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Naguib IA, Abdallah FF, Emam AA, Abdelaleem EA. Determination of Pyridostigmine Bromide in Presence of its Related Impurities by Four Modified Classical Least Square Based Models: A Comparative Study. CURR PHARM ANAL 2020. [DOI: 10.2174/1573412915666190715094347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Quantitative determination of pyridostigmine bromide in the presence of its two related substances;
impurity A and impurity B was considered as a case study to construct the comparison.
Introduction:
Novel manipulations of the well-known classical least squares multivariate
calibration model were explained in detail as a comparative analytical study in this research work. In
addition to the application of plain classical least squares model, two preprocessing steps were tried,
where prior to modeling with classical least squares, first derivatization and orthogonal projection to
latent structures were applied to produce two novel manipulations of the classical least square-based
model. Moreover, spectral residual augmented classical least squares model is included in the present
comparative study.
Methods:
3 factor 4 level design was implemented constructing a training set of 16 mixtures with different
concentrations of the studied components. To investigate the predictive ability of the studied models;
a test set consisting of 9 mixtures was constructed.
Results:
The key performance indicator of this comparative study was the root mean square error of
prediction for the independent test set mixtures, where it was found 1.367 when classical least squares
applied with no preprocessing method, 1.352 when first derivative data was implemented, 0.2100 when
orthogonal projection to latent structures preprocessing method was applied and 0.2747 when spectral
residual augmented classical least squares was performed.
Conclusion:
Coupling of classical least squares model with orthogonal projection to latent structures
preprocessing method produced significant improvement of the predictive ability of it.
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Affiliation(s)
- Ibrahim A. Naguib
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514, Beni-Suef, Egypt
| | - Fatma F. Abdallah
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514, Beni-Suef, Egypt
| | - Aml A. Emam
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514, Beni-Suef, Egypt
| | - Eglal A. Abdelaleem
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514, Beni-Suef, Egypt
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Abdallah FF, Darwish HW, Darwish IA, Naguib IA. Orthogonal projection to latent structures and first derivative for manipulation of PLSR and SVR chemometric models' prediction: A case study. PLoS One 2019; 14:e0222197. [PMID: 31553757 PMCID: PMC6760832 DOI: 10.1371/journal.pone.0222197] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/24/2019] [Indexed: 11/19/2022] Open
Abstract
Novel manipulations of the well-established multivariate calibration models namely; partial least square regression (PLSR) and support vector regression (SVR) are introduced in the presented comparative study. Two preprocessing methods comprising first derivatization and orthogonal projection to latent structures (OPLS) are implemented prior to modeling with PLSR and SVR. Quantitative determination of pyridostigmine bromide (PR) in existence of its two associated substances; impurity a (IMP A) and impurity b (IMP B); was utilized as a case study for achieving comparison. A series consisting of 16 mixtures with numerous percentages of the studied compounds was applied for implementation of a 3 factor 4 level experimental design. Additionally, a series consisting of 9 mixtures was employed in an independent test to verify the predictive power of the suggested models. Significant improvement of predictive abilities of the two studied chemometric models was attained via implementation of OPLS processing method. The root mean square error of prediction RMSEP for the test set mixtures was employed as a key comparison tool. About PLSR model, RMSEP was found 0.5283 without preprocessing method, 1.1750 when first derivative data was used and 0.2890 when OPLS preprocessing method was applied. With regard to SVR model, RMSEP was found 0.2173 without preprocessing method, 0.3516 when first derivative data was used and 0.1819 when OPLS preprocessing method was applied.
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Affiliation(s)
- Fatma F. Abdallah
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., Beni-Suef, Egypt
| | - Hany W. Darwish
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia
- Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo, Egypt
- * E-mail:
| | - Ibrahim A. Darwish
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia
| | - Ibrahim A. Naguib
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., Beni-Suef, Egypt
- Department of Pharmaceutical Chemistry, College of Pharmacy, Taif University, Al-Hawiah, Taif, Saudi Arabia
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Naguib IA, Abdelaleem EA, Emam AA, Abdallah FF. Green Simultaneous Chromatographic Separation of Pyridostigmine Bromide and Its Related Substances in Pure Form, Tablets and Spiked Human Plasma. J Chromatogr Sci 2019; 57:653-661. [PMID: 31204433 DOI: 10.1093/chromsci/bmz043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 01/04/2019] [Accepted: 04/29/2019] [Indexed: 11/14/2022]
Abstract
A green, accurate and specific high-performance thin-layer chromatographic (HPTLC) method was developed and validated for simultaneous quantitative determination of pyridostigmine bromide (PR), impurity B (IMP B);3-hydroxy-N-methylpyridinium bromide and impurity A (IMP A); pyridin-3-yl-dimethylcarbamate. The two pharmacopeial impurities are also its main inactive metabolites. Furthermore, IMP B is known to be its alkaline-induced degradation product. Achievable separation of the studied components required silica gel HPTLC F254 plates as a stationary phase and acetone: acetic acid (80:20, v/v) as a developing system. Scanning of the separated bands was done at 260 nm. According to green solvent selection guidelines, acetone and acetic acid are eco-friendly solvents. Validation of the developed method was insured by its acquiesce to international conference on harmonization (ICH) guidelines. The introduced method was successfully achieved for the quantitative determination of PR, IMP B and IMP A in the range of 0.4-10, 2-11 and 0.4-3.5 μg/band, respectively. Successful application of the developed method was done for determination of PR in human plasma in the range of 0.6-10 μg/band, so the proposed HPTLC can be applied in the pharmacokinetic studies. The studied drug was also analyzed in Mestinon® tablets using the developed method.
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Affiliation(s)
- Ibrahim A Naguib
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., Beni-Suef, Egypt
- Department of Pharmaceutical Chemistry, College of Pharmacy, Taif University, Al-Hawiah, Taif, Saudi Arabia
| | - Eglal A Abdelaleem
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., Beni-Suef, Egypt
| | - Aml A Emam
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., Beni-Suef, Egypt
| | - Fatma F Abdallah
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., Beni-Suef, Egypt
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Abdelaleem EA, Emam AA, Naguib IA, Abdallah FF. Novel manipulations of ratio spectra as powerful tools for resolution and quantitative determination of Pyridostigmine bromide and its' related substances; A comparative study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 210:66-75. [PMID: 30448633 DOI: 10.1016/j.saa.2018.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 10/10/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Resolution and quantitative determination of ternary mixture with severely overlapped spectra without any preliminary separation steps represents a big challenge for any analyst. Smart and novel spectrophotometric methods are continuously innovated for achieving the above mentioned target. Novel applications of ratio difference spectrophotometric technique utilizing ratio spectra and derivative ratio spectra are applied in presented work. The proposed methods included derivative ratio difference (DRD) and ratio subtraction ratio difference (RSRD) methods. Comparative study was achieved between the proposed methods and the recently developed induced ratio difference (IRD) method. The developed methods were assessed through the analysis of ternary mixtures with different ratios of Pyridostigmine bromide (PR) and its related substances; impurity a (IMP A) and impurity b (IMP B). Analysis of PR in a pharmaceutical dosage form without any interference from other inactive ingredients was also a successful application of the proposed methods. As per ICH guidelines, the proposed methods were validated ensuring their accuracy, precision and specificity. Statistical comparison between the developed methods and the reference method was done, where calculated F and t values were less than the theoretical ones in regards to accuracy and precision.
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Affiliation(s)
- Eglal A Abdelaleem
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514 Beni-Suef, Egypt
| | - Aml A Emam
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514 Beni-Suef, Egypt
| | - Ibrahim A Naguib
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514 Beni-Suef, Egypt
| | - Fatma F Abdallah
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514 Beni-Suef, Egypt.
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Abdelaleem EA, Naguib IA, Abdallah FF, Ali NW. Development and validation of three spectrophotometric methods for determination of pyridostigmine bromide in the presence of its alkaline-induced degradation product. ACTA ACUST UNITED AC 2015. [DOI: 10.5155/eurjchem.6.3.350-356.1283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Chaichi MJ, Alijanpour SO. A new chemiluminescence method for determination of clonazepam and diazepam based on 1-Ethyl-3-Methylimidazolium Ethylsulfate/copper as catalyst. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 118:36-41. [PMID: 24036305 DOI: 10.1016/j.saa.2013.08.087] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 08/20/2013] [Accepted: 08/22/2013] [Indexed: 06/02/2023]
Abstract
A novel chemiluminescence (CL) reaction, Benzodiazepines-H2O2-1-Ethyl-3-Methylimidazolium Ethylsulfate/copper, for determination of clonazepam and diazepam at nanogram per milliliter level in batch-type system have been described. The method relies on the catalytic effect of 1-Ethyl-3-Methylimidazolium Ethylsulfate/copper on the chemiluminescence reaction of Benzodiazepines, the oxidation of Benzodiazepines with hydrogen peroxide in natural medium. The influences of various experimental parameters such as solution pH, the ratio of 1-Ethyl-3 Methylimidazolium ethylsulfate concentration to copper ion, the type of buffer and the concentration of CL reagents were investigated. Under the optimum condition, the proposed method was satisfactorily applied for the determination of these drugs in tablets and urine without the interference of their potential impurities.
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Affiliation(s)
- M J Chaichi
- Faculty of Chemistry, Mazandaran University, Babolsar, Iran.
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Uddin MN, Samanidou VF, Papadoyannis IN. Bio-Sample Preparation and Gas Chromatographic Determination of Benzodiazepines--A Review. J Chromatogr Sci 2013; 51:587-98. [DOI: 10.1093/chromsci/bms263] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Han S, Jia S, Guo L. Flow-injection chemiluminescence determination of diazepam by oxidation withN-bromosuccinimide. LUMINESCENCE 2012; 28:888-93. [DOI: 10.1002/bio.2452] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/18/2012] [Accepted: 10/18/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Suqin Han
- School of Chemistry and Material Science; Shanxi Normal University; Linfen 041004 P.R. China
| | - Shize Jia
- School of Chemistry and Material Science; Shanxi Normal University; Linfen 041004 P.R. China
| | - Liang Guo
- School of Chemistry and Material Science; Shanxi Normal University; Linfen 041004 P.R. China
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Vardini MT, Mashayekhi HA, Saber-Tehrani M. DISPERSIVE LIQUID-LIQUID MICROEXTRACTION FOLLOWED BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY AS AN EFFICIENT AND SENSITIVE TECHNIQUE FOR THE SIMULTANEOUS DETERMINATION OF ALPRAZOLAM, OXAZEPAM, AND DIAZEPAM IN HUMAN URINE SAMPLES. J LIQ CHROMATOGR R T 2012. [DOI: 10.1080/10826076.2011.637277] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
| | - Hossein Ali Mashayekhi
- b Department of Chemistry , Tonekabon Branch, Islamic Azad University , Tonekabon , Iran
| | - Mohammad Saber-Tehrani
- c Department of Chemistry , Science and Research Branch, Islamic Azad University , Tehran , Iran
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Benzodiazepines: sample preparation and HPLC methods for their determination in biological samples. Bioanalysis 2011; 1:755-84. [PMID: 21083137 DOI: 10.4155/bio.09.43] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Benzodiazepines (BDZs) belong to a group of substances known for their sedative, antidepressive, muscle relaxant, tranquilizer, hypnotic and anticonvulsant properties. Their determination in biological fluids is essential in clinical assays as well as in forensics and toxicological studies. Researchers focus on the development of rapid, accurate, precise and sensitive methods for the determination of BDZs and their metabolites. A large number of analytical methods using different techniques have been reported, but none can be considered as the method of choice. BDZs are usually present at trace levels (microgram or nanogram per milliliter) in a complex biological matrix and the potentially interfering compounds must be isolated by various extraction techniques before analysis. An extended and comprehensive review is presented herein, focusing on sample preparation (pretreatment and extraction) and HPLC conditions applied by different authors. These methods enable bioanalysts to achieve detection limits down to 1-2 ng/ml using UV/diode array detection, readily available in most laboratories, and better than 1 ng/ml using electron capture detection, which is lower than that obtained using a nitrogen phosphorus detector. MS interfaced with electrospray ionization offered a similar sensitivity, while negative chemical ionization MS or sonic spray ionization MS provided sensitivity down to 0.1 ng/ml.
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Tyszczuk K. Determination of Diazepam, Temazepam and Oxazepam at the Lead Film Electrode by Adsorptive Cathodic Stripping Voltammetry. ELECTROANAL 2010. [DOI: 10.1002/elan.201000011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Agarwal S, Gowda KV, Mandal U, Ghosh D, Bose A, Sarkar AK, Pal TK, Chattaraj TK. Analysis of Pyridostigmine Bromide in Human Plasma and its Application in Bioequivalence Studies. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070701540605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- S. Agarwal
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
| | - K. V. Gowda
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
| | - U. Mandal
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
| | - D. Ghosh
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
| | - A. Bose
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
| | - A. K. Sarkar
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
| | - T. K. Pal
- a Dept. of Pharmaceutical Technology , Jadavpur University , Kolkata, West Bengal, India
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Aurora Prado MS, Steppe M, Tavares MFM, Kedor-Hackmann ERM, Santoro MIRM. Comparison of capillary electrophoresis and reversed-phase liquid chromatography methodologies for determination of diazepam in pharmaceutical tablets. J Pharm Biomed Anal 2005; 37:273-9. [PMID: 15708667 DOI: 10.1016/j.jpba.2004.10.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 10/13/2004] [Accepted: 10/20/2004] [Indexed: 11/26/2022]
Abstract
Two novel analytical methodologies using capillary electrophoresis (CE) and reversed-phase high-performance liquid chromatography (RP-HPLC) for the determination of diazepam in commercial and simulated tablet formulations were developed and compared. The CE analysis was carried out in a bare fused-silica capillary with 75 microm i.d. and total length of 50 cm (28 cm to the detector) with a buffer solution containing 20 mmol L(-1) sodium tetraborate and 20 mmolL(-1) sodium dodecylsulfate (SDS), pH 9.23. The applied voltage was 20 kV and bromazepam was used as internal standard (IS). The RP-HPLC analysis was carried out in a LiChrospher((R)) 100 RP-18 (5 microm) column with a mobile phase constituted of methanol, acetonitrile and water (45:25:30) with a flow rate of 0.8 mL/min, using acetaminophen as IS. In both cases, detection was carried out by ultraviolet (UV) absorption at 242 nm. Under the optimized conditions, the CE retention times for the standard diazepam and bromazepam (IS) were 4.08 and 3.43 min, respectively, and the retention times of the RP-HPLC analysis for the standard diazepam and acetaminophen (IS) were 4.86 and 1.58 min, respectively. The resolution and efficiency for CE were 7.4 and 1.18 x 10(5)plates/m and for RP-HPLC, 7.5 and 1.76 x 10(4) plates/m. Analytical curves of peak area versus concentration presented correlation coefficients of 0.9996 for CE and 0.9994 for RP-HPLC. The limits of detection (LOD) and quantitation (LOQ) were 4.24 and 12.85 microg/mL for CE and 1.44 and 4.36 microg/mL for RP-HPLC. Relative standard deviations (R.S.D.) were 1.62 and 0.98% for CE and RP-HPLC, respectively. The percentage recovery determined with CE was 100.27+/-1.25 and with RP-HPLC was 101.12+/-2.48. Although both methodologies were shown to be suitable for the determination of diazepam in tablets, performing in a similar manner with regards to several aspects (linearity, recovery and specificity), CE provided a faster analysis and column efficiency whereas RP-HPLC presented a superior repeatability and sensitivity.
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Affiliation(s)
- María S Aurora Prado
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Av. Prof. Lineu Prestes 580, 05508-900 Sao Paulo, SP, Brazil
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van der Ven K, Van Dongen W, Maes BUW, Esmans EL, Blust R, De Coen WM. Determination of diazepam in aquatic samples by capillary liquid chromatography-electrospray tandem mass spectrometry. CHEMOSPHERE 2004; 57:967-973. [PMID: 15488587 DOI: 10.1016/j.chemosphere.2004.08.062] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Revised: 06/22/2004] [Accepted: 08/23/2004] [Indexed: 05/24/2023]
Abstract
In recent years growing attention has been paid toward the discharge, presence and potential adverse effects of pharmaceuticals in the environment. Using different existing analytical methods several studies have already identified a variety of drugs in waste-, surface- and drinking water. The monitoring of surface waters for drugs is of great importance because drugs are designed to be biological very active substances. A capillary LC/ES-MS-MS method has been developed that enables the sensitive and specific detection of diazepam in water samples up to 0.1 ng/ml (LOD). It requires neither multiple extraction steps, nor the use of large volumes of organic solvent. Applying this assay we have detected diazepam in 'in/effluent samples' collected in Belgium and demonstrated the applicability for water analysis without off-line pre-concentration of the analyte.
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Affiliation(s)
- Karlijn van der Ven
- Department of Biology, Laboratory of Ecophysiology, Biochemistry and Toxicology, University of Antwerp (RUCA), Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
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Wang J, Shen X, Fenyk-Melody J, Pivnichny JV, Tong X. Simple and sensitive liquid chromatography/tandem mass spectrometry method for the determination of diazepam and its major metabolites in rat cerebrospinal fluid. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2003; 17:519-525. [PMID: 12621612 DOI: 10.1002/rcm.942] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Diazepam (DZP) is one of the most commonly prescribed drugs for treating status epilepticus (SE). A simple, sensitive and selective LC/MS/MS method with a wide linear calibration range was developed to quantify DZP and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP), and oxazepam (OZP), in rat cerebrospinal fluid (CSF). The method was used to simultaneously determine the concentrations of all analytes in a small sample volume (as little as 25 microL) of rat CSF. The lower limits of quantification (LLOQ) of the method are 0.04 ng/mL for DZP and 0.1 ng/mL for its metabolites. The calibration range is 0.04-200 ng/mL for DZP and 0.1-200 ng/ml for the metabolites. All intra- and inter-assay coefficients of variation (%CV) and mean percent errors of the method are less than 12%. This method successfully addresses the need to determine low therapeutic drug concentrations in small physiological samples, namely rat CSF. Moreover, it can be used to investigate the distribution of the drug and its metabolites among blood plasma, brain tissue, and CSF in pharmacokinetic and pharmacodynamic studies in a variety of laboratory animals. With respect to animal experiments involving assays in CSF, this method addresses two of the three criteria of Russell and Bruch (Principles of Humane Experimental Techniques, 1959, Methuen and Co., London) for minimizing animal use, namely refinement and reduction.
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Affiliation(s)
- Junying Wang
- Department of Basic Chemistry, Merck & Co Inc, Rahway, NJ 07065, USA.
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