Dehydration, hydration behavior, and structural analysis of fenoprofen calcium**This work is presented in memory of one of the authors, Jia Xu.

Zhu, Haijian; Xu, Jia; Varlashkin, Peter; Long, Stacey T.; Kidd, Chris

doi:10.1002/jps.1038

Cited by 40 publications

(27 citation statements)

References 9 publications

(14 reference statements)

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“…There are few examples in the literature that report similar values for dehydration processes [40,41,42]; we assume that this behavior could be related to the discrete character of the water sub-network in this phase which, in turn, increases the initial barrier for water diffusion; however, further exhaustive research is required for a better insight into this phenomenon.…”

Section: Resultsmentioning

confidence: 86%

Dehydration Process of Hofmann-Type Layered Solids

et al. 2013

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In the present work the dehydration process of layered solids with formula unit M(H2O)2[Ni(CN)4]·nH2O, M = Ni, Co, Mn; n = 1, 2, 4 is studied using modulated thermogravimetry. The results show that water molecules need to overcome an energetic barrier (activation energy between 63 and 500 kJ/mol) in order to diffuse through the interlayer region. The related kinetic parameters show a dependence on the water partial pressure. On the other hand, X-ray diffraction results provide evidence that the dehydration process is accompanied by framework collapse, limiting the structural reversibility, except for heating below 80 °C where the ordered structure remains. Removal of water molecules from the interlayer region disrupts the long-range structural order of the solid.

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Section: Resultsmentioning

confidence: 86%

Dehydration Process of Hofmann-Type Layered Solids

et al. 2013

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“…2c). Calcium is coordinated by eight oxygen atoms in total, which is known to be a common coordination system as indicated by analysis of calcium‐containing compounds in the CCD 16…”

Section: Resultsmentioning

confidence: 99%

Structure and Physical Stability of Hydrates and Thermotropic Mesophase of Calcium Benzoate

Terakita

Byrn

2006

Journal of Pharmaceutical Sciences

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“…Each of the individual salts of a particular API can be considered a unique chemical entity with its own distinct physicochemical and biopharmaceutical properties 19,20 . Due to the absence of any predictive relationships between the physicochemical properties of the free base or free acid and any of the resultant salts, selection of the best salt with the desired properties is a difficult, semi‐empirical undertaking 21,22 …”

Section: Utility Of Sulfonic Acids As Salt‐forming Entitiesmentioning

confidence: 99%

Drug substances presented as sulfonic acid salts: overview of utility, safety and regulation

Elder

Snodin

2009

Journal of Pharmacy and Pharmacology

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Objectives Controlling genotoxic impurities represents a significant challenge to both industry and regulators. The potential for formation of genotoxic short-chain alkyl esters of sulfonic acids during synthesis of sulfonic acid salts is a long-standing regulatory concern. This review provides a general overview of the utility of sulfonic acids as salt-forming moieties and discusses strategies for effectively minimizing the potential for alkyl sulfonate formation during the synthesis and processing of sulfonate salt active pharmaceutical ingredients. The potential implications of the recent establishment of a substantial human threshold dose for ethyl methanesulfonate for the safety assessment of alkyl sulfonates in general are also discussed. Key findings The formation of alkyl sulfonates requires highly acidic conditions, possibly combined with long reaction times and/or elevated temperatures, to generate significant amounts, and these conditions are most unlikely to be present in the synthesis of active pharmaceutical ingredient sulfonate salts. It is possible to design salt formation conditions, using a short-chain alcohol as solvent, to manufacture sulfonate salts that are essentially free of alkyl sulfonate impurities. Processes using non-acidic conditions such as ethanol recrystallization or wet granulation should not raise any concerns of alkyl sulfonate formation. Summary An understanding of the mechanism of formation of alkyl sulfonates is critical in order to avoid restricting or over-controlling sulfonic acid salts, which have many technical advantages as pharmaceutical counterions. Recent regulatory acceptance of a human threshold limit dose of 2 mg/kg per day for ethyl methanesulfonate, indicating that its toxicological risks have previously been considerably overestimated, could signal the beginning of the end over safety concerns on alkyl sulfonate residues, thus removing a major constraint from the exploitation of sulfonic acid counterions.

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Dehydration, hydration behavior, and structural analysis of fenoprofen calcium**This work is presented in memory of one of the authors, Jia Xu.

Cited by 40 publications

References 9 publications

Dehydration Process of Hofmann-Type Layered Solids

Dehydration Process of Hofmann-Type Layered Solids

Structure and Physical Stability of Hydrates and Thermotropic Mesophase of Calcium Benzoate

Drug substances presented as sulfonic acid salts: overview of utility, safety and regulation

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