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Iyer J, Brunsteiner M, Ray A, Davis A, Saraf I, Paudel A. Theoretical and Experimental Investigation of Autoxidation Propensity of Selected Drugs in Solution State. Mol Pharm 2023; 20:1768-1778. [PMID: 36757102 DOI: 10.1021/acs.molpharmaceut.2c00967] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The C-H bond dissociation energy (BDE) of drug molecules is often used to estimate their relative propensities to undergo autoxidation. BDE calculations based on electronic structures provide a convenient means to estimate the risk for a given compound to degrade via autoxidation. This study aimed to verify the utility of calculated C-H BDEs of a range of drug molecules in predicting their autoxidation propensities, in the solution state. For the autoxidation study, 2,2'-azobis (2-methylpropionitrile) was employed as the solution state stressor, and the experimental reaction rate constants were determined employing ultraperformance liquid chromatographic (UPLC) methods. Reaction rates in the solution state were compared to the calculated C-H BDE values of the respective compounds. The results indicated a poor correlation for compounds in the solution state, and their relative stabilities could not be explained with C-H BDE. On the other hand, a favorable relationship was observed between the relative extent of ionization and the autoxidation rates of the selected compounds. In the solution state, factors such as the type and extent of drug ionization, degree and type of solvation have been shown to contribute to differences in reactivity. By applying the computational method involving the effect of H-atom abstraction and potential ionization sites in the molecule, the calculated C-H BDE should relate better to the experimental autoxidation rates.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria
| | | | - Andrew Ray
- Dew Modalities Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Adrian Davis
- Pfizer Worldwide Research and Development, Sandwich, Kent CT13 9NJ, United Kingdom
| | - Isha Saraf
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz 8010, Austria.,Graz University of Technology, Institute of Process and Particle Engineering, Graz 8010, Austria
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Iyer J, Brunsteiner M, Modhave D, Paudel A. Role of Crystal Disorder and Mechanoactivation in Solid-State Stability of Pharmaceuticals. J Pharm Sci 2023; 112:1539-1565. [PMID: 36842482 DOI: 10.1016/j.xphs.2023.02.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/20/2023] [Accepted: 02/20/2023] [Indexed: 02/28/2023]
Abstract
Common energy-intensive processes applied in oral solid dosage development, such as milling, sieving, blending, compaction, etc. generate particles with surface and bulk crystal disorder. An intriguing aspect of the generated crystal disorder is its evolution and repercussion on the physical- and chemical stabilities of drugs. In this review, we firstly examine the existing literature on crystal disorder and its implications on solid-state stability of pharmaceuticals. Secondly, we discuss the key aspects related to the generation and evolution of crystal disorder, dynamics of the disordered/amorphous phase, analytical techniques to measure/quantify them, and approaches to model the disordering propensity from first principles. The main objective of this compilation is to provide special impetus to predict or model the chemical degradation(s) resulting from processing-induced manifestation in bulk solid manufacturing. Finally, a generic workflow is proposed that can be useful to investigate the relevance of crystal disorder on the degradation of pharmaceuticals during stability studies. The present review will cater to the requirements for developing physically- and chemically stable drugs, thereby enabling early and rational decision-making during candidate screening and in assessing degradation risks associated with formulations and processing.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria
| | | | - Dattatray Modhave
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria; Graz University of Technology, Institute of Process and Particle Engineering, Graz Austria.
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4
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Tunjic TM, Weber N, Brunsteiner M. Computer aided drug design in the development of proteolysis targeting chimeras. Comput Struct Biotechnol J 2023; 21:2058-2067. [PMID: 36968015 PMCID: PMC10030821 DOI: 10.1016/j.csbj.2023.02.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/18/2023] Open
Abstract
Proteolysis targeting chimeras represent a class of drug molecules with a number of attractive properties, most notably a potential to work for targets that, so far, have been in-accessible for conventional small molecule inhibitors. Due to their different mechanism of action, and physico-chemical properties, many of the methods that have been designed and applied for computer aided design of traditional small molecule drugs are not applicable for proteolysis targeting chimeras. Here we review recent developments in this field focusing on three aspects: de-novo linker-design, estimation of absorption for beyond-rule-of-5 compounds, and the generation and ranking of ternary complex structures. In spite of this field still being young, we find that a good number of models and algorithms are available, with the potential to assist the design of such compounds in-silico, and accelerate applied pharmaceutical research.
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5
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Iyer J, Saraf I, Ray A, Brunsteiner M, Paudel A. Assessment of Diverse Solid−State Accelerated Autoxidation Methods for Droperidol. Pharmaceutics 2022; 14:pharmaceutics14061114. [PMID: 35745687 PMCID: PMC9227907 DOI: 10.3390/pharmaceutics14061114] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/17/2022] [Accepted: 05/22/2022] [Indexed: 02/06/2023] Open
Abstract
The present study aimed to investigate methods for accelerating autoxidation of crystalline drugs in the solid-state that can potentially predict real−time stability. Solid droperidol (DPD) was selected as the model drug. A common free−radical initiator, 2,2′−azobisisobutyronitrile (AIBN), was used to induce autoxidation in solutions. AIBN decomposes at elevated temperatures to yield carbon−centred cyano−isopropyl free radicals that can auto−oxidize neighboring drug molecules. Although the reaction of AIBN is relatively straightforward in solution, it is less so in solids. In this study, we used solid AIBN mixed with DPD powder in the presence and absence of pressurized oxygen headspace. Samples were prepared directly in the form of binary mixtures with DPD and additionally in the form of powder compact/pellet with DPD. The main challenge in carrying out the reaction was related to the preservation of AIBN at elevated temperatures due to the disintegration of the pellet containing the latter. A commercially available free−radical coated silica particle (i.e., 2,2,6,6−tetramethyl−1−piperinyloxy (TEMPO) or (SiliaCATTM TEMPO)) was tested as a potential stressor, but with limited success to induce autoxidation. The most valuable results were obtained when a physical mixture of pre−milled PVP K−60 containing free radicals and DPD was exposed to elevated oxygen−temperature conditions, which yielded significant degradation of DPD. The study highlights the practical challenges for conducting accelerated solid−state stress studies to assess the autoxidation susceptibility of drugs using traditional free−radical initiators and presents a proof of application of milled PVP with free−radical as a potential alternative.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria; (J.I.); (I.S.); (M.B.)
| | - Isha Saraf
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria; (J.I.); (I.S.); (M.B.)
| | - Andrew Ray
- Global Product Development, Pharmaceutical Technology & Development, AstraZeneca, Macclesfield Campus, Macclesfield SK11 8LF, UK;
| | - Michael Brunsteiner
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria; (J.I.); (I.S.); (M.B.)
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), 8010 Graz, Austria; (J.I.); (I.S.); (M.B.)
- Institute of Process and Particle Engineering, Graz University of Technology, 8010 Graz, Austria
- Correspondence: ; Tel.: +43-316-873-30912
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6
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Saraf I, Roskar R, Modhave D, Brunsteiner M, Karn A, Neshchadin D, Gescheidt G, Paudel A. Forced Solid-State Oxidation Studies of Nifedipine-PVP Amorphous Solid Dispersion. Mol Pharm 2022; 19:568-583. [PMID: 35060741 DOI: 10.1021/acs.molpharmaceut.1c00678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, the oxidative degradation behavior of nifedipine (NIF) in amorphous solid dispersions (ASDs) prepared with poly(vinyl pyrrolidone) (PVP) with a short (K30) and a long (K90) chain length was investigated. The ASDs were prepared via dry ball-milling and analyzed using Fourier transform infrared (IR) spectroscopy, X-ray scattering, and differential scanning calorimetry. The ASDs were exposed to accelerated thermal-oxidative conditions using a pressurized oxygen headspace (120 °C for 1 day) and high temperatures at atmospheric pressure (60-120 °C for a period of 42 days). Additionally, solution-state oxidative degradation studies showed that pure NIF degrades to a greater extent than in the presence of PVP. Electronic structure calculations were performed to understand the impact of drug-polymer intermolecular interactions on the autoxidation of drugs. While no drug degradation was observed in freshly prepared ASD samples, alkyl free radicals were detected via electron paramagnetic resonance (EPR) spectroscopy. The free radicals were found to be consumed to a greater extent by PVP K30- than PVP K90-based ASDs upon exposure to high oxygen pressures. This was consistent with the greater solid-state oxidative degradation of NIF observed in ASDs with PVP K30 than with PVP K90. As no drug recrystallization occurred during this study period, the lower glass-transition temperature and presumed greater molecular mobility of PVP K30 and its ASD as compared to the PVP K90 system appear to contribute to the greater drug degradation in PVP-K30-based ASDs. The extent and the rate of oxidative degradation were higher in the case of PVP-K30-based ASD as compared to that in PVP-K90-based ASD, and the overall degradation increased with an increase in temperature. IR spectral analysis of drug-polymer interactions supports the electronic calculations of the oxidation process. We infer that, apart from the initial free radical content, the difference in the extent of drug-polymer intermolecular interactions in ASDs and amorphous stabilization during the forced oxidation experiments contribute to the observed differences in the autoxidative reactivity of the drug in ASDs with different PVP chain lengths. Overall, the chemical degradation of NIF in ASDs with two PVP chain lengths obtained from accelerated solid-state oxidation studies was in qualitative agreement with that obtained from long-term (3 years) storage under ambient conditions. The study highlights the ability of accelerated processes to determine the oxidative degradation behavior of polymeric ASDs and suggests that the polymer chain length could factor into chemical as well as physical stability considerations.
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Affiliation(s)
- Isha Saraf
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria
| | - Robert Roskar
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, 1000 Ljubljana, Slovenia
| | - Dattatray Modhave
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria
| | - Michael Brunsteiner
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria
| | - Anjali Karn
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria.,Institute for Process and Particle Engineering, Graz University of Technology, Inffeldgasse 13, 8010 Graz, Austria
| | - Dmytro Neshchadin
- Graz University of Technology, Institute of Physical and Theoretical Chemistry, Stremayrgasse 9, 8010 Graz, Austria
| | - Georg Gescheidt
- Graz University of Technology, Institute of Physical and Theoretical Chemistry, Stremayrgasse 9, 8010 Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering (RCPE) GmbH, Inffeldgasse 13, 8010 Graz, Austria.,Institute for Process and Particle Engineering, Graz University of Technology, Inffeldgasse 13, 8010 Graz, Austria
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7
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Brunsteiner M, Zellnitz S, Pinto JT, Karrer J, Paudel A. Can we predict trends in tribo-charging of pharmaceutical materials from first principles? POWDER TECHNOL 2019. [DOI: 10.1016/j.powtec.2019.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Modhave D, Laggner P, Brunsteiner M, Paudel A. Solid-State Reactivity of Mechano-Activated Simvastatin: Atypical Relation to Powder Crystallinity. J Pharm Sci 2019; 108:3272-3280. [PMID: 31173762 DOI: 10.1016/j.xphs.2019.05.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/15/2019] [Accepted: 05/29/2019] [Indexed: 12/19/2022]
Abstract
The present study investigated the impact of solid-state disorders generated during milling on the chemical reactivity of simvastatin. An amorphous and a partially crystalline simvastatin powders were generated via cryomilling simvastatin crystals for either 90 or 10 min, respectively. The thoroughly characterized milled powders were stored at 40°C/75% RH, in open and closed containers. The effect of milling and storage conditions on physical stability was investigated using simultaneous small and wide-angle X-ray scattering and differential scanning calorimetry. The chemical degradation was evaluated using liquid chromatography-mass spectrometry. Compared with the fully amorphous state, the partially crystalline simvastatin crystallized to a lower extent in the expense of higher chemical degradation on open storage. The closely stored samples degraded to a lower extent and crystallized to a higher extent than the openly stored ones. However, the trends of the total crystallinity and degradation between amorphous and partially crystalline powders were similar. Small-angle X-ray scattering revealed that the partially crystalline simvastatin comprised a higher extent of nanoscale density heterogeneity than the fully amorphous powder. The overall results pointed toward the role of the remaining amorphous content and the nanoscale and mesoscale density heterogeneity on the chemical reactivity in the disordered simvastatin.
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Affiliation(s)
- Dattatray Modhave
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria
| | - Peter Laggner
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria
| | | | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria; University of Technology, Institute of Process and Particle Engineering, Graz Austria.
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9
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Zellnitz S, Pinto JT, Brunsteiner M, Schroettner H, Khinast J, Paudel A. Tribo-Charging Behaviour of Inhalable Mannitol Blends with Salbutamol Sulphate. Pharm Res 2019; 36:80. [PMID: 30968221 PMCID: PMC6456482 DOI: 10.1007/s11095-019-2612-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/19/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE The performance of carrier-based dry powder inhaler (DPI) formulations can be critically impacted by interfacial interactions driven by tribo-electrification. Therefore, the aim of the present work was to understand how distinct API particle characteristics affect the charging behaviour of blends intended for DPI delivery. METHODS Salbutamol sulphate (SBS) particles engineered via spray-drying and jet milling were used as model APIs. D-mannitol was selected as a model carrier. The materials were characterized concerning their different particle properties and their charge was analysed alone and in blends before and after flow over a stainless-steel pipe. RESULTS The spray-dried SBS (amorphous and spherical) charged positively and to a higher extent than jet milled SBS (crystalline and acicular) that charged negatively and to a lower extent. D-mannitol charged positively and to a higher extent than the APIs. All drug-excipient blends charged negatively and differences were found between the spray-dried and jet milled SBS blends at 2% and 5% drug loads. CONCLUSIONS It was demonstrated how distinct solid-states, particle shape, size and morphology as well as different water contents of the different materials can affect tribo-charging. For their binary blends, the amount and nature of fines seem to govern inter-particle contacts critically impacting charge evolution.
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Affiliation(s)
- S Zellnitz
- Research Center Pharmaceutical Engineering GmbH, 8010, Graz, Austria
| | - J T Pinto
- Research Center Pharmaceutical Engineering GmbH, 8010, Graz, Austria
| | - M Brunsteiner
- Research Center Pharmaceutical Engineering GmbH, 8010, Graz, Austria
| | - H Schroettner
- Austrian Centre for Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010, Graz, Austria
| | - J Khinast
- Research Center Pharmaceutical Engineering GmbH, 8010, Graz, Austria
- Institute of Process and Particle Engineering, Graz University of Technology, 8010, Graz, Austria
| | - A Paudel
- Research Center Pharmaceutical Engineering GmbH, 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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Gressl C, Brunsteiner M, Davis A, Landis M, Pencheva K, Scrivens G, Sluggett GW, Wood GPF, Gruber-Woelfler H, Khinast JG, Paudel A. Drug–Excipient Interactions in the Solid State: The Role of Different Stress Factors. Mol Pharm 2017; 14:4560-4571. [DOI: 10.1021/acs.molpharmaceut.7b00677] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Corinna Gressl
- Research Center Pharmaceutical Engineering, 8010 Graz, Austria
| | | | | | - Margaret Landis
- Pfizer Worldwide R&D, Groton, Connecticut 06340, United States
| | | | | | | | | | - Heidrun Gruber-Woelfler
- Research Center Pharmaceutical Engineering, 8010 Graz, Austria
- Institute
of Process and Particle Engineering, University of Technology, 8010 Graz, Austria
| | - Johannes G. Khinast
- Research Center Pharmaceutical Engineering, 8010 Graz, Austria
- Institute
of Process and Particle Engineering, University of Technology, 8010 Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering, 8010 Graz, Austria
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11
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Feenstra P, Gruber-Wölfler H, Brunsteiner M, Khinast J. Retention-time prediction for polycyclic aromatic compounds in reversed-phase capillary electro-chromatography. J Mol Model 2015; 21:124. [DOI: 10.1007/s00894-015-2668-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/31/2015] [Indexed: 11/28/2022]
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12
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Feenstra P, Brunsteiner M, Khinast J. Investigation of Migrant–Polymer Interaction in Pharmaceutical Packaging Material Using the Linear Interaction Energy Algorithm. J Pharm Sci 2014; 103:3197-204. [DOI: 10.1002/jps.24115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/05/2014] [Accepted: 07/10/2014] [Indexed: 12/29/2022]
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13
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Abdelkarim H, Brunsteiner M, Neelarapu R, Bai H, Madriaga A, van Breemen RB, Blond SY, Gaponenko V, Petukhov PA. Photoreactive "nanorulers" detect a novel conformation of full length HDAC3-SMRT complex in solution. ACS Chem Biol 2013; 8:2538-49. [PMID: 24010878 DOI: 10.1021/cb400601g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Histone deacetylase 3 (HDAC3) is a promising epigenetic drug target for multiple therapeutic applications. Direct interaction between the Deacetylase Activating Domain of the silencing mediator for retinoid or thyroid-hormone receptors (SMRT-DAD) is required for activation of enzymatic activity of HDAC3. The structure of this complex and the nature of interactions with HDAC inhibitors in solution are unknown. Using novel photoreactive HDAC probes, "nanorulers", we determined the distance between the catalytic site of the full-length HDAC3 and SMRT-DAD in solution at physiologically relevant conditions and found it to be substantially different from that predicted by the X-ray model with a Δ379-428 aa truncated HDAC3. Further experiments indicated that in solution this distance might change in response to chemical stimuli, while the enzymatic activity remained unaffected. These observations were further validated by Saturation Transfer Difference (STD) NMR experiments. We propose that the observed changes in the distance are an important part of the histone code that remains to be explored. Mapping direct interactions and distances between macromolecules with such "nanorulers" as a function of cellular events facilitates better understanding of basic biology and ways for its manipulation in a cell- and tissue-specific manner.
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Affiliation(s)
- Hazem Abdelkarim
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
| | - Michael Brunsteiner
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
| | - Raghupathi Neelarapu
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
| | - He Bai
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
| | - Antonett Madriaga
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
| | - Richard B. van Breemen
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
| | | | | | - Pavel A. Petukhov
- Department
of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, United States
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14
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Schiefer IT, Tapadar S, Litosh V, Siklos M, Scism R, Wijewickrama GT, Chandrasena EP, Sinha V, Tavassoli E, Brunsteiner M, Fa' M, Arancio O, Petukhov P, Thatcher GRJ. Design, synthesis, and optimization of novel epoxide incorporating peptidomimetics as selective calpain inhibitors. J Med Chem 2013; 56:6054-68. [PMID: 23834438 DOI: 10.1021/jm4006719] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hyperactivation of the calcium-dependent cysteine protease calpain 1 (Cal1) is implicated as a primary or secondary pathological event in a wide range of illnesses and in neurodegenerative states, including Alzheimer's disease (AD). E-64 is an epoxide-containing natural product identified as a potent nonselective, calpain inhibitor, with demonstrated efficacy in animal models of AD. By use of E-64 as a lead, three successive generations of calpain inhibitors were developed using computationally assisted design to increase selectivity for Cal1. First generation analogues were potent inhibitors, effecting covalent modification of recombinant Cal1 catalytic domain (Cal1cat), demonstrated using LC-MS/MS. Refinement yielded second generation inhibitors with improved selectivity. Further library expansion and ligand refinement gave three Cal1 inhibitors, one of which was designed as an activity-based protein profiling probe. These were determined to be irreversible and selective inhibitors by kinetics studies comparing full length Cal1 with the general cysteine protease papain.
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Affiliation(s)
- Isaac T Schiefer
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL 60612-7231, USA
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15
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Brunsteiner M, Flock M, Nidetzky B. Structure based descriptors for the estimation of colloidal interactions and protein aggregation propensities. PLoS One 2013; 8:e59797. [PMID: 23565169 PMCID: PMC3614552 DOI: 10.1371/journal.pone.0059797] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 02/19/2013] [Indexed: 11/19/2022] Open
Abstract
The control of protein aggregation is an important requirement in the development of bio-pharmaceutical formulations. Here a simple protein model is proposed that was used in molecular dynamics simulations to obtain a quantitative assessment of the relative contributions of proteins' net-charges, dipole-moments, and the size of hydrophobic or charged surface patches to their colloidal interactions. The results demonstrate that the strength of these interactions correlate with net-charge and dipole moment. Variation of both these descriptors within ranges typical for globular proteins have a comparable effect. By comparison no clear trends can be observed upon varying the size of hydrophobic or charged patches while keeping the other parameters constant. The results are discussed in the context of experimental literature data on protein aggregation. They provide a clear guide line for the development of improved algorithms for the prediction of aggregation propensities.
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Affiliation(s)
- Michael Brunsteiner
- Research Center Pharmaceutical Engineering, Graz, Austria
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria
| | - Michaela Flock
- Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria
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Eixelsberger T, Sykora S, Egger S, Brunsteiner M, Kavanagh KL, Oppermann U, Brecker L, Nidetzky B. Structure and mechanism of human UDP-xylose synthase: evidence for a promoting role of sugar ring distortion in a three-step catalytic conversion of UDP-glucuronic acid. J Biol Chem 2012; 287:31349-58. [PMID: 22810237 PMCID: PMC3438964 DOI: 10.1074/jbc.m112.386706] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
UDP-xylose synthase (UXS) catalyzes decarboxylation of UDP-d-glucuronic acid to UDP-xylose. In mammals, UDP-xylose serves to initiate glycosaminoglycan synthesis on the protein core of extracellular matrix proteoglycans. Lack of UXS activity leads to a defective extracellular matrix, resulting in strong interference with cell signaling pathways. We present comprehensive structural and mechanistic characterization of the human form of UXS. The 1.26-Å crystal structure of the enzyme bound with NAD+ and UDP reveals a homodimeric short-chain dehydrogenase/reductase (SDR), belonging to the NDP-sugar epimerases/dehydratases subclass. We show that enzymatic reaction proceeds in three chemical steps via UDP-4-keto-d-glucuronic acid and UDP-4-keto-pentose intermediates. Molecular dynamics simulations reveal that the d-glucuronyl ring accommodated by UXS features a marked 4C1chair to BO,3boat distortion that facilitates catalysis in two different ways. It promotes oxidation at C4 (step 1) by aligning the enzymatic base Tyr147 with the reactive substrate hydroxyl and it brings the carboxylate group at C5 into an almost fully axial position, ideal for decarboxylation of UDP-4-keto-d-glucuronic acid in the second chemical step. The protonated side chain of Tyr147 stabilizes the enolate of decarboxylated C4 keto species (2H1half-chair) that is then protonated from the Si face at C5, involving water coordinated by Glu120. Arg277, which is positioned by a salt-link interaction with Glu120, closes up the catalytic site and prevents release of the UDP-4-keto-pentose and NADH intermediates. Hydrogenation of the C4 keto group by NADH, assisted by Tyr147 as catalytic proton donor, yields UDP-xylose adopting the relaxed 4C1chair conformation (step 3).
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Affiliation(s)
- Thomas Eixelsberger
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria
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17
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Feenstra P, Brunsteiner M, Khinast J. Prediction of drug-packaging interactions via molecular dynamics (MD) simulations. Int J Pharm 2012; 431:26-32. [PMID: 22521710 DOI: 10.1016/j.ijpharm.2012.03.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/16/2012] [Accepted: 03/26/2012] [Indexed: 11/15/2022]
Abstract
The interaction between packaging materials and drug products is an important issue for the pharmaceutical industry, since during manufacturing, processing and storage a drug product is continuously exposed to various packaging materials. The experimental investigation of a great variety of different packaging material-drug product combinations in terms of efficacy and safety can be a costly and time-consuming task. In our work we used molecular dynamics (MD) simulations in order to evaluate the applicability of such methods to pre-screening of the packaging material-solute compatibility. The solvation free energy and the free energy of adsorption of diverse solute/solvent/solid systems were estimated. The results of our simulations agree with experimental values previously published in the literature, which indicates that the methods in question can be used to semi-quantitatively reproduce the solid-liquid interactions of the investigated systems.
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Affiliation(s)
- Peter Feenstra
- Institute for Process and Particle Engineering, Graz University of Technology, Graz, Austria
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18
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Klimacek M, Brunsteiner M, Nidetzky B. Dynamic mechanism of proton transfer in mannitol 2-dehydrogenase from Pseudomonas fluorescens: mobile GLU292 controls proton relay through a water channel that connects the active site with bulk solvent. J Biol Chem 2011; 287:6655-67. [PMID: 22194597 PMCID: PMC3307286 DOI: 10.1074/jbc.m111.289223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The active site of mannitol 2-dehydrogenase from Pseudomonas fluorescens (PfM2DH) is connected with bulk solvent through a narrow protein channel that shows structural resemblance to proton channels utilized by redox-driven proton pumps. A key element of the PfM2DH channel is the "mobile" Glu(292), which was seen crystallographically to adopt distinct positions up and down the channel. It was suggested that the "down → up" conformational change of Glu(292) could play a proton relay function in enzymatic catalysis, through direct proton shuttling by the Glu or because the channel is opened for water molecules forming a chain along which the protons flow. We report evidence from site-directed mutagenesis (Glu(292) → Ala) substantiated by data from molecular dynamics simulations that support a role for Glu(292) as a gate in a water chain (von Grotthuss-type) mechanism of proton translocation. Occupancy of the up and down position of Glu(292) is influenced by the bonding and charge state of the catalytic acid base Lys(295), suggesting that channel opening/closing motions of the Glu are synchronized to the reaction progress. Removal of gatekeeper control in the E292A mutant resulted in a selective, up to 120-fold slowing down of microscopic steps immediately preceding catalytic oxidation of mannitol, consistent with the notion that formation of the productive enzyme-NAD(+)-mannitol complex is promoted by a corresponding position change of Glu(292), which at physiological pH is associated with obligatory deprotonation of Lys(295) to solvent. These results underscore the important role of conformational dynamics in the proton transfer steps of alcohol dehydrogenase catalysis.
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Affiliation(s)
- Mario Klimacek
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria
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Neelarapu R, Holzle DL, Velaparthi S, Bai H, Brunsteiner M, Blond SY, Petukhov PA. Design, synthesis, docking, and biological evaluation of novel diazide-containing isoxazole- and pyrazole-based histone deacetylase probes. J Med Chem 2011; 54:4350-64. [PMID: 21548582 DOI: 10.1021/jm2001025] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The design, synthesis, docking, and biological evaluation of novel potent HDAC3 and HDAC8 isoxazole- and pyrazole-based diazide probes suitable for binding ensemble profiling with photoaffinity labeling (BEProFL) experiments in cells is described. Both the isoxazole- and pyrazole-based probes exhibit low nanomolar inhibitory activity against HDAC3 and HDAC8, respectively. The pyrazole-based probe 3f appears to be one of the most active HDAC8 inhibitors reported in the literature with an IC(50) of 17 nM. Our docking studies suggest that unlike the isoxazole-based ligands the pyrazole-based ligands are flexible enough to occupy the second binding site of HDAC8. Probes/inhibitors 2b, 3a, 3c, and 3f exerted the antiproliferative and neuroprotective activities at micromolar concentrations through inhibition of nuclear HDACs, indicating that they are cell permeable and the presence of an azide or a diazide group does not interfere with the neuroprotection properties, or enhance cellular cytotoxicity, or affect cell permeability.
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Affiliation(s)
- Raghupathi Neelarapu
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
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He B, Velaparthi S, Pieffet G, Pennington C, Mahesh A, Holzle DL, Brunsteiner M, van Breemen R, Blond SY, Petukhov PA. Binding ensemble profiling with photoaffinity labeling (BEProFL) approach: mapping the binding poses of HDAC8 inhibitors. J Med Chem 2009; 52:7003-13. [PMID: 19886628 DOI: 10.1021/jm9005077] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A binding ensemble profiling with (f)photoaffinity labeling (BEProFL) approach that utilizes photolabeling of HDAC8 with a probe containing a UV-activated aromatic azide, mapping of the covalent modifications by liquid chromatography-tandem mass spectrometry, and a computational method to characterize the multiple binding poses of the probe is described. By use of the BEProFL approach, two distinct binding poses of the HDAC8 probe were identified. The data also suggest that an "upside-down" pose with the surface binding group of the probe bound in an alternative pocket near the catalytic site may contribute to the binding.
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Affiliation(s)
- Bai He
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, USA
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21
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Velaparthi S, Brunsteiner M, Uddin R, Wan B, Franzblau SG, Petukhov PA. 5-tert-butyl-N-pyrazol-4-yl-4,5,6,7-tetrahydrobenzo[d]isoxazole-3-carboxamide derivatives as novel potent inhibitors of Mycobacterium tuberculosis pantothenate synthetase: initiating a quest for new antitubercular drugs. J Med Chem 2008; 51:1999-2002. [PMID: 18335974 DOI: 10.1021/jm701372r] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pantothenate synthetase (PS) is one of the potential new antimicrobial targets that may also be useful for the treatment of the nonreplicating persistent forms of Mycobacterium tuberculosis. In this Letter we present a series of 5- tert-butyl- N-pyrazol-4-yl-4,5,6,7-tetrahydrobenzo[ d]isoxazole-3-carboxamide derivatives as novel potent Mycobacterium tuberculosis PS inhibitors, their in silico molecular design, synthesis, and inhibitory activity.
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Affiliation(s)
- Subash Velaparthi
- Department of Medicinal Chemistry and Pharmacognosy and Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL 60612, USA
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Affiliation(s)
- Michael Brunsteiner
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Sarah L. Price
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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Brunsteiner M, Boresch S. Influence of the treatment of electrostatic interactions on the results of free energy calculations of dipolar systems. J Chem Phys 2000. [DOI: 10.1063/1.481290] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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