scholarly journals Comparative Study of Different Crystallization Methods in the Case of Cilostazol Crystal Habit Optimization

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 295 ◽  
Author(s):  
Tímea Tari ◽  
Piroska Szabó-Révész ◽  
Zoltán Aigner
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Mixing Time ◽  
Average Particle Size ◽  
Aqueous Solubility ◽  
Impinging Jet ◽  
Polymorphic Form ◽  
Crystal Habit ◽  
Narrow Particle Size Distribution ◽  
Average Particle

The therapeutic usage of cilostazol is limited owing to its poor aqueous solubility and oral bioavailability. Our aim was to produce cilostazol crystals with small average particle size; besides suitable roundness, narrow particle size distribution and stable polymorphic form to increase its dissolution rate and improve processability. Different conventional crystallization methods with or without sonication were compared with impinging jet crystallization combined with cooling, and the optimization of the various parameters was also implemented. The effects of post-mixing time and temperature difference were studied by means of a full factorial design. The physical properties of powder particles were characterized by, i.a., XRPD, DSC and SEM. The dissolution rate and the contact angle of solid surfaces were also determined to elucidate the relationship between wettability and dissolution. It was observed that impinging jet crystallization combined with cooling is a very effective and reproducible method for reducing the particle size of cilostazol. This method resulted in significantly smaller particle size (d(0.5) = 3–5 μm) and more uniform crystals compared to the original ground material (d(0.5) = 24 μm) or the conventional methods (d(0.5) = 8–14 μm), and it also resulted in a stable polymorphic form and enhanced the dissolution rate.

Azithromycin nanosuspension preparation using evaporative precipitation into aqueous solution (EPAS) method and its comparative dissolution study

2020 ◽  
Vol 17 ◽  
Author(s):  
Mohammad Hossain Shariare ◽  
Tonmoy Kumar Mondal ◽  
Hani Alothaid ◽  
Md. Didaruzzaman Sohel ◽  
MD Wadud ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Scale Up ◽  
Average Particle ◽  
Total Drug ◽  
Residual Solvent ◽  
Dissolution Study ◽  
Drug Content

Aim: EPAS (evaporative precipitation into aqueous solution) was used in the current studies to prepare azithromycin nanosuspensions and investigate the physicochemical characteristics for the nanosuspension batches with the aim of enhancing the dissolution rate of the nanopreparation to improve bioavailability. Methods: EPAS method used in this study for preparing azithromycin nanosuspension was achieved through developing an in-house instrumentation method. Particle size distribution was measured using Zetasizer Nano S without sample dilution. Dissolved azithromycin nanosuspensions were also compared with raw azithromycin powder and commercially available products. Total drug content of nanosuspension batches were measured using an Ultra-Performance Liquid Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent was measured using gas chromatography (GC). Results: The average particle size of azithromycin nanosuspension was 447.2 nm and total drug content was measured to be 97.81% upon recovery. Dissolution study data showed significant increase in dissolution rate for nanosuspension batch when compared to raw azithromycin and commercial version (microsuspension). The residual solvent found for azithromycin nanosuspension is 0.000098023 mg/ mL or 98.023 ppb. Conclusion: EPAS was successfully used to prepare azithromycin nanoparticles that exhibited significantly enhanced dissolution rate. Further studies are required to scale up the process and determine long term stability of the nanoparticles.

scholarly journals Synthesis, Characterization of Nano-β-Tricalcium Phosphate and the Inhibition on Hepatocellular Carcinoma Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Langlang Liu ◽  
Yanzeng Wu ◽  
Chao Xu ◽  
Suchun Yu ◽  
Xiaopei Wu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Particle Size ◽  
Cell Viability ◽  
Tricalcium Phosphate ◽  
Hepg2 Cells ◽  
Drug Carrier ◽  
Average Particle Size ◽  
Crystal Habit ◽  
Average Particle ◽  
Dependent Manner

It is difficult to synthesize nano-β-tricalcium phosphate (nano-β-TCP) owing to special crystal habit. The aim of this work was to synthesize nano-β-TCP using ethanol-water system and characterize it by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Malvern laser particle size analyzer, and transmission electron microscope (TEM). In addition, the inhibitory effect of nano-β-TCP on human hepatocellular carcinoma (HepG2) cells was also investigated using MTT assay, lactate dehydrogenase (LDH) leakage test, and 4′-6-diamidino-2-phenylindole (DAPI) staining. The results showed that negatively charged rod-like nano-β-TCP with about 55 nm in diameter and 120 nm in length was synthesized, and the average particle size of nano-β-TCP was 72.7 nm. The cell viability revealed that nano-β-TCP caused reduced cell viability of HepG2 cells in a time- and dose-dependent manner. These findings presented here may provide valuable reference data to guide the design of nano-β-TCP-based anticancer drug carrier and therapeutic systems in the future.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

scholarly journals Application of surfactants for the synthesis of qualitative hydroxide and metallic cobalt nanopowders

2021 ◽  
pp. 4-11
Author(s):  
Van Minh Nguyen ◽  
Tien Hiep Nguyen ◽  
Stanislav V. Gorobinsky
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Cetylpyridinium Chloride ◽  
Average Particle Size ◽  
Sodium Dodecyl ◽  
Chemical Precipitation ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Application Of Surfactants

In this work, nanopowders (NP) Co(OH)2 were obtained by chemical precipitation from aqueous solutions of cobalt nitrate Co(NO3)2 and alkali NaOH (10 wt. %) using surfactants: sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC) (0.1 wt. %). It was shown that Co(OH)2 NP with 0.1% SDS is the best quality product, since its dispersion increases more than 2 times compared to the samples with 0.1% CPC and without surfactants. In this case, the Co(OH)2 NP has the form of flakes with an irregular shape and a nanometer size (about 100 nm) with an average thickness of 30 nm. It was found that the average particle size of Co NP obtained by hydrogen reduction of Co(OH)2 NP with 0.1% SDS at 280°C has a maximum on the distribution histogram shifted to the interval 41–50 nm, which is characterized by a narrow particle size distribution and represents spherical particles sintered with each other.

scholarly journals Structural and Optical Properties of Silicon Carbide Powders Synthesized from Organosilane Using High-Temperature High-Pressure Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3111
Author(s):  
Evgeny A. Ekimov ◽  
Vladimir S. Krivobok ◽  
Mikhail V. Kondrin ◽  
Dmitry A. Litvinov ◽  
Ludmila N. Grigoreva ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Synthesis Temperature ◽  
Narrow Particle Size Distribution ◽  
High Tech ◽  
Average Particle ◽  
Coupled Modes ◽  
Dominant Type ◽  
High Structure

The development of new strategies for the mass synthesis of SiC nanocrystals with high structure perfection and narrow particle size distribution remains in demand for high-tech applications. In this work, the size-controllable synthesis of the SiC 3C polytype, free of sp2 carbon, with high structure quality nanocrystals, was realized for the first time by the pyrolysis of organosilane C12H36Si6 at 8 GPa and temperatures up to 2000 °C. It is shown that the average particle size can be monotonically changed from ~2 nm to ~500 nm by increasing the synthesis temperature from 800 °C to 1400 °C. At higher temperatures, further enlargement of the crystals is impeded, which is consistent with the recrystallization mechanism driven by a decrease in the surface energy of the particles. The optical properties investigated by IR transmission spectroscopy, Raman scattering, and low-temperature photoluminescence provided information about the concentration and distribution of carriers in nanoparticles, as well as the dominant type of internal point defects. It is shown that changing the growth modes in combination with heat treatment enables control over not only the average crystal size, but also the LO phonon—plasmon coupled modes in the crystals, which is of interest for applications related to IR photonics.

Formulation and Characterization of Nateglinide Nanosuspension by Precipitation Method

2014 ◽  
Vol 7 (4) ◽  
pp. 2685-2691
Author(s):  
Amruta Papdiwal ◽  
Kishor Sagar ◽  
Vishal Pande
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Water Solubility ◽  
Average Particle Size ◽  
Biologically Active ◽  
In Vitro Dissolution ◽  
Precipitation Method ◽  
Average Particle ◽  
Scanning Calorimetry

Poor water solubility and slow dissolution rate are major issues for the majority of upcoming and existing biologically active pharmaceutical compounds. Nateglinide is Biopharmaceutical Classification System Class-II drug that has low solubility and high permeability. The purpose of the present study was to improve the solubility and dissolution rate of Nateglinide by the preparation of nanosuspension by the nanoprecipitation technique. Nateglinide nanosuspension was evaluated for its particle size, in vitro dissolution study, and characterized by differential scanning calorimetry and scanning electron microscopy. The optimized formulation showed an average particle size of 207 nm and zeta potential of -25.8 mV. The rate of dissolution of the optimized nanosuspension was enhanced by 83% in 50 min relative to micronized suspension of nateglinide (37% in 50 min). This improvement was mainly due to the formulation of nanosized particles of Nateglinide. Stability study revealed that nanosuspension was more stable at room temperature and refrigerator condition with no significant change in particle size distribution. These results indicate that the nateglinide loaded nanosuspension may significantly improve in vitro dissolution rate and thereby possibly enhance the onset of therapeutic effect.

Preparation of Monodispersed and Nano-Sized Spherical SiO2 Particles by Emulsion Method

2004 ◽  
Vol 449-452 ◽  
pp. 1161-1164 ◽  
Author(s):  
Jong Hwa Baek ◽  
Young Soo Kang ◽  
Seog Young Yoon ◽  
Hong Chae Park
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mixing Time ◽  
Average Particle Size ◽  
Average Particle ◽  
Amorphous Sio2 ◽  
Emulsion Method ◽  
Sio2 Particles ◽  
20 Nm

Spherical nano-sized SiO2 particles have been synthesized from sodium silicate by emulsion method. The influence of emulsifier content and mixing time on the morphology and particle size distribution of the resulting materials was investigated. The characteristics of the obtained SiO2 particles were examined by means of XRD, SEM, TEM, and PSA. The monodispersed shperical SiO2 with the average particle size 20 nm was obtained at a emulsifer content of 3vol% and mixing time of 60 min using ultrasonic disruptor. After calcining at 1200oC for 2 hrs, the amorphous SiO2 transformed wholly to the crystalline cristobalite. As increase in emulsifier content from 1 to 3 vol% did not nearly influence on the morphology of SiO2 particle but slightly changed the particle size distribution. The average particle size of SiO2 decreased significantly from 100 nm to 20 nm with increasing the mixing time.

A New Process for Preparing Nanosize Ceramic Powders

1994 ◽  
Vol 351 ◽  
Author(s):  
Yong S. Zhen ◽  
Kenneth E. Hrdina ◽  
Robert J. Remick
Keyword(s):  
Particle Size ◽  
Metal Oxides ◽  
Average Particle Size ◽  
Cost Effective ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Mixed Metal Oxides ◽  
Ceramic Powders ◽  
New Process ◽  
The Cost

ABSTRACTWe have developed a new poly-foam process for the cost effective preparation of ceramic nanoparticles. The process utilizes the chemistry of polyurethane reactions and is proven to be effective for forming nanometer size ceramic powders of a great variety of single metal oxides and mixed metal oxides. In general, ceramic powders can be prepared by this process having a range of average particle size between 3 to 50 nm, with very narrow particle size distribution. They are free of hard agglomerates, are chemically pure and uniform, and are essentially spherical in shape.

scholarly journals Effect of dopants [Gd3+, Sm3+, Ca2+, Sr2+ and Ba2+] on the performance characteristics of ceria based electrolytes for application in solid oxide fuel cells

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
M.L. Reni ◽  
A. Samson Nesaraj
Keyword(s):  
Particle Size ◽  
Fuel Cells ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Average Particle Size ◽  
Solid Oxide ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Doped Ceria ◽  
Oxide Fuel

Doped CeO2 based materials are now-a-days proposed as alternate electrolyte materials for solid oxide fuel cells (SOFCs) working at low temperature (~723 – 873 K). In this research work, nanoparticles of CeO2 doped with Gd3+, Sm3+, Ca2+, Sr2+ and Ba2+were prepared by a simple homogeneous chemical precipitation method. The prepared materials (after heat treatment at 1023 K for 2 hours) were systematically characterized by XRD, EDAX analysis, FTIR , particle size analysis and SEM.  Lattice parameters were calculated from the XRD data. The XRD results indicate that all the doped ceria samples studied are single phase with a cubic fluorite structure. The average particle size of the doped ceria powder was about 48 – 115 nm and the particles have shown narrow particle size distribution patterns. AC impedance spectroscopy studies performed on the sintered specimens have shown better oxide ion conductivity values and hence these materials may be suitable for application as electrolyte materials in solid oxide fuel cells working at low temperature (~723 – 873 K). ________________________________________GRAPHICAL ABSTRACT

scholarly journals β-hexanitrohexaazaisowurtzitane Particles Prepared by Spray Drying and its Characterization

2021 ◽  
Vol 27 (1) ◽  
pp. 119-124
Author(s):  
Wenzheng XU ◽  
Hao LI ◽  
Xin LIANG ◽  
Jie WANG ◽  
Jinyu PENG ◽  
...  
Keyword(s):  
Particle Size ◽  
Spray Drying ◽  
Ultrafine Particles ◽  
Average Particle Size ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Thermal Stimulus ◽  
Particle Size Analyzer ◽  
Xrd Patterns ◽  
The Impact

In this paper, the ultrafine β-hexanitrohexaazaisowurtzitane (β – CL – 20) particles were prepared by spray drying method. The CL – 20 samples were characterized by scanning electron microscope (SEM), particle size analyzer, X-ray diffraction (XRD), and Differential Scanning Calorimeter (DSC). Furthermore, the safety properties of samples under impact and thermal stimulus were tested and analyzed. The results of SEM showed that the average particle size of ultrafine CL – 20 particles with a narrow particle size distribution, were about 320 nm, and the shape was elliptical. The XRD patterns indicated that the polymorphic phase of ultrafine particles was mainly β-type. Compared with that of raw CL – 20, the impact sensitivity of the ultrafine CL – 20 had been decreased significantly, for the drop height (H50) was increased from 13.0 to 33.5 cm. The critical explosion temperature of the ultrafine CL – 20 decreased from 232.16 ℃ to 227.93 ℃, indicating that the thermal stability of the ultrafine CL – 20 is lower than that of raw CL – 20.

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