scholarly journals PCL/PHBV Microparticles as Innovative Carriers for Oral Controlled Release of Manidipine Dihydrochloride

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fernanda Malaquias Barboza ◽  
Willian Moreira Machado ◽  
Luiz Renato Olchanheski Junior ◽  
Josiane Padilha de Paula ◽  
Sônia Faria Zawadzki ◽  
...  
Keyword(s):  
Controlled Release ◽  
Animal Studies ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Chemically Modified ◽  
Diffraction Patterns

Microparticles of poly(ε-caprolactone) (PCL) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing manidipine dihydrochloride (MAN) were successfully prepared by the simple emulsion/solvent evaporation method. All formulations showed loading efficiency rates greater than 80% and average particle size less than 8 μm. Formulations had spherical shape with smooth and porous surface for PCL and PHBV, respectively. According to Fourier-transform infrared spectroscopy, initial components were not chemically modified during microencapsulation. X-ray diffraction patterns and differential scanning calorimetry demonstrated that this process led to drug amorphization.In vitrodissolution studies showed that all microparticles prolonged MAN release, mainly which one obtained using PCL that contained 5% of drug loaded (PCL-M5). Animal studies demonstrated that formulationPCL-M5was able to keep the variation of mean arterial pressure after phenylephrine administration up to 24 hours. These data confirmed the sustained antihypertensive effect of the investigated microparticles. Results provided an experimental basis for using formulationPCL-M5as a feasible carrier for oral controlled release of MAN intended for treating high blood pressure.

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.

Pb2+ and Ce3+ Doped SrZnO2: New Blue Luminescent Phosphors

2006 ◽  
Vol 916 ◽  
Author(s):  
Alp Manavbasi ◽  
Jeffrey C LaCombe
Keyword(s):  
Sol Gel ◽  
Average Particle Size ◽  
Broad Band ◽  
Emission Spectra ◽  
Broad Emission Band ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Broad Emission ◽  
Diffraction Patterns ◽  
Individual Particles

AbstractTwo new blue emitting phosphors, SrZnO2:Pb2+ and Ce3+ were synthesized by adipic acid and sucrose templated sol-gel routes, respectively. The resulting phosphor particles were fine, nanocrystalline and pure. The optimum activator concentrations were found to be 1 mol% Pb2+ and 12 mol% Ce3+. Two excitation bands centered at 283 and 317 nm, plus a weak shoulder at 275 nm were observed for Pb2+ doped samples, however only one broad excitation band with a maximum at 294 nm was observed for Ce3+ doped samples fired at 1000 °C for 2h. The emission spectra of SrZnO2:Pb2+ showed a very broad band extending from 374 to 615 nm with a maximum at ~455 nm which was ascribed to the 3P1 ¡æ 1S0 transition on the Pb2+ ions allowed by the strong spin-orbit (SO) coupling. Similarly, SrZnO2:Ce3+ showed a broad emission band extending from 374 to 609 nm and centered at 467 nm. This broad emission was attributed to the 5d1 ¡æ 4f1 transition of Ce3+ ions. The lower level 2F5/2 of the 4f1 is populated but the level 2F7/2 is almost empty at room temperature where all measurements were taken. The luminescence properties of Ce3+, K+ co-doped SrZnO2 revealed that the characteristic band locations remained the same and the ratio of emission to excitation intensities were constant. X-ray diffraction patterns showed that the SrZnO2 phase started to form at 900 °C (after 2 hrs), and the single-phase SrZnO2 obtained at 1000 °C. SEM micrographs of both phosphors have a rounded and filled morphology for individual particles with an approximate diameter of 50-250 nm. Dynamic light scattering studies revealed that average particle size is around 1 ¥ìm for both phosphors.

OPTICAL AND STRUCTURAL PROPERTIES OF Zn(1-x)FexS NANOPARTICLES SYNTHESIZED BY CHEMICAL BATH DEPOSITION METHOD

2011 ◽  
Vol 04 (01) ◽  
pp. 101-105 ◽  
Author(s):  
S. SELMANI ◽  
H. ABDULLAH ◽  
S. SHAARI ◽  
R. ABD-SHUKOR
Keyword(s):  
Chemical Bath Deposition ◽  
Average Particle Size ◽  
Chemical Bath Deposition Method ◽  
Average Particle ◽  
Deposition Method ◽  
X Ray Diffraction ◽  
Quenching Effect ◽  
Optical Absorbance ◽  
Band Transition ◽  
Diffraction Patterns

Nanoparticles of Zn (1-x) Fe x S with x = 0.0, 0.05, 0.1, 0.15, 0.2 and 0.3 were synthesized using the chemical bath deposition method, using tri-sodium citrate as a complexion agent. These nanoparticles were characterized using XRD, SEM, optical absorbance and photoluminescence. SEM micrographs of the films revealed the combination of Zn (1-x) Fe x S nanoparticles with an average particle size D ~ 60.3 to 19.3 nm ± 0.01 nm for x = 0.0 to 0.3. X-ray diffraction patterns confirmed the nanocrystalline cubic ZnS phase formation. UV-visible spectrometer measurement showed high absorbance for Fe concentration x ≥ 0.15 in the wavelength range 325–800 nm. However, for x ≤ 0.1, the absorbance of the films decreased with further increase of Fe concentration. From the absorbance data, the direct bandgap values have been calculated to be in the range Eg = 3.5 to 2.23 eV for x = 0.0 to 0.3. The bandgap decreased with the increase of Fe concentration in the films. The photoluminescence spectra of the films showed two emission peaks, the first in the low wavelengths due to band-to-band transition, and the second in the high wavelengths due to the transitions probabilities and to the concentration of Fe ions. Due to the quenching effect, the intensity of PL spectra decreased on further increase of Fe doping.

Investigation on the Preparation, Characteristics, and Controlled Release Model of Paeonol-Loaded Liposome in Carbomer Hydrogel

2020 ◽  
Vol 17 (2) ◽  
pp. 159-173
Author(s):  
Qinqin Liu ◽  
Hongmei Xia ◽  
Yinxiang Xu ◽  
Yongfeng Cheng ◽  
Zhiqing Cheng
Keyword(s):  
Particle Size ◽  
Controlled Release ◽  
Average Particle Size ◽  
Entrapment Efficiency ◽  
Average Particle ◽  
Filtration Method ◽  
Ethanol Injection ◽  
Soybean Phospholipid ◽  
Release Model

Objective: Paeonol is a phenolic compounce that is volatile. In order to decrease its volatility and achieve controlled release, paeonol-loaded liposome in carbomer hydrogel was prepared by coating with soybean phospholipid via ethanol injection method and then added into the carbomer hydrogel. Methods: The quality of paeonol-loaded liposome in carbomer hydrogel was evaluated by the degree of roundness, particle size distribution, zeta potential, entrapment efficiency (filtration method and chitosan neutralization method), viscosity, infrared spectrum, etc. Furthermore, the diffusion from paeonolloaded liposome in hydrogel was studied in vitro. Results: The results showed that the average particle size of paeonol-loaded liposome was about 401 nm, the potential was -17.8 mV, and the entrapment efficiency was above 45%. The viscosity of paeonol- loaded liposome in hydrogel was 23.972×10-3 Pa*s, and the diffusion rate from paeonol-loaded liposome in hydrogel in vitro was obviously slower than that from the other paeonol preparations. Conclusion: The conclusions could be drawn that paeonol-loaded liposome in hydrogel was a kind of novel preparation, and its diffusion in vitro had obvious controlled-release characteristics, which further proved that it might improve the bioavailability of paeonol.

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.

scholarly journals Spherical crystals of celecoxib to improve solubility, dissolution rate and micromeritic properties

2007 ◽  
Vol 57 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Venkadari Gupta ◽  
Srinivas Mutalik ◽  
Madhobhai Patel ◽  
Girish Jani
Keyword(s):  
Dissolution Rate ◽  
Spherical Shape ◽  
Aqueous Solubility ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Acetone Water ◽  
Ir Spectroscopic ◽  
Spherical Crystals

Spherical crystals of celecoxib to improve solubility, dissolution rate and micromeritic propertiesCelecoxib spherical agglomerates were prepared with polyvinylpyrrolidone (PVP) using acetone, water and chloroform as solvent, non-solvent and bridging liquid, respectively. The agglomerates were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), IR spectroscopic studies and scanning electron microscopy (SEM). The IR spectroscopy and DSC results indicated the absence of any interactions between drug and additives. XRD studies showed a decrease in crystallinity in agglomerates. The crystals exhibited significantly improved micromeritic properties compared to pure drug. The loading efficiency (% or mg drug per 100 mg crystals) was in the range of 93.9 ± 2.3 and 97.3 ± 1.3% (n = 3) with all formulations. The aqueous solubility and dissolution rate of the drug from crystals was significantly (p < 0.05) increased (nearly two times). The solubility andin vitrodrug release rates increased with an increase in PVP concentration (from 2.5 to 10%). The SEM studies showed that the crystal posseses a good spherical shape with smooth and regular surface.

scholarly journals Preparation, characterization and analysis of zinc oxide nano-particles using a sol-gel technique as an inhibitor for bacteria

2020 ◽  
Vol 11 (1) ◽  
pp. 747-754
Author(s):  
Saja S. Al-Taweel ◽  
Rana S. Al-Taweel ◽  
Hasan M. Luaibi
Keyword(s):  
Zinc Oxide ◽  
Sol Gel ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Nano Particles ◽  
Klebsiella Pneumonia ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Atomic Force

In this work, zinc oxide nanoparticles (ZnO - NPs) were prepared using a sol-gel methodology and tested for their antibacterial activity against each of the following pathogenic species: Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus by well diffusion assay. The sample prepared was characterized by different techniques: Atomic Force Microscope AFM; Fourier Transform Infrared FT-IR; Scanning Electron Microscope SEM and X-Ray Diffraction Spectroscopy XRD. The XRD result showed that ZnO - NPs presence in wurtzite the structure of ZnO. The AFM and SEM of the surface analysis indicate that the most ZnO – NPs appear approximately in a spherical shape with some agglomeration. The average particle size for  ZnO - NPs is nearly 37 nm. Volumes 25µl, 50µl, 75µl, 100µl, 125µl, and 150µl of 10 mg\ ml concentration of  ZnO - NPs were used, the antimicrobial activity results showed that ability for  ZnO - NPs to inhibit the growth of S.aureus increased as the solution volume increased, while the growing of (K. pneumonia) and (E. coli) was inhibited only with the volume 75µl where the inhibition zones diameters were 15mm and 10mm respectively.

scholarly journals Preparation and Characterization of Chitosan Coated PLGA Nanoparticles of Resveratrol: Improved Stability, Antioxidant and Apoptotic Activities in H1299 Lung Cancer Cells

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 439 ◽  
Author(s):  
Hibah M. Aldawsari ◽  
Nabil A. Alhakamy ◽  
Rayees Padder ◽  
Mohammad Husain ◽  
Shadab Md
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Entrapment Efficiency ◽  
Aqueous Solubility ◽  
Plga Nanoparticles ◽  
Steady Increase ◽  
Average Particle

Resveratrol (RES) is a polyphenolic compound which has shown beneficial pharmacological effects such as anti-inflammatory, antioxidant, and anti-cancer effects. However, poor aqueous solubility, bioavailability, and low stability are the major limitations to the clinical application of RES. Therefore, in the present study, chitosan (CS) coated PLGA nanoparticles of RES (CS-RES-PLGA NPs) was developed, characterized and its anticancer activity was evaluated in the H1299 lung carcinoma cell line. The effects of the increase in CS coating and cryoprotectant concentration on particle size, polydispersity index (PDI) and zeta potential (ZP) were determined. The particle size, PDI, ZP and entrapment efficiency of the optimized CS-RES-PLGA NPs were found to be 341.56 ± 7.90 nm, 0.117 ± 0.01, 26.88 ± 2.69 mV and 75.13% ± 1.02% respectively. The average particle size and ZP showed a steady increase with an increase in CS concentration. The increase in positive zeta potential is evident for higher CS concentrations. The effect of trehalose as cryoprotectant on average particle size was decreased significantly (p < 0.05) when it was increased from 1%−5% w/v. TEM and SEM showed uniform particle distribution with a smooth surface and spherical shape. The CS coating provides modulation of in vitro drug release and showed a sustained release pattern. The stability of RES loaded PLGA NPs was improved by CS coating. CS-coated NPs showed greater cytotoxicity and apoptotic activities compared to free RES. The CS coated NPs had a higher antioxidant effect than the free RES. Therefore, CS coated PLGA NPs could be a potential nanocarrier of RES to improve drug solubility, entrapment, sustain release, stability and therapeutic application.

scholarly journals Antioxidant Effects of Quercetin and Catechin Encapsulated into PLGA Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Hector Pool ◽  
David Quintanar ◽  
Juan de Dios Figueroa ◽  
Camila Marinho Mano ◽  
J. Etelvino H. Bechara ◽  
...  
Keyword(s):  
Controlled Release ◽  
Oral Delivery ◽  
Polymeric Nanoparticles ◽  
Antioxidant Properties ◽  
Differential Pulse ◽  
Plga Nanoparticles ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Release Profiles

Polymeric nanoparticles (PLGA) have been developed for the encapsulation and controlled release of quercetin and catechin. Nanoparticles were fabricated using a solvent displacement method. Physicochemical properties were measured by light scattering, scanning electron microscopy andζ-potential, X-ray diffraction, infrared spectroscopy and differential scanning calorimetry. Encapsulation efficiency andin vitrorelease profiles were obtained from differential pulse voltammetry experiments. Antioxidant properties of free and encapsulated flavonoids were determined by TBARS, fluorescence spectroscopy and standard chelating activity methods. Relatively small (d≈ 400 nm) polymeric nanoparticles were obtained containing quercetin or catechin in a non-crystalline form (EE≈79%) and the main interactions between the polymer and each flavonoid were found to consist of hydrogen bonds.In vitrorelease profiles were pH-dependant, the more acidic pH, the faster release of each flavonoid from the polymeric nanoparticles. The inhibition of the action of free radicals and chelating properties, were also enhanced when quercetin and catechin were encapsulated within PLGA nanoparticles. The information obtained from this study will facilitate the design and fabrication of polymeric nanoparticles as possible oral delivery systems for encapsulation, protection and controlled release of flavonoids aimed to prevent oxidative stress in human body or food products.

scholarly journals Effects of Hydrothermal and Microwave Dual Treatment and Zein on the Enzymolysis of High Amylose Corn Starch

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 29
Author(s):  
Jie Liu ◽  
Qiuye Yang ◽  
Tiantian Yuan ◽  
Yawei Liu ◽  
Guihong Fang
Keyword(s):  
Moisture Content ◽  
Corn Starch ◽  
Average Particle Size ◽  
Microwave Treatment ◽  
Decomposition Temperature ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Amylose

Resistant starch (RS) type 2-high-amylose corn starch (HACS) was subjected to simultaneous hydrothermal (25% moisture content, 90 °C for 12 h) and microwave (35% moisture content, 40 W/g microwaving for 4 min) treatment and zein (at a zein to treated starch ratio of 1:5, 50 °C for 1 h) to improve its resistance to enzymolysis. Scanning electron microscopy (SEM) highlighted the aggregation and adhesion of the composite. The average particle size of the composite (27.65 μm) was exceeded that of both the HACS (12.52 μm) and the hydrothermal and microwave treated HACS (hydro-micro-HACS) (12.68 μm). The X-ray diffraction results revealed that the hydro-micro-HACS and composite remained B-type, while their crystallinity significantly decreased to 16.98% and 12.11%, respectively. The viscosity of the hydro-micro-HACS and composite at 50 °C was 25.41% and 35.36% lower than that of HACS. The differential scanning calorimetry (DSC) results demonstrated that the composite displayed a new endothermic peak at 95.79 °C, while the weight loss rate and decomposition temperature were 7.61% and 2.39% lower than HACS, respectively. The RS content in HACS, the hydro-micro-HACS, and composite was 47.12%, 57.28%, and 62.74%, respectively. In conclusion, hydrothermal and microwave treatment combined with zein provide an efficient physical strategy to enhance the RS type 2-HACS.

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