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Senger CM, Dornelles IS, Queiroz JM, Mello PA, Muller EI, Muller ALH. Greening microwave-assisted digestion method using hydrogen peroxide for determination of elemental impurities by ICP-OES in antihypertensive active pharmaceutical ingredients. J Pharm Biomed Anal 2024; 238:115802. [PMID: 37871418 DOI: 10.1016/j.jpba.2023.115802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/11/2023] [Accepted: 10/15/2023] [Indexed: 10/25/2023]
Abstract
Microwave-assisted wet digestion (MAWD) using only H2O2 was proposed for oxidizing active pharmaceutical ingredients (APIs) for hypertension treatment and subsequent determination by inductively coupled plasma optical emission spectrometry (ICP-OES). Diltiazem hydrochloride (DIL) presented the most refractory characteristic for oxidation using MAWD-H2O2. This proposed MAWD-H2O2 method was validated for specificity, accuracy, and precision according to United States Pharmacopeia (USP) Chapter 233 guidelines. Regarding specificity, the most sensitive emission lines were utilized to analyze all elemental impurities in the digests, and no significant spectral interferences were observed. Sample masses of 500 mg for all APIs and a digestion temperature of 250 °C provided digests with residual carbon (RC) below 2400 mg L-1 of C. Additionally, the residual acidity of the MAWD-H2O2 digests was lower than the acidity presented by the HNO3 digests. The highest and lowest residual carbon content (RCC) for digests were observed for DIL and captopril (CAP), respectively, using MAWD-H2O2. When comparing the RCC for MAWD-H2O2 and MAWD-HNO3 digests for APIs containing aromatic rings, it was evident that H2O2 offered equivalent conditions for digesting these compounds. Accuracy tests showed recovery values of 91-110% for all elemental impurities, as recommended by USP chapter 233. Validation experiments for precision presented relative standard deviation (RSD) values below 6.4% and 10% under repeatability and intermediate precision conditions, respectively. The limits of quantification (LOQs) provided by MAWD-H2O2 are at most half of those recommended by of USP and International Council for Harmonisation of Technical Requirements (ICH). In conclusion, MAWD-H2O2 can be considered an alternative method for API digestion, aligning with green analytical chemistry principles, as it does not employ toxic reagents, minimizes waste, and the main products of H2O2 oxidation are water and oxygen. Considering the analytical Eco-Scale, the MAWD-H2O2 method scored 81, classifying it as an excellent green analysis.
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Affiliation(s)
- Caroline M Senger
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Isadora S Dornelles
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Jennefer M Queiroz
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Paola A Mello
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Edson I Muller
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Aline L H Muller
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
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2
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Xu S, Zhang L, Bai Q, Wang L, Chen X. Elemental impurities determination in bromhexine hydrochloride injections. J Pharm Biomed Anal 2023; 229:115379. [PMID: 37011549 DOI: 10.1016/j.jpba.2023.115379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/18/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023]
Abstract
Elemental impurities in drug products have no therapeutic effect and may pose toxicological concerns, therefore it is urgent to assess the safety of elements especially in parenteral exposure drug. In the present work, a high throughput inductively coupled plasma mass spectrometry (ICP-MS) method was developed for the quantitative determination of 31 elemental impurities in bromhexine hydrochloride injections from 9 manufactures. The method was successfully validated for linearity, accuracy, precision, stability, the LOD and the LOQ according to the United States Pharmacopeia (USP) < 233 > . All the elemental impurities determined were below the permitted daily exposure (PDE) limits proposed by the International Council for Harmonisation (ICH). However, significant differences were found between different manufactures' products for some elements, particularly for Al, As, B, Ba and Zn. Besides, discussions considering potential risks of elemental contamination were also presented.
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3
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Fontoura BM, Barros AI, Nóbrega JA. Analysis of urine by MIP-OES: challenges and strategies to correct matrix effects. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:154-163. [PMID: 36533314 DOI: 10.1039/d2ay01613c] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
This work investigated the potential of microwave-induced plasma optical emission spectrometry (MIP-OES) for urine analysis using a complex matrix containing carbon and high concentrations of easily ionizable elements (EIEs). The goals were to study interferences originating from the urine matrix for 14 analytes with total energies varying from 1.85 to 12.07 eV, along with strategies to correct matrix effects and compare the results with those reported in the literature using inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that the urine matrix caused suppression of the signals for some elements and increased them for others. Therefore, an internal standardization calibration method and three levels of dilution, i.e., 2-, 20-, and 200-fold, were applied as strategies to correct non-spectral interferences. Also, Ga, Ge, Pd, Rh, Sc and Y and four molecular species present in the nitrogen plasma (i.e., CN, N2, N2+, and OH) were investigated as potential internal standards (ISs). The accuracy and precision were evaluated by addition and recovery experiments and best results were obtained using ISs Ge, Rh and Sc for 20-fold dilution and N2+ for 200-fold dilution. The LODs ranged from 0.33 to 329 μg L-1 and deviations were lower than 11%. The combined use of these strategies led to successful urine analysis for a spiked sample by MIP-OES.
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Affiliation(s)
- Beatriz M Fontoura
- Group for Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P. O. Box 676, São Carlos, SP, 13565-905, Brazil.
| | - Ariane I Barros
- Institute of Agricultural and Technological Sciences, Federal University of Rondonópolis, Rondonópolis, MT, 78736-900, Brazil
| | - Joaquim A Nóbrega
- Group for Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P. O. Box 676, São Carlos, SP, 13565-905, Brazil.
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4
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Narukawa T, Suzuki T, Okabayashi S, Chiba K. An online internal standard technique for high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:240-246. [PMID: 36533554 DOI: 10.1039/d2ay01696f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
An online internal standard correction technique for high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was designed using an autosampler system equipped with HPLC to improve the analytical precision. The autosampler was programed to operate in the following sequence: it first takes up a portion of sample solution, rinses the nozzle, sucks air as a spacer, takes an internal standard solution and finally injects all of them into a sampling loop through an injection valve. The repeatability of the sampling (amount 20 μL) was improved from 2.5 to 1.2% using the online internal standard technique. This technique was applied to As speciation in food samples, since food safety monitoring requires high precision and high sample throughput. Rhenium was very suitable as an internal standard element due to its retention time, peak shape and water solubility. This technique effectively improved the analytical precision of the As speciation and got rid of the operation of adding an internal standard solution into samples.
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Affiliation(s)
- Tomohiro Narukawa
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan.
| | - Toshihiro Suzuki
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan.
| | - Satoki Okabayashi
- Department of Applied Chemistry for Environment, Kwansei Gakuin University, 1 Uegahara, Gakuen, Sanda, Hyogo, 669-1337, Japan
| | - Koichi Chiba
- Department of Applied Chemistry for Environment, Kwansei Gakuin University, 1 Uegahara, Gakuen, Sanda, Hyogo, 669-1337, Japan
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5
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Farh MK, Gruschwitz FV, Ziegenbalg N, Abul-Futouh H, Görls H, Weigand W, Brendel JC. Dual Function of β-hydroxy Dithiocinnamic Esters: RAFT Agent and Ligand for Metal Complexation. Macromol Rapid Commun 2022; 43:e2200428. [PMID: 35751415 DOI: 10.1002/marc.202200428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/12/2022] [Indexed: 11/06/2022]
Abstract
The reversible addition-fragmentation chain-transfer (RAFT) process has become a versatile tool for the preparation of defined polymers tolerating a large variety of functional groups. Several dithioesters, trithiocarbonates, xanthates, or dithiocarbamates have been developed as effective chain transfer agents (CTA), but only few examples have been reported, where the resulting end groups are directly considered for a secondary use besides controlling the polymerization. We here demonstrate that β-hydroxy dithiocinnamic esters represent a hitherto overlooked class of materials, which were originally designed for the complexation of transition metals but might as well act as reversible CTA. Modified with a suitable leaving group (R-group), these vinyl conjugated dithioesters indeed provide reasonable control over the polymerization of acrylates, acrylamides, or styrene via the RAFT process. Kinetic studies revealed linear evolutions of molar mass with conversion, while different substituents on the aromatic unit had only a minor influence. Block extensions prove the livingness of the polymer chains, although extended polymerization times may lead to side reactions. The resulting dithiocinnamic ester end groups are still able to form complexes with platinum, which verifies that the structural integrity of the end group is maintained. These findings open a versatile new route to tailor-made polymer bound metal complexes. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Micheal K Farh
- Department of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany.,Department of Chemistry, Faculty of Science, Assiut University, Assiut, 71515, Egypt.,Department of Chemistry, Faculty of Science, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan
| | - Franka V Gruschwitz
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany.,Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Nicole Ziegenbalg
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
| | - Hassan Abul-Futouh
- Department of Chemistry, Faculty of Science, The Hashemite University, P.O. Box 330127, Zarqa, 13133, Jordan
| | - Helmar Görls
- Department of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Wolfgang Weigand
- Department of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany.,Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Johannes C Brendel
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany.,Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
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6
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An overview of sample preparation procedures for determination of elemental impurities in medicines. Microchem J 2022. [DOI: 10.1016/j.microc.2022.107189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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7
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Cai JY, Liu S, Yu YL, Wang JH. MoS 2-Covalent Organic Framework Composite as a Bifunctional Supporter for the Determination of Trace Nickel by Photochemical Vapor Generation-Microplasma Optical Emission Spectrometry. Anal Chem 2022; 94:2288-2297. [PMID: 35043637 DOI: 10.1021/acs.analchem.1c05002] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A microplasma-based optical emission spectrometry (OES) system has emerged as a potential tool for field analysis of heavy metal pollution due to its features of portability and low energy consumption, while the development of an efficient sample introduction approach against matrix interference is crucial to meet the requirements of complex sample analysis. Herein, a MoS2-covalent organic framework (COF) composite serves as a bifunctional supporter for efficient sample separation/enrichment and photochemical vapor generation (PVG) enhancement, thereby achieving highly selective and sensitive detection of heavy metals in environmental water by dielectric barrier discharge (DBD) microplasma-OES. With trace nickel analysis as a model, the MoS2-COF composite with a large specific surface area and a porous structure can not only efficiently separate and enrich nickel ions from a sample matrix through electrostatic interaction and coordination to reduce the interference of coexisting ions but also significantly improve the subsequent PVG efficiency due to the formed heterojunction and more negative reduction potential. Under optimized conditions, a linear range of 0.1-10 μg L-1 along with a detection limit of 0.03 μg L-1 is obtained for nickel. Compared with direct PVG, the tolerance to coexisting ions is greatly enhanced, and the detection limit is also improved by 43-fold. The accuracy and practicability of the present PVG-DBD-OES system are verified by measuring several certified reference materials and real water samples. MoS2-COF as a bifunctional supporter promotes the performance of the PVG-DBD-OES system in terms of anti-interference ability and detection sensitivity, especially for robust and efficient on-site analysis of complex samples.
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Affiliation(s)
- Ji-Ying Cai
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang 110819, China
| | - Shuang Liu
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang 110819, China
| | - Yong-Liang Yu
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang 110819, China
| | - Jian-Hua Wang
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang 110819, China
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8
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Sloop JT, Donati GL, Jones BT. Multi-internal standard calibration applied to inductively coupled plasma optical emission spectrometry. Anal Chim Acta 2022; 1190:339258. [PMID: 34857134 DOI: 10.1016/j.aca.2021.339258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/01/2021] [Accepted: 11/05/2021] [Indexed: 11/01/2022]
Abstract
Several species are simultaneously used for internal standardization to improve accuracy in inductively coupled plasma optical emission spectrometry (ICP-OES). In multi-internal standard calibration (MISC), signal ratios between the analyte and each of several internal standard species are used for calibration. A single calibration solution is required, and the MISC graph is built with intensity ratios calculated with analytical signals recorded for the sample (IA,sam) on the y-axis, while those recorded for the calibration standard (IA,std) are plot on the x-axis (i.e. IA,sam/IIS(i)vs. IA,std/IIS(i), where IIS(i) represents the signal intensity for a given internal standard species). Nine analytes (As, Cd, Cr, Cu, Fe, Mg, Mn, Pb and Zn), and two sets of internal standard species (i.e. Bi, Ge, In, Rh, Sc, Te, Tl and Y in solution, or eighteen emission lines from plasma naturally occurring Ar) were evaluated in this proof-of-concept study. The MISC method's efficiency was evaluated by analyte addition and recovery experiments and by analyzing two certified reference materials. Figures of merit for MISC (limit of detection, repeatability and trueness) were comparable to those obtained for the traditional external standard calibration (EC) and internal standard (IS) methods. Different from IS, MISC requires no time-consuming study to identify an ideal internal standard species, and signal biases are minimized by an averaged, more encompassing internal standardization effect.
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Affiliation(s)
- John T Sloop
- Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC, 27109, United States
| | - George L Donati
- Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC, 27109, United States.
| | - Bradley T Jones
- Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC, 27109, United States
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9
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Dispersive liquid-liquid microextraction based on deep eutectic solvent for elemental impurities determination in oral and parenteral drugs by inductively coupled plasma optical emission spectrometry. Anal Chim Acta 2021; 1185:339052. [PMID: 34711330 DOI: 10.1016/j.aca.2021.339052] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/03/2021] [Accepted: 09/07/2021] [Indexed: 01/09/2023]
Abstract
A simple, fast, sensitive and green pretreatment method for determination of Cd, Co, Hg, Ni, Pb and V in oral and parenteral drug samples using inductively coupled plasma optical emission spectrometry (ICP OES) has been developed. According to United States Pharmacopoeia (USP), those metals must be reported in all pharmaceutical products for quality control evaluation (i.e., elemental impurities from classes 1 and 2A of USP Chapter 232). To improve the analytical capabilities of ICP OES, a dispersive liquid-liquid microextraction (DLLME) has performed using a safe, cheap and biodegradable deep eutectic solvent (DES) as extractant solvent (a mixture of 2:1 M ratio of DL-menthol and decanoic acid). Seven parameters affecting the microextraction efficiency have carefully optimized by multivariate analysis. Under optimized conditions, the DES-based DLLME-ICP OES procedure improved limit of quantitation (LOQ) values on range from 12 to 85-fold and afforded an enrichment factor on average 60-times higher than those obtained to direct ICP OES analysis. Consequently, LOQ values for Cd, Co, Hg, Ni, Pb and V have been on average 10-times lower than target limits recommended for drugs from parenteral route of administration. Trueness has evaluated by addition and recovery experiments following USP recommendations for three oral drug samples in liquid dosage form and three parenteral drugs. Recovery and RSD values have been within the range of 90-109% and 1-6%, respectively. All analytes were below the respectives LOQ values, hence, lower than the limits proposed by USP Chapter 232.
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Maziero M, Adolfo FR, Camera Leal G, de Carvalho LM, Nascimento PCD, Viana C. Elemental Analysis of Pharmaceutical Products for Chronic Kidney Disease by High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry (HR–CS GFAAS). ANAL LETT 2021. [DOI: 10.1080/00032719.2021.1918702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Maiara Maziero
- Department of Pharmaceutical Sciences, Federal University of Santa Maria, Santa Maria, Brazil
| | | | - Gabriela Camera Leal
- Department of Pharmaceutical Sciences, Federal University of Santa Maria, Santa Maria, Brazil
| | | | | | - Carine Viana
- Department of Pharmaceutical Sciences, Federal University of Santa Maria, Santa Maria, Brazil
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11
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Costa VC, de Mello ML, Babos DV, Castro JP, Pereira-Filho ER. Calibration strategies for determination of Pb content in recycled polypropylene from car batteries using laser-induced breakdown spectroscopy (LIBS). Microchem J 2020. [DOI: 10.1016/j.microc.2020.105558] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Janchevska K, Stafilov T, Memed-Sejfulah S, Bogdanoska M, Ugarkovic S, Petrushevski G. ICH Q3D based elemental impurities study in liquid pharmaceutical dosage form with high daily intake - comparative analysis by ICP-OES and ICP-MS. Drug Dev Ind Pharm 2020; 46:456-461. [PMID: 31999195 DOI: 10.1080/03639045.2020.1724136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Guideline for Elemental Impurities-Q3D of the International Conference on Harmonisation represents a new paradigm in the control of elemental impurities (EIs) in pharmaceuticals. It changes the approach toward control of EIs from the historical 'heavy metals test', to a scientific-based risk assessment and testing by modern analytical instrumentation such as inductively coupled plasma-optical emission spectroscopy (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS). Management of EIs related to all finished drug products must be implemented in strict compliance with the regulatory requirements of pharmaceutical industry due to their quality and safety concerns. Testing for presence of EIs from Class 1 and Class 2a in methadone hydrochloride 1 mg/ml oral solution with recommended daily intake of 150 mg methadone hydrochloride was initially performed on ICP-OES using in-house validated method according to the requirements of pharmacopoeias, in line with Q3D. During the procedure, it became apparent that ICP-OES has its own limitations, especially when it comes to testing arsenic and lead in low concentrations. ICP-MS in-house validated method was developed and employed for determination of trace concentrations of arsenic and lead, providing resourceful information that were compared and correlated to the data obtained by ICP-OES analysis. Sample preparation using microwave digestion technique was applied for the analyses by both techniques. Although the applied ICP-OES in-house method is suitable for determination of Hg, Cd, Co, V, and Ni, more sensitive technique such as ICP-MS is required for accurate determination of As and Pb concerning pharmaceuticals with high daily intakes.
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Affiliation(s)
- Katerina Janchevska
- Institute of Research and Development, Alkaloid AD, Skopje, North Macedonia.,Faculty of Science, Institute of Chemistry, Ss Cyril and Methodius University, Skopje, North Macedonia
| | - Trajče Stafilov
- Faculty of Science, Institute of Chemistry, Ss Cyril and Methodius University, Skopje, North Macedonia
| | | | - Mirjana Bogdanoska
- Institute of Research and Development, Alkaloid AD, Skopje, North Macedonia
| | - Sonja Ugarkovic
- Institute of Research and Development, Alkaloid AD, Skopje, North Macedonia
| | - Gjorgji Petrushevski
- Institute of Research and Development, Alkaloid AD, Skopje, North Macedonia.,Faculty of Science, Institute of Chemistry, Ss Cyril and Methodius University, Skopje, North Macedonia
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Costa VC, Pinheiro FC, Amorim FAC, Paranhos da Silva EG, Pereira-Filho ER. Multivariate optimization for the development of a sample preparation procedure and evaluation of calibration strategies for nutrient elements determination in handmade chocolate. Microchem J 2019. [DOI: 10.1016/j.microc.2019.104166] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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14
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Microwave-assisted digestion using dilute nitric acid solution and investigation of calibration strategies for determination of As, Cd, Hg and Pb in dietary supplements using ICP-MS. J Pharm Biomed Anal 2019; 174:471-478. [DOI: 10.1016/j.jpba.2019.06.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 11/15/2022]
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