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Veselý L, Štůsek R, Mikula O, Yang X, Heger D. Freezing-induced acidification of sea ice brine. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174194. [PMID: 38925394 DOI: 10.1016/j.scitotenv.2024.174194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 06/14/2024] [Accepted: 06/20/2024] [Indexed: 06/28/2024]
Abstract
The acidity of sea ice and snow plays a key role in the chemistry of the cryosphere; an important example lies in the photochemical catalytic release of reactive bromine in polar regions, facilitated at pHs below 6.5. We apply in-situ acid-base indicators to probe the microscopic acidity of the brine within the ice matrix in artificial sea water at a range of concentrations (0.35-70 PPT) and initial pHs (6-9). The results are supported by analogous measurements of the most abundant salts in seawater: NaCl, Na2SO4, and CaCO3. In the research herein, the acidity is expressed in terms of the Hammett acidity function, H2-. The obtained results show a pronounced acidity increase in sea water after freezing at -15 °C and during the subsequent cooling down to -50 °C. Importantly, we did not observe any significant hysteresis; the values of acidity upon warming markedly resembled those at the corresponding temperatures at cooling. The acidity increase is attributed to the minerals' crystallization, which is accompanied by a loss of the buffering capacity. Our observations show that lower salinity sea water samples (≤ 3.5 PPT) reach pH values below 6.5 at the temperature of -15 °C, whereas higher salinity ices attain such values only at -30 °C. The ensuing implications for polar chemistry and the relevance to the field measurements are discussed.
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Affiliation(s)
- Lukáš Veselý
- Masaryk University, Faculty of Science, Department of Chemistry, Czech Republic
| | - Radim Štůsek
- Masaryk University, Faculty of Science, Department of Chemistry, Czech Republic
| | - Ondřej Mikula
- Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Czech Republic
| | - Xin Yang
- British Antarctic Survey, UK Research Innovation, Cambridge, UK
| | - Dominik Heger
- Masaryk University, Faculty of Science, Department of Chemistry, Czech Republic.
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2
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Lay-Fortenbery A, Yuan X, Veselý L, Heger D, Shalaev E, Su Y, Munson E. Determination of Solid-State Acidity of Lyophilized Trehalose Containing Citrate, Phosphate, and Histidine Buffers Using UV/VIS Diffuse Reflectance and Solid-State NMR Spectroscopy. J Pharm Sci 2024:S0022-3549(24)00426-X. [PMID: 39313152 DOI: 10.1016/j.xphs.2024.09.019] [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: 03/22/2024] [Revised: 08/23/2024] [Accepted: 09/16/2024] [Indexed: 09/25/2024]
Abstract
Changes in the protonation state of lyophilized proteins can impact structural integrity, chemical stability, and propensity to aggregate upon reconstitution. When a buffer is chosen, the freezing/drying process may result in dramatic changes in the protonation state of the protein due to ionization shift of the buffer. In order to determine whether protonation shifts are occurring, ionizable probes can be added to the formulation. Optical probes (dyes) have shown dramatic ionization changes in lyophilized products, but it is unclear whether the pH indicator is uniform throughout the matrix and whether the change in the pH indicator actually mirrors drug ionization changes. In solid-state NMR (SSNMR) spectroscopy, the chemical shift of the carbonyl carbon in carboxylic acids is very sensitive to the ionization state of the acid. Therefore, SSNMR can be used to measure ionization changes in a lyophilized matrix by employing a small quantity of an isotopically-labeled carboxylic acid species in the formulation. This paper compares the apparent pH of six trehalose-containing lyophilized buffer systems using SSNMR and UV-Vis diffuse reflectance spectroscopy (UVDRS). Both SSNMR and UVDRS results using two different ionization probes (butyric acid and bromocresol purple, respectively) showed little change in apparent acidity compared to the pre-lyophilized solution in a sodium citrate buffer, but a greater change was observed in potassium phosphate, sodium phosphate, and histidine buffers. While the trends between the two methods were similar, there were differences in the numerical values of equivalent pH (pHeq) observed between the two methods. The potential causes contributing to the differences are discussed.
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Affiliation(s)
- Ashley Lay-Fortenbery
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40526, USA
| | - Xiaoda Yuan
- Development Sciences, Research and Development, AbbVie Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Lukáš Veselý
- Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 5-A8, Brno 62500, Czech Republic
| | - Dominik Heger
- Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 5-A8, Brno 62500, Czech Republic
| | - Evgenyi Shalaev
- Development Sciences, Research and Development, AbbVie Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Yongchao Su
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Eric Munson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40526, USA; Current address: Department of Industrial and Molecular Pharmaceutics, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA.
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3
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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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4
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Avdeef A, Sugano K. Salt Solubility and Disproportionation - Uses and Limitations of Equations for pH max and the In-silico Prediction of pH max. J Pharm Sci 2021; 111:225-246. [PMID: 34863819 DOI: 10.1016/j.xphs.2021.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 10/19/2022]
Abstract
A multiphasic mass action equilibrium model was used to study the phase properties near the critical pH ('pHmax') in an acid-base transformation of a solid drug salt into its corresponding solid free base form in pure water slurries. The goal of this study was to better define the characteristics of disproportionation of pharmaceutical salts, objectively (i) to classify salts as μ-type (microclimate stable) or δ-type (disproportionation prone) based on the relationship between the calculated pHmax and the calculated pH of the saturated salt solution, (ii) to compare the distribution of μ/δ-type salts to predictions from the disproportionation potential equation introduced by Merritt et al.,20 (iii) to determine if the intrinsic solubility of the free base, S0, can be predicted from the measured μ-type salt solubility as a means of estimating the value of pHmax, (iv) to determine S0 directly from the measured δ-type salt solubility, and (v) to address some of the limitations of the equations commonly used to calculate pHmax. When the salt solubility is measured for a basic API (pKa of which is known), but the experimental value of S0 is unavailable, a potentially useful simple screen for disproportionation is still possible, since pHmax can be estimated from a 'μ-predicted' (objective iii) or 'δ-measured' S0 (objective iv). Twelve model weak base API were selected in the study. For each API, 2-17 different salt forms with reported salt solubilities in distilled water were sourced from the literature. In all, 73 salt solubility values based on 29 different salt-forming acids comprise the studied set. All the corresponding free base solubility values were available. The pKa values for all the acids and bases studied are generally well known. For each API salt, an acid-base titration simulation was performed, anchored to the measured salt solubility value, using the general mass action analysis program pDISOL-X. The log S-pH profiles were drawn out by analytic continuity from pH 0 to 13, as described in detail previously.24 Potentially useful in-silico models were developed that correlate pS0 to linear functions of the salt solubility in water, pSw, the partition coefficient of the salt-forming acid (log POCTacid) and the melting point (mp) of the drug salt, thereby enabling the derivation of the approximate pHmax value from the predicted pS0.
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Affiliation(s)
- Alex Avdeef
- in-ADME Research, 1732 First Avenue, #102, New York, NY, 10128, USA.
| | - Kiyohiko Sugano
- Molecular Pharmaceutics Lab., College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga, 525-8577, Japan
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5
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Abstract
A multiphasic mass action equilibrium model is used to show that the critical pH in the acid-base disproportionation of a solid salt into its corresponding solid free-base form in aqueous suspensions, widely known as "pHmax", is incompletely interpreted. It is shown that the traditional thermodynamic model does not predict the invariance of pH and solubility during the salt-to-free-base conversion process in an alkalimetric titration. Rather, the conversion entails a range of pH and solubility values, depending on the amount of added excess salt above that needed to form a saturated solution. A more precise definition is proposed for pHmax (pH at the maximum solubility of a eutectic mixture), and three new terms are introduced: pHmin (pH at the minimum solubility of the eutectic mixture), pHδ (disproportionation invariant pH within the eutectic, i.e., the equilibrium pH of a spontaneously disproportionating salt slurry), and pHγ (Gibbs pH at which disproportionation yields equimolar amounts of excess salt and excess free-base solids within the eutectic). Two test compounds with reported multiple salts and the free-base solubility values were selected to illustrate the expanded concepts, the bases WR-122455 and RPR-127963. Also, dibasic calcium phosphate was selected as an ionizable test excipient. The salts are designated in the study as μ-type, when they are thermodynamically stable with respect to spontaneous disproportionation in pure water (e.g., WR-122455 salts), and δ-type, when they are predicted to spontaneously disproportionate in pure water (e.g., RPR-127963 salts). In an alkalimetric titration, when an acidified suspension of a salt of a basic molecule is titrated with a strong base (e.g., NaOH), the passage across the eutectic domain (bounded by pHmax and pHmin) is often characterized by (a) minimum in ionic strength either at pHmax (μ-type salt) or pHδ (δ-type salt) and (b) maximum buffer capacity at pHγ. When the alkalimetric titration is performed with a large excess of added salt, a wide eutectic domain forms: pHmax and pHδ remain invariant, but pHmin and pHγ shift substantially in pH. The acid-base mass action model described here can be useful in predicting the stability of salt formulations in mixtures with excipients that can act as pH modifiers.
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Affiliation(s)
- Alex Avdeef
- in-ADME Research, 1732 First Avenue #102, New York, New York 10128, United States
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6
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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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7
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Zarmpi P, Flanagan T, Meehan E, Mann J, Fotaki N. Impact of Magnesium Stearate Presence and Variability on Drug Apparent Solubility Based on Drug Physicochemical Properties. AAPS JOURNAL 2020; 22:75. [PMID: 32440810 PMCID: PMC7242257 DOI: 10.1208/s12248-020-00449-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/20/2020] [Indexed: 11/30/2022]
Abstract
Excipients are major components of oral solid dosage forms, and changes in their critical material attributes (excipient variability) and/or amount (excipient variation) in pharmaceutical formulations may present a challenge for product performance. Understanding the biopharmaceutical factors affecting excipient performance is recommended for the successful implementation of excipient variability on Quality by Design (QbD) approaches. The current study investigated the impact of magnesium stearate (MgSt) variability on the apparent solubility of drugs with a wide range of physicochemical properties (drug ionization, drug lipophilicity, drug aqueous solubility). Compendial and biorelevant media were used to assess the role of gastrointestinal (GI) conditions on the excipient effects on drug apparent solubility. The lipophilic nature of MgSt decreased the apparent solubility of most compounds. The reduction in drug apparent solubility was more pronounced for highly soluble and/or highly ionized drugs and in presence of more highly crystalline or smaller particle size MgSt. The use of multivariate data analysis revealed the critical physicochemical and biopharmaceutical factors and the complex nature of excipient variability on the reduction in drug apparent solubility. The construction of a roadmap combining drug, excipient and medium characteristics allowed the identification of the cases where the presence of excipient or excipient variability may present risks for oral drug performance.
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Affiliation(s)
- P Zarmpi
- Department of Pharmacy and Pharmacology, University of Bath, Bath, BA2 7AY, UK
| | - T Flanagan
- Pharmaceutical Technology & Development, AstraZeneca, Macclesfield, UK.,UCB Pharma, Chemin du Foriest, B-1420, Braine-l'Alleud, Belgium
| | - E Meehan
- Pharmaceutical Technology & Development, AstraZeneca, Macclesfield, UK
| | - J Mann
- Pharmaceutical Technology & Development, AstraZeneca, Macclesfield, UK
| | - Nikoletta Fotaki
- Department of Pharmacy and Pharmacology, University of Bath, Bath, BA2 7AY, UK.
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8
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Koranne S, Lalge R, Suryanarayanan R. Modulation of Microenvironmental Acidity: A Strategy to Mitigate Salt Disproportionation in Drug Product Environment. Mol Pharm 2020; 17:1324-1334. [DOI: 10.1021/acs.molpharmaceut.0c00024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sampada Koranne
- Merck & Co., Inc. 126 East Lincoln Avenue, Rahway, New Jersey 07065, United States
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-177 WDH, 308 Harvard Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Rahul Lalge
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-177 WDH, 308 Harvard Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Raj Suryanarayanan
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, 9-177 WDH, 308 Harvard Street Southeast, Minneapolis, Minnesota 55455, United States
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9
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Kaur N, Duggirala NK, Thakral S, Suryanarayanan R. Role of Lattice Disorder in Water-Mediated Dissociation of Pharmaceutical Cocrystal Systems. Mol Pharm 2019; 16:3167-3177. [DOI: 10.1021/acs.molpharmaceut.9b00386] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Navpreet Kaur
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Naga Kiran Duggirala
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Seema Thakral
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Raj Suryanarayanan
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, United States
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10
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Koranne S, Sahoo A, Krzyzaniak JF, Luthra S, Arora KK, Suryanarayanan R. Challenges in Transitioning Cocrystals from Bench to Bedside: Dissociation in Prototype Drug Product Environment. Mol Pharm 2018; 15:3297-3307. [DOI: 10.1021/acs.molpharmaceut.8b00340] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sampada Koranne
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Room 9-177 Weaver-Densford
Hall, 308 Harvard Street S.E., Minneapolis, Minnesota 55455, United States
| | - Anasuya Sahoo
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Room 9-177 Weaver-Densford
Hall, 308 Harvard Street S.E., Minneapolis, Minnesota 55455, United States
| | - Joseph F. Krzyzaniak
- Groton Laboratories, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Suman Luthra
- Groton Laboratories, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Kapildev K. Arora
- Groton Laboratories, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Raj Suryanarayanan
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Room 9-177 Weaver-Densford
Hall, 308 Harvard Street S.E., Minneapolis, Minnesota 55455, United States
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11
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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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12
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Nie H, Byrn SR, Zhou Q(T. Stability of pharmaceutical salts in solid oral dosage forms. Drug Dev Ind Pharm 2017; 43:1215-1228. [PMID: 28276282 DOI: 10.1080/03639045.2017.1304960] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Haichen Nie
- Formulation Sciences, Teva Pharmaceuticals, West Chester, PA, USA
| | - Stephen R. Byrn
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN, USA
| | - Qi (Tony) Zhou
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN, USA
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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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Thakral NK, Kelly RC. Salt disproportionation: A material science perspective. Int J Pharm 2017; 520:228-240. [DOI: 10.1016/j.ijpharm.2017.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 11/25/2022]
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15
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Crystalline solid dispersion-a strategy to slowdown salt disproportionation in solid state formulations during storage and wet granulation. Int J Pharm 2017; 517:203-215. [DOI: 10.1016/j.ijpharm.2016.12.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 11/27/2022]
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16
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Nie H, Xu W, Ren J, Taylor LS, Marsac PJ, John CT, Byrn SR. Impact of Metallic Stearates on Disproportionation of Hydrochloride Salts of Weak Bases in Solid-State Formulations. Mol Pharm 2016; 13:3541-3552. [PMID: 27542728 DOI: 10.1021/acs.molpharmaceut.6b00630] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Excipient-induced salt disproportionation (conversion from salt form to free form) in the solid state during storage or manufacturing is a severe formulation issue that can negatively influence product performance. However, the role of excipient properties on salt disproportionation and mechanisms of proton transfer between salt and excipients are still unclear. Moreover, knowledge about the formation of disproportionation products and the consequent impact of these reactions products on the disproportionation process is still inadequate. In the present study, three commonly used lubricants (sodium stearate, calcium stearate, and magnesium stearate) were mixed with a hydrochloride salt as binary mixtures to examine their different capabilities for inducing salt disproportionation at a stressed storage condition (40 °C/65% RH). The overall objective of this research is to explore factors influencing the kinetics and extent of disproportionation including surface area, alkalinity, hygroscopicity, formation of new species, etc. In addition, we also aim to clarify the reaction mechanism and proton transfer between the model salt and stearates to provide insight into the in situ formed reaction products. We found that the properties of stearates significantly affect the disproportionation process in the initial stage of storage, while properties of the reaction products negatively affect the hygroscopicity of the powder mixture promoting disproportionation during longer-term storage. In addition, lubrication difference among three stearates was evaluated by performing compaction studies. The findings of this study provide an improved understanding of the proton transfer mechanism between the ionized form of an active pharmaceutical ingredient and excipients in solid dosage forms. It also provides pragmatic information for formulation scientists to select appropriate lubricants and other excipients, and to design robust formulations.
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Affiliation(s)
- Haichen Nie
- Department of Industrial and Physical Pharmacy, Purdue University , 575 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Wei Xu
- Preformulation Sciences, Merck & Co., Inc. , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Jie Ren
- Oral Formulation Science, Merck & Co., Inc. , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Lynne S Taylor
- Department of Industrial and Physical Pharmacy, Purdue University , 575 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Patrick J Marsac
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Christopher T John
- Discovery Pharmaceutical Science, Merck & Co., Inc. , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Stephen R Byrn
- Department of Industrial and Physical Pharmacy, Purdue University , 575 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
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17
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Adams ML, Sharma V, Gokhale M, Huang Y, Stefanski K, Su C, Hussain MA. Dehydration and Stabilization of a Reactive Tertiary Hydroxyl Group in Solid Oral Dosage Forms of BMS-779788. J Pharm Sci 2016; 105:1478-88. [DOI: 10.1016/j.xphs.2015.12.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/30/2015] [Accepted: 12/18/2015] [Indexed: 11/25/2022]
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18
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Evaluating drug delivery with salt formation: Drug disproportionation studied in situ by ATR-FTIR imaging and Raman mapping. J Pharm Biomed Anal 2015; 111:248-56. [DOI: 10.1016/j.jpba.2015.03.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 11/17/2022]
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19
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Salt Stability – The Effect of pHmax on Salt to Free Base Conversion. Pharm Res 2015; 32:3110-8. [DOI: 10.1007/s11095-015-1691-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/26/2015] [Indexed: 12/01/2022]
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20
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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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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: 2] [Impact Index Per Article: 0.2] [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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Alsante KM, Huynh-Ba KC, Baertschi SW, Reed RA, Landis MS, Furness S, Olsen B, Mowery M, Russo K, Iser R, Stephenson GA, Jansen P. Recent trends in product development and regulatory issues on impurities in active pharmaceutical ingredient (API) and drug products. Part 2: Safety considerations of impurities in pharmaceutical products and surveying the impurity landscape. AAPS PharmSciTech 2014; 15:237-51. [PMID: 24363207 DOI: 10.1208/s12249-013-0061-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 11/15/2013] [Indexed: 11/30/2022] Open
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23
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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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John CT, Xu W, Lupton LK, Harmon PA. Formulating Weakly Basic HCl Salts: Relative Ability of Common Excipients to Induce Disproportionation and the Unique Deleterious Effects of Magnesium Stearate. Pharm Res 2013; 30:1628-41. [DOI: 10.1007/s11095-013-1002-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 02/06/2013] [Indexed: 11/30/2022]
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25
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Implementing Quality by Design in Pharmaceutical Salt Selection: A Modeling Approach to Understanding Disproportionation. Pharm Res 2012; 30:203-17. [DOI: 10.1007/s11095-012-0863-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 08/09/2012] [Indexed: 10/28/2022]
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26
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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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27
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Terife G, Wang P, Faridi N, Gogos CG. Hot melt mixing and foaming of soluplus® and indomethacin. POLYM ENG SCI 2012. [DOI: 10.1002/pen.23106] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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28
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Waterman KC. The application of the Accelerated Stability Assessment Program (ASAP) to quality by design (QbD) for drug product stability. AAPS PharmSciTech 2011; 12:932-7. [PMID: 21748541 DOI: 10.1208/s12249-011-9657-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 06/20/2011] [Indexed: 11/30/2022] Open
Abstract
An isoconversion paradigm, where times in different temperature and humidity-controlled stability chambers are set to provide a fixed degradant level, is shown to compensate for the complex, non-single order kinetics of solid drug products. A humidity-corrected Arrhenius equation provides reliable estimates for temperature and relative humidity effects on degradation rates. A statistical protocol is employed to determine best fits for chemical stability data, which in turn allows for accurate estimations of shelf life (with appropriate confidence intervals) at any storage condition including inside packaging (based on the moisture vapor transmission rate of the packaging and moisture sorption isotherms of the internal components). These methodologies provide both faster results and far better predictions of chemical stability limited shelf life (expiry) than previously possible. Precise shelf-life estimations are generally determined using a 2-week, product-specific protocol. Once the model for a product is developed, it can play a critical role in providing the product understanding necessary for a quality by design (QbD) filing for product approval and enable rational control strategies to assure product stability. Moreover, this Accelerated Stability Assessment Program (ASAP) enables the coupling of product attributes (e.g., moisture content, packaging options) to allow for flexibility in how control strategies are implemented to provide a balance of cost, speed, and other factors while maintaining adequate stability.
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29
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Stephenson GA, Aburub A, Woods TA. Physical Stability of Salts of Weak Bases in the Solid-State. J Pharm Sci 2011; 100:1607-17. [DOI: 10.1002/jps.22405] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 10/18/2010] [Accepted: 10/18/2010] [Indexed: 11/10/2022]
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30
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Hailu SA, Bogner RH. Complex Effects of Drug/Silicate Ratio, Solid-State Equivalent pH, and Moisture on Chemical Stability of Amorphous Quinapril Hydrochloride Coground with Silicates. J Pharm Sci 2011; 100:1503-15. [DOI: 10.1002/jps.22387] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 08/30/2010] [Accepted: 09/30/2010] [Indexed: 11/07/2022]
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31
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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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32
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Bassi P, Kaur G. pH modulation: a mechanism to obtain pH-independent drug release. Expert Opin Drug Deliv 2010; 7:845-57. [DOI: 10.1517/17425247.2010.491508] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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33
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Hailu SA, Bogner RH. Effect of the pH grade of silicates on chemical stability of coground amorphous quinapril hydrochloride and its stabilization using pH-modifiers. J Pharm Sci 2009; 98:3358-72. [DOI: 10.1002/jps.21767] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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34
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Role of Salt and Excipient Properties on Disproportionation in the Solid-State. Pharm Res 2009; 26:2015-26. [DOI: 10.1007/s11095-009-9918-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 05/27/2009] [Indexed: 11/25/2022]
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35
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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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Affiliation(s)
- F. LARA-OCHOA
- a Instituto de Química, Universidad Nacional Autónoma de México , Ciudad Universitaria, Coyoacán, México DF, CP 04510, México
| | - G. ESPINOSA-PÉREZ
- a Instituto de Química, Universidad Nacional Autónoma de México , Ciudad Universitaria, Coyoacán, México DF, CP 04510, México
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