1
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Rantanen J, Rades T, Strachan C. Solid-state analysis for pharmaceuticals: Pathways to feasible and meaningful analysis. J Pharm Biomed Anal 2023; 236:115649. [PMID: 37657177 DOI: 10.1016/j.jpba.2023.115649] [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: 05/18/2023] [Revised: 08/12/2023] [Accepted: 08/13/2023] [Indexed: 09/03/2023]
Abstract
The solid state of matter is the preferred starting point for designing a pharmaceutical product. This is driven by both patient preferences and the relative ease of supplying a solid pharmaceutical product with desired quality and performance. Solid form diversity is increasingly prevalent as a crucial element in designing these products, which underpins the importance of solid-state analytical methods. This paper provides a critical analysis of challenges related to solid-state analytics, as well as considerations and suggestions for feasible and meaningful pharmaceutical analysis.
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Affiliation(s)
- Jukka Rantanen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Thomas Rades
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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2
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Iyer J, Brunsteiner M, Modhave D, Paudel A. Role of Crystal Disorder and Mechanoactivation in Solid-State Stability of Pharmaceuticals. J Pharm Sci 2023; 112:1539-1565. [PMID: 36842482 DOI: 10.1016/j.xphs.2023.02.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/20/2023] [Accepted: 02/20/2023] [Indexed: 02/28/2023]
Abstract
Common energy-intensive processes applied in oral solid dosage development, such as milling, sieving, blending, compaction, etc. generate particles with surface and bulk crystal disorder. An intriguing aspect of the generated crystal disorder is its evolution and repercussion on the physical- and chemical stabilities of drugs. In this review, we firstly examine the existing literature on crystal disorder and its implications on solid-state stability of pharmaceuticals. Secondly, we discuss the key aspects related to the generation and evolution of crystal disorder, dynamics of the disordered/amorphous phase, analytical techniques to measure/quantify them, and approaches to model the disordering propensity from first principles. The main objective of this compilation is to provide special impetus to predict or model the chemical degradation(s) resulting from processing-induced manifestation in bulk solid manufacturing. Finally, a generic workflow is proposed that can be useful to investigate the relevance of crystal disorder on the degradation of pharmaceuticals during stability studies. The present review will cater to the requirements for developing physically- and chemically stable drugs, thereby enabling early and rational decision-making during candidate screening and in assessing degradation risks associated with formulations and processing.
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Affiliation(s)
- Jayant Iyer
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria
| | | | - Dattatray Modhave
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria
| | - Amrit Paudel
- Research Center Pharmaceutical Engineering GmbH (RCPE), Graz, Austria; Graz University of Technology, Institute of Process and Particle Engineering, Graz Austria.
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3
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Yivlialin R, Filoni C, Goto F, Calloni A, Duò L, Ciccacci F, Bussetti G. Optical Anisotropy of Porphyrin Nanocrystals Modified by the Electrochemical Dissolution. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27228010. [PMID: 36432111 PMCID: PMC9697289 DOI: 10.3390/molecules27228010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022]
Abstract
Reflectance anisotropy spectroscopy (RAS) coupled to an electrochemical cell represents a powerful tool to correlate changes in the surface optical anisotropy to changes in the electrochemical currents related to electrochemical reactions. The high sensitivity of RAS in the range of the absorption bands of organic systems, such as porphyrins, allows us to directly correlate the variations of the optical anisotropy signal to modifications in the solid-state aggregation of the porphyrin molecules. By combining in situ RAS to electrochemical techniques, we studied the case of vacuum-deposited porphyrin nanocrystals, which have been recently observed dissolving through electrochemical oxidation in diluted sulfuric acid. Specifically, we could identify the first stages of the morphological modifications of the nanocrystals, which we could attribute to the single-electron transfers involved in the oxidation reaction; in this sense, the simultaneous variation of the optical anisotropy with the electron transfer acts as a precursor of the dissolution process of porphyrin nanocrystals.
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4
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Herzberg M, Larsen AS, Hassenkam T, Madsen AØ, Rantanen J. Effect of pH on the Surface Layer of Molecular Crystals at the Solid-Liquid Interface. Mol Pharm 2022; 19:1598-1603. [PMID: 35451842 DOI: 10.1021/acs.molpharmaceut.2c00087] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dissolution of solid matter into aqueous solution is one of the most challenging physicochemical aspects related to drug development. While influenced by several parameters, the effect of pH remains the most important one to be fully understood. The dissolution process is essentially controlled by activity at the surface of the molecular crystals, which is difficult to characterize experimentally. To address this, a combination of in situ atomic force microscopy (AFM) with molecular dynamics (MD) simulation is reported. AFM allows for direct visualization of the crystal surface of basic and acidic model compounds (carvedilol and ibuprofen) in contact with an aqueous medium with varying pH. A dramatic increase in surface mobility in the solid-liquid interface could be observed experimentally as a function of pH. The in situ AFM approach opens up for a more detailed understanding of the behavior of particulate matter in solution with importance at different levels, ranging from engineering aspects related to crystallization, and biological considerations related to bioavailability of the final drug product.
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Affiliation(s)
- Mikkel Herzberg
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Anders S Larsen
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Tue Hassenkam
- Globe Institute, University of Copenhagen, Øster Voldgade 5, 1350 Copenhagen, Denmark
| | - Anders Ø Madsen
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Jukka Rantanen
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
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5
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Ravichandran SA, Hutfles J, Velasco J, Killgore J, Pellegrino J. Surface versus bulk CaCO3 crystals with ethylene vinyl alcohol co-polymers and polyamide thin-film composite membranes. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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6
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Park H, Ha ES, Kim MS. Physicochemical analysis techniques specialized in surface characterization of inhalable dry powders. JOURNAL OF PHARMACEUTICAL INVESTIGATION 2021. [DOI: 10.1007/s40005-021-00526-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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7
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Herzberg M, Larsen AS, Hassenkam T, Madsen AØ, Rantanen J. In situ nanoscale visualization of solvent effects on molecular crystal surfaces. CrystEngComm 2021. [DOI: 10.1039/d1ce00209k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomic force microscopy and molecular dynamics simulations probed the crystallinity and hydrophobicity of a paracetamol crystal surface in water–ethanol mixtures. We observe the formation of a dynamic heterogenous disordered surface (DHDS) layer.
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Affiliation(s)
- Mikkel Herzberg
- Department of Pharmacy
- University of Copenhagen
- 2100 Copenhagen
- Denmark
| | - Anders S. Larsen
- Department of Pharmacy
- University of Copenhagen
- 2100 Copenhagen
- Denmark
| | - Tue Hassenkam
- Globe Institute
- University of Copenhagen
- 1350 Copenhagen
- Denmark
| | - Anders Ø. Madsen
- Department of Pharmacy
- University of Copenhagen
- 2100 Copenhagen
- Denmark
| | - Jukka Rantanen
- Department of Pharmacy
- University of Copenhagen
- 2100 Copenhagen
- Denmark
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8
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Lansakara TI, Tong F, Bardeen CJ, Tivanski AV. Mechanical Properties and Photomechanical Fatigue of Macro- and Nanodimensional Diarylethene Molecular Crystals. NANO LETTERS 2020; 20:6744-6749. [PMID: 32822202 DOI: 10.1021/acs.nanolett.0c02631] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The diarylethene derivative, 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene, undergoes a reversible photoisomerization between its ring-open and ring-closed forms in the solid-state and has applications as a photomechanical material. Mechanical properties of macrocrystals, nanowire single crystals, and amorphous films as a function of multiple sequential UV and visible light exposures have been quantified using atomic force microscopy nanoindentation. The isomerization reaction has no effect on the elastic modulus of each solid. But going from the macro- to the nanowire crystal results in a remarkable over 3-fold decrease in the elastic modulus. The macrocrystal and amorphous solids are highly resistant to photomechanical fatigue, while nanowire crystals show clear evidence of photomechanical fatigue attributed to a transition from crystal to amorphous forms. This study provides first experimental evidence of size-dependent photomechanical fatigue in photoreactive molecular crystalline solids and suggests crystal morphology and size must be considered for future photomechanical applications.
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Affiliation(s)
| | - Fei Tong
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Christopher J Bardeen
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Alexei V Tivanski
- Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242, United States
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9
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Maddali H, House KL, Emge TJ, O'Carroll DM. Identification of the local electrical properties of crystalline and amorphous domains in electrochemically doped conjugated polymer thin films. RSC Adv 2020; 10:21454-21463. [PMID: 35518769 PMCID: PMC9054526 DOI: 10.1039/d0ra02796k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022] Open
Abstract
Doped polymer thin films have several applications in electronic, optoelectronic and thermoelectric devices. Often the electrical properties of doped conjugated polymer thin films are affected by their local physical and mechanical characteristics. However, investigations into the effects of doping on local domain properties have not been carried out. Here, we study the physical, mechanical and optical properties of electrochemically doped P3HT thin films at the nanoscale and establish a relation between doping level and the physical properties of P3HT thin films. Bulk crystallinity of both pristine and doped P3HT thin films, characterized using grazing incidence X-ray diffraction, shows a clear loss in crystallinity upon doping. Nanoscale crystalline and amorphous domains in the films are visualized by multimode atomic force microscopy (AFM). It is apparent that the crystalline domains are most affected by doping and have a higher degree of doping compared to amorphous domains. This results in crystalline domains exhibiting superior electrical conductivity at a local level. These results are further supported by Raman mapping and elemental analysis of doped films. A direct relation is established between the physical, mechanical and electrical properties of doped P3HT thin films based on the AFM data. The findings demonstrate that higher dopant concentrations are found in crystalline domains compared to amorphous domains, which has not been shown before to the best of our knowledge. This study can be used to optimize the electronic properties of doped P3HT thin films for use in electronic and optoelectronic device applications.
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Affiliation(s)
- Hemanth Maddali
- Department of Chemistry and Chemical Biology, Rutgers University 610 Taylor Road., Piscataway NJ 08854 USA
| | - Krystal L House
- Department of Chemistry and Chemical Biology, Rutgers University 610 Taylor Road., Piscataway NJ 08854 USA
| | - Thomas J Emge
- Department of Chemistry and Chemical Biology, Rutgers University 610 Taylor Road., Piscataway NJ 08854 USA
| | - Deirdre M O'Carroll
- Department of Chemistry and Chemical Biology, Rutgers University 610 Taylor Road., Piscataway NJ 08854 USA
- Department of Materials Science and Engineering, Rutgers University 607 Taylor Rd., Piscataway NJ 08854 USA
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10
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Zhao Z, Katai H, Higashi K, Ueda K, Kawakami K, Moribe K. Cryo-TEM and AFM Observation of the Time-Dependent Evolution of Amorphous Probucol Nanoparticles Formed by the Aqueous Dispersion of Ternary Solid Dispersions. Mol Pharm 2019; 16:2184-2198. [DOI: 10.1021/acs.molpharmaceut.9b00158] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Zhijing Zhao
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Hiroaki Katai
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Kenjirou Higashi
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Keisuke Ueda
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Kohsaku Kawakami
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Kunikazu Moribe
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
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11
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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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12
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Badal Tejedor M, Nordgren N, Schuleit M, Pazesh S, Alderborn G, Millqvist-Fureby A, Rutland MW. Determination of Interfacial Amorphicity in Functional Powders. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:920-926. [PMID: 28045271 DOI: 10.1021/acs.langmuir.6b03969] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The nature of the surfaces of particles of pharmaceutical ingredients, food powders, and polymers is a determining factor for their performance in for example tableting, powder handling, or mixing. Changes on the surface structure of the material will impact the flow properties, dissolution rate, and tabletability of the powder blend. For crystalline materials, surface amorphization is a phenomenon which is known to impact performance. Since it is important to measure and control the level of amorphicity, several characterization techniques are available to determine the bulk amorphous content of a processed material. The possibility of characterizing the degree of amorphicity at the surface, for example by studying the mechanical properties of the particles' surface at the nanoscale, is currently only offered by atomic force microscopy (AFM). The AFM PeakForce QNM technique has been used to measure the variation in energy dissipation (eV) at the surface of the particles which sheds light on the mechanical changes occurring as a result of amorphization or recrystallization events. Two novel approaches for the characterization of amorphicity are presented here. First, since particles are heterogeneous, we present a methodology to present the results of extensive QNM analysis of multiple particles in a coherent and easily interpreted manner, by studying cumulative distributions of dissipation data with respect to a threshold value which can be used to distinguish the crystalline and amorphous states. To exemplify the approach, which is generally applicable to any material, reference materials of purely crystalline α-lactose monohydrate and completely amorphous spray dried lactose particles were compared to a partially amorphized α-lactose monohydrate sample. Dissipation data are compared to evaluations of the lactose samples with conventional AFM and SEM showing significant topographical differences. Finally, the recrystallization of the surface amorphous regions in response to humidity was followed by studying the dissipation response of a well-defined surface region over time, which confirms both that dissipation measurement is a useful measure of surface amorphicity and that significant recrystallization occurs at the surface in response to humidity.
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Affiliation(s)
- Maria Badal Tejedor
- SP Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden , Box 5607, SE-114 86 Stockholm, Sweden
- Division of Surface and Corrosion Science, KTH Royal Institute of Technology , Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Niklas Nordgren
- SP Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden , Box 5607, SE-114 86 Stockholm, Sweden
| | - Michael Schuleit
- Novartis Institutes for Biomedical Research, GDC, Novartis Pharma AG , Novartis Campus, 4002 Basel, Switzerland
| | - Samaneh Pazesh
- Department of Pharmacy, Uppsala University , Uppsala, Sweden
| | - Göran Alderborn
- Department of Pharmacy, Uppsala University , Uppsala, Sweden
| | - Anna Millqvist-Fureby
- SP Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden , Box 5607, SE-114 86 Stockholm, Sweden
| | - Mark W Rutland
- SP Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden , Box 5607, SE-114 86 Stockholm, Sweden
- Division of Surface and Corrosion Science, KTH Royal Institute of Technology , Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
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13
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Monitoring the recrystallisation of amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering. Int J Pharm 2016; 508:71-82. [DOI: 10.1016/j.ijpharm.2016.04.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/22/2016] [Accepted: 04/27/2016] [Indexed: 11/23/2022]
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14
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Lu M, Xing H, Yang T, Yu J, Yang Z, Sun Y, Ding P. Dissolution enhancement of tadalafil by liquisolid technique. Pharm Dev Technol 2016; 22:77-89. [PMID: 27268461 DOI: 10.1080/10837450.2016.1189563] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This study aimed to enhance the dissolution of tadalafil, a poorly water-soluble drug by applying liquisolid technique. The effects of two critical formulation variables, namely drug concentration (17.5% and 35%, w/w) and excipients ratio (10, 15 and 20) on dissolution rates were investigated. Pre-compression tests, including particle size distribution, flowability determination, Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and scanning electron microscopy (SEM), were carried out to investigate the mechanism of dissolution enhancement. Tadalafil liquisolid tablets were prepared and their quality control tests, dissolution study, contact angle measurement, Raman mapping, and storage stability test were performed. The results suggested that all the liquisolid tablets exhibited significantly higher dissolution rates than the conventional tablets and pure tadalafil. FT-IR spectrum reflected no drug-excipient interactions. DSC and XRD studies indicated reduction in crystallinity of tadalafil, which was further confirmed by SEM and Raman mapping outcomes. The contact angle measurement demonstrated obvious increase in wetting property. Taken together, the reduction of particle size and crystallinity, and the improvement of wettability were the main mechanisms for the enhanced dissolution rate. No significant changes were observed in drug crystallinity and dissolution behavior after storage based on XRD, SEM and dissolution results.
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Affiliation(s)
- Mei Lu
- a School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Haonan Xing
- a School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Tianzhi Yang
- b Department of Basic Pharmaceutical Sciences , School of Pharmacy, Husson University , Bangor , ME , USA
| | - Jiankun Yu
- a School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Zhen Yang
- a School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Yanping Sun
- a School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
| | - Pingtian Ding
- a School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China
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15
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Iuraş A, Scurr DJ, Boissier C, Nicholas ML, Roberts CJ, Alexander MR. Imaging of Crystalline and Amorphous Surface Regions Using Time-of-Flight Secondary-Ion Mass Spectrometry (ToF-SIMS): Application to Pharmaceutical Materials. Anal Chem 2016; 88:3481-7. [DOI: 10.1021/acs.analchem.5b02621] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreea Iuraş
- Laboratory
of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, England
| | - David J. Scurr
- Laboratory
of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, England
| | | | - Mark L. Nicholas
- AstraZeneca R&D Mölndal, Pepparedsleden 1, Mölndal, SE-431 83, Sweden
| | - Clive J. Roberts
- Laboratory
of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, England
| | - Morgan R. Alexander
- Laboratory
of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, England
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16
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Raphael AP, Crichton ML, Falconer RJ, Meliga S, Chen X, Fernando GJP, Huang H, Kendall MAF. Formulations for microprojection/microneedle vaccine delivery: Structure, strength and release profiles. J Control Release 2016; 225:40-52. [PMID: 26795684 DOI: 10.1016/j.jconrel.2016.01.027] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/25/2015] [Accepted: 01/12/2016] [Indexed: 10/22/2022]
Abstract
To develop novel methods for vaccine delivery, the skin is viewed as a high potential target, due to the abundance of immune cells that reside therein. One method, the use of dissolving microneedle technologies, has the potential to achieve this, with a range of formulations now being employed. Within this paper we assemble a range of methods (including FT-FIR using synchrotron radiation, nanoindentation and skin delivery assays) to systematically examine the effect of key bulking agents/excipients - sugars/polyols - on the material form, structure, strength, failure properties, diffusion and dissolution for dissolving microdevices. We investigated concentrations of mannitol, sucrose, trehalose and sorbitol from 1:1 to 30:1 with carboxymethylcellulose (CMC), although mannitol did not form our micro-structures so was discounted early in the study. The other formulations showed a variety of crystalline (sorbitol) and amorphous (sucrose, trehalose) structures, when investigated using Fourier transform far infra-red (FT-FIR) with synchrotron radiation. The crystalline structures had a higher elastic modulus than the amorphous formulations (8-12GPa compared to 0.05-11GPa), with sorbitol formulations showing a bimodal distribution of results including both amorphous and crystalline behaviour. In skin, diffusion properties were similar among all formulations with dissolution occurring within 5s for our small projection array structures (~100μm in length). Overall, slight variations in formulation can significantly change the ability of our projections to perform their required function, making the choice of bulking/vaccine stabilising agents of great importance for these devices.
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Affiliation(s)
- Anthony P Raphael
- The University of Queensland, Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, QLD 4072, Australia
| | - Michael L Crichton
- The University of Queensland, Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, QLD 4072, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, Australia
| | - Robert J Falconer
- University of Sheffield, Department of Chemical & Biological Engineering, ChELSI Institute, Sheffield S1 3JD, England, United Kingdom
| | - Stefano Meliga
- The University of Queensland, Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, QLD 4072, Australia
| | - Xianfeng Chen
- The University of Queensland, Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, QLD 4072, Australia
| | - Germain J P Fernando
- The University of Queensland, Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, QLD 4072, Australia
| | - Han Huang
- The University of Queensland, School of Mechanical and Mining Engineering, QLD 4072, Australia
| | - Mark A F Kendall
- The University of Queensland, Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, QLD 4072, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, Australia; The University of Queensland, Faculty of Medicine and Biomedical Sciences, Royal Brisbane and Women's Hospital, Herston, Queensland 4006, Australia.
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17
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Nie H, Liu Z, Marks BC, Taylor LS, Byrn SR, Marsac PJ. Analytical approaches to investigate salt disproportionation in tablet matrices by Raman spectroscopy and Raman mapping. J Pharm Biomed Anal 2016; 118:328-337. [DOI: 10.1016/j.jpba.2015.10.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 10/22/2022]
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18
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Weiss C, McLoughlin P, Cathcart H. Characterisation of dry powder inhaler formulations using atomic force microscopy. Int J Pharm 2015; 494:393-407. [DOI: 10.1016/j.ijpharm.2015.08.051] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 07/27/2015] [Accepted: 08/17/2015] [Indexed: 11/30/2022]
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19
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Egami K, Higashi K, Yamamoto K, Moribe K. Crystallization of Probucol in Nanoparticles Revealed by AFM Analysis in Aqueous Solution. Mol Pharm 2015; 12:2972-80. [PMID: 26106951 DOI: 10.1021/acs.molpharmaceut.5b00236] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The crystallization behavior of a pharmaceutical drug in nanoparticles was directly evaluated by atomic force microscopy (AFM) force curve measurements in aqueous solution. A ternary spray-dried sample (SPD) was prepared by spray drying the organic solvent containing probucol (PBC), hypromellose (HPMC), and sodium dodecyl sulfate (SDS). The amorphization of PBC in the ternary SPD was confirmed by powder X-ray diffraction (PXRD) and solid-state 13C NMR measurements. A nanosuspension containing quite small particles of 25 nm in size was successfully prepared immediately after dispersion of the ternary SPD into water. Furthermore, solution-state 1H NMR measurements revealed that a portion of HPMC coexisted with PBC as a mixed state in the freshly prepared nanosuspension particles. After storing the nanosuspension at 25 °C, a gradual increase in the size of the nanoparticles was observed, and the particle size changed to 93.9 nm after 7 days. AFM enabled the direct observation of the morphology and agglomeration behavior of the nanoparticles in water. Moreover, AFM force-distance curves were changed from (I) to (IV), depending on the storage period, as follows: (I) complete indentation within an applied force of 1 nN, (II) complete indentation with an applied force of 1-5 nN, (III) partial indentation with an applied force of 5 nN, and (IV) nearly no indentation with an applied force of 5 nN. This stiffness increase of the nanoparticles was attributed to gradual changes in the molecular state of PBC from the amorphous to the crystal state. Solid-state 13C NMR measurements of the freeze-dried samples demonstrated the presence of metastable PBC Form II crystals in the stored nanosuspension, strongly supporting the AFM results.
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Affiliation(s)
- Kiichi Egami
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Kenjirou Higashi
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Keiji Yamamoto
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Kunikazu Moribe
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
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Decoupling the Contribution of Surface Energy and Surface Area on the Cohesion of Pharmaceutical Powders. Pharm Res 2014; 32:248-59. [DOI: 10.1007/s11095-014-1459-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/02/2014] [Indexed: 11/28/2022]
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21
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Whiteside PT, Zhang J, Parker AP, Madden-Smith CE, Patel N, Jensen J, Sloth J, Roberts CJ. A physical and chemical comparison of material from a conventional spray-dried system and a single particle spray-dried system. Int J Pharm 2013; 455:306-11. [DOI: 10.1016/j.ijpharm.2013.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/04/2013] [Indexed: 01/08/2023]
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22
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Morphology, nanomechanical and thermodynamic surface characteristics of nylon 6/feather keratin blend films: an atomic force microscopy investigation. POLYM INT 2012. [DOI: 10.1002/pi.3227] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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23
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24
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Lauer ME, Grassmann O, Siam M, Tardio J, Jacob L, Page S, Kindt JH, Engel A, Alsenz J. Atomic force microscopy-based screening of drug-excipient miscibility and stability of solid dispersions. Pharm Res 2011; 28:572-84. [PMID: 21046435 PMCID: PMC3044090 DOI: 10.1007/s11095-010-0306-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 10/13/2010] [Indexed: 10/26/2022]
Abstract
PURPOSE Development of a method to assess the drug/polymer miscibility and stability of solid dispersions using a melt-based mixing method. METHODS Amorphous fractured films are prepared and characterized with Raman Microscopy in combination with Atomic Force Microscopy to discriminate between homogenously and heterogeneously mixed drug/polymer combinations. The homogenous combinations are analyzed further for physical stability under stress conditions, such as increased humidity or temperature. RESULTS Combinations that have the potential to form a molecular disperse mixture are identified. Their potential to phase separate is determined through imaging at molecular length scales, which results in short observation time. De-mixing is quantified by phase separation analysis, and the drug/polymer combinations are ranked to identify the most stable combinations. CONCLUSIONS The presented results demonstrate that drug/polymer miscibility and stability of solid dispersions, with many mechanistic details, can be analyzed with Atomic Force Microscopy. The assay allows to identify well-miscible and stable combinations within hours or a few days.
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Affiliation(s)
- Matthias Eckhard Lauer
- Center for Cellular Imaging and Nanoanalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH 4006 Basel, Switzerland.
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25
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Weuts I, Van Dycke F, Voorspoels J, De Cort S, Stokbroekx S, Leemans R, Brewster ME, Xu D, Segmuller B, Turner YTA, Roberts CJ, Davies MC, Qi S, Craig DQ, Reading M. Physicochemical Properties of the Amorphous Drug, Cast Films, and Spray Dried Powders to Predict Formulation Probability of Success for Solid Dispersions: Etravirine. J Pharm Sci 2011; 100:260-74. [DOI: 10.1002/jps.22242] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 11/08/2022]
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26
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Gordon KC, McGoverin CM. Raman mapping of pharmaceuticals. Int J Pharm 2010; 417:151-62. [PMID: 21194560 DOI: 10.1016/j.ijpharm.2010.12.030] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 12/21/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
Abstract
Raman spectroscopy may be implemented through a microscope to provide fine scale axial and lateral chemical maps. The molecular structure of many drugs makes Raman spectroscopy particularly well suited to the investigation of pharmaceutical systems. Chemometric methods currently used to assess bulk Raman spectroscopic data are typically applied to Raman mapping data from pharmaceuticals; few reports exist where the spatial information inherent to a mapped dataset is used for the calculation of chemical maps. Both univariate and multivariate methods have been applied to Raman mapping data to determine the distribution of active pharmaceutical ingredients (APIs) in tablets, solid dispersions for increased solubility and controlled release devices. The ability to axially (depth) profile using Raman mapping has been used in studies of API penetration through membranes, cellular uptake of drug delivery liposomes, and initial API distribution and subsequent elution from coatings of medical devices. New instrumental developments will increase the efficiency of Raman mapping and lead to greater utilisation of Raman mapping for analyses of pharmaceutical systems.
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Affiliation(s)
- Keith C Gordon
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Chemistry Department, University of Otago, Dunedin 9054, New Zealand
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27
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Crean B, Parker A, Roux DL, Perkins M, Luk SY, Banks SR, Melia CD, Roberts CJ. Elucidation of the internal physical and chemical microstructure of pharmaceutical granules using X-ray micro-computed tomography, Raman microscopy and infrared spectroscopy. Eur J Pharm Biopharm 2010; 76:498-506. [DOI: 10.1016/j.ejpb.2010.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 08/05/2010] [Accepted: 08/22/2010] [Indexed: 10/19/2022]
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Detection of trace crystallinity in an amorphous system using Raman microscopy and chemometric analysis. Eur J Pharm Sci 2010; 42:45-54. [PMID: 20969956 DOI: 10.1016/j.ejps.2010.10.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 08/26/2010] [Accepted: 10/13/2010] [Indexed: 11/21/2022]
Abstract
A novel analytical method to detect and characterize active pharmaceutical ingredient (API) trace crystallinity in an amorphous system using Raman microscopy and chemometric methods, namely band-target entropy minimization (BTEM) and target transformation factor analysis (TTFA) is developed. The method starts with Raman mapping measurements performed on some random areas of the amorphous system. This is followed by chemometric data analysis. In the case of a system without any a priori information, the BTEM algorithm is used to recover a set of pure component Raman spectral estimates followed by component and/or crystal structure identification. In the case of a system with some a priori information, TTFA is used to predict the presence or existence of a suspected component and/or crystal structure in the observed system. Four different amorphous systems were used as models. It is demonstrated that combined Raman microscopy and chemometric methods (BTEM or TTFA) outperformed powder X-ray diffraction (PXRD) in detecting trace crystallinity in amorphous systems. The spatial distributions of drug and polymer can also be directly obtained in order to study the homogeneity of the APIs in the solid dispersions. The present methodology appears very general and applicable to many other types of systems.
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Planins̄ek O, Zadnik J, Kunaver M, Src̄ic̄ S, Godec A. Structural evolution of indomethacin particles upon milling: Time‐resolved quantification and localization of disordered structure studied by IGC and DSC. J Pharm Sci 2010; 99:1968-81. [DOI: 10.1002/jps.21986] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Perkins M, Bunker M, James J, Rigby-Singleton S, Ledru J, Madden-Smith C, Luk S, Patel N, Roberts C. Towards the understanding and prediction of material changes during micronisation using atomic force microscopy. Eur J Pharm Sci 2009; 38:1-8. [DOI: 10.1016/j.ejps.2009.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 04/29/2009] [Accepted: 05/06/2009] [Indexed: 10/20/2022]
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32
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Furuyama N, Hasegawa S, Hamaura T, Yada S, Nakagami H, Yonemochi E, Terada K. Evaluation of solid dispersions on a molecular level by the Raman mapping technique. Int J Pharm 2008; 361:12-8. [DOI: 10.1016/j.ijpharm.2008.05.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 04/25/2008] [Accepted: 05/01/2008] [Indexed: 11/26/2022]
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Pharmaceutical applications of vibrational chemical imaging and chemometrics: a review. J Pharm Biomed Anal 2008; 48:533-53. [PMID: 18819769 DOI: 10.1016/j.jpba.2008.08.014] [Citation(s) in RCA: 273] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 08/04/2008] [Accepted: 08/09/2008] [Indexed: 11/20/2022]
Abstract
The emergence of chemical imaging (CI) has gifted spectroscopy an additional dimension. Chemical imaging systems complement chemical identification by acquiring spatially located spectra that enable visualization of chemical compound distributions. Such techniques are highly relevant to pharmaceutics in that the distribution of excipients and active pharmaceutical ingredient informs not only a product's behavior during manufacture but also its physical attributes (dissolution properties, stability, etc.). The rapid image acquisition made possible by the emergence of focal plane array detectors, combined with publication of the Food and Drug Administration guidelines for process analytical technology in 2001, has heightened interest in the pharmaceutical applications of CI, notably as a tool for enhancing drug quality and understanding process. Papers on the pharmaceutical applications of CI have been appearing in steadily increasing numbers since 2000. The aim of the present paper is to give an overview of infrared, near-infrared and Raman imaging in pharmaceutics. Sections 2 and 3 deal with the theory, device set-ups, mode of acquisition and processing techniques used to extract information of interest. Section 4 addresses the pharmaceutical applications.
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34
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Chow K, Tong HH, Lum S, Chow AH. Engineering of Pharmaceutical Materials: An Industrial Perspective. J Pharm Sci 2008; 97:2855-77. [DOI: 10.1002/jps.21212] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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35
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Šašić S. Chemical imaging of pharmaceutical granules by Raman global illumination and near-infrared mapping platforms. Anal Chim Acta 2008; 611:73-9. [DOI: 10.1016/j.aca.2008.01.063] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/11/2008] [Accepted: 01/20/2008] [Indexed: 11/30/2022]
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Turner YTA, Roberts CJ, Davies MC. Scanning probe microscopy in the field of drug delivery. Adv Drug Deliv Rev 2007; 59:1453-73. [PMID: 17920719 DOI: 10.1016/j.addr.2007.08.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 08/10/2007] [Indexed: 01/14/2023]
Abstract
The scanning probe microscopes (SPMs) are a group of powerful surface sensitive instruments which when used complimentarily with traditional analytical techniques can provide invaluable, definitive information aiding our understanding and development of drug delivery systems. In this review, the main use of the SPMs (particularly the atomic force microscopy (AFM)) and their successes in forwarding drug delivery are highlighted and categorised into two interlinked sections namely, preformulation and formulation. SPM in preformulation concentrates on applications in pharmaceutical processes including, crystal morphology and modification, discriminating polymorphs, drug dissolution and release, solid state stability and interaction. The ability of the AFM to detect forces between different surfaces and at the same time to operate in liquids or controlled humidity and defined temperatures has also been particularly useful in the study of drug delivery. In formulation, the use of SPMs in different drug delivery systems is discussed in light of different host entry routes.
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Affiliation(s)
- Ya Tsz A Turner
- Laboratory of Biophysics and Surface Analysis, School of Pharmacy, The University of Nottingham, NG7 2RD, UK
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Mansour HM, Hickey AJ. Raman characterization and chemical imaging of biocolloidal self-assemblies, drug delivery systems, and pulmonary inhalation aerosols: a review. AAPS PharmSciTech 2007; 8:E99. [PMID: 18181559 PMCID: PMC2750560 DOI: 10.1208/pt0804099] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 03/07/2007] [Accepted: 03/18/2007] [Indexed: 12/29/2022] Open
Abstract
This review presents an introduction to Raman scattering and describes the various Raman spectroscopy, Raman microscopy, and chemical imaging techniques that have demonstrated utility in biocolloidal self-assemblies, pharmaceutical drug delivery systems, and pulmonary research applications. Recent Raman applications to pharmaceutical aerosols in the context of pulmonary inhalation aerosol delivery are discussed. The "molecular fingerprint" insight that Raman applications provide includes molecular structure, drug-carrier/excipient interactions, intramolecular and intermolecular bonding, surface structure, surface and interfacial interactions, and the functional groups involved therein. The molecular, surface, and interfacial properties that Raman characterization can provide are particularly important in respirable pharmaceutical powders, as these particles possess a higher surface-area-to-volume ratio; hence, understanding the nature of these solid surfaces can enable their manipulation and tailoring for functionality at the nanometer level for targeted pulmonary delivery and deposition. Moreover, Raman mapping of aerosols at the micro- and nanometer level of resolution is achievable with new, sophisticated, commercially available Raman microspectroscopy techniques. This noninvasive, highly versatile analytical and imaging technique exhibits vast potential for in vitro and in vivo molecular investigations of pulmonary aerosol delivery, lung deposition, and pulmonary cellular drug uptake and disposition in unfixed living pulmonary cells.
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Affiliation(s)
- Heidi M Mansour
- University of North Carolina at Chapel Hill, School of Pharmacy, Division of Molecular Pharmaceutics, Campus Box #7360, 311 Pharmacy Lane, 1311 Kerr Hall, Dispersed Systems Laboratory, Chapel Hill, NC 27599-7360, USA.
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38
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Hickey AJ, Mansour HM, Telko MJ, Xu Z, Smyth HDC, Mulder T, McLean R, Langridge J, Papadopoulos D. Physical characterization of component particles included in dry powder inhalers. I. Strategy review and static characteristics. J Pharm Sci 2007; 96:1282-301. [PMID: 17455324 DOI: 10.1002/jps.20916] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The performance of dry powder aerosols for the delivery of drugs to the lungs has been studied extensively in the last decade. The focus for different research groups has been on aspects of the powder formulation, which relate to solid state, surface and interfacial chemistry, bulk properties (static and dynamic) and measures of performance. The nature of studies in this field, tend to be complex and correlations between specific properties and performance seem to be rare. Consequently, the adoption of formulation approaches that on a predictive basis lead to desirable performance has been an elusive goal but one that many agree is worth striving towards. The purpose of this paper is to initiate a discussion of the use of a variety of techniques to elucidate dry particle behavior that might guide the data collection process. If the many researchers in this field can agree on this, or an alternative, guide then a database can be constructed that would allow predictive models to be developed. This is the first of two papers that discuss static and dynamic methods of characterizing dry powder inhaler formulations.
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Affiliation(s)
- Anthony J Hickey
- Division of Molecular Pharmaceutics, School of Pharmacy, University of North Carolina, Campus Box #7360, 1310 Kerr Hall, Kerr Hall, Chapel Hill, North Carolina 27599-7360, USA.
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39
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Harding L, King WP, Dai X, Craig DQM, Reading M. Nanoscale characterisation and imaging of partially amorphous materials using local thermomechanical analysis and heated tip AFM. Pharm Res 2007; 24:2048-54. [PMID: 17554606 DOI: 10.1007/s11095-007-9339-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Accepted: 05/07/2007] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose is to investigate the use of thermal nanoprobes in thermomechanical and heated tip pulsed force modes as novel means of discriminating between amorphous and crystalline material on a sub-micron scale. MATERIALS AND METHODS Indometacin powder was compressed and partially converted into amorphous material. Thermal nanoprobes were used to perform localised thermomechanical analysis (L-TMA) and heated tip pulsed force mode imaging as a function of temperature. RESULTS L-TMA with submicron lateral spatial resolution and sub-100 nm depth penetration was achieved, allowing us to thermomechanically discriminate between amorphous and crystalline material at a nanoscale for the first time. The amorphous and crystalline regions were imaged as a function of temperature using heated tip pulsed force AFM and a resolution of circa 50 nm was achieved. We are also able to observe tip-induced recrystallisation of the amorphous material. DISCUSSION The study demonstrates that we are able to discriminate and characterise amorphous and crystalline regions at a submicron scale of scrutiny. We have demonstrated the utility of two methods, L-TMA and heated tip pulsed force mode AFM, that allow us to respectively characterise and image adjacent amorphous and crystalline regions at a nanoscale. CONCLUSIONS The study has demonstrated that thermal nanoprobes represent a novel method of characterising and imaging partially amorphous materials.
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Affiliation(s)
- Ljiljana Harding
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
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40
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Perkins M, Ebbens SJ, Hayes S, Roberts CJ, Madden CE, Luk SY, Patel N. Elastic modulus measurements from individual lactose particles using atomic force microscopy. Int J Pharm 2007; 332:168-75. [PMID: 17074456 DOI: 10.1016/j.ijpharm.2006.09.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 09/19/2006] [Accepted: 09/21/2006] [Indexed: 10/24/2022]
Abstract
The elastic modulus of pharmaceutical materials affects a number of pharmaceutical processes and subsequently formulation performance and is currently assessed by bulk methods, such as beam bending of compacts. Here we demonstrate the accurate measurement of the elastic modulus of alpha monohydrate lactose from the dominant (011) face of single crystals using atomic force microscopy (AFM) as 3.45+/-0.90GPa. The criteria to ensure this data is recorded within the elastic limit and can be modelled using Hertzian theory are established. We compare and contrast this AFM method to a permanent indentation technique based upon a much larger Berkovich pyramidal indenter on a lactose compact and the wider literature. Finally the AFM was utilized to study the elastic response of amorphous lactose, demonstrating that the physical state of the amorphous material changes under repeated loading and behaves in a more crystalline manner under repeated force measurements, suggesting a pressure induced phase transition. The AFM based approach demonstrated has the significant advantages of requiring minimal sample, no need for producing a compact, being non-destructive in that no permanent indent is required and providing a technique capable of detecting variations in material properties across a single particle or a number of particles.
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Affiliation(s)
- Mark Perkins
- Molecular Profiles Ltd., 8 Orchard Place, Nottingham Business Park, Nottingham NG8 6PX, UK
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41
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Zhang J, Ebbens S, Chen X, Jin Z, Luk S, Madden C, Patel N, Roberts CJ. Determination of the Surface Free Energy of Crystalline and Amorphous Lactose by Atomic Force Microscopy Adhesion Measurement. Pharm Res 2006; 23:401-7. [PMID: 16421667 DOI: 10.1007/s11095-005-9144-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Accepted: 10/17/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE This study was conducted to accurately measure the dispersive surface free energy of lactose solids in ordered and disordered states. METHODS Atomic force microscopy (AFM) was used to determine the contact adhesion force between an AFM tip and lactose under low humidity (ca. 1% RH). The geometry of the tip contacting apex was characterized by scanning a porous aluminum film with ultrasharp spikes (radius 2-3 nm). A sphere vs. flat surface model was employed to relate the adhesion force determined to the surface energy based upon the Johnson-Kendal-Roberts theory. Spray-dried amorphous lactose in a compressed-disk form and single crystals of alpha-lactose monohydrate were prepared as model samples. RESULTS The condition of the smooth sample surface and sphere-shaped tip used was shown to be appropriate to the application of the JKR model. The surface energy of crystalline [(0,-1,-1) face] and amorphous lactose was determined to be 23.3 +/- 2.3 and 57.4 +/- 7.9 mJ m(-2), respectively. CONCLUSIONS We have demonstrated the capability of AFM to measure the dispersive surface free energy of pharmaceutical materials directly through a blank probe at the nanometer scale. These data, although consistent with results from more traditional methods, illustrate some unique attributes of this approach, namely, surface energies are directly derived from solid-solid interactions, measurements may be made on specific crystalline faces, and the potential exists to identify the submicron heterogeneity of organic solids in terms of their molecular energy states (such as ordered and disordered lactose).
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Affiliation(s)
- Jianxin Zhang
- Molecular Profiles Ltd., 8 Orchard Place, Nottingham Business Park, Nottingham, NG8 6PX, UK
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