scholarly journals PREPARATION OF SPRAY DRIED COAMORPHOUS SOLIDS TO IMPROVE THE SOLUBILITY AND DISSOLUTION RATE OF ATORVASTATIN CALCIUM

2021 ◽  
Vol 83 (2) ◽  
pp. 77-83
Author(s):  
Yudi Wicaksono ◽  
Viddy Agustian Rosidi ◽  
Sri Yessika Saragih ◽  
Lyta Septi Fauziah ◽  
Dwi Setyawan
Keyword(s):  
Intermolecular Interactions ◽  
Single Phase ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Amorphous Form ◽  
Atorvastatin Calcium ◽  
Statin Drug ◽  
Low Solubility ◽  
Spray Dried

Atorvastatin calcium (AC) is a statin drug used to lower cholesterol. Its crystalline form is usually found in the market with low solubility properties. The amorphization of crystalline AC is a technique used to increase its solubility however; the amorphous form has less thermodynamic stability. Therefore, to increase the solubility properties of its crystalline form, an AC coamorphous solid was prepared. This coamorphous solid was prepared using spray drying techniques, and coformers such as isonicotinamide (INA) and maleic acid (MA). Furthermore, characterization was carried out using powder X-ray diffraction, differential scanning calorimetry, fourier transform infrared spectroscopy, and scanning electron microscopy, while the solubility properties test was conducted using the shake-flask and paddle method. The results showed that the spray-dried solids were coamorphous with single-phase homogeneous systems. Furthermore, the coamorphous solids, AC-INA and AC-MA were found to have a higher Tg than the melting points of other components, and formed intermolecular interactions between them. The higher Tg and presence of intermolecular interactions indicate that coamorphous solids are more stable than the amorphous form. Therefore, the results of the solubility and dissolution test showed that the coamorphous solid of AC-INA and AC-MA have better solubility properties compared to the AC crystalline form.

scholarly journals EFFECT OF SELECTED POLYMERS ON DISSOLUTION AND STABILIZATION OF AMORPHOUS FORM OF MELOXICAM

2017 ◽  
Vol 9 (9) ◽  
pp. 33
Author(s):  
Rana Obaidat ◽  
Bashar Al-taani ◽  
Hanan Al-quraan
Keyword(s):  
Polyethylene Glycol ◽  
Solid Dispersions ◽  
Dissolution Profile ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Polyethylene Glycol 4000 ◽  
Amorphous Form ◽  
Molecular Weights ◽  
Low Solubility ◽  
Reproducible Manner

Objective: Meloxicam is classified as class II corresponding to its high permeability and low solubility (12μg/ml). This study aims to compare the effect of selected polymers on stabilization of amorphous form, and dissolution of meloxicam by preparation of different solid dispersions using selected polymers (chitosan oligomers, polyvinylpyrrolidone K30, and polyethylene glycols).Methods: These solid dispersions were prepared using two different methods; solvent evaporation method for the two molecular weights chitosan carriers (16 and 11KDa) and polyvinylpyrrolidone-K30 and melting method for the two different molecular weights polyethylene glycol (4000 and 6000). The physicochemical properties of solid dispersions were analyzed using differential scanning calorimetry, Fourier transform infra-red analysis, Powder X-ray diffraction, and scanning electron microscopy. Selected dispersions were then compared to two selected marketed drugs (Mobic® and Moven®).Results: Best dissolution rates were obtained for both polyvinylpyrrolidone-K30 and polyethylene glycol 6000, followed by chitosan 16 kDa, chitosan 11 kDa, and polyethylene glycol 4000. Increasing polymeric ratio increased dissolution rate except for chitosan. Precipitation of the drug as amorphous form occurred in chitosan and polyvinylpyrrolidone-K30 dispersions, while no change in crystallinity obtained for polyethylene glycol dispersions. Failure of polyvinylpyrrolidone-K30 in the maintenance of stability during storage time was observed while re-crystallization occurred in chitosan-based dispersions, which ends with preferences to polyethylene glycol dispersions. After comparing the release of selected dispersions with the two selected polymers; all dispersions got a higher release than that of the two marketed drugs release.Conclusion: The dissolution profile of meloxicam has been increased successfully in a reproducible manner.

scholarly journals Amorphous Form of Carvedilol Phosphate—The Case of Divergent Properties

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5318
Author(s):  
Szymon Sip ◽  
Natalia Rosiak ◽  
Andrzej Miklaszewski ◽  
Patrycja Talarska ◽  
Ewa Dudziec ◽  
...  
Keyword(s):  
Solid Dispersions ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Amorphous Form ◽  
Lower Solubility ◽  
Ft Ir ◽  
Amorphous Dispersions ◽  
Diffraction Patterns ◽  
Crystalline Forms

The amorphous form of carvedilol phosphate (CVD) was obtained as a result of grinding. The identity of the obtained amorphous form was confirmed by powder X-ray diffraction (PXRD), different scanning calorimetry (DSC), and FT-IR spectroscopy. The process was optimized in order to obtain the appropriate efficiency and time. The crystalline form of CVD was used as the reference standard. Solid dispersions of crystalline and amorphous CVD forms with hydrophilic polymers (hydroxypropyl-β-cyclodextrin, Pluronic® F-127, and Soluplus®) were obtained. Their solubility at pH 1.2 and 6.8 was carried out, as well as their permeation through a model system of biological membranes suitable for the gastrointestinal tract (PAMPA-GIT) was established. The influence of selected polymers on CVD properties was defined for the amorphous form regarding the crystalline form of CVD. As a result of grinding (four milling cycles lasting 15 min with 5 min breaks), amorphous CVD was obtained. Its presence was confirmed by the “halo effect” on the diffraction patterns, the disappearance of the peak at 160.5 °C in the thermograms, and the changes in position/disappearance of many characteristic bands on the FT-IR spectra. As a result of changes in the CVD structure, its lower solubility at pH 1.2 and pH 6.8 was noted. While the amorphous dispersions of CVD, especially with Pluronic® F-127, achieved better solubility than combinations of crystalline forms with excipients. Using the PAMPA-GIT model, amorphous CVD was assessed as high permeable (Papp > 1 × 10−6 cm/s), similarly with its amorphous dispersions with excipients (hydroxypropyl-β-cyclodextrin, Pluronic® F-127, and Soluplus®), although in their cases, the values of apparent constants permeability were decreased.

Preparation and Property of Al87Ce3Ni8.5Mn1.5 Nanophase Amorphous Composites

2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Phase ◽  
Volume Fraction ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.

Exploring concomitant/conformational dimorphism in a difluoro-substituted phosphoramidate derivative

2019 ◽  
Vol 75 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Avantika Hasija ◽  
Deepak Chopra
Keyword(s):  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dispersion Energy ◽  
Torsion Angles ◽  
X Ray ◽  
Electrostatic Contribution ◽  
Distinguished Contribution

The concomitant occurrence of dimorphs of diphenyl (3,4-difluorophenyl)phosphoramidate, C18H14F2NO3P, was observed via a solution-mediated crystallization process with variation in the symmetry-free molecules (Z′). The existence of two forms, i.e. Form I (block, Z′ = 1) and Form II (needle, Z′ = 2), was characterized by single-crystal X-ray diffraction, differential scanning calorimetry and powder X-ray diffraction. Furthermore, a quantitative analysis of the energetics of the different intermolecular interactions was carried out via the energy decomposition method (PIXEL), which corroborates with inputs from the energy framework and looks at the topology of the various intermolecular interactions present in both forms. The unequivocally distinguished contribution of strong N—H...O hydrogen bonds along with other interactions, such as C—H...O, C—H...F, π–π and C—H...π, mapped on the Hirshfeld surface is depicted by two-dimensional fingerprint plots. Apart from the major electrostatic contribution from N—H...O hydrogen bonds, the crystal structures are stabilized by contributions from the dispersion energy. The closely related melting points and opposite trends in the calculated lattice energies are interesting to investigate with respect to the thermodynamic stability of the observed dimorphs. The significant variation in the torsion angles in both forms helps in classifying them in the category of conformational polymorphs.

A Calcination Technology for Ultrafine La3NbO7 Powder Prepared by Sol-Gel Process

2011 ◽  
Vol 412 ◽  
pp. 271-274
Author(s):  
Ying Li ◽  
Qiang Xu ◽  
Ling Dai
Keyword(s):  
Single Phase ◽  
Sol Gel ◽  
Average Particle Size ◽  
Complex Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Acid Complex ◽  
Calcination Process ◽  
Sol Gel Process

In order to prepare ultrafine La3NbO7 powder, a potential material for thermal barrier coatings, the calcination process of La3NbO7 was studied in this paper.The precursor of La3NbO7 was synthesized by using a citric acid complex method. A calcination process had been systematically investigated. The reaction temperature was determined by differential scanning calorimetry (DSC). The phase composition of powders was characterized by X-ray diffraction (XRD), and the morphology was obtained by scanning electron microscope (SEM). The results revealed that the single-phase La3NbO7 powder could be successfully prepared while the calcination temperature exceeded 800°C and a better morphology could be maintained at 800°C for 4 hours. Considering all above, an optimum calcination scheme was adopted at 800°C for 4 hours. The as-prepared La3NbO7 powders had a grain size of about 50nm and an average particle size of about 300nm.

Hardness evolution of Al–Cr–N coatings under thermal load

2008 ◽  
Vol 23 (11) ◽  
pp. 2880-2885 ◽  
Author(s):  
Herbert Willmann ◽  
Paul H. Mayrhofer ◽  
Lars Hultman ◽  
Christian Mitterer
Keyword(s):  
Thermal Load ◽  
Structural Changes ◽  
Single Phase ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Al Content ◽  
Annealing Temperatures ◽  
Transmission Electron

Microstructure and hardness evolution of arc-evaporated single-phase cubic Al0.56Cr0.44N and Al0.68Cr0.32N coatings have been investigated after thermal treatment in Ar atmosphere. Based on a combination of differential scanning calorimetry and x-ray diffraction studies, we can conclude that Al0.56Cr0.44N undergoes only small structural changes without any decomposition for annealing temperatures Ta ⩽ 900 °C. Consequently, the hardness decreases only marginally from the as-deposited value of 30.0 ± 1.1 GPa to 29.4 ± 0.9 GPa with Ta increasing to 900 °C, respectively. The film with higher Al content (Al0.68Cr0.32N) exhibits formation of hexagonal (h) AlN at Ta ⩾ 700 °C, which occurs preferably at grain boundaries as identified by analytical transmission electron microscopy. Hence, the hardness increases from the as-deposited value of 30.1 ± 1.3 GPa to 31.6 ± 1.4 GPa with Ta = 725 °C. At higher temperatures, where the size and volume fraction of the h-AlN phase increases, the hardness decreases to 27.5 ± 1.0 GPa with Ta = 900 °C.

A Study of Amorphous Erbium-Based Alloys Formed by Near-Isothermal Cold-Rolling of Elemental Composites

1985 ◽  
Vol 58 ◽  
Author(s):  
Michael Atzmon ◽  
Karl M. Unruh ◽  
Constantin Politis ◽  
William L. Johnson ◽  
W. M. Keck
Keyword(s):  
Cold Rolling ◽  
Single Phase ◽  
Enthalpy Of Mixing ◽  
High Energy ◽  
Distribution Functions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Energy Ball ◽  
Constituent Elements ◽  
Good Agreement

ABSTRACTWe report the formation of single-phase amorphous Cu-Er and Ni-Er alloys in bulk form by cold-rolling of composites prepared from elemental foils. As for previously reported cases of metallic glass formation by solid-state reaction, the driving force for the reaction is the negative enthalpy of mixing of the constituent elements. It occurs during deformation close to room temperature. Amorphous Cu7 2 Er2 8 was also produced by high-energy ball-milling of the elemental powders as well as by sputtering and liquid quenching. The alloys obtained were characterized by means of differential scanning calorimetry and x-ray diffraction. The crystallization behavior observed and the radial distribution functions obtained showed good agreement between the alloys prepared by different methods.

scholarly journals Novel Solid Dispersions of Naphthoquinone Using Different Polymers for Improvement of Antichagasic Activity

Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1136
Author(s):  
Verônica da Silva Oliveira ◽  
Elen Diana Dantas ◽  
Anna Thereza de Sousa Queiroz ◽  
Johny Wysllas de Freitas Oliveira ◽  
Marcelo de Sousa da Silva ◽  
...  
Keyword(s):  
Biological Activities ◽  
Solid Dispersions ◽  
Hydroxypropyl Methylcellulose ◽  
Chemical Characterization ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rotary Evaporation ◽  
A Value ◽  
Low Solubility

IVS320 (3a,10b-dihydro-1H-cyclopenta[b]naphtho[2,3-d]furan-5,10-dione) is a naphthoquinone that has low solubility in aqueous medium, a physical behavior that limits its biological activities, considering that compounds from this class have several activities. In this work, solid dispersions (SDs) prepared between IVS320 and polymers hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG), and polyvinylpyrrolidone (PVP) were developed using physical mixture (PM), kneading (KN), and rotary evaporation (RE) methods. Dispersions were investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). In addition, in vitro antiparasitic activity in Trypanosoma cruzi Y strains was evaluated. Physical-chemical characterization demonstrated the formation of SDs through the interaction of IVS320 with polymeric matrices. SDs of IVS320-polymer presented a significant potentiation of antichagasic activity, with inhibitory growth around 62% (IVS320-HPMC/RE), 55% (IVS320-PEG/RE), and 85% (IVS320-PVP/RE), while pure IVS320 showed a value of 48% for the highest concentrations evaluated (50 µg/mL).

Pressureless Sintering of MoSi2 Materials

1994 ◽  
Vol 364 ◽  
Author(s):  
Roland Scholl ◽  
Thomas JÜngling ◽  
Bernd Kieback
Keyword(s):  
Phase Formation ◽  
Single Phase ◽  
Bending Strength ◽  
Milling Process ◽  
Full Density ◽  
Pressureless Sintering ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Powder Mixtures ◽  
Molybdenum Silicides

AbstractVarious powder mixtures were prepared by a modified mechanical alloying technique. Starting from elemental Mo-, Si- and C-powders the influence of milling conditions on phase formation during the milling process and the subsequent heat treatment was investigated. Phase formation during sintering and sintering kinetics of activated starting mixtures were studied by differential scanning calorimetry (DSC), thermal graphimetry (TG), X-ray diffraction (XRD) and dilatometry. The results show that phase formation during milling or sintering strongly depends on milling conditions. Optimized powder mixtures of single phase and reinforced molybdenum silicides show high densities up to 98,5 % TD by pressureless sintering in various atmospheres. Full density is possible by post-HIP because the samples show only closed porosity. The microstructure was studied in dependence of sintering parameters. The level of impurities, i.e. C, O2 was determined. Hardness, fracture toughness and bending strength were measured for single phase and particle reinforced materials.

Mechanical Properties of Ti-Fe-Sn Biomedical Alloys with or without Aging Treatment

2014 ◽  
Vol 783-786 ◽  
pp. 2423-2428 ◽  
Author(s):  
Hideki Hosoda ◽  
Kenta Kasuya ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Shuichi Miyazaki
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Aging Effect ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Α Phase

In order to develop new β (bcc) Ti alloys, the Ti-Fe-Sn system was focused and phase constitution, microstructure, mechanical properties of Ti-5mol%Fe-6mol%Sn and Ti-6mol%Fe-3mol%Sn were clarified in addition to aging effect. It was estimated by differential scanning calorimetry (DSC) that α phase is formed at temperature from 773-779K and that β transus temperature is 1019K in both the alloys. X-ray diffraction analysis revealed that, in both alloys, β single phase is formed after the solution treatment (ST) at 1273K followed by water quenching, while α phase is formed after the aging at 773K and 873K for 3.6ks. The formation of α phase is also confirmed by optical microscopy. The volume fraction of α phase reaches to 90% in Ti-5Fe-6Sn and 80% in Ti-6Fe-3Sn after the aging at 873K for 3.6ks. The 0.2% proof stress was increased by aging at 873K from 550MPa to 650MPa in Ti-5Fe-6Sn and 500MPa to 690MPa in Ti-6Fe-3Sn. Besides, apparent Young’s modulus measured by dynamic mechanical analysis was raised by the aging treatment. These changes in the mechanical properties were discussed in connection with α phase precipitation.

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