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Susrisweta B, Veselý L, Štůsek R, Hauptmann A, Loerting T, Heger D. Investigating freezing-induced acidity changes in citrate buffers. Int J Pharm 2023; 643:123211. [PMID: 37422143 DOI: 10.1016/j.ijpharm.2023.123211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/10/2023]
Abstract
Citrate buffers are commonly utilized in the field of biomolecule stabilization. We investigate their applicability in the frozen state within a range of initial pHs (2.5 to 8.0) and concentrations (0.02 to 0.60 M). Citrate buffer solutions subjected to various cooling and heating temperatures are examined in terms of the freezing-induced acidity changes, revealing that citrate buffers acidify upon cooling. The acidity is assessed with sulfonephthalein molecular probes frozen in the samples. Optical cryomicroscopy combined with differential scanning calorimetry was employed to investigate the causes of the observed acidity changes. The buffers partly crystallize and partly vitrify in the ice matrix; these processes influence the resulting pH and allow designing the optimal storage temperatures in the frozen state. The freezing-induced acidification apparently depends on the buffer concentration; at each pH, we suggest pertinent concentration, at which freezing causes minimal acidification.
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Affiliation(s)
- Behera Susrisweta
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Radim Štůsek
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | | | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
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2
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Chakravarty P, Dash A, Shalaev E, Sun CC, Zhang GGZ, Thakral S. Professor Raj Suryanarayanan: Scientist, Educator, Mentor, Family Man and Giant in Pharmaceutical Research. J Pharm Sci 2023; 112:2-7. [PMID: 36332722 DOI: 10.1016/j.xphs.2022.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
This special edition of the Journal of Pharmaceutical Sciences is dedicated to Professor Raj Suryanarayanan (Professor and William & Mildred Peters Endowed Chair, University of Minnesota, School of Pharmacy) and honors his extensive and distinguished career as a scientist, educator and mentor. The goal of this commentary is to provide an overview of Professor Suryanarayanan's noteworthy career path and summarize his key research contributions. The commentary concludes with the personal summaries by guest editors.
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Affiliation(s)
- Paroma Chakravarty
- Small Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, California, 94080, USA
| | - Alekha Dash
- Department of Pharmacy Sciences, School Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178
| | - Evgenyi Shalaev
- Pharmaceutical Sciences R&D, Abbvie, 2525 DuPont Dr, Irvine, CA, USA
| | - Changquan Calvin Sun
- Pharmaceutical Materials Science and Engineering Laboratory, Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Geoff G Z Zhang
- Development Sciences, Research and Development, AbbVie Inc, North Chicago, Illinois 60064
| | - Seema Thakral
- Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, Ridgefield, Connecticut 06877, United States.
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3
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Lambros M, Tran T(H, Fei Q, Nicolaou M. Citric Acid: A Multifunctional Pharmaceutical Excipient. Pharmaceutics 2022; 14:972. [PMID: 35631557 PMCID: PMC9148065 DOI: 10.3390/pharmaceutics14050972] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/15/2022] [Accepted: 04/23/2022] [Indexed: 02/04/2023] Open
Abstract
Citric acid, a tricarboxylic acid, has found wide application in the chemical and pharmaceutical industry due to its biocompatibility, versatility, and green, environmentally friendly chemistry. This review emphasizes the pharmaceutical uses of citric acid as a strategic ingredient in drug formulation while focusing on the impact of its physicochemical properties. The functionality of citric acid is due to its three carboxylic groups and one hydroxyl group. These allow it to be used in many ways, including its ability to be used as a crosslinker to form biodegradable polymers and as a co-former in co-amorphous and co-crystal applications. This paper also analyzes the effect of citric acid in physiological processes and how this effect can be used to enhance the attributes of pharmaceutical preparations, as well as providing a critical discussion on the issues that may arise out of the presence of citric acid in formulations.
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Affiliation(s)
- Maria Lambros
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 E Second Street, Pomona, CA 91766, USA; (T.T.); (Q.F.)
| | - Thac (Henry) Tran
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 E Second Street, Pomona, CA 91766, USA; (T.T.); (Q.F.)
| | - Qinqin Fei
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 E Second Street, Pomona, CA 91766, USA; (T.T.); (Q.F.)
| | - Mike Nicolaou
- Doric Pharma LLC, 5270 California Ave, Suite 300, Irvine, CA 92617, USA;
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4
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Impact of lyoprotectors on protein-protein separation in the solid state: Neutron- and X-ray-scattering investigation. Biochim Biophys Acta Gen Subj 2022; 1866:130101. [PMID: 35151821 DOI: 10.1016/j.bbagen.2022.130101] [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: 10/29/2021] [Revised: 01/28/2022] [Accepted: 02/03/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Polyhydroxycompounds (PHC) are used as lyoprotectors to minimize aggregation of pharmaceutical proteins during freeze-drying and storage. METHODS Lysozyme/PHC mixtures with 1:1 and 1:3 (w/w) ratios are freeze-dried from either H2O or D2O solutions. Disaccharides (sucrose and trehalose), monosaccharide (glucose), and sugar alcohol (sorbitol) are used in the study. Small-angle neutron and X-ray scattering (SANS and SAXS) are applied to study protein-protein interaction in the freeze-dried samples. RESULTS Protein interaction peak in the freeze-dried mixtures has been detected by both SANS (D2O-based samples only) and SAXS (both D2O- and H2O-based). In the 1:1 mixtures, protein separation distances are similar (center-of-mass distance of approx. 31 Å) between all lyoprotectors studied. Mixtures with a higher content of the disaccharides (1:3 ratio) have a higher separation distance of approx 40 Å. The higher separation could reduce protein-protein contacts and therefore be associated with less favourable aggregation conditions. In the 1:3 mixtures with glucose and sorbitol, complex SANS and SAXS/WAXS patterns are observed. The pattern for the glucose sample indicate two populations of lysozyme molecules, while the origin of multiple SAXS peaks in the lysozyme/sorbitol 1:3 mixture is uncertain. CONCLUSIONS Protein-protein separation distance is determined predominantly by the lyoprotector/protein weight ratio. GENERAL SIGNIFICANCE Use of SANS and SAXS improves understanding of mechanisms of protein stabilization by sugars in freeze-dried formulations, and provide a tool to verify hypothesis on relationship between protein/protein separation and aggregation propensity in the dried state.
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5
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Thakral S, Sonje J, Munjal B, Suryanarayanan R. Stabilizers and their interaction with formulation components in frozen and freeze-dried protein formulations. Adv Drug Deliv Rev 2021; 173:1-19. [PMID: 33741437 DOI: 10.1016/j.addr.2021.03.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/06/2021] [Accepted: 03/03/2021] [Indexed: 02/06/2023]
Abstract
This review aims to provide an overview of the current knowledge on protein stabilization during freezing and freeze-drying in relation to stress conditions commonly encountered during these processes. The traditional as well as refined mechanisms by which excipients may stabilize proteins are presented. These stabilizers encompass a wide variety of compounds including sugars, sugar alcohols, amino acids, surfactants, buffers and polymers. The rational selection of excipients for use in frozen and freeze-dried protein formulations is presented. Lyophilized protein formulations are generally multicomponent systems, providing numerous possibilities of excipient-excipient and protein-excipient interactions. The interplay of different formulation components on the protein stability and excipient functionality in the frozen and freeze-dried systems are reviewed, with discussion of representative examples of such interactions.
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Veselý L, Susrisweta B, Heger D. Making good's buffers good for freezing: The acidity changes and their elimination via mixing with sodium phosphate. Int J Pharm 2021; 593:120128. [PMID: 33271311 DOI: 10.1016/j.ijpharm.2020.120128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 10/22/2022]
Abstract
Solutions of three Good's buffers (HEPES, MOPS, and MES), both pure and mixed with sodium phosphate buffers (Na-P), are investigated in terms of the freezing-induced acidity changes in their operational pH ranges. The Good's buffers have the tendency to basify upon freezing and, more intensively, at lower pHs. The acidity varies most prominently in MES, where the change may reach the value of two. Importantly, the Good's buffers are shown to mitigate the strong acidification in the Na-P buffer. Diverse concentrations of the Good's buffers are added to cancel out the strong, freezing-induced acidity drop in 50 mM Na-P that markedly contributes to the solution's acidity; the relevant values are 3 mM HEPES, 10 mM MOPS, and 80 mM MES. These buffer blends are therefore proposed to be applied in maintaining approximately the acidity of solutions even after the freezing process and, as such, should limit the stresses for frozen chemicals and biochemicals.
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Affiliation(s)
- Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Behera Susrisweta
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
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7
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Altaani BM, Alkhamis KA, Abu Baker S, Haddad R. The relationship between the Hammett acidity and the decomposition of cefotaxime sodium in the solid state. Drug Dev Ind Pharm 2020; 46:1632-1638. [DOI: 10.1080/03639045.2020.1813754] [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]
Affiliation(s)
- Bashar M. Altaani
- Department of Pharmaceutical Technology, Jordan University of Science and Technology, Irbid, Jordan
| | - Khouloud A. Alkhamis
- Department of Pharmaceutical Technology, Jordan University of Science and Technology, Irbid, Jordan
| | - Shaima’a Abu Baker
- Department of Pharmaceutical Technology, Jordan University of Science and Technology, Irbid, Jordan
| | - Razan Haddad
- Department of Pharmaceutical Technology, Jordan University of Science and Technology, Irbid, Jordan
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8
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Vetráková Ľ, Neděla V, Runštuk J, Tihlaříková E, Heger D, Shalaev E. Dynamical in-situ observation of the lyophilization and vacuum-drying processes of a model biopharmaceutical system by an environmental scanning electron microscope. Int J Pharm 2020; 585:119448. [PMID: 32461002 DOI: 10.1016/j.ijpharm.2020.119448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/23/2020] [Accepted: 05/18/2020] [Indexed: 01/22/2023]
Abstract
The paper discusses the real-time monitoring of the changing sample morphology during the entire lyophilization (freeze-drying) and vacuum-drying processes of model biopharmaceutical solutions by using an environmental scanning electron microscope (ESEM); the device's micromanipulators were used to study the interior of the samples in-situ without exposing the samples to atmospheric water vapor. The individual collapse temperatures (Tc) of the formulations, pure bovine serum albumin (BSA) and BSA/sucrose mixtures, ranged from -5 to -29 °C. We evaluated the impact of the freezing method (spontaneous freezing, controlled ice nucleation, and spray freezing) on the morphologies of the lyophiles at the constant drying temperature of -20 °C. The formulations with Tc above -20 °C resulted in the lyophiles' morphologies significantly dependent on the freezing method. We interpret the observations as an interplay of the freezing rates and directionalities, both of which markedly influence the morphologies of the frozen formulations, and, subsequently, the drying process and the mechanical stability of the freeze-dried cake. The formulation with Tc below -20 °C yielded a collapsed cake with features independent of the freezing method. The vacuum-drying produced a material with a smooth and pore-free surface, where deep cracks developed at the end of the process.
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Affiliation(s)
- Ľubica Vetráková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic.
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jiří Runštuk
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Evgenyi Shalaev
- Pharmaceutical Development, Allergan plc, Irvine, CA, United States.
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9
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Imrichová K, Veselý L, Gasser TM, Loerting T, Neděla V, Heger D. Vitrification and increase of basicity in between ice Ihcrystals in rapidly frozen dilute NaCl aqueous solutions. J Chem Phys 2019; 151:014503. [DOI: 10.1063/1.5100852] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Kamila Imrichová
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
- Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, 61264 Brno, Czech Republic
| | - Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Tobias M. Gasser
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Vilém Neděla
- Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, 61264 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
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10
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Shalaev E, Soper A, Zeitler JA, Ohtake S, Roberts CJ, Pikal MJ, Wu K, Boldyreva E. Freezing of Aqueous Solutions and Chemical Stability of Amorphous Pharmaceuticals: Water Clusters Hypothesis. J Pharm Sci 2018; 108:36-49. [PMID: 30055227 DOI: 10.1016/j.xphs.2018.07.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 11/24/2022]
Abstract
Molecular mobility has been traditionally invoked to explain physical and chemical stability of diverse pharmaceutical systems. Although the molecular mobility concept has been credited with creating a scientific basis for stabilization of amorphous pharmaceuticals and biopharmaceuticals, it has become increasingly clear that this approach represents only a partial description of the underlying fundamental principles. An additional mechanism is proposed herein to address 2 key questions: (1) the existence of unfrozen water (i.e., partial or complete freezing inhibition) in aqueous solutions at subzero temperatures and (2) the role of water in the chemical stability of amorphous pharmaceuticals. These apparently distant phenomena are linked via the concept of water clusters. In particular, freezing inhibition is associated with the confinement of water clusters in a solidified matrix of an amorphous solute, with nanoscaled water clusters being observed in aqueous glasses using wide-angle neutron scattering. The chemical instability is suggested to be directly related to the catalysis of proton transfer by water clusters, considering that proton transfer is the key elementary reaction in many chemical processes, including such common reactions as hydrolysis and deamidation.
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Affiliation(s)
- Evgenyi Shalaev
- Pharmaceutical Development, Allergan plc., Irvine, California 92612.
| | - Alan Soper
- ISIS Facility, UKRI-STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon OX11 OQX, UK
| | - J Axel Zeitler
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
| | - Satoshi Ohtake
- Pfizer BioTherapeutics Pharmaceutical Sciences, Chesterfield, Missouri 63198
| | | | - Michael J Pikal
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut 06269
| | - Ke Wu
- Pharmaceutical Development, Allergan plc., Irvine, California 92612
| | - Elena Boldyreva
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation; Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090, Russian Federation
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11
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Ohtake S, Feng S, Shalaev E. Effect of Water on the Chemical Stability of Amorphous Pharmaceuticals: 2. Deamidation of Peptides and Proteins. J Pharm Sci 2018; 107:42-56. [DOI: 10.1016/j.xphs.2017.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/11/2017] [Indexed: 01/14/2023]
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12
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Comparing the acidities of aqueous, frozen, and freeze-dried phosphate buffers: Is there a “pH memory” effect? Int J Pharm 2017; 530:316-325. [DOI: 10.1016/j.ijpharm.2017.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 07/25/2017] [Accepted: 08/01/2017] [Indexed: 11/20/2022]
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13
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Koranne S, Govindarajan R, Suryanarayanan R. Investigation of Spatial Heterogeneity of Salt Disproportionation in Tablets by Synchrotron X-ray Diffractometry. Mol Pharm 2017; 14:1133-1144. [DOI: 10.1021/acs.molpharmaceut.6b01052] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sampada Koranne
- Department
of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-177 WDH, 308 Harvard Street S.E., Minneapolis, Minnesota 55455, United States
| | - Ramprakash Govindarajan
- Department
of Pharmaceutical Sciences and Experimental Therapeutics, College
of Pharmacy, University of Iowa, S215 PHAR, 115 S. Grand Avenue, Iowa City, Iowa 52242-1112, United States
| | - Raj Suryanarayanan
- Department
of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-177 WDH, 308 Harvard Street S.E., Minneapolis, Minnesota 55455, United States
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14
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Al-Nimry SS, Alkhamis KA, Alzarieni KZ. The Effect of Specific Surface Area of Chitin–Metal Silicate Coprocessed Excipient on the Chemical Decomposition of Cefotaxime Sodium. J Pharm Sci 2017; 106:570-578. [DOI: 10.1016/j.xphs.2016.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/10/2016] [Accepted: 10/13/2016] [Indexed: 10/20/2022]
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15
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Krausková Ľ, Procházková J, Klašková M, Filipová L, Chaloupková R, Malý S, Damborský J, Heger D. Suppression of protein inactivation during freezing by minimizing pH changes using ionic cryoprotectants. Int J Pharm 2016; 509:41-49. [PMID: 27224008 DOI: 10.1016/j.ijpharm.2016.05.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022]
Abstract
Freezing and lyophilization are often used for stabilization of biomolecules; however, this sometimes results in partial degradation and loss of biological function in these molecules. In this study we examined the effect of freezing-induced acidity changes on denaturation of the model enzyme haloalkane dehalogenase under various experimental conditions. The effective local pH of frozen solutions is shown to be the key causal factor in protein stability. To preserve the activity of frozen-thawed enzymes, acidity changes were prevented by the addition of an ionic cryoprotectant, a compound which counteracts pH changes during freezing due to selective incorporation of its ions into the ice. This approach resulted in complete recovery of enzyme activity after multiple freeze-thaw cycles. We propose the utilization of ionic cryoprotectants as a new and effective cryopreservation method in research laboratories as well as in industrial processes.
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Affiliation(s)
- Ľubica Krausková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Jitka Procházková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Martina Klašková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Lenka Filipová
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Radka Chaloupková
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Stanislav Malý
- Central Institute for Supervising and Testing in Agriculture, Hroznová 2, CZ-656 06, Czech Republic
| | - Jiří Damborský
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic.
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16
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Govindarajan R, Landis M, Hancock B, Gatlin LA, Suryanarayanan R, Shalaev EY. Surface acidity and solid-state compatibility of excipients with an acid-sensitive API: case study of atorvastatin calcium. AAPS PharmSciTech 2015; 16:354-63. [PMID: 25319055 DOI: 10.1208/s12249-014-0231-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/25/2014] [Indexed: 11/30/2022] Open
Abstract
The objectives of this study were to measure the apparent surface acidity of common excipients and to correlate the acidity with the chemical stability of an acid-sensitive active pharmaceutical ingredient (API) in binary API-excipient powder mixtures. The acidity of 26 solid excipients was determined by two methods, (i) by measuring the pH of their suspensions or solutions and (ii) the pH equivalent (pHeq) measured via ionization of probe molecules deposited on the surface of the excipients. The chemical stability of an API, atorvastatin calcium (AC), in mixtures with the excipients was evaluated by monitoring the appearance of an acid-induced degradant, atorvastatin lactone, under accelerated storage conditions. The extent of lactone formation in AC-excipient mixtures was presented as a function of either solution/suspension pH or pHeq. No lactone formation was observed in mixtures with excipients having pHeq > 6, while the lactone levels were pronounced (> 0.6% after 6 weeks at 50°C/20% RH) with excipients exhibiting pHeq < 3. The three pHeq regions (> 6, 3-6, and < 3) were consistent with the reported solution pH-stability profile of AC. In contrast to the pHeq scale, lactone formation did not show any clear trend when plotted as a function of the suspension/solution pH. Two mechanisms to explain the discrepancy between the suspension/solution pH and the chemical stability data were discussed. Acidic excipients, which are expected to be incompatible with an acid-sensitive API, were identified based on pHeq measurements. The incompatibility prediction was confirmed in the chemical stability tests using AC as an example of an acid-sensitive API.
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17
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Cysewski P. Apparent basicities of the surfaces characterizing the dominant crystal habits of distinct polymorphic forms of 4-aminosulfonamide. J Mol Model 2014; 20:2276. [PMID: 24935108 PMCID: PMC4107284 DOI: 10.1007/s00894-014-2276-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/25/2014] [Indexed: 11/30/2022]
Abstract
A new approach for estimating local basicities/acidities of groups exposed on crystal surfaces was formulated and validated. The model, constructed within a quantitative structure-property relationship (QSPR) framework, allowed the expression of the protonic properties of amine and sulfonamide groups as functions of simple molecular descriptors of geometric types. This enabled the application of a QM/MM approach for the structural optimization of SNM molecules located on the surfaces of the dominant crystal habits. The obtained pKa values were used for classification of the protonic properties of four p-aminosulfonamide (SNM) polymorphs. The computed distributions of the surface pK a values suggested that, for all polymorphs, the amino group has statistically the same proton-accepting ability on the crystal surface as in bulk water solution. Although sulfonamide groups on the crystal surface-especially those distributed on β- and γ-dominant faces-seem to be more acidic compared to bulk water solution, the pK a values are statistically indistinguishable irrespective of the morphology. This suggests that experimentally observed differences in the perichromic properties of SNM polymorphs do not arise from local pH changes, Thus, apparent local basicities are to be relaed to structural similarity of SNM surfaces and thymol blue conformers anabling direct interactions.
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Affiliation(s)
- Piotr Cysewski
- Department of Physical Chemistry, Collegium Medicum of Bydgoszcz, Nicolaus Copernicus University in Toruń, Kurpińskiego 5, 85-950, Bydgoszcz, Poland,
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Morgan NK, Walk CL, Bedford MR, Burton EJ. The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization. Poult Sci 2014; 93:354-63. [PMID: 24570457 DOI: 10.3382/ps.2013-03305] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed 1 of 2 experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d posthatch. Dietary Ca content had no significant effect on in situ pH, but it contributed toward variance in ex situ pH of both gizzard and duodenum digesta. Digesta pH read higher when the digesta was removed from the tract, but the amount of time the digesta was exposed to air did not affect the reading. Digesta pH read higher when measured at room temperature than when measured at 41°C; temperature made the strongest unique contribution to explaining variance in duodenum pH, and the second strongest contribution to explaining variance in gizzard pH, after diet. When water was added to the digesta, before pH determination, the pH of the digesta read higher (P < 0.001) than when measured in situ. The method that resulted in pH readings that were most representative of bird gastrointestinal environment was insertion of a pH probe directly into the gut lumen posteuthanasia, because measurement ex situ likely encourages dissociation of carbonic acid, the major buffer in the gastrointestinal tract, which causes pH to read to be higher than when measured in situ. This study shows that the method of pH measurement needs careful consideration to ensure the validity of the result.
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Affiliation(s)
- N K Morgan
- School of Animal, Rural and Environmental Science, Nottingham Trent University, Southwell, Nottinghamshire, England, NG25 0QF, United Kingdom
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19
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Cysewski P. Structural origin of apparent surface basicities of p-aminosulanamide polymorphs. CRYSTAL RESEARCH AND TECHNOLOGY 2013. [DOI: 10.1002/crat.201300197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- P. Cysewski
- Department of Physical Chemistry; Collegium Medicum of Bydgoszcz; Nicolaus Copernicus University; Kurpińskiego 5 85-950 Bydgoszcz Poland
- Department of General Chemistry; University of Technology And Life Sciences In Bydgoszcz; Seminaryjna 3 85-326 Bydgoszcz Poland
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20
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Ohtake S, Shalaev E. Effect of Water on the Chemical Stability of Amorphous Pharmaceuticals: I. Small Molecules. J Pharm Sci 2013; 102:1139-54. [DOI: 10.1002/jps.23440] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 10/10/2012] [Accepted: 12/11/2012] [Indexed: 11/07/2022]
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21
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Luthra SA, Shalaev EY, Medek A, Hong J, Pikal MJ. Chemical Stability of Amorphous Materials: Specific and General Media Effects in the Role of Water in the Degradation of Freeze-Dried Zoniporide. J Pharm Sci 2012; 101:3110-23. [DOI: 10.1002/jps.23128] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 02/02/2012] [Accepted: 03/02/2012] [Indexed: 11/12/2022]
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22
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Gana FZ, Rashid I, Badwan A, Alkhamis KA. Determination of solid-state acidity of chitin-metal silicates and their effect on the degradation of cephalosporin antibiotics. J Pharm Sci 2012; 101:2398-407. [PMID: 22499263 DOI: 10.1002/jps.23142] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/06/2012] [Accepted: 03/16/2012] [Indexed: 11/11/2022]
Abstract
It was of interest to determine the solid-state acidity of chitin-metal silicate coprocessed excipients and to correlate this acidity to the chemical stability of cefotaxime sodium in the presence of the aforementioned excipients. The solid-state acidities of chitin aluminum silicate, chitin magnesium silicate, and chitin calcium silicate were determined by reflectance spectroscopy using structurally different dye molecules. The chemical stability of cefotaxime sodium was assessed at 50 °C in a 4% (w/v) slurry system in the pH range 6.6-10.5 and in the solid-state in the Hammett acidity range 6.1-7.8. The solid-state acidity was found to be reproducible because one or more structurally different dye molecules gave reliable solid-state acidity values. A significant discrepancy in pH stability profile of cefotaxime sodium between the solid-state and the slurry system was observed. Furthermore, chitin aluminum silicate showed minimum drug stability in the solid-state, close to where the maximum drug stability in the slurry was observed. This unexpected effect might be ascribed to the catalytic properties of chitin aluminum silicate. The slurry method was not able to predict efficiently the solid-state surface acidity and stability of cefotaxime sodium. Moreover, the solid-state chemical stability might be influenced by factors other than the solid-state acidity.
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Affiliation(s)
- Fatima Zohra Gana
- Faculty of Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
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Hailu SA, Bogner RH. Solid-State Surface Acidity and pH-Stability Profiles of Amorphous Quinapril Hydrochloride and Silicate Formulations. J Pharm Sci 2010; 99:2786-99. [DOI: 10.1002/jps.22051] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Enxian L, Ewing S, Gatlin L, Suryanarayanan R, Shalaev E. The Effect of Bulking Agents on the Chemical Stability of Acid-Sensitive Compounds in Freeze-Dried Formulations: Sucrose Inversion Study. J Pharm Sci 2009; 98:3387-96. [DOI: 10.1002/jps.21727] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Phase Transitions in Frozen Systems and During Freeze–Drying: Quantification Using Synchrotron X-Ray Diffractometry. Pharm Res 2009; 26:1596-606. [DOI: 10.1007/s11095-009-9868-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 02/26/2009] [Indexed: 11/26/2022]
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Pudipeddi M, Zannou EA, Vasanthavada M, Dontabhaktuni A, Royce AE, Joshi YM, Serajuddin ATM. Measurement of Surface pH of Pharmaceutical Solids: A Critical Evaluation of Indicator Dye-Sorption Method and its Comparison With Slurry pH Method. J Pharm Sci 2008; 97:1831-42. [PMID: 17879289 DOI: 10.1002/jps.21052] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two methods for the measurement of surface pH of pharmaceutical solids, namely, the dye-sorption method and the slurry pH method, were compared. High purity drug substances, instead of excipients, were used as model solids, because acidic or basic impurities present in excipients could influence slurry pH. Solid test samples were prepared by sorption of methanol-water solutions of several indicator dyes, and their diffuse reflectance UV-visible spectra were measured. The solid surface pH values were estimated by comparing base-to-acid peak ratios of the diffuse reflectance UV-visible spectra of solid samples to the calibration plots of dye solutions in aqueous standard buffers of known pH. In the slurry pH method, pH values of concentrated slurries of the compounds in water were considered to represent solid surface pH. The agreement between the two methods was mixed and depended on the compound or the indicator used. It was concluded that in many cases calibration plots of indicator dye spectra in aqueous buffers were not applicable to the solid state, and, as a result, the reliability of the method was low. The slurry method provided a simple and reliable measurement of surface pH indicating that concentrated slurry may closely represent solid surface pH.
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Affiliation(s)
- Madhu Pudipeddi
- Novartis Healthcare Pvt. Ltd., 8th Floor, D Wing, I Labs, Hitech City, Hyderabad 500081, India.
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Chatterjee K, Shalaev EY, Suryanarayanan R, Govindarajan R. Correlation between chemical reactivity and the Hammett acidity function in amorphous solids using inversion of sucrose as a model reaction. J Pharm Sci 2008; 97:274-86. [PMID: 17828730 DOI: 10.1002/jps.21081] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The goal was to evaluate the effects of acidity, expressed as the Hammett acidity function, on chemical reactivity in freeze-dried materials (lyophiles). Dextran-sucrose-citrate and polyvinyl pyrrolidone (PVP)-sucrose-citrate aqueous solutions, adjusted to pH values of 2.6, 2.8, and 3.0 were freeze dried, and characterized by X-ray powder diffractometry, DSC, isothermal microcalorimetry, and Karl Fischer titrimetry. Lyophiles were also prepared from identical solutions but containing bromophenol blue (BB). Diffuse reflectance-visible spectroscopy was used to measure the extent of BB protonation from which the Hammett acidity functions were determined. The stability studies were performed at 60 degrees C. All the freeze-dried samples were observed to be X-ray amorphous with <0.15% w/w water content. The T(g) of dextran lyophiles were approximately 20 degrees C higher than that of PVP lyophiles whereas enthalpy relaxation rates at 60 degrees C were similar. The Hammett acidity functions were significantly lower (i.e., higher acidity) for dextran systems (<2.2-2.6) when compared with PVP systems (3.3-3.9). The rate of sucrose inversion was significantly (an order of magnitude) higher in dextran lyophiles. This study showed that in amorphous matrices with comparable water content and structural relaxation times, chemical reactivity could be significantly different depending on the matrix "acidity".
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Affiliation(s)
- Koustuv Chatterjee
- College of Pharmacy, 308, Harvard St. S.E., University of Minnesota, Minneapolis, MN 55455, USA
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Abstract
There are many reports in the literature referring to the effect of microenvironmental pH on solid dosage form performance, particularly stability and dissolution profiles. Several techniques have been proposed for the measurement of the microenvironmental pH. Those techniques use certain assumptions and approximations and many of them employ a solution calibration curve of a probe to predict hydrogen ion activity in a substantially dry solid. Despite the limitation of the methodology, it is clear from the literature that microenvironmental pH has a significant impact on stability of compounds which demonstrate pH dependent stability in solution. Degradation kinetics of such compounds, and in some cases degradation profile as well, are dependent on the microenvironmental pH of the solid. Modulation of the microenvironmental pH through the use of pH modifiers can hence prove to be a very effective tool in maximizing solid dosage form stability. Judicial selection of the appropriate pH modifier, its concentration and the manufacturing process used to incorporate the pH modifier is necessary to enhance stability. Control of microenvironmental pH to maximize stability can be achieved without the use of pH modifier in some cases if an appropriate counter ion is used to provide an inherently optimal pH for the salt. Microenvironmental pH modulation was also shown to control the dissolution profile of both immediate and controlled release dosage forms of compounds with pH dependent solubility. The pH modifiers have been used in conjunction with high energy or salt forms in immediate release formulations to minimize the precipitation of the less soluble free form during initial dissolution. Additionally, pH modifiers were utilized in controlled release dosage forms of weakly basic drugs which exhibit diminished release in dissolution media with high pH. The incorporation of acidic pH modifiers in the controlled release formulation increases the solubility of the basic drug even as the high pH dissolution medium enters into the dosage form hence increasing drug release rate.
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Affiliation(s)
- Sherif I Farag Badawy
- Bristol-Myers Squibb Pharmaceutical Research Institute, New Brunswick, New Jersey, USA
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Varshney DB, Kumar S, Shalaev EY, Sundaramurthi P, Kang SW, Gatlin LA, Suryanarayanan R. Glycine Crystallization in Frozen and Freeze-dried Systems: Effect of pH and Buffer Concentration. Pharm Res 2007; 24:593-604. [PMID: 17245648 DOI: 10.1007/s11095-006-9178-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 10/11/2006] [Indexed: 11/27/2022]
Abstract
PURPOSE (1) To determine the effect of solution pH before lyophilization, over the range of 1.5 to 10, on the salt and polymorphic forms of glycine crystallizing in frozen solutions and in lyophiles. (2) To quantify glycine crystallization during freezing and annealing as a function of solution pH before lyophilization. (3) To study the effect of phosphate buffer concentration on the extent of glycine crystallization before and after annealing. MATERIALS AND METHODS Glycine solutions (10% w/v), with initial pH ranging from 1.5 to 10, were cooled to -50 degrees C, and the crystallized glycine phases were identified using a laboratory X-ray source. Over the same pH range, glycine phases in lyophiles obtained from annealed solutions (0.25, 2 and 10% w/v glycine), were characterized by synchrotron X-ray diffractometry (SXRD). In the pH range of 3.0 to 5.9, the extent of glycine crystallization during annealing was monitored by SXRD. Additionally, the effect of phosphate buffer concentration (50 to 200 mM) on the extent of glycine crystallization during freezing, followed by annealing, was determined. RESULTS In frozen solutions, beta-glycine was detected when the initial solution pH was < or =4. In the lyophiles, in addition to beta- and gamma-glycine, glycine HCl, diglycine HCl, and sodium glycinate were also identified. In the pH range of 3.0 to 5.9, decreasing the pH reduced the extent of glycine crystallization in the frozen solution. When the initial pH was fixed at 7.4, and the buffer concentration was increased from 50 to 200 mM, the extent of glycine crystallization in frozen solutions decreased with an increase in buffer concentration. CONCLUSION Both solution pH and solute concentration before lyophilization influenced the salt and polymorphic forms of glycine crystallizing in frozen solutions and in lyophiles. The extent of glycine crystallization in frozen solutions was affected by the initial pH and buffer concentration of solutions. The high sensitivity of SXRD allowed simultaneous detection and quantification of multiple crystalline phases.
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Affiliation(s)
- Dushyant B Varshney
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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Govindarajan R, Zinchuk A, Hancock B, Shalaev E, Suryanarayanan R. Ionization States in the Microenvironment of Solid Dosage Forms: Effect of Formulation Variables and Processing. Pharm Res 2006; 23:2454-68. [PMID: 16933092 DOI: 10.1007/s11095-006-9085-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Accepted: 05/31/2006] [Indexed: 11/28/2022]
Abstract
PURPOSE Evaluation of the effect of formulation composition and processing variables on the microenvironment in solid dosage forms, based on ionization of indicator probes. MATERIALS AND METHODS Sulfonephthalein indicators were intimately mixed with individual excipients, binary excipient mixtures or multi-component blends by the solvent deposition method. Diffuse reflectance visible spectroscopy of these solids provided a measure of indicator ionization extent. Indicator solution studies yielded equations relating solution pH to the ratio of the absorbance signals of the ionized to that of the unionized form, for each indicator. These equations and the spectral data of the indicator-treated solids were used to calculate an acidity function, 'pH(eq)' for the solids. The ionization of incorporated probes was also monitored during various stages of simulated pharmaceutical processing viz. wet and dry mixing. RESULTS The pH(eq) provided a measure of the physicochemical environment experienced by the probe in the solid. The surface nature of formulation components and their surface area available for interaction influenced the overall properties of the final blend. The extent of probe ionization varied at different stages of a simulated wet mixing-drying process. The pH of the excipient suspension was not a good predictor of the probe ionization in the final dried solid. Indicator ionization is expected to be influenced by the microenvironmental acidity, polarity and ionic strength. Individual excipient properties contributed to the overall microenvironment in powder mixtures even when dry mixed at low water contents. CONCLUSIONS The environment experienced by a drug in the final solid dosage form will be influenced by the nature of the excipients, the extent of their surfaces available for interaction, surface modification during processing and the amount and nature of solvent used.
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Affiliation(s)
- Ramprakash Govindarajan
- Department of Pharmaceutics, University of Minnesota, 308 Harvard St. SE, Minneapolis, MN 55455, USA.
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