Assessment of the chemical and enantiomeric purity of organic reference materials

Yip, Yiu-chung; Wong, Siu-Kay; Choi, Sik-man

doi:10.1016/j.trac.2010.12.003

Cited by 31 publications

(29 citation statements)

References 60 publications

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“…The most known mechanism was proposed by Scholz in 1984: 28 where R'N represents a base, e.g., pyridine or the less toxic imidazole, 9,29 while ROH represents an alcohol, usually methanol, 9,24 but also ethanol, ethylene glycol and 2-methoxyethanol. 11 The Karl Fischer method is used to determine the total water content, i.e., surface and crystallization water. 7,9,11 For larger water amounts (1-100%), 24,30 the volumetric titration (titrant added directly to the titration chamber) is the most indicated, while the coulometric titration (iodine titrant formed in the generator electrode) is appropriate for water amounts in the order of 10-20 μg, 11 50-100 ppm, 24 or few μg g -1 .…”

Section: Introductionmentioning

confidence: 99%

“…11 The Karl Fischer method is used to determine the total water content, i.e., surface and crystallization water. 7,9,11 For larger water amounts (1-100%), 24,30 the volumetric titration (titrant added directly to the titration chamber) is the most indicated, while the coulometric titration (iodine titrant formed in the generator electrode) is appropriate for water amounts in the order of 10-20 μg, 11 50-100 ppm, 24 or few μg g -1 . 30 Both methods can be carried out either by direct introduction of samples in the titration chamber or by using an oven that heats the sample to vaporize the water, which is then transferred to the titration cell by a stream of an inert gas.…”

Section: Introductionmentioning

confidence: 99%

“…Residual solvents may be introduced in active pharmaceutical ingredients (API) during their synthesis, especially if the final purification step is carried out by crystallization in different solvents, as well as during drug products formulation and manufacturing. 1,7,8 In the particular case of certified reference materials (CRM) of APIs, the determination of volatiles is essential both to demonstrate the compliance with Pharmacopeial acceptance criteria and to allow the mass balance calculation (100% -∑ impurities) [10][11][12] of the API mass fraction. CRMs are produced according to the ISO Guides 34:2009 13 and 35:2006 14 and find application in equipment calibration, method validation and quality control.…”

Section: Introductionmentioning

confidence: 99%

“…6 The oven method can differentiate between bound surface and crystallization water by using a defined temperature gradient, 29 but it cannot be applied for thermolabile compounds. 24 Another drawback of the technique is the restriction to use the direct addition in case of analytes that are not soluble in or that react with the KF reagent, 6,29 for instance thiols, 11,31 aldehydes, cetones, amines, cupric salts and ferric salts. 11 Furthermore, it does not provide information about residual solvents.…”

Section: Introductionmentioning

confidence: 99%

“…LOD is considered a non-specific technique 3 and may form interfering volatile components due to sample thermal degradation. 11,29 Additionally, the technique may not release all the entrained solvent 1 or tightly bound crystallization water. 29,32 Other disadvantages are the large amount of sample required 1,3,29 and the long analysis time.…”

Section: Introductionmentioning

confidence: 99%

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Determination of volatiles in pharmaceutical certified reference materials

Nogueira¹,

Queiroz²,

Silva³

et al. 2012

J. Braz. Chem. Soc.

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Este trabalho compara os resultados obtidos na determinação de voláteis (água e solventes residuais) em novos materiais de referência certificados (MRC) ou candidatos a MRC dos ingredientes ativos farmacêuticos (API) captopril, metronidazol, diclofenaco sódico, diclofenaco potássico e furosemida, através do uso de diferentes técnicas: perda por dessecação (LOD), titulação coulométrica tipo Karl Fisher (KF), cromatografia gasosa (injeção por headspace estático) com detector por ionização em chama (sHS-GC-FID) e com espectrômetro de massas (sHS-GC-MS), análise termogravimétrica (TGA) e espectroscopia no infravermelho próximo (NIR) com análise estatística multivariada dos resultados. As três primeiras técnicas levaram a resultados complementares na determinação de voláteis, enquanto as outras duas mostraram pouca sensibilidade para a determinação de voláteis na faixa de concentração avaliada. A perda por dessecação foi considerada a técnica mais apropriada para determinação da fração mássica de voláteis a ser utilizada no cálculo do teor de API por balanço de massa.This work compares the results obtained for the determination of volatiles (water and residual solvents) in new certified reference materials (CRM) or candidate CRMs of the active pharmaceutical ingredients (API) captopril, metronidazole, sodium diclofenac, potassium diclofenac and furosemide, by means of different techniques: loss on drying (LOD), Karl Fischer (KF) coulometric titration, static headspace gas chromatography with flame ionization detection (sHS-GC-FID) and with mass spectrometry (sHS-GC-MS), thermogravimetric analysis (TGA) and near infrared spectroscopy (NIR) with multivariate chemometric analysis of results. The first three methods led to complementary results. The two other techniques were not sufficiently sensitive to determine volatiles in the concentration range evaluated. The loss on drying method was considered the most appropriate to determine the mass fraction of the volatiles to be used in the mass balance calculation of the API mass fraction in the pharmaceutical CRMs.Keywords: volatiles, water, residual solvents, active pharmaceutical ingredient (API), certified reference materials (CRM), analytical quality control IntroductionSeveral are the reasons for determining the mass fractions of water and residual solvents in pharmaceuticals, including their influence on the physicochemical 1-7 and microbiological stability of raw materials and finished products, their potential toxicity [1][2][3]8 and also economic aspects 9 since their presence results in analyte mass fractions smaller than 100%. Residual solvents may be introduced in active pharmaceutical ingredients (API) during their synthesis, especially if the final purification step is carried out by crystallization in different solvents, as well as during drug products formulation and manufacturing. 1,7,8 In the particular case of certified reference materials (CRM) of APIs, the determination of volatiles is essential both to demonstrate the compliance with Pharmacopeial acc...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Determination of volatiles in pharmaceutical certified reference materials

Nogueira¹,

Queiroz²,

Silva³

et al. 2012

J. Braz. Chem. Soc.

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New Chiral Zwitterionic Phosphorus Heterocycles: Synthesis, Structure, Properties and Application as Chiral Solvating Agents

Sheshenev

Boltukhina

Grishina

et al. 2013

Chemistry A European J

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A family of new chiral zwitterionic phosphorus-containing heterocycles (zPHC) have been derived from methylene-bridged bis(imidazolines). These structures were unambiguously determined, including single-crystal XRD analysis for two compounds. The stability, acid/base and electronic properties of these dipolar phosphorus heterocycles were subsequently investigated. zPHCs can be successfully employed as a new class of chiral solvating agents for the enantiodifferentiation of chiral carboxylic and sulfonic acids by NMR spectroscopy. The stoichiometry and binding constants for the donor-acceptor complexes formed were established by NMR titration methods.

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Production of certified reference materials for the sports doping control of the REV‐ERB agonist SR9009

Davies

Chan

Moawad

et al. 2018

Drug Testing and Analysis

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Two human metabolites of the REV-ERB agonist SR9009, identified by researchers with an interest in sports doping control, have been synthesized and assessed for purity. The synthesis employed was a modification of published procedures for the parent SR9009, careful attention to the purification of intermediates and the final product ensuring materials of the highest purity were available for certification. For each candidate material impurities of related structure were identified and quantified as a relative mass fraction using high performance liquid chromatography-ultraviolet (HPLC-UV) detection and proton nuclear magnetic resonance ( H NMR) spectroscopy. The quantification of water, occluded solvent, and inorganic residue was assessed using Karl Fischer, H NMR, and thermogravimetric analysis, thereby completing the assessment of all impurities typically characterized by the mass balance approach. Summation and subtraction from 1000 mg/g afforded the mass fraction of the main component, the associated uncertainty ensuring certified reference material status can be applied to the resulting pure substance calibration standards. The availability of these standards to the sports doping control community will facilitate delivery of metrological traceability to the SI unit for mass (kg) to routine testing results and aid method development for the detection and quantification of SR9009 abuse.

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Assessment of the chemical and enantiomeric purity of organic reference materials

Cited by 31 publications

References 60 publications

Determination of volatiles in pharmaceutical certified reference materials

Determination of volatiles in pharmaceutical certified reference materials

New Chiral Zwitterionic Phosphorus Heterocycles: Synthesis, Structure, Properties and Application as Chiral Solvating Agents

Production of certified reference materials for the sports doping control of the REV‐ERB agonist SR9009

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