1
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Zelesky T, Baertschi SW, Foti C, Allain LR, Hostyn S, Franca JR, Li Y, Marden S, Mohan S, Ultramari M, Huang Z, Adams N, Campbell JM, Jansen PJ, Kotoni D, Laue C. Pharmaceutical Forced Degradation (Stress Testing) Endpoints: A Scientific Rationale and Industry Perspective. J Pharm Sci 2023; 112:2948-2964. [PMID: 37690775 DOI: 10.1016/j.xphs.2023.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 09/12/2023]
Abstract
Forced degradation (i.e., stress testing) of small molecule drug substances and products is a critical part of the drug development process, providing insight into the intrinsic stability of a drug that is foundational to the development and validation of stability-indicating analytical methods. There is a lack of clarity in the scientific literature and regulatory guidance as to what constitutes an "appropriate" endpoint to a set of stress experiments. That is, there is no clear agreement regarding how to determine if a sample has been sufficiently stressed. Notably, it is unclear what represents a suitable justification for declaring a drug substance (DS) or drug product (DP) "stable" to a specific forced degradation condition. To address these concerns and to ensure all pharmaceutically-relevant, potential degradation pathways have been suitably evaluated, we introduce a two-endpoint classification designation supported by experimental data. These two endpoints are 1) a % total degradation target outcome (e.g., for "reactive" drugs) or, 2) a specified amount of stress, even in the absence of any degradation (e.g., for "stable" drugs). These recommended endpoints are based on a review of the scientific literature, regulatory guidance, and a forced degradation data set from ten global pharmaceutical companies. The experimental data set, derived from the Campbell et al. (2022) benchmarking study,1 provides justification for the recommendations. Herein we provide a single source reference for small molecule DS and DP forced degradation stress conditions and endpoint best practices to support regulatory submissions (e.g., marketing applications). Application of these forced degradation conditions and endpoints, as part of a well-designed, comprehensive and a sufficiently rigorous study plan that includes both the DS and DP, provides comprehensive coverage of pharmaceutically-relevant degradation and avoids unreasonably extreme stress conditions and drastic endpoint recommendations sometimes found in the literature.
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Affiliation(s)
- Todd Zelesky
- Analytical Research & Development, Pfizer Inc., Eastern Point Road, Groton, CT 06340, USA.
| | | | - Chris Foti
- Analytical Development and Operations, Gilead Sciences Inc., Foster City, California, USA.
| | | | - Steven Hostyn
- Predictive Analytics & Stability Sciences CoE, Janssen Pharmaceutica, Johnson & Johnson, Beerse, Belgium
| | | | - Yi Li
- Analytical Development and Operations, Gilead Sciences Inc., Foster City, California, USA
| | - Stacey Marden
- Advanced Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, Boston, MA, USA
| | - Shikhar Mohan
- Analytical Development and Operations, Gilead Sciences Inc., Foster City, California, USA
| | - Mariah Ultramari
- Spektra Soluções Científico-Regulatórias Ltda, São Paulo, Brazil
| | - Zongyun Huang
- Bristol-Myers Squibb Company, 1 Squibb Drive, New Brunswick, NJ 08901, USA
| | - Neal Adams
- Pfizer, Scientific and Laboratory Services - Analytical Sciences, Pfizer Inc., 7000 Portage Road, Kalamazoo, MI 49001, USA
| | - John M Campbell
- Analytical Development, GSK, Upper Providence, PA 19426, USA
| | - Patrick J Jansen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA
| | - Dorina Kotoni
- Chemical & Analytical Development, Novartis Pharma AG, Basel, Switzerland
| | - Christian Laue
- Chemical & Pharmaceutical Development, Merck Healthcare KGaA, Darmstadt, Germany
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2
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Iyer J, Karn A, Brunsteiner M, Ray A, Davis A, Saraf I, Paudel A. Screening Autoxidation Propensities of Drugs in the Solid-State Using PVP and in the Solution State Using N-Methyl Pyrrolidone. Pharmaceutics 2023; 15:pharmaceutics15030848. [PMID: 36986709 PMCID: PMC10058359 DOI: 10.3390/pharmaceutics15030848] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/23/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Oxidative degradation of drugs is one of the major routes of drug substance and drug product instability. Among the diverse routes of oxidation, autoxidation is considered to be challenging to predict and control, potentially due to the multi-step mechanism involving free radicals. C–H bond dissociation energy (C–H BDE) is evidenced to be a calculated descriptor shown to predict drug autoxidation. While computational predictions for the autoxidation propensity of drugs are both swift and possible, no literature to date has highlighted the relationship between the computed C–H BDE and the experimentally-derived autoxidation propensities of solid drugs. The objective of this study is to investigate this missing relationship. The present work is an extension to the previously reported novel autoxidation approach that involves subjecting a physical mixture of pre-milled polyvinyl pyrrolidone (PVP) K-60 and a crystalline drug under high temperature and pressurized oxygen setup. The drug degradation was measured using chromatographic methods. An improved trend between the extent of solid autoxidation and C–H BDE could be observed after normalizing the effective surface area of drugs in the crystalline state, pointing to a positive relationship. Additional studies were conducted by dissolving the drug in N-methyl pyrrolidone (NMP) and exposing the solution under a pressurized oxygen setup at diverse elevated temperatures. Chromatographic results of these samples indicated a similarity in the formed degradation products to the solid-state experiments pointing to the utility of NMP, a PVP monomer surrogate, as a stressing agent for faster and relevant autoxidation screening of drugs in formulations.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria
| | - Anjali Karn
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria
| | | | - Andrew Ray
- New Modalities and Parenteral Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, UK
| | - Adrian Davis
- Pfizer Worldwide Research and Development, Sandwich, Kent CT13 9NJ, UK
| | - Isha Saraf
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria
- Institute of Process and Particle Engineering, Graz University of Technology, 8010 Graz, Austria
- Correspondence: ; Tel.: +43-316-873-30912
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3
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Schamel E, Wehnert G, Schlachter H, Söthje D. Chemical Recycling of Carbon Fiber Reinforced Epoxy Composites Using Mild Conditions. CHEM-ING-TECH 2021. [DOI: 10.1002/cite.202100048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Elisabeth Schamel
- Nuremberg Institute of Technology Department of Applied Chemistry Laboratory of Macromolecular Chemistry Keßlerplatz 12 90489 Nuremberg Germany
| | - Gerd Wehnert
- Nuremberg Institute of Technology Department of Applied Chemistry Laboratory of Macromolecular Chemistry Keßlerplatz 12 90489 Nuremberg Germany
| | - Herbert Schlachter
- Nuremberg Institute of Technology Department of Applied Chemistry Laboratory of Macromolecular Chemistry Keßlerplatz 12 90489 Nuremberg Germany
| | - Dominik Söthje
- Aschaffenburg University of Applied Sciences Department of Engineering Wuerzburger Straße 45 63743 Aschaffenburg Germany
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4
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Grinberg Dana A, Wu H, Ranasinghe DS, Pickard FC, Wood GPF, Zelesky T, Sluggett GW, Mustakis J, Green WH. Kinetic Modeling of API Oxidation: (1) The AIBN/H 2O/CH 3OH Radical "Soup". Mol Pharm 2021; 18:3037-3049. [PMID: 34236207 DOI: 10.1021/acs.molpharmaceut.1c00261] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stress testing of active pharmaceutical ingredients (API) is an important tool used to gauge chemical stability and identify potential degradation products. While different flavors of API stress testing systems have been used in experimental investigations for decades, the detailed kinetics of such systems as well as the chemical composition of prominent reactive species, specifically reactive oxygen species, are unknown. As a first step toward understanding and modeling API oxidation in stress testing, we investigated a typical radical "soup" solution an API is subject to during stress testing. Here we applied ab initio electronic structure calculations to automatically generate and refine a detailed chemical kinetics model, taking a fresh look at API oxidation. We generated a detailed kinetic model for a representative azobis(isobutyronitrile) (AIBN)/H2O/CH3OH stress-testing system with a varied cosolvent ratio (50%/50%-99.5%/0.5% vol water/methanol) for 5.0 mM AIBN and representative pH values of 4-10 at 40 °C that was stirred and open to the atmosphere. At acidic conditions, hydroxymethyl alkoxyl is the dominant alkoxyl radical, and at basic conditions, for most studied initial methanol concentrations, cyanoisopropyl alkoxyl becomes the dominant alkoxyl radical, albeit at an overall lower concentration. At acidic conditions, the levels of cyanoisopropyl peroxyl, hydroxymethyl peroxyl, and hydroperoxyl radicals are relatively high and comparable, while, at both neutral and basic pH conditions, superoxide becomes the prominent radical in the system. The present work reveals the prominent species in a common model API stress testing system at various cosolvent and pH conditions, sets the stage for an in-depth quantitative API kinetic study, and demonstrates the usage of novel software tools for automated chemical kinetic model generation and ab initio refinement.
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Affiliation(s)
- Alon Grinberg Dana
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Wolfson Department of Chemical Engineering, Technion, Israel Institute of Technology, Haifa 3200003, Israel
| | - Haoyang Wu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Duminda S Ranasinghe
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Frank C Pickard
- Pfizer Global Research & Development, Groton Laboratories, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Geoffrey P F Wood
- Pfizer Global Research & Development, Groton Laboratories, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Todd Zelesky
- Pfizer Global Research & Development, Groton Laboratories, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Gregory W Sluggett
- Pfizer Global Research & Development, Groton Laboratories, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Jason Mustakis
- Pfizer Global Research & Development, Groton Laboratories, Eastern Point Road, Groton, Connecticut 06340, United States
| | - William H Green
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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5
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Campbell JM, Foti C, Wang C, Adams N, Allain LR, Araujo G, Azevedo R, Franca JR, Hicks SR, Hostyn S, Jansen PJ, Kotoni D, Kuemmell A, Marden S, Rullo G, Santos ACO, Sluggett GW, Zelesky T, Baertschi SW. Assessing the Relevance of Solution Phase Stress Testing of Solid Dosage Form Drug Products: A Cross-Industry Benchmarking Study. J Pharm Sci 2021; 111:298-305. [PMID: 34111446 DOI: 10.1016/j.xphs.2021.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 10/21/2022]
Abstract
Stress testing (also known as forced degradation) of pharmaceutical products has long been recognized as a critical part of the drug development process, providing foundational information related to intrinsic stability characteristics and to the development of stability-indicating analytical methods. A benchmarking study was undertaken by nine pharmaceutical companies and the Brazilian Health Regulatory Agency (Agência Nacional de Vigilância Sanitária, or ANVISA) with a goal of understanding the utility of various stress testing conditions for producing pharmaceutically-relevant chemical degradation of drugs. Special consideration was given to determining whether solution phase stress testing of solid drug products produced degradation products that were both unique when compared to other stress conditions and relevant to the formal drug product stability data. The results from studies of 62 solid dosage form drug products were compiled. A total of 387 degradation products were reported as being observed in stress testing studies, along with 173 degradation products observed in accelerated and/or long-term stability studies for the 62 drug products. Among these, 25 of the stress testing degradation products were unique to the solution phase stress testing of the drug products; however, none of these unique degradation products were relevant to the formal stability data. The relevant degradation products were sufficiently accounted for by stress testing studies that included only drug substance stressing (in solution and in the solid state) and drug product stressing (in the solid state). Based on these results, it is the opinion of the authors that for solid dosage form drug products, well-designed stress testing studies need not include solution phase stress testing of the drug product in order to be comprehensive.
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Affiliation(s)
- John M Campbell
- CMC Analytical, GlaxoSmithKline, Upper Providence, PA 19426, USA.
| | - Chris Foti
- Analytical Core Teams, Gilead Sciences Inc., Foster City, CA, USA.
| | - Chloe Wang
- Analytical Core Teams, Gilead Sciences Inc., Foster City, CA, USA
| | - Neal Adams
- Pfizer, Scientific and Laboratory Services - Analytical Sciences, Pfizer Inc., Kalamazoo, MI 49001, USA
| | | | - Gabriela Araujo
- Global Technology & Engineering, Pfizer Inc., Itapevi, SP, Brazil
| | - Renan Azevedo
- Global Technology & Engineering, Pfizer Inc., Itapevi, SP, Brazil
| | | | - Simon R Hicks
- CMC Analytical, GlaxoSmithKline, Stevenage, Hertfordshire, UK
| | - Steven Hostyn
- Predictive Analytics & Stability Sciences CoE, Janssen Pharmaceutica, Johnson & Johnson, Beerse, Belgium
| | - Patrick J Jansen
- Eli Lilly and Company, Synthetic Molecule Design and Development
| | - Dorina Kotoni
- Chemical & Analytical Development, Novartis Pharma AG, Basel, Switzerland
| | - Andreas Kuemmell
- Analytical Research & Development, Novartis Pharma AG, Basel, Switzerland
| | - Stacey Marden
- Advanced Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, Boston, MA, USA
| | - Gregory Rullo
- Global Regulatory Affairs, AstraZeneca Pharmaceuticals Gaithersburg, MD, USA, 20878
| | - Ana Cláudia O Santos
- Global Analytical Technology, Merck S.A., Rio de Janeiro, RJ, Brazil, an affiliate of Merck KGaA, Darmstadt, Germany
| | - Gregory W Sluggett
- Analytical Research & Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
| | - Todd Zelesky
- Analytical Research & Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
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6
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Developability profile framework for lead candidate selection in topical dermatology. Int J Pharm 2021; 604:120750. [PMID: 34051321 DOI: 10.1016/j.ijpharm.2021.120750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 11/23/2022]
Abstract
The development of molecules for topical dermatology has primarily relied on drug repurposing or on combination therapies, leading to an average of only one New Chemical Entity (NCE) approved per year by the FDA. Topical products offer benefits to patients by enabling localized treatment, while minimizing systemic exposure and the likelihood of adverse events. New therapies are further justified by the burden skin diseases cause on patients' quality of life. Notwithstanding the opportunities, the selection of a topical NCE presents challenges, primarily derived from a target product profile uncommon to oral drugs. Beyond a more stringent range of physicochemical properties, the molecule must display adequate solubility and chemical stability in topical-relevant excipients; must effectively cross the stratum corneum, considerably less permeable than the intestinal epithelium, and elicit a local therapeutic response; and must enable a formulation with robust physical stability. A novel framework intended to de-risk NCE selection is presented and based on four calculated physicochemical properties: molecular weight, clogP, topological polar surface area, and aromatic ring count. The use of topical-relevant solvents to assess the molecule's solubility profile, and a 2-day accelerated chemical stability methodology, are also described as critical steps in early dermal development.
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7
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Walter J, Schwarting J, Plesnila N, Terpolilli NA. Influence of Organic Solvents on Secondary Brain Damage after Experimental Traumatic Brain Injury. Neurotrauma Rep 2020; 1:148-156. [PMID: 34223539 PMCID: PMC8240898 DOI: 10.1089/neur.2020.0029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many compounds tested for a possible neuroprotective effect after traumatic brain injury (TBI) are not readily soluble and therefore organic solvents need to be used as a vehicle. It is, however, unclear whether these organic solvents have intrinsic pharmacological effects on secondary brain damage and may therefore interfere with experimental results. Thus, the aim of the current study was to evaluate the effect of four widely used organic solvents, dimethylsulfoxide (DMSO), Miglyol 812 (Miglyol®), polyethyleneglycol 40 (PEG 40), and N-2-methyl-pyrrolidone (NMP) on outcome after TBI in mice. A total of 143 male C57Bl/6 mice were subjected to controlled cortical impact (CCI). Contusion volume, brain edema formation, and neurological function were assessed 24 h after TBI. Test substances or saline were injected intraperitoneally (i.p.) 10 min before CCI. DMSO, Miglyol, and PEG 40 had no effect on post-traumatic contusion volume after CCI; NMP, however, significantly reduced contusion volume and brain edema formation at different concentrations. The use of DMSO, Miglyol, and PEG 40 is unproblematic for studies investigating neuroprotective treatment strategies as they do not influence post-traumatic brain damage. NMP seems to have an intrinsic neuroprotective effect that should be considered when using this agent in pharmacological experiments; further, a putative therapeutic effect of NMP needs to be elucidated in future studies.
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Affiliation(s)
- Johannes Walter
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany
| | - Julian Schwarting
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Department of Neurosurgery, Munich University Hospital, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany
| | - Nicole A Terpolilli
- Institute for Stroke and Dementia Research, Munich University Hospital, Munich, Germany.,Department of Neurosurgery, Munich University Hospital, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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8
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Effect of Temperature Exposition of Casting Solution on Properties of Polysulfone Hollow Fiber Membranes. FIBERS 2019. [DOI: 10.3390/fib7120110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
It was shown for the first time that the conditions of thermal treatment of the casting solution significantly affect the morphology and transport properties of porous, flat, and hollow fiber polysulfone (PSf) membranes. It is ascertained that the main solution components that are subjected to thermo-oxidative destruction are the pore-forming agent polyethylene glycol (PEG) and solvent N-methyl-2-pyrrolidone (NMP). It is proved that hydroxyl groups of PEG actively react in the process of the casting solution thermo-oxidative destruction. It is shown that despite the chemical conversion taking place in the casting solution, their stability towards coagulation virtually does not change. The differences in the membrane morphology associated with the increase of thermal treatment time at 120 °C are not connected to the thermodynamic properties of the casting solutions, but with the kinetics of the phase separation. It is revealed that the change of morphology and transport properties of membranes is connected with the increase of the casting solution viscosity. The rise of solution viscosity resulted in the slowdown of the phase separation and formation of a more densely packed membrane structure with less pronounced macropores. It is determined experimentally that with the increase of casting solution thermal treatment time, the membrane selective layer thickness increases. This leads to the decrease of gas permeance and the rise of the He/CO2 selectivity for flat and hollow fiber membranes. In the case of hollow fibers, the fall of gas permeance is also connected with the appearance of the sponge-like layer at the outer surface of membranes. The increase of selectivity and decline of permeance indicates the reduction of selective layer pore size and its densification, which agrees well with the calculation results of the average membrane density. The results obtained are relevant to any polymeric casting solution containing NMP and/or PEG and treated at temperatures above 60 °C.
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9
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Modhave D, Barrios B, Paudel A. PVP-H 2O 2 Complex as a New Stressor for the Accelerated Oxidation Study of Pharmaceutical Solids. Pharmaceutics 2019; 11:pharmaceutics11090457. [PMID: 31484442 PMCID: PMC6781290 DOI: 10.3390/pharmaceutics11090457] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/27/2019] [Accepted: 08/30/2019] [Indexed: 11/27/2022] Open
Abstract
Reactive impurities, such as hydrogen peroxide in excipients, raise a great concern over the chemical stability of pharmaceutical products. Traditional screening methods of spiking impurities into solid drug-excipient mixtures oversimplify the micro-environment and the physical state of such impurities in real dosage form. This can lead to an inaccurate prediction of the long-term product stability. This study presents the feasibility of using a polyvinylpyrrolidone-hydrogen peroxide complex (PVP-H2O2) as an oxidative agent for the solid state forced degradation of a selected drug, vortioxetine HBr. The PVP-H2O2 complex was prepared and characterized using FT-IR spectroscopy. The tablet compacts were made using a mixture of solid PVP-H2O2 complex and crystalline vortioxetine HBr powder. The compacts were exposed to 40 °C/75% RH condition in open and closed states for different time intervals. The extent and the type of drug degradation were analysed using LC and LC-MS. The extent of degradation was higher in the samples stored at the open state as compared to the close state. The solution state forced oxidation was conducted to verify the peroxide induced degradation reactions. The results evidence the utility of the proposed solid-state stressor and the method for screening the sensitivity of drugs to the excipient reactive impurities involving peroxides in solid-state.
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Affiliation(s)
- Dattatray Modhave
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria
| | - Brenda Barrios
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria.
- Institute of Process and Particle Engineering, Graz University of Technology, 8010 Graz, Austria.
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10
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Tao H, Zhang Y, Gao Y, Sun Z, Yan C, Texter J. Scalable exfoliation and dispersion of two-dimensional materials - an update. Phys Chem Chem Phys 2018; 19:921-960. [PMID: 27976772 DOI: 10.1039/c6cp06813h] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The preparation of dispersions of single- and few-sheet 2D materials in various solvents, as well as the characterization methods applied to such dispersions, is critically reviewed. Motivating factors for producing single- and few-sheet dispersions of 2D materials in liquids are briefly discussed. Many practical applications are expected for such materials that do not require high purity formulations and tight control of donor and acceptor concentrations, as required in conventional Fab processing of semiconductor chips. Approaches and challenges encountered in exfoliating 2D materials in liquids are reviewed. Ultrasonication, mechanical shearing, and electrochemical processing approaches are discussed, and their respective limitations and promising features are critiqued. Supercritical and more conventional liquid and solvent processing are then discussed in detail. The effects of various types of stabilizers, including surfactants and other amphiphiles, as well as polymers, including homopolymeric electrolytes, nonionic polymers, and nanolatexes, are discussed. Consideration of apparent successes of stabilizer-free dispersions indicates that extensive exfoliation in the absence of dispersing aids results from processing-induced surface modifications that promote stabilization of 2D material/solvent interactions. Also apparent paradoxes in "pristineness" and optical extinctions in dispersions suggest that there is much we do not yet quantitatively understand about the surface chemistry of these materials. Another paradox, emanating from modeling dilute solvent-only exfoliation by sonication using polar components of solubility parameters and surface tension for pristine graphene with no polar structural component, is addressed. This apparent paradox appears to be resolved by realizing that the reactivity of graphene to addition reactions of solvent radicals produced by sonolysis is accompanied by unintended polar surface modifications that promote attractive interactions with solvent. This hypothesis serves to define important theoretical and experimental studies that are needed. We conclude that the greatest promise for high volume and high concentration processing lies in applying methods that have not yet been extensively reported, particularly wet comminution processing using small grinding media of various types.
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Affiliation(s)
- Hengcong Tao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Yuqin Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Yunnan Gao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Zhenyu Sun
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Chao Yan
- School of Material Science & Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - John Texter
- School of Engineering Technology, Eastern Michigan University, Ypsilanti, MI 48197, USA.
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11
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Reynolds DW, Campbell JM, Johnson BS, Joshi BK, Facchine KL, Long S, O’Connell TM, Paulus IV, Sides SL, Kraft ES, Wolters AM. The Degradation Chemistry of Farglitazar and Elucidation of the Oxidative Degradation Mechanisms. J Pharm Sci 2017; 106:982-993. [DOI: 10.1016/j.xphs.2016.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/03/2016] [Accepted: 12/07/2016] [Indexed: 11/29/2022]
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12
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Klõšeiko J. Cupric Ferricyanide Reaction in Solution for Determination of Reducing Properties of Plant Antioxidants. FOOD ANAL METHOD 2016. [DOI: 10.1007/s12161-015-0177-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Suhartono J, Tizaoui C. Polyvinylidene fluoride membranes impregnated at optimised content of pristine and functionalised multi-walled carbon nanotubes for improved water permeation, solute rejection and mechanical properties. Sep Purif Technol 2015. [DOI: 10.1016/j.seppur.2015.09.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Ueyama E, Tamura K, Mizukawa K, Kano K. Realistic prediction of solid pharmaceutical oxidation products by using a novel forced oxidation system. J Pharm Sci 2014; 103:1184-93. [PMID: 24497072 DOI: 10.1002/jps.23889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 01/10/2014] [Accepted: 01/16/2014] [Indexed: 11/11/2022]
Abstract
This study investigated a novel solid-state-based forced oxidation system to enable a realistic prediction of pharmaceutical product oxidation, a key consideration in drug development and manufacture. Polysorbate 80 and ferric(III) acetylacetonate were used as an organic hydroperoxide source and a transition metal catalyst, respectively. Homogeneous solutions of target compounds and these reagents were prepared in a mixed organic solvent. The organic solvent was removed rapidly under reduced pressure, and the oxidation of the resulting dried solid was investigated. Analysis of the oxidation products generated in test compounds by this proposed forced oxidation system using HPLC showed a high similarity with those generated during more prolonged naturalistic drug oxidation. The proposed system provided a better predictive performance in prediction of realistic oxidative degradants of the drugs tested than did other established methods. Another advantage of this system was that the generation of undesired products of hydrolysis, solvolysis, and thermolysis was prevented because efficient oxidation was achieved under mild conditions. The results of this study suggest that this system is suitable for a realistic prediction of oxidative degradation of solid pharmaceuticals.
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Affiliation(s)
- Eiji Ueyama
- Analytical and Quality Evaluation Research Laboratories, Pharmaceutical Technology Division, Daiichi Sankyo, Hiratsuka, Kanagawa, 254-0014, Japan
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15
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Alsante KM, Huynh-Ba K, Baertschi SW, Reed RA, Landis MS, Kleinman MH, Foti C, Rao VM, Meers P, Abend A, Reynolds DW, Joshi BK. Recent trends in product development and regulatory issues on impurities in active pharmaceutical ingredient (API) and drug products. Part 1: Predicting degradation related impurities and impurity considerations for pharmaceutical dosage forms. AAPS PharmSciTech 2014; 15:198-212. [PMID: 24281749 DOI: 10.1208/s12249-013-0047-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 10/22/2013] [Indexed: 11/30/2022] Open
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16
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Ueyama E, Suzuki N, Kano K. Mechanistic Study of the Oxidative Degradation of the Triazole Antifungal Agent CS-758 in an Amorphous Form. J Pharm Sci 2013; 102:104-13. [DOI: 10.1002/jps.23339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 09/13/2012] [Indexed: 11/08/2022]
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