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Acta of Bioengineering and Biomechanics 2018Electrophysical stimulation is used to support fracture healing and bone regeneration. For design optimization of electrostimulative implants, in combination with...
Determination of electrophysical and structural properties of human cancellous bone and synthetic bone substitute material using impedance spectroscopy and X-ray powder diffraction.
Electrophysical stimulation is used to support fracture healing and bone regeneration. For design optimization of electrostimulative implants, in combination with applied human donor bone or synthetic bone scaffolds, the knowledge of electrophysical properties is fundamental. Hence further investigations of the structural properties of native and synthetic bone is of high interest to improve biofunctionality of bone scaffolds and subsequent healing of the bone defect. The investigation of these properties was taken as an objective of this study. Therefore, surgically extracted fresh cylindrical and consecutively ashed cancellous bone samples from human osteoarthritic femoral heads were characterized and compared to synthetic bone substitute material. Thereby, impedance spectroscopy is used to determine the electrophysical properties and X-ray powder diffraction (XRD) for analysis of structural information of the bone samples. Conductivity and permittivity of fresh and ashed cancellous bone amounted to 1.710-2 S/m and 7.5106 and 210-5 S/m and 7.2103, respectively. Electrical conductivity and dielectric permittivity of bone scaffold resulted in 1.710-7 S/m and 49. Analysis of the structural properties showed that the synthetic bone scaffolds made of Brushite exhibited some reflections which correspond to the native bone samples. The information in present study of the bone material (synthetic and autologous) could be used for later patient individual application of electrostimulative implants.
Topics: Bone Substitutes; Cancellous Bone; Dielectric Spectroscopy; Electric Conductivity; Femur Head; Humans; Minerals; Powder Diffraction; Tissue Scaffolds
PubMed: 29658523
DOI: No ID Found -
Pharmaceutical Development and... Feb 2017Only one crystal form of metoprolol succinate (Form I) was reported during previous researches and production. In this study, a new polymorph of metoprolol succinate...
Only one crystal form of metoprolol succinate (Form I) was reported during previous researches and production. In this study, a new polymorph of metoprolol succinate (here named as Form II) was discovered and investigated by X-ray diffraction, thermoanalysis and infrared spectroscopy. The results show its crystal structure and thermal properties are significantly different with Form I. Compared with Form I, Form II exhibits specific diffraction pattern, lower melting temperature and weaker hydrogen bond effect. The thermostability testing suggests Form II is a metastable crystal form and will gradually transform into Form I undergoing treatment of high temperature and humidity. Metastable crystal form generally has better dissolubility than its corresponding stable form. Subsequent measurement also verified that Form II can dissolve in the water more quickly than Form I.
Topics: Antihypertensive Agents; Crystallization; Drug Stability; Hydrogen Bonding; Metoprolol; Powder Diffraction; Solubility; Spectroscopy, Fourier Transform Infrared; Temperature; X-Ray Diffraction
PubMed: 26906168
DOI: 10.3109/10837450.2016.1146295 -
European Journal of Pharmaceutical... Mar 2019The direct quantification of Active Pharmaceutical Ingredients in solid formulations is a challenging open issue. A consolidated analytical technique based on X-ray...
The direct quantification of Active Pharmaceutical Ingredients in solid formulations is a challenging open issue. A consolidated analytical technique based on X-ray Powder Diffraction is available, being the definitive test for the identification of polymorphs and crystal phases. However, its application for quantitative analysis is hindered by matrix effects: refinement methods (e.g. Rietveld method) require a complete knowledge of samples' composition, while univariate calibration methods require the matrix effect to be studied and severely suffer from the co-presence of crystalline and amorphous phases in the sample. Multivariate analysis is the only way to bypass problems affecting refinements procedures and univariate calibration. In particular, the multivariate standard addition method (SAM) is promising; however, it is straightforward only when the analytical blank (matrix devoid of analyte) is available: in that case SAM is applied by simply extrapolating the SAM model to the matrix experimental signal. In this work, the quantitative analysis of polymorphic forms of Active Pharmaceutical Ingredients based on X-ray Powder Diffraction is performed for the first time by a method based on multivariate standard addition method combined with net analyte signal procedure; it allows for reliable quantification of polymorphs of active principles in solid formulations, which are rapidly analyzed without any sample pre-treatment. Two test cases are presented: quantification of two polymorphs of piracetam in binary mixtures (forms II and III), and quantification of paracetamol (form I) in Tachifludec®.
Topics: Acetaminophen; Analgesics, Non-Narcotic; Drug Compounding; Multivariate Analysis; Neuroprotective Agents; Piracetam; Powder Diffraction; X-Ray Diffraction
PubMed: 30654113
DOI: 10.1016/j.ejps.2019.01.014 -
International Journal of Pharmaceutics Oct 2017As powder agglomeration during storage causes a decrease in the performance of dry powder inhalers (DPIs), it is important to understand the properties of powder...
As powder agglomeration during storage causes a decrease in the performance of dry powder inhalers (DPIs), it is important to understand the properties of powder agglomeration in developing DPIs. Generally, powder agglomeration is caused by capillary force and crystalline transformation in conditions of higher humidity. It is, however, difficult to correlate crystalline transformation and powder agglomeration, especially when the crystalline transformation is limited. In this study, we focused on the application of inverse gas chromatography (iGC) to detect powder agglomeration directly. There was a slight change between the powder state and lactose agglomerates using powder X-ray diffraction, and dynamic vapor sorption. On the other hand, a change in pressure drop was found during measurement of lactose using iGC. After measurement by iGC, powdered lactose agglomerated. This finding suggests that a pressure drop is related to powder agglomeration and can be employed to detect the onset of powder agglomeration. Based on these findings, we propose a novel index-the Void Forming Index (VFI)-which is related to the pressure drop with iGC. The VFI is a useful index in the evaluation of powder agglomeration, and will be especially useful during DPI development.
Topics: Adhesiveness; Chemistry, Pharmaceutical; Chromatography, Gas; Dry Powder Inhalers; Lactose; Powder Diffraction; Powders; Pressure; X-Ray Diffraction
PubMed: 28842308
DOI: 10.1016/j.ijpharm.2017.08.085 -
International Journal of Pharmaceutics Jun 2020The development over the past decade of design strategies for cocrystal preparation have led to numerous methods for the synthesis of cocrystal without take care of...
The development over the past decade of design strategies for cocrystal preparation have led to numerous methods for the synthesis of cocrystal without take care of their influence on the precise structure and stability of cocrystalline states. On the other hand the mechanism of cocrystal formation remains widely unclear, especially the identification of the type of interactions mostly responsible for the cocrystalline stability. The present study focuses on the influence of the crystalline synthesis method on the polymorphism of cocrystals was analyzed from the preparation of S-ibuprofen/nicotinamide and RS-ibuprofen/nicotinamide cocrystals by co-milling, slow solvent evaporation and crystallization from the melt. X-ray diffraction and Raman spectroscopy experiments have shown that the polymorphic form of the cocrystals obtained by recrystallization from the melt (Form A) is different from that prepared by milling and by slow evaporation in solution (Form B). It was shown that both isothermal and non-isothermal recrystallizations from the melt blending are observed via a transient metastable micro/nano structure of form A. Additionally, it was observed that form A transforms into Form B upon heating via very weak changes in the hydrogen bond network. The crystallization in form A from the melt, instead of form B by other methods, was explained by the difficulty to form a supramolecular organization too far energetically from that existing in the melt. This study shows the crucial role of supramolecular H-bonding on the formation mechanism of cocrystals and how does the synthesis method of cocrystals change the supramolecular organization and the related structure of cocrystals.
Topics: Calorimetry, Differential Scanning; Crystallization; Ibuprofen; Niacinamide; Powder Diffraction; Spectrum Analysis, Raman; X-Ray Diffraction
PubMed: 32464230
DOI: 10.1016/j.ijpharm.2020.119454 -
Spectrochimica Acta. Part A, Molecular... Sep 2015This paper reports the temperature-dependent measurements in the C form of stearic acid. Raman scattering, X-ray diffraction, and differential scanning calorimetry...
This paper reports the temperature-dependent measurements in the C form of stearic acid. Raman scattering, X-ray diffraction, and differential scanning calorimetry measurements were performed at low temperatures. The polarized Raman spectra were measured for temperatures ranging from 8 to 300 K over the spectral range of 30-3000 cm(-1). The spectral changes observed in both the lattice vibrational modes and the internal vibrational modes regions of the Raman spectrum, allowed to identify a phase transition undergone by the stearic acid crystal occurring between 210 and 170 K and a change in the structure continues to be observed down to 8 K. The anharmonicity of some vibrational modes and the possible space groups presented by the crystal at low temperatures were also discussed. Low-temperature X-ray diffraction measurements were performed from 290 to 80 K and the results showed slight changes in the lattice parameters at ∼200 K. Furthermore, the evidence of the phase transformation was provided by the differential scanning calorimetry measurements, which identified an enthalpic anomaly at about 160 K.
Topics: Cold Temperature; Models, Molecular; Phase Transition; Powder Diffraction; Spectrum Analysis, Raman; Stearic Acids; X-Ray Diffraction
PubMed: 25909902
DOI: 10.1016/j.saa.2015.04.003 -
Journal of Pharmaceutical Sciences Aug 2018Owing to the increasing interest in multifunctional excipients for tableting, coprocessing of individual excipients is regularly used to produce excipients of improved...
Owing to the increasing interest in multifunctional excipients for tableting, coprocessing of individual excipients is regularly used to produce excipients of improved multifunctionality superior to individual excipients or their physical mix. The use of chitin as an excipient in tablet formulation is limited because of certain drawbacks such as poor flowability and low true density. The objective of this work is to improve these properties through coprocessing of chitin with calcium carbonate (CaCO) by precipitating CaCO on chitin particles using different methods. In addition, optimization of the coprocessed chitin was carried out to improve the excipient's properties. Physicochemical (CaCO content, true density, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy) and functional testing (swelling force, flowability, tensile strength, deformation mechanism, and disintegration time) were used to characterize the coprocessed product. Results showed that the calcite CaCO polymorph is precipitated on the chitin surface and that it interacts with chitin at carbonyl- and amide-group level. In addition, the coprocessed excipient has an improved true density and powder flowability, with CaCO forming single layer on the chitin particles surface. Tableting studies showed that the coprocessed powder exhibited an intermediate deformation behavior between CaCO (most brittle) and chitin (most plastic). Tablets showed acceptable tensile strength and rapid disintegration (2-4 s). These results show the potential use of coprocessed chitin-CaCO as a multifunctional excipient for fast disintegration of tablets produced by direct compression.
Topics: Calcium Carbonate; Chemical Precipitation; Chitin; Drug Compounding; Excipients; Powder Diffraction; Pressure; Solubility; Tablets; Tensile Strength; X-Ray Diffraction
PubMed: 29698724
DOI: 10.1016/j.xphs.2018.04.013 -
Current Drug Delivery 2021Current work focuses on the improvement of the solubility and dissolution of ACF by the cocrystal approach.
AIM
Current work focuses on the improvement of the solubility and dissolution of ACF by the cocrystal approach.
BACKGROUND
Aceclofenac (ACF) is one of the commonly used Nonsteroidal Anti-Inflammatory Drug (NSAID) representing a variety of therapeutic applications including management of pain, inflammation, rheumatoid arthritis, and osteoarthritis, . But very low solubility and dissolution rate of ACF compromise its therapeutic utility. Now a day's cocrystallization technique has emerged as a novel technique for modulation of the said problems.
OBJECTIVE
The Specific objectives of this research work were mechanochemical synthesis, characterization, and performance evaluation of aceclofenac cocrystal.
METHODS
ACF was screened with various pharmaceutically acceptable coformers (Selected from GRAS and EAFUS list) using MOPAC software and physical screening method to find out novel cocrystals of ACF with enhanced solubility and dissolution rate. Novel cocrystals (multi-component crystalline solid) of ACF with l-cystine were prepared by a neat grinding method and by liquid assisted grinding method. The synthesized cocrystals (ACF-l-CYS NG and ACF-l-CYS LAG) were characterized carefully by Differential Scanning Calorimetry (DSC), Infrared Spectroscopy (IR), and Powder XRay Diffraction (PXRD) to verify the formation of the cocrystals. Pharmaceutically significant properties such as powder dissolution rate, solubility, and stability of the prepared cocrystals were evaluated.
RESULTS
Compared to pure ACF, the prepared cocrystals showed superior solubility and dissolution rate. The prepared cocrystals were found to be stable and non-hygroscopic under study conditions.
CONCLUSION
The cocrystallization technique was successfully utilized to increase the solubility and dissolution rate of aceclofenac.
Topics: Calorimetry, Differential Scanning; Crystallization; Cystine; Diclofenac; Powder Diffraction; Solubility; X-Ray Diffraction
PubMed: 32807053
DOI: 10.2174/1567201817666200817110949 -
Pharmaceutical Development and... Feb 2017The objective of this study was to prepare ibuprofen (IBP) microparticles by pH-change method and enhance the dissolution rate in vitro. Tween80 and Cremophor RH40 were...
The objective of this study was to prepare ibuprofen (IBP) microparticles by pH-change method and enhance the dissolution rate in vitro. Tween80 and Cremophor RH40 were selected as stabilizers to change the microparticles morphology. The microparticles were evaluated by dissolution profiles and characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), laser particle size analyzer, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). IBP microparticle prepared with surfactants showed a significant increase in dissolution rate (more than three times within 10 min) and an obvious decrease in mean particle size. The morphology of microparticles was obviously changed. XRD and DSC results revealed that the crystalline state of the untreated IBP and the prepared IBP microparticles were similar. The crystallinity of microparticles produced might be lightly reduced by adding surfactants in preparation process. All results showed that it was useful to prepare high dispersion microparticle by adding surfactants in the preparation process for improving the dissolution.
Topics: Anti-Inflammatory Agents, Non-Steroidal; Calorimetry, Differential Scanning; Crystallization; Excipients; Ibuprofen; Particle Size; Polyethylene Glycols; Polysorbates; Powder Diffraction; Solubility; Spectroscopy, Fourier Transform Infrared; Surface-Active Agents; X-Ray Diffraction
PubMed: 27055726
DOI: 10.3109/10837450.2016.1163386 -
Bioorganic & Medicinal Chemistry Letters Mar 20156-Mercaptopurine (6-MP) is a clinically important antitumor drug. The commercially available form was provided as monohydrate and belongs to BCS class II category....
6-Mercaptopurine (6-MP) is a clinically important antitumor drug. The commercially available form was provided as monohydrate and belongs to BCS class II category. Co-crystallization screening by reaction crystallization method (RCM) and monitored by powder X-ray diffraction led to the discovery of a new co-crystal formed between 6-MP and isonicotinamide (co-crystal 1). Co-crystal 1 was thoroughly characterized by X-ray diffraction, FT-IR and Raman spectroscopy, and thermal analysis. Noticeably, the in vitro and in vivo studies revealed that co-crystal 1 possesses improved dissolution rate and superior bioavailability on animal model.
Topics: Animals; Antimetabolites, Antineoplastic; Crystallization; Crystallography, X-Ray; Mercaptopurine; Models, Molecular; Niacinamide; Powder Diffraction; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; X-Ray Diffraction
PubMed: 25630224
DOI: 10.1016/j.bmcl.2015.01.022