-2.82. Zopiclone's TST was SMD = 2.47, 95% CI: 1.36-3.58. We recommend DORA as the best intervention for insomnia because it is highly effective in inducing and maintaining sleep without impairing cognition. Although zolpidem has a more pronounced effect on maintaining sleep, it is best to reduce its use because of its side effects. Eszopiclone and zopiclone improved sleep quality, but their safety in cognition remains to be verified.

Risk of falls and fractures similar with zopiclone and trazodone

Risk of falls and fractures similar with zopiclone and trazodone

Development and evaluation of zopiclone compression coated tablet for time-controlled pulse release: Mechanism and in vivo study

Early-morning awakening is a special insomnia characterized with circadian rhythm. In this study, zopiclone (ZOP), one of the common hypnotics, was selected to prepare zopiclone pulse release tablet via compression coating. Single-factor analysis combined with Box–Behnken design (BBD) was used to optimize the formulations. Finally, ZOP compression coated tablets (CCTs) with burst release after a 2.5–3 h lag time (Tlag) were successfully obtained. A study of mechanical properties revealed that the generation of Tlag resulted from the break of the mechanical equilibrium between core swelling force and coating fracture strength, moreover, the time-varying curves of these two forces were both consistent with the Weibull distribution. Compared with the commercial tablets, CCTs in beagle dogs showed a significant delay about 2.67 h which was similar to the Tlag in vitro. There was no significant difference in main pharmacokinetic parameters such as T1/2, AUC and Cmax. The relative bioavailability was 106.64%, indicating that Tlag of ZOP CCTs had no effect on the following pharmacokinetic process. Furthermore, a good in vivo-in vitro correlation (IVIVC) of ZOP CCTs was verified (R2 = 0.9625). The development of the ZOP CCTs provided a modified drug delivery system for early-morning awakening insomnia.

Validated stability-indicating high-performance liquid chromatography and thin-layer chromatography methods for the determination of zopiclone in pharmaceutical formulation

Two novel, sensitive, and selective stability-indicating chromatographic methods were described for the analysis of zopiclone (ZOP) in the presence of its degradation products, namely, 7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazin-5-yl-4-methylpiperazine-1-carboxylate (hydrolytic DEG) and 5H-pyrrolo[3,4-b]pyrazine-5,7(6H)-dione (oxidative DEG), in drug substance and product. The first method was an isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) using Inertsil ODS3 (250 × 4 mm, 5 μm) column. Upon using HPLC, the run time could be reduced, and actually, the solvents consumption decreased. Quantification was achieved by detection wavelength at 237 nm, based on peak area. Chromatographic separation was performed over the range of 1–10 μg mL−1 with limits of detection (LOD) and quantification (LOQ) of 0.18 and 0.55 μg mL−1 and a mean recovery of 99.98 ± 0.55. The analysis was achieved at 30°C using a mixture of acetonitrile and water (50:50 v/v) as the mobile phase. The second method was thin-layer chromatography (TLC) applied for the separation and analysis of zopiclone in the presence of its alkaline, acidic, and oxidative degradation products. Chromatography was performed on silica gel 60 F254 plates with ethyl acetate–methanol–ammonia 33% (17:2:1 v/v) as the mobile phase. Successful resolution was observed with significant difference in the RF values, followed by densitometric measurement at 303 nm. Evaluation was carried out over the range of 0.1–2 μg per spot with a mean recovery of 100.52% ± 0.24. The developed methods were successfully applied to the analysis of ZOP in bulk powder, laboratory-prepared mixtures containing different percentages of its degradation products, and pharmaceutical dosage form. The degradation products were separated by HPLC as well as identified by TLC, infrared (IR), and mass spectrometry (MS) to confirm its structures and elucidate degradation pathway. The developed methods were validated as per the International Conference on Harmonization (ICH) guidelines. The results obtained by the proposed methods were statistically compared with the reported methods revealing high accuracy and good precision.

Zopiclone abuse

Zopiclone abuse

First derivative spectrofluorimetric determination of zopiclone and its degradation product, 2-amino-5-chloropyridine, in pharmaceutical formulations with preliminary tool in biological fluids for clinical evidence of zopiclone intake

A simple, fast, sensitive and stability-indicating derivative spectrofluorimetric method is presented for the assay of zopiclone (ZOP), a drug with hypnotic effect, and its main degradation product and major contaminant, 2-amino-5-chloropyridine (ACP). The method is based on measuring the inherent fluorescence intensity of both drugs at λex=300nm in methanol, then differentiation using D1 (first derivative technique). The developed method was found to be rectilinear over a range of 0.2–4μg/mL of ZOP and 4–100ng/mL of ACP. The limits of detection were 0.05μg/mL of ZOP and 0.2ng/mL of ACP with the limit of quantitation of 0.17μg/mL of ZOP and 0.7ng/mL of ACP. The outcoming results of the proposed method were compared to those obtained by a reference method showing no significant statistical difference between them concerning precision and accuracy. Additionally, the developed method was applied for detecting ACP in spiked human urine and plasma specimens as a tool of clinical evidence of zopiclone intake that can be easily implemented in forensic laboratories. The proposed method was validated as per ICH guidelines.

Macrocyclic β-cyclodextrin derivative-based aqueous-two phase systems: Phase behaviors and applications in enantioseparation

In this work, three macrocyclic β-cyclodextrin (β-CD) derivatives, namely carboxymethyl-β-cyclodextrin (CM-β-CD), sulfobutyl ether-β-cyclodextrin (SBE-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD), were employed in the formation of novel aqueous two-phase system (ATPS) with several hydrophilic solvents respectively. It was observed that anionic β-CD derivatives (CM-β-CD and SBE-β-CD) facilitated the ATPS formation and the obtained binodal curves showed a decreasing order in inducing ATPS as acetonitrile≈1-propanol>2-propanol>ethanol. Furthermore, the proposed ATPS as a novel enantioselective liquid–liquid extraction technique was evaluated by enantioseparating racemic zopiclone (ZPC). Opposite partitioning orientations for ZPC in two groups of the investigated ATPS were studied systematically and 1-propanol/CM-β-CD ATPS was selected as the optimal enantioseparation system. Under the optimal conditions, moderate enantioseparation efficiency (α=2.58 and e.e.%=32.66%) and high recovery (RT(S)=95.54% and RT(R)=98.22%) were achieved simultaneously via a single run of extraction.

A new and fast DLLME-CE method for the enantioselective analysis of zopiclone and its active metabolite after fungal biotransformation

Zopiclone (ZO) is a chiral drug that undergoes extensive metabolism to N-desmethylzopiclone (N-Des-ZO) and zopiclone-N-oxide (N-Ox-ZO). Pharmacological studies have shown (S)-N-Des-ZO metabolite presents anxiolytic activity and a patent for this metabolite was requested for anxiety treatment and related disorders. In this context, biotransformation employing fungi may be a promising strategy to obtain N-Des-ZO. To perform the biotransformation study in this work, an enantioselective method based on capillary electrophoresis (CE) and dispersive liquid–liquid microextraction (DLLME) was developed. CE analyses were carried out in sodium phosphate buffer (pH 2.5; 50mmolL−1) containing 0.5% (w/v) carboxymethyl-β-CD, at a constant voltage of +25kV. DLLME was conducted using 2mL of liquid culture medium pH 9.5. Chloroform (100μL) and methanol (300μL) were employed as extraction and disperser solvent, respectively. After CE and DLLME optimization, the analytical method was fully validated. The method was linear over a concentration range of 90–6000ngmL−1 for each ZO enantiomer (r>0.999) and 50–1000ngmL−1 for each N-Des-ZO enantiomer (r>0.998). Absolute recovery of 51 and 82% was achieved for N-Des-ZO and ZO, respectively. The accuracy and precision results agreed with the EMA (European Medicines Agency) guideline, and so did the stability study. Application of the developed method in a biotransformation study was conducted in order to investigate the ability of fungi, belonging to the genus Cunninghamella, in metabolizing ZO chiral drug. Fungi Cunninghamella elegans ATCC 10028B and Cunninghamella echinulata var elegans ATCC 8688A demonstrated to be able to enantioselectively biotransform ZO to its active metabolite, N-Des-ZO. Therefore, the proposed goals of this work, i.e. a fast DLLME-CE method and an outstanding strategy to obtain N-Des-ZO, were successfully attained.

HPTLC Method for Quantitative Determination of Zopiclone and Its Impurity.

This study was designed to establish, optimize and validate a sensitive, selective and accurate high-performance thin layer chromatographic (HPTLC) method for determination of zopiclone (ZPC) and its main impurity, 2-amino-5-chloropyridine, one of its degradation products, in raw material and pharmaceutical formulation. The proposed method was applied for analysis of ZPC and its impurity over the concentration range of 0.3-1.4 and 0.05-0.8 µg/band with accuracy of mean percentage recovery 99.92% ± 1.521 and 99.28% ± 2.296, respectively. The method is based on the separation of two components followed by densitometric measurement of the separated peaks at 305 nm. The separation was carried out on silica gel HPTLC F254 plates, using chloroform-methanol-glacial acetic acid (9:1:0.1, by volume) as a developing system. The suggested method was validated according to International Conference on Harmonization guidelines and can be applied for routine analysis in quality control laboratories. The results obtained by the proposed method were statistically compared with the reported method revealing high accuracy and good precision.

Quantitative determination of zopiclone and its impurity by four different spectrophotometric methods

Four simple, sensitive and selective spectrophotometric methods are presented for determination of Zopiclone (ZPC) and its impurity, one of its degradation products, namely; 2-amino-5-chloropyridine (ACP). Method A is a dual wavelength spectrophotometry; where two wavelengths (252 and 301nm for ZPC, and 238 and 261nm for ACP) were selected for each component in such a way that difference in absorbance is zero for the second one. Method B is isoabsorptive ratio method by combining the isoabsorptive point (259.8nm) in the ratio spectrum using ACP as a divisor and the ratio difference for a single step determination of both components. Method C is third derivative (D3) spectrophotometric method which allows determination of both ZPC at 283.6nm and ACP at 251.6nm without interference of each other. Method D is based on measuring the peak amplitude of the first derivative of the ratio spectra (DD1) at 263.2nm for ZPC and 252nm for ACP. The suggested methods were validated according to ICH guidelines and can be applied for routine analysis in quality control laboratories. Statistical analysis of the results obtained from the proposed methods and those obtained from the reported method has been carried out revealing high accuracy and good precision.

Validation of an LC-MS/MS method for the determination of zopiclone, N-desmethylzopiclone and 2-amino-5-chloropyridine in whole blood and its application to estimate the original zopiclone concentration in stored specimens.

2-Amino-5-chloropyridine (ACP) is a degradation product of zopiclone (ZOP) and its two main metabolites N-desmethylzopiclone (NDZOP) and zopiclone N-oxide (ZOPNO). ACP may be formed when specimens are stored. ZOP instability in blood makes interpretation of concentrations difficult especially in cases of prolonged sample storage. This study investigated how ACP could be used to estimate the original concentration of ZOP in authentic samples. For that purpose, an analytical liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the quantitation of ACP, ZOP, and NDZOP in blood was developed and validated. Due to poor extraction recovery, ZOPNO was not included in the analytical method. The method was then applied to investigate ACP formation, ZOP and NDZOP degradation in stored ZOP post-dosed authentic whole blood and two mathematical models were used to calculate the original concentration of ZOP. During storage, ACP was formed in amounts equimolar to the ZOP and NDZOP degradation. Results from samples in which ACP had been formed were used to test two models to estimate the original ZOP concentration. The correlation tests of the models showed strong correlations to the original ZOP concentration (r = 0.960 and r = 0.955) with p < 0.01 and explained more than 90% of the ZOP concentration. This study showed that the equimolar degradation of ZOP and NDZOP to ACP could be used to estimate the original concentration of ZOP.

Quantitative analysis of zopiclone, N-desmethylzopiclone, zopiclone N-oxide and 2-amino-5-chloropyridine in urine using LC-MS-MS.

A simple liquid chromatography-tandem mass spectrometry method was validated to allow determination of zopiclone (ZOP), N-desmethylzopiclone (NDZOP), zopiclone N-oxide (ZOPNO) and 2-amino-5-chloropyridine (ACP) in urine at concentrations up to 3,000 ng/mL within 3.5 min. This method was used for quantitative analysis of the analytes in authentic urine samples obtained 10 h after oral administration of zopiclone (Imovane(®)) and in aliquots of the same urine samples after different storage conditions. In addition, pH of each studied urine sample was measured over time. The results showed that formation of ACP occurred at elevated pH and/or temperature by degradation of ZOP, NDZOP and ZOPNO. This method was also applied to samples obtained from two female victims of drug-facilitated assault. One sample had been exposed to long-term storage conditions at different temperatures and at pH >8.2, which resulted in high concentrations of ACP. The other sample, which was exposed to pH <6.5, showed no formation of ACP. ACP is formed both from ZOP and from its metabolites NDZOP and ZOPNO depending on the pH of the urine, time of storage and/or the temperature conditions. For correct interpretation in forensic cases, ZOP, its major metabolites and ACP should be analyzed. When ACP is identified in urine, the concentrations of ZOP, NDZOP and ZOPNO should be interpreted with great caution.

Determination of stability indicating assay method for eszopiclone in pharmaceutical drug substances a comparative study by UPLC and HPLC

Eszopiclone is a nonbenzodiazepine hypnotic used as a treatment for insomnia . Eszopiclone is the active dextrorotatory stereoisomer of zopiclone , and belongs to the class of drugs known as cyclopyrrolones . A simple, Isocratic, rapid and selective RP-UPLC method was developed for the quantification of Capecitabine in active pharmaceutical ingredients (API’S) using a simple mobile phase of solution A (5.0g of sodium dodecyl sulfate and 2.0 g of monobasic sodium phosphate were dissolved in one liter of water and adjusted the pH to 3.8 with 10% phosphoric acid) and solution B acetonitrile in the ratio of 65:35 at a flow rate of 0.50 mL/min. The chromatographic separation was achieved on a Poroshell C18 column of dimension 4.6 X 50 mm, 2.7µm. The column and sample compartment temperatures were maintained at ambient. UV detector was monitored at 303nm. The retention time (RT) of Eszopiclone was about 8.4min at an overall runtime of 12min. The developed method was validated as per the requirements of ICH guidelines. Finally a comparison of the method was done against conventional HPLC. The developed method was superior with respect to analysis time , efficiency and sensitivity. The runtime of Eszopiclone in conventional hplc method was about 60.0min. Compare to HPLC method the developed method is cost effective and more rugged. The method can be used for routine analysis of assay in Quality Control laboratory on regular basis.

Simultaneous determination of zopiclone and its degradation product and main impurity (2-amino-5-chloropyridine) by micellar liquid chromatography with time-programmed fluorescence detection: Preliminary investigation for biological monitoring

A simple and reliable HPLC method was developed and validated for the simultaneous determination of the hypnotic drug, zopiclone (ZPC) and its degradation product and main impurity, 2-amino-5-chloropyridine (ACP). The analyses were carried out on BDS Hypersil phenyl column (4.6mm×250mm, 5μm particle size) using micellar mobile phase consisting of 0.15M SDS, 10% n-propanol, 0.3% triethylamine, and 0.02M orthophosphoric acid (pH 3.5) with timed programmable fluorescence detection. The proposed method was found to be rectilinear over the concentration ranges of 0.5–10.0μg/mL for ZPC and 2.5–50ng/mL for ACP. Moreover, the method was applied for the determination of ZPC in commercial tablets with mean percentage recovery of 99.06±1.49. The results of the proposed method were statistically compared with those obtained by the comparison method revealing no significance differences in the performance of the two methods regarding accuracy and precision. Furthermore, the proposed method was applied for the detection and determination of ACP in human urine as a marker for ZPC intake.

On the zopiclone enantioselective binding to human albumin and plasma proteins. An electrokinetic chromatography approach

In this work, a methodology for the chiral separation of zopiclone (ZPC) by electrokinetic chromatography (EKC) using carboxymethylated-β-cyclodextrin as chiral selector has been developed and applied to the evaluation of the enantioselective binding of ZPC enantiomers to HSA and total plasma proteins. Two mathematical approaches were used to estimate protein binding ( PB), affinity constants ( K 1) and enantioselectivity ( ES) for both enantiomers of ZPC. Contradictory results in the literature, mainly related to plasma protein binding reported data, suggest that this is an unresolved matter and that more information is needed. Discrepancies and coincidences with previous data are highlighted.

Zopiclone abuse

Zopiclone abuse

Zopiclone abuse

Zopiclone abuse

Zopiclone, but not temazepam, appears to impair driving in the elderly the morning after administration,

Zopiclone, but not temazepam, appears to impair driving in the elderly the morning after administration,

Clinical effects of olanzapine combine zopiclone on chronic insomnia

Objective To research the effective treatment on chronic insomnia. Methods 120 insomnia patients were randomly divided into olanzapine group,zopiclone group and olanzapine combine zopiclone group,each group included 40 patients which received the treatment respectively for 8 weeks as a course. The clinical effects were evaluated by Pittsburgh sleep quality index(PSQI), and the side effects were estimated by treatment emergence symptoms scale (TESS). Results The olanzapine combine zopiclone group patients were better in total score PSQI,HAMD,HAMA and excellently effective power(discerned for 5.1±1.9,11.8±5.9,5.2±2.1,90.00%) than the olanzapine group's (discerned for 6.1±2.3,11.7±5.3,5.4±1.8,71.25%)and the zopiclone group's(discerned for 6.7±2.3,17.5±7.8,10.3±6.4,71.25%) at the end of 8 weeks treatment,and the difference was statistical significance(P<0.05). Conclusion Combining olanzapine and zopiclone on chronic insomnia can improve treatment effective, and improve the day function significantly. Key words: Olanzapine; Zopiclone; Insomnia; PSQI