1
|
Harwacki J, Pisklak DM, Szeleszczuk L. Solid state 13C NMR spectroscopy as a tool for identification of counterfeit Viagra tablets and guide for develop new identification approach of falsified product. Int J Pharm 2023; 636:122837. [PMID: 36921742 DOI: 10.1016/j.ijpharm.2023.122837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 03/16/2023]
Abstract
Counterfeit drugs are a global problem that is directly related to the safety and effectiveness of pharmacotherapy. The black market for counterfeit products is constantly growing and related to the wide availability through online shopping. Therefore, there is a constant need to develop analytical methods that would allow for the unambiguous identification of counterfeit products from the original ones. One of such techniques is solid-state NMR spectroscopy, which allows for direct registration and analysis of spectra of multicomponent solid forms of pharmaceutical formulations. The paper explores the possibility of using this technique in the identification of counterfeit Viagra tablets. In this study, solid-state NMR has been used to detect the non-pharmacopoeial cellulose present in the samples of counterfeit Viagra tablets. Besides, the NMR results allowed to develop a rapid dying technique that can be used to distinguish between the counterfeit and original drug. It has been shown that solid-state NMR spectroscopy allows for numerous analyses such as identification of counterfeit products, assessment of the composition of analyte, estimation of qualitative differences between the original and falsified product, and the development of simple analytical methods based on tablets composition differences.
Collapse
Affiliation(s)
- Jakub Harwacki
- Medical University of Warsaw, Faculty of Pharmacy, Department of Organic and Physical Chemistry, Stefana Banacha 1, 02-097 Warsaw, Poland.
| | - Dariusz Maciej Pisklak
- Medical University of Warsaw, Faculty of Pharmacy, Department of Organic and Physical Chemistry, Stefana Banacha 1, 02-097 Warsaw, Poland.
| | - Lukasz Szeleszczuk
- Medical University of Warsaw, Faculty of Pharmacy, Department of Organic and Physical Chemistry, Stefana Banacha 1, 02-097 Warsaw, Poland.
| |
Collapse
|
2
|
Holmes ST, Vojvodin CS, Veinberg N, Iacobelli EM, Hirsh DA, Schurko RW. Hydrates of active pharmaceutical ingredients: A 35Cl and 2H solid-state NMR and DFT study. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 122:101837. [PMID: 36434925 DOI: 10.1016/j.ssnmr.2022.101837] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/19/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
This study uses 35Cl and 2H solid-state NMR (SSNMR) spectroscopy and dispersion-corrected plane-wave density functional theory (DFT) calculations to characterize the molecular-level structures and dynamics of hydrates of active pharmaceutical ingredients (APIs). We use 35Cl SSNMR to measure the EFG tensors of the chloride ions to characterize hydrated forms of hydrochloride salts of APIs, along with two corresponding anhydrous forms. DFT calculations are used to refine the crystal structures of the APIs and determine relationships between the 35Cl EFG tensors and the spatial arrangements of proximate hydrogen bonds, which are particularly influenced by interactions with water molecules. We find that the relationship between 35Cl EFG tensors and local hydrogen bonding geometries is complex, but meaningful structure/property relationships can be garnered through use of DFT calculations. Specifically, for every case in which such a comparison could be made, we find that the hydrate has a smaller magnitude of CQ than the corresponding anhydrous form, indicating a chloride ion environment with a ground-state electron density of higher spherical symmetry in the former. Finally, variable-temperature 35Cl and 2H SSNMR experiments on a deuterium-exchanged sample of the API cimetidine hydrochloride monohydrate are used to monitor temperature-dependent influences on the spectra that may arise from motional influences on the 35Cl and 2H EFG tensors. From the 2H SSNMR spectra, we determine that the motions of water molecules are characterized by jump-like motions about their C2 rotational axes that occur on timescales that are unlikely to influence the 35Cl central-transition (+1/2 ↔︎ -1/2) powder patterns (this is confirmed by 35Cl SSNMR). Together, these methods show great promise for the future study of APIs in their bulk and dosage forms, especially variable hydrates in which crystallographic water content varies with external conditions such as humidity.
Collapse
Affiliation(s)
- Sean T Holmes
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, 32306, USA; National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Cameron S Vojvodin
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, 32306, USA; National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Natan Veinberg
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, ON, N9B 3P4, USA
| | - Emilia M Iacobelli
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, ON, N9B 3P4, USA
| | - David A Hirsh
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, ON, N9B 3P4, USA
| | - Robert W Schurko
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, 32306, USA; National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA.
| |
Collapse
|
3
|
Al-Ani A, Szell PMJ, Rehman Z, Blade H, Wheatcroft HP, Hughes LP, Brown SP, Wilson CC. Combining X-ray and NMR Crystallography to Explore the Crystallographic Disorder in Salbutamol Oxalate. CRYSTAL GROWTH & DESIGN 2022; 22:4696-4707. [PMID: 35971412 PMCID: PMC9374327 DOI: 10.1021/acs.cgd.1c01093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Salbutamol is an active pharmaceutical ingredient commonly used to treat respiratory distress and is listed by the World Health Organization as an essential medicine. Here, we establish the crystal structure of its oxalate form, salbutamol oxalate, and explore the nature of its crystallographic disorder by combined X-ray crystallography and 13C cross-polarization (CP) magic-angle spinning (MAS) solid-state NMR. The *C-OH chiral center of salbutamol (note that the crystal structures are a racemic mixture of the two enantiomers of salbutamol) is disordered over two positions, and the tert-butyl group is rotating rapidly, as revealed by 13C solid-state NMR. The impact of crystallization conditions on the disorder was investigated, finding variations in the occupancy ratio of the *C-OH chiral center between single crystals and a consistency across samples in the bulk powder. Overall, this work highlights the contrast between investigating crystallographic disorder by X-ray diffraction and solid-state NMR experiment, and gauge-including projector-augmented-wave (GIPAW) density functional theory (DFT) calculations, with their combined use, yielding an improved understanding of the nature of the crystallographic disorder between the local (i.e., as viewed by NMR) and longer-range periodic (i.e., as viewed by diffraction) scale.
Collapse
Affiliation(s)
- Aneesa
J. Al-Ani
- Centre
for Sustainable and Circular Technologies (CSCT), University of Bath, Claverton Down, Bath BA2
7AY, U.K.
| | | | - Zainab Rehman
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
| | - Helen Blade
- Oral
Product Development, Pharmaceutical Technology & Development,
Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Helen P. Wheatcroft
- Chemical
Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Leslie P. Hughes
- Oral
Product Development, Pharmaceutical Technology & Development,
Operations, AstraZeneca, Macclesfield SK10 2NA, U.K.
| | - Steven P. Brown
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
| | - Chick C. Wilson
- Centre
for Sustainable and Circular Technologies (CSCT), University of Bath, Claverton Down, Bath BA2
7AY, U.K.
| |
Collapse
|
4
|
Evans CL, Evans IR, Hodgkinson P. Resolving alternative structure determinations of indapamide using 13C solid-state NMR. Chem Commun (Camb) 2022; 58:4767-4770. [PMID: 35343549 DOI: 10.1039/d1cc06256e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conflict between alternative crystal structures in the Cambridge Structural Database for the diuretic drug indapamide hemihydrate (IND) has been resolved with the aid of 13C solid-state NMR. IND is seen to contain multiple distinct molecules in the asymmetric unit (Z' = 4) rather than exhibiting disorder in the orientation of sulfonamide groups. The NMR crystallographic approach is a more effective tool for distinguishing between alternative structures than naïve judgements of quality based on crystallographic refinement agreement factors.
Collapse
Affiliation(s)
- Caitlin L Evans
- Department of Chemistry, Durham University, Stockton Road, Durham, DH1 3LE, UK.
| | | | - Paul Hodgkinson
- Department of Chemistry, Durham University, Stockton Road, Durham, DH1 3LE, UK.
| |
Collapse
|
5
|
Barbas R, Llinas A, Prohens R. The Solid State Landscape of the Sildenafil Drug. J Pharm Sci 2021; 111:1104-1109. [PMID: 34419482 DOI: 10.1016/j.xphs.2021.08.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022]
Abstract
Sildenafil, the active ingredient of the drug developed by Pfizer for the treatment of erectile dysfunction was firstly synthesized in 1989 in the United Kingdom and since then it has become one of the most prescribed drugs for sexual performance in the western world with more than 2.7 million prescriptions in the US in 2021. Since its discovery, this drug compound has attracted the interest of formulators and crystallographers, with a high number of crystal forms of sildenafil being found and characterized, including polymorphs, hydrates, solvates, salts and cocrystals, converting it in one of the most promiscuous multicomponent crystal former drugs in the pharmaceutical sciences arena. In this minireview, the polymorph, pseudopolymorph and multicomponent solid forms landscape of sildenafil is presented through a comprehensive compilation of their 42 solid forms reported in literature.
Collapse
Affiliation(s)
- Rafael Barbas
- Unitat de Polimorfisme i Calorimetria, Centres Científics i Tecnològics, Universitat de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain.
| | - Antonio Llinas
- Inhalation Product Development, Pharmaceutical Technology and Development, AstraZeneca, Gothenburg 43150, Sweden
| | - Rafel Prohens
- Unitat de Polimorfisme i Calorimetria, Centres Científics i Tecnològics, Universitat de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| |
Collapse
|
6
|
Ouranidis A, Tsiaxerli A, Vardaka E, Markopoulou CK, Zacharis CK, Nicolaou I, Hatzichristou D, Haidich AB, Kostomitsopoulos N, Kachrimanis K. Sildenafil 4.0-Integrated Synthetic Chemistry, Formulation and Analytical Strategies Effecting Immense Therapeutic and Societal Impact in the Fourth Industrial Era. Pharmaceuticals (Basel) 2021; 14:365. [PMID: 33920975 PMCID: PMC8071249 DOI: 10.3390/ph14040365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 12/14/2022] Open
Abstract
Sildenafil is a potent selective, reversible inhibitor of phosphodiesterase type 5 (PDE5) approved for the treatment of erectile dysfunction and pulmonary arterial hypertension. Whilst twenty years have passed since its original approval by the US Food and Drug Administration (USFDA), sildenafil enters the fourth industrial era catalyzing the treatment advances against erectile dysfunction and pulmonary hypertension. The plethora of detailed clinical data accumulated and the two sildenafil analogues marketed, namely tadalafil and vardenafil, signify the relevant therapeutic and commercial achievements. The pharmacokinetic and pharmacodynamic behavior of the drug appears complex, interdependent and of critical importance whereas the treatment of special population cohorts is considered. The diversity of the available formulation strategies and their compatible administration routes, extend from tablets to bolus suspensions and from per os to intravenous, respectively, inheriting the associated strengths and weaknesses. In this comprehensive review, we attempt to elucidate the multi-disciplinary elements spanning the knowledge fields of chemical synthesis, physicochemical properties, pharmacology, clinical applications, biopharmaceutical profile, formulation approaches for different routes of administration and analytical strategies, currently employed to guide the development of sildenafil-based compositions.
Collapse
Affiliation(s)
- Andreas Ouranidis
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.T.); (E.V.)
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Anastasia Tsiaxerli
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.T.); (E.V.)
| | - Elisavet Vardaka
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.T.); (E.V.)
| | - Catherine K. Markopoulou
- Laboratory of Pharmaceutical Analysis, Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.K.M.); (C.K.Z.)
| | - Constantinos K. Zacharis
- Laboratory of Pharmaceutical Analysis, Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (C.K.M.); (C.K.Z.)
| | - Ioannis Nicolaou
- Laboratory of Pharmaceutical Chemistry, Department of Pharmaceutical Chemistry, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Dimitris Hatzichristou
- Department of Urology, Medical School, Aristotle University of Thessaloniki, 54635 Thessaloniki, Greece;
| | - Anna-Bettina Haidich
- Department of Hygiene, Social-Preventive Medicine and Medical Statistics, Medical School, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Nikolaos Kostomitsopoulos
- Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece;
| | - Kyriakos Kachrimanis
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (A.T.); (E.V.)
| |
Collapse
|
7
|
Jurczak E, Mazurek AH, Szeleszczuk Ł, Pisklak DM, Zielińska-Pisklak M. Pharmaceutical Hydrates Analysis-Overview of Methods and Recent Advances. Pharmaceutics 2020; 12:pharmaceutics12100959. [PMID: 33050621 PMCID: PMC7601571 DOI: 10.3390/pharmaceutics12100959] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/26/2020] [Accepted: 10/07/2020] [Indexed: 11/16/2022] Open
Abstract
This review discusses a set of instrumental and computational methods that are used to characterize hydrated forms of APIs (active pharmaceutical ingredients). The focus has been put on highlighting advantages as well as on presenting some limitations of the selected analytical approaches. This has been performed in order to facilitate the choice of an appropriate method depending on the type of the structural feature that is to be analyzed, that is, degree of hydration, crystal structure and dynamics, and (de)hydration kinetics. The presented techniques include X-ray diffraction (single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD)), spectroscopic (solid state nuclear magnetic resonance spectroscopy (ssNMR), Fourier-transformed infrared spectroscopy (FT-IR), Raman spectroscopy), thermal (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)), gravimetric (dynamic vapour sorption (DVS)), and computational (molecular mechanics (MM), Quantum Mechanics (QM), molecular dynamics (MD)) methods. Further, the successful applications of the presented methods in the studies of hydrated APIs as well as studies on the excipients' influence on these processes have been described in many examples.
Collapse
Affiliation(s)
- Ewa Jurczak
- Department of Physical Chemistry, Chair and Department of Physical Pharmacy and Bioanalysis, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 str., 02-093 Warsaw, Poland; (E.J.); (A.H.M.); (D.M.P.)
| | - Anna Helena Mazurek
- Department of Physical Chemistry, Chair and Department of Physical Pharmacy and Bioanalysis, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 str., 02-093 Warsaw, Poland; (E.J.); (A.H.M.); (D.M.P.)
| | - Łukasz Szeleszczuk
- Department of Physical Chemistry, Chair and Department of Physical Pharmacy and Bioanalysis, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 str., 02-093 Warsaw, Poland; (E.J.); (A.H.M.); (D.M.P.)
- Correspondence: ; Tel.: +48-501-255-121
| | - Dariusz Maciej Pisklak
- Department of Physical Chemistry, Chair and Department of Physical Pharmacy and Bioanalysis, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 str., 02-093 Warsaw, Poland; (E.J.); (A.H.M.); (D.M.P.)
| | - Monika Zielińska-Pisklak
- Department of Biomaterials Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1 str., 02-093 Warsaw, Poland;
| |
Collapse
|
8
|
Hodgkinson P. NMR crystallography of molecular organics. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 118-119:10-53. [PMID: 32883448 DOI: 10.1016/j.pnmrs.2020.03.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/25/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
Developments of NMR methodology to characterise the structures of molecular organic structures are reviewed, concentrating on the previous decade of research in which density functional theory-based calculations of NMR parameters in periodic solids have become widespread. With a focus on demonstrating the new structural insights provided, it is shown how "NMR crystallography" has been used in a spectrum of applications from resolving ambiguities in diffraction-derived structures (such as hydrogen atom positioning) to deriving complete structures in the absence of diffraction data. As well as comprehensively reviewing applications, the different aspects of the experimental and computational techniques used in NMR crystallography are surveyed. NMR crystallography is seen to be a rapidly maturing subject area that is increasingly appreciated by the wider crystallographic community.
Collapse
Affiliation(s)
- Paul Hodgkinson
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, UK.
| |
Collapse
|
9
|
Dudek MK, Wielgus E, Paluch P, Śniechowska J, Kostrzewa M, Day GM, Bujacz GD, Potrzebowski MJ. Understanding the formation of apremilast cocrystals. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2019; 75:803-814. [PMID: 32830759 DOI: 10.1107/s205252061900917x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 06/26/2019] [Indexed: 06/11/2023]
Abstract
Apremilast (APR), an anti-psoriatic agent, easily forms isostructural cocrystals and solvates with aromatic entities, often disobeying at the same time Kitaigorodsky's rule as to the saturation of possible hydrogen-bonding sites. In this paper the reasons for this peculiar behavior are investigated, employing a joint experimental and theoretical approach. This includes the design of cocrystals with coformers having a high propensity towards the formation of both aromatic-aromatic and hydrogen-bonding interactions, determination of their structure, using solid-state NMR spectroscopy and X-ray crystallography, as well as calculations of stabilization energies of formation of the obtained cocrystals, followed by crystal structure prediction calculations and solubility measurements. The findings indicate that the stabilization energies of cocrystal formation are positive in all cases, which results from strain in the APR conformation in these crystal forms. On the other hand, solubility measurements show that the Gibbs free energy of formation of the apremilast:picolinamide cocrystal is negative, suggesting that the formation of the studied cocrystals is entropy driven. This entropic stabilization is associated with the disorder observed in almost all known cocrystals and solvates of APR.
Collapse
Affiliation(s)
- Marta K Dudek
- Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, 90363, Poland
| | - Ewelina Wielgus
- Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, 90363, Poland
| | - Piotr Paluch
- Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, 90363, Poland
| | - Justyna Śniechowska
- Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, 90363, Poland
| | - Maciej Kostrzewa
- Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, 90363, Poland
| | - Graeme M Day
- Computational Systems Chemistry, School of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Grzegorz D Bujacz
- Institute of Technical Biochemistry, Technical University of Lodz, Stefanowskiego 4/10, Lodz, 90-924, Poland
| | - Marek J Potrzebowski
- Centre of Molecular and Macromolecular Studies PAS, Sienkiewicza 112, Lodz, 90363, Poland
| |
Collapse
|
10
|
Liu S, Li J, Bennett KC, Ganoe B, Stauch T, Head-Gordon M, Hexemer A, Ushizima D, Head-Gordon T. Multiresolution 3D-DenseNet for Chemical Shift Prediction in NMR Crystallography. J Phys Chem Lett 2019; 10:4558-4565. [PMID: 31305081 PMCID: PMC6922005 DOI: 10.1021/acs.jpclett.9b01570] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have developed a deep learning algorithm for chemical shift prediction for atoms in molecular crystals that utilizes an atom-centered Gaussian density model for the 3D data representation of a molecule. We define multiple channels that describe different spatial resolutions for each atom type that utilizes cropping, pooling, and concatenation to create a multiresolution 3D-DenseNet architecture (MR-3D-DenseNet). Because the training and testing time scale linearly with the number of samples, the MR-3D-DenseNet can exploit data augmentation that takes into account the property of rotational invariance of the chemical shifts, thereby also increasing the size of the training data set by an order of magnitude without additional cost. We obtain very good agreement for 13C, 15N, and 17O chemical shifts when compared to ab initio quantum chemistry methods, with the highest accuracy found for 1H chemical shifts that is comparable to the error between the ab initio results and experimental measurements. Principal component analysis (PCA) is used to both understand these greatly improved predictions for 1H , as well as indicating that chemical shift prediction for 13C, 15N, and 17O, which have far fewer training environments than the 1H atom type, will improve once more unique training samples are made available to exploit the deep network architecture.
Collapse
Affiliation(s)
- Shuai Liu
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Jie Li
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Kochise C Bennett
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Brad Ganoe
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Tim Stauch
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Martin Head-Gordon
- Pitzer Center for Theoretical Chemistry, Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Alexander Hexemer
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Daniela Ushizima
- Computational Research Division, Center for Advanced Mathematics for Energy Research Applications (CAMERA) , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Teresa Head-Gordon
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, Department of Bioengineering, Department of Chemical and Biomolecular Engineering , University of California , Berkeley , California 94720 , United States
| |
Collapse
|
11
|
Venâncio T, Oliveira LM, Pawlak T, Ellena J, Boechat N, Brown SP. The use of variable temperature 13 C solid-state MAS NMR and GIPAW DFT calculations to explore the dynamics of diethylcarbamazine citrate. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:200-210. [PMID: 30114322 DOI: 10.1002/mrc.4790] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 07/25/2018] [Accepted: 08/06/2018] [Indexed: 06/08/2023]
Abstract
Experimental 13 C solid-state magic-angle spinning (MAS) Nuclear Magnetic Resonance (NMR) as well as Density-Functional Theory (DFT) gauge-including projector augmented wave (GIPAW) calculations were used to probe disorder and local mobility in diethylcarbamazine citrate, (DEC)+ (citrate)- . This compound has been used as the first option drug for the treatment of filariasis, a disease endemic in tropical countries and caused by adult worms of Wuchereria bancrofti, which is transmitted by mosquitoes. We firstly present 2D 13 C─1 H dipolar-coupling-mediated heteronuclear correlation spectra recorded at moderate spinning frequency, to explore the intermolecular interaction between DEC and citrate molecules. Secondly, we investigate the dynamic behavior of (DEC)+ (citrate)- by varying the temperature and correlating the experimental MAS NMR results with DFT GIPAW calculations that consider two (DEC)+ conformers (in a 70:30 ratio) for crystal structures determined at 293 and 235 K. Solid-state NMR provides insights on slow exchange dynamics revealing conformational changes involving particularly the DEC ethyl groups.
Collapse
Affiliation(s)
- Tiago Venâncio
- Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP, Brazil
- Department of Physics, University of Warwick, Coventry, UK
| | | | - Tomasz Pawlak
- Department of Physics, University of Warwick, Coventry, UK
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Łodz, Poland
| | - Javier Ellena
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Nubia Boechat
- Fundação Oswaldo Cruz-FioCruz, Instituto de Tecnologia em Fármacos-FarManguinhos, Rio de Janeiro, RJ, Brazil
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry, UK
| |
Collapse
|
12
|
Ashbrook SE, Hodgkinson P. Perspective: Current advances in solid-state NMR spectroscopy. J Chem Phys 2018; 149:040901. [PMID: 30068173 DOI: 10.1063/1.5038547] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In contrast to the rapid and revolutionary impact of solution-state Nuclear Magnetic Resonance (NMR) on modern chemistry, the field of solid-state NMR has matured more slowly. This reflects the major technical challenges of much reduced spectral resolution and sensitivity in solid-state as compared to solution-state spectra, as well as the relative complexity of the solid state. In this perspective, we outline the technique developments that have pushed resolution to intrinsic limits and the approaches, including ongoing major developments in the field of Dynamic Nuclear Polarisation, that have enhanced spectral sensitivity. The information on local structure and dynamics that can be obtained using these gains in sensitivity and resolution is illustrated with a diverse range of examples from large biomolecules to energy materials and pharmaceuticals and from both ordered and highly disordered materials. We discuss how parallel developments in quantum chemical calculation, particularly density functional theory, have enabled experimental data to be translated directly into information on local structure and dynamics, giving rise to the developing field of "NMR crystallography."
Collapse
Affiliation(s)
- Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Paul Hodgkinson
- Department of Chemistry, Durham University, Durham DH1 4RD, United Kingdom
| |
Collapse
|
13
|
Zhao L, Pinon AC, Emsley L, Rossini AJ. DNP-enhanced solid-state NMR spectroscopy of active pharmaceutical ingredients. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:583-609. [PMID: 29193278 DOI: 10.1002/mrc.4688] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/15/2017] [Accepted: 11/19/2017] [Indexed: 06/07/2023]
Abstract
Solid-state NMR spectroscopy has become a valuable tool for the characterization of both pure and formulated active pharmaceutical ingredients (APIs). However, NMR generally suffers from poor sensitivity that often restricts NMR experiments to nuclei with favorable properties, concentrated samples, and acquisition of one-dimensional (1D) NMR spectra. Here, we review how dynamic nuclear polarization (DNP) can be applied to routinely enhance the sensitivity of solid-state NMR experiments by one to two orders of magnitude for both pure and formulated APIs. Sample preparation protocols for relayed DNP experiments and experiments on directly doped APIs are detailed. Numerical spin diffusion models illustrate the dependence of relayed DNP enhancements on the relaxation properties and particle size of the solids and can be used for particle size determination when the other factors are known. We then describe the advanced solid-state NMR experiments that have been enabled by DNP and how they provide unique insight into the molecular and macroscopic structure of APIs. For example, with large sensitivity gains provided by DNP, natural isotopic abundance, 13 C-13 C double-quantum single-quantum homonuclear correlation NMR spectra of pure APIs can be routinely acquired. DNP also enables solid-state NMR experiments with unreceptive quadrupolar nuclei such as 2 H, 14 N, and 35 Cl that are commonly found in APIs. Applications of DNP-enhanced solid-state NMR spectroscopy for the molecular level characterization of low API load formulations such as commercial tablets and amorphous solid dispersions are described. Future perspectives for DNP-enhanced solid-state NMR experiments on APIs are briefly discussed.
Collapse
Affiliation(s)
- Li Zhao
- Department of Chemistry, Iowa State University, Ames, IA, USA
- US DOE Ames Laboratory, Ames, IA, USA
| | - Arthur C Pinon
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Aaron J Rossini
- Department of Chemistry, Iowa State University, Ames, IA, USA
- US DOE Ames Laboratory, Ames, IA, USA
| |
Collapse
|
14
|
Assessing the Detection Limit of a Minority Solid-State Form of a Pharmaceutical by 1H Double-Quantum Magic-Angle Spinning Nuclear Magnetic Resonance Spectroscopy. J Pharm Sci 2017; 106:3372-3377. [DOI: 10.1016/j.xphs.2017.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/05/2017] [Accepted: 07/18/2017] [Indexed: 01/20/2023]
|
15
|
Bryce DL. NMR crystallography: structure and properties of materials from solid-state nuclear magnetic resonance observables. IUCRJ 2017; 4:350-359. [PMID: 28875022 PMCID: PMC5571798 DOI: 10.1107/s2052252517006042] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/21/2017] [Indexed: 05/20/2023]
Abstract
This topical review provides a brief overview of recent developments in NMR crystallography and related NMR approaches to studying the properties of molecular and ionic solids. Areas of complementarity with diffraction-based methods are underscored. These include the study of disordered systems, of dynamic systems, and other selected examples where NMR can provide unique insights. Highlights from the literature as well as recent work from my own group are discussed.
Collapse
Affiliation(s)
- David L. Bryce
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada
| |
Collapse
|
16
|
Pöppler AC, Walker D, Brown SP. A combined NMR crystallographic and PXRD investigation of the structure-directing role of water molecules in orotic acid and its lithium and magnesium salts. CrystEngComm 2017. [DOI: 10.1039/c6ce02101h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
17
|
Dudek MK, Bujacz G, Potrzebowski MJ. Experimental tests for quality validation of computationally predicted crystal structures – a case of a conformationally flexible procyanidin A-2 dihydrate. CrystEngComm 2017. [DOI: 10.1039/c7ce00618g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
18
|
Dittrich B, Luger P. Invariom-based comparative electron density studies of iso-sildenafil and sildenafil. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2016. [DOI: 10.1515/znb-2016-0178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The title compounds have raised considerable medical and broad public interest in that sildenafil is used as an agent against male erectile dysfunction; iso-sildenafil is not in clinical use. A comparison of their structural and electronic properties therefore seems of interest. The electron densities of iso-sildenafil and the cationic and neutral forms of sildenafil were examined by the application of the invariom formalism relying on diffraction data reported in the literature. The electron-density distributions obtained were subjected to topological analysis using the quantum theory of atoms in molecules (QTAIM) formalism to yield bond topological and atomic properties. Moreover, molecular Hirshfeld surfaces and electrostatic potentials (ESPs) were calculated. A number of structural and electronic differences were thus identified between sildenafil and the iso-analog. In both sildenafil structures, the phenyl ring and the pyrazolopyrimidine fragment are practically coplanar (planar conformation), whereas in the iso-analog they exhibit an angle of 44° (inclined form). Related to differences in molecular structure are completely different hydrogen bonding patterns and differences in the ESPs, the latter ones being influenced by different methylation at the pyrazolopyrimidine fragment. Iso-sildenafil is present as a hydrogen-bond dimer in the crystal, and the ESP of this dimer is dominated by a surrounding positive potential.
Collapse
Affiliation(s)
- Birger Dittrich
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Peter Luger
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 36a, D-14195 Berlin, Germany
| |
Collapse
|
19
|
Kerr HE, Mason HE, Sparkes HA, Hodgkinson P. Testing the limits of NMR crystallography: the case of caffeine–citric acid hydrate. CrystEngComm 2016. [DOI: 10.1039/c6ce01453d] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The effects of geometry optimisation on the ability to predict linewidths due to disorder and crystal packing energies is investigated on a previously unreported caffeine citric acid cocrystal system.
Collapse
Affiliation(s)
- Hannah E. Kerr
- Department of Chemistry
- Durham University
- Durham DH1 3LE, UK
| | - Helen E. Mason
- Department of Chemistry
- Durham University
- Durham DH1 3LE, UK
| | | | | |
Collapse
|
20
|
Dudek MK, Jeziorna A, Potrzebowski MJ. Computational and experimental study of reversible hydration/dehydration processes in molecular crystals of natural products – a case of catechin. CrystEngComm 2016. [DOI: 10.1039/c6ce00932h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|