Synthesis of highly stable κ/ι-hybrid carrageenan micro- and nanogels via a sonication-assisted microemulsion route

2020 ◽  
Vol 11 (3-4) ◽  
pp. 69-82
Author(s):  
Sol Rodriguez ◽  
Fernando G Torres ◽  
Junior Arroyo ◽  
Karen N Gonzales ◽  
Omar P Troncoso ◽  
...  
Keyword(s):  
Zeta Potential ◽  
High Stability ◽  
Tween 80 ◽  
Processing Route ◽  
Cross Linking ◽  
Swelling Ratio ◽  
Potential Value ◽  
First Time

Novel carrageenan micro- and nanogels were developed via a sonication-assisted microemulsion processing route. The diameter of the dry samples ranged 197.3 −421.35 nm whereas the diameter of the samples suspended in water ranged 467.8–605.9 nm. Hybrid κ/ι-carrageenan, rather than κ- or ι-carrageenan was used for the first time for the preparation of micro- and nanogels. KCl was used as a cross-linking agent and Tween 80 was used as surfactant. The micro- and nanogels suspended in water were found to simultaneously exhibit a lower diameter, and a lower swelling ratio with higher Tween 80 content. The micro- and nanogel suspension yields a zeta potential value of −50.5 mV, superior to values reported elsewhere for pure κ- or ι-carrageenan micro- and nanogels. The high stability was attributed to the high hydrophile-lipophile balance (HLB = 15) value of Tween 80. These results suggest that hybrid κ/ι-carrageenan micro- and nanogels are promising candidates for smart therapeutics applications.

Novel Formulation Development and Evaluation of Nanoparticles Based in Situ Gelling System for The Ophthalmic Delivery of Ciprofloxacin Hydrochloride

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Drug Loading ◽  
In Vitro Release ◽  
Formulation Development ◽  
Ciprofloxacin Hydrochloride ◽  
Potential Value ◽  
The Mean ◽  
In Situ Gelling

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

scholarly journals Manipulation of surface charges of oil droplets and carbonate rocks to improve oil recovery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Hou ◽  
Ming Han ◽  
Jinxun Wang
Keyword(s):  
Zeta Potential ◽  
Oil Recovery ◽  
Carbonate Rocks ◽  
Zwitterionic Surfactant ◽  
Surface Charges ◽  
Oil Droplets ◽  
Zeta Potentials ◽  
Potential Value ◽  
Oil Water ◽  
Incremental Oil Recovery

AbstractThis work investigates the effect of the surface charges of oil droplets and carbonate rocks in brine and in surfactant solutions on oil production. The influences of the cations in brine and the surfactant types on the zeta-potentials of both oil droplets and carbonate rock particles are studied. It is found that the addition of anionic and cationic surfactants in brine result in both negative or positive zeta-potentials of rock particles and oil droplets respectively, while the zwitterionic surfactant induces a positive charge on rock particles and a negative charge on oil droplets. Micromodels with a CaCO3 nanocrystal layer coated on the flow channels were used in the oil displacement tests. The results show that when the oil-water interfacial tension (IFT) was at 10−1 mN/m, the injection of an anionic surfactant (SDS-R1) solution achieved 21.0% incremental oil recovery, higher than the 12.6% increment by the injection of a zwitterionic surfactant (SB-A2) solution. When the IFT was lowered to 10−3 mM/m, the injection of anionic/non-ionic surfactant SMAN-l1 solution with higher absolute zeta potential value (ζoil + ζrock) of 34 mV has achieved higher incremental oil recovery (39.4%) than the application of an anionic/cationic surfactant SMAC-l1 solution with a lower absolute zeta-potential value of 22 mV (30.6%). This indicates that the same charge of rocks and oil droplets improves the transportation of charged oil/water emulsion in the porous media. This work reveals that the surface charge in surfactant flooding plays an important role in addition to the oil/water interfacial tension reduction and the rock wettability alteration.

Formulation, Physical and Chemical Stability of Ocimum gratissimum L. Leaf Oil Nanoemulsion

2021 ◽  
Vol 901 ◽  
pp. 117-122
Author(s):  
Netnapa Ontao ◽  
Sirivan Athikomkulchai ◽  
Sarin Tadtong ◽  
Phuriwat Leesawat ◽  
Chuda Chittasupho
Keyword(s):  
Essential Oil ◽  
Zeta Potential ◽  
Chemical Stability ◽  
Polydispersity Index ◽  
Hydrodynamic Diameter ◽  
Potential Value ◽  
Yellow Color ◽  
Leaf Oil ◽  
The Stability ◽  
Physical And Chemical

Ocimum gratissimum L. leaf oil exhibited many pharmacological properties. This study aimed to formulate and evaluate the physical and chemical stability of O.gratissimum leaf oil nanoemulsion. O.gratissimum leaf oil was extracted by hydrodistillation. The major component of the essential oil eugenol, was analyzed by UV-Vis spectrophotometry. Nanoemulsions of O.gratissimum leaf oil were formulated using polysorbate 80, hyaluronic acid, poloxamer 188, and deionized water by phase inversion composition method. The hydrodynamic diameter, polydispersity index, and zeta potential value of O.gratissimum leaf oil nanoemulsion was evaluated by a dynamic light scattering technique. The %remaining of eugenol in the nanoemulsion was analyzed by UV-Vis spectrophotometry. The essential oil extracted from of O. gratissimum leaf oil was a clear, pale yellow color. The %yield of the essential oil was 0.15 ± 0.03% v/w. The size of the nanoemulsion was less than 106 nm. The polydispersity index of the nanoemulsion was ranging from 0.303 - 0.586 and the zeta potential value of the nanoemulsion was closely to zero, depending on the formulation component. O. gratissimum leaf oil at concentrations ranging from 0.002 - 0.012% v/v contained 35 - 41% of eugenol. The size of nanoemulsion was significantly decreased after storage at 4 °C, while significantly increased upon storage at 45 °C. The size of nanoemulsion stored at 30 °C did not significantly change. The %remaining of eugenol in the nanoemulsion was more than 90% after storage at 4 °C and 30 °C for 28 days. The percentage of eugenol remaining in the nanoemulsion stored at 45 °C was more than 85 - 90%, suggesting that the temperature affected the stability of eugenol in the nanoemulsion.

scholarly journals ADSORBATIVE SEPARATION OF DOXYCYCLINE FROM AQUEOUS SOLUTION WITH N,N-DIETHYL N-METHYL CHITOSAN, GUM AND POLYACRYLIC ACID BASED HYDROGELS

2021 ◽  
Vol 11 (07) ◽  
pp. 44-53
Author(s):  
Mirvari Hasanova Mirvari Hasanova
Keyword(s):  
Aqueous Solution ◽  
Ion Exchange ◽  
Zeta Potential ◽  
Polyacrylic Acid ◽  
Inorganic Materials ◽  
Biologically Active ◽  
Cross Linking ◽  
Separation And Purification ◽  
Inorganic Substances ◽  
The Cross

The separation and purification of antibiotics with sorption by ion-exchange materials, as well as their delivery in biological processes by immobilization, are now widely used in biotechnology. There are many scientific studies in the literature on the sorption of antibiotics by polymer-based sorbents and inorganic materials, as well as the study of thermodynamics and kinetics of the process. In the literature, the acquisition of biologically active systems from the sorption of antibiotics by ion-exchange fibers based on various polymers and inorganic substances was carried out. However, the synthesis of selective gels for the effective separation of doxycycline and its delivery in different pH mediums by sorption with biodegradable, biocompatible polysaccharide-containing composites is one of the topical issues. Gel was synthesized from the cross-linking of N,N-diethyl N-methyl derivative of a natural polyaminosaccharide of chitosan by glutaric aldehyde. Also, pH-sensitive hydrogels that can swollen in water were synthesized from the cross-linking of a graft copolymer of cherry source gummiarabic with N-vinylpyrrolidone, as well as synthetic polymer polyacrylic acid with N,N-methylene-bis-acrylamide. The structure of the gels were identified by FTIR and NMR spectroscopy, and the sorption of doxycycline antibiotic from an aqueous solution was investigated. According to the values of zeta potential, the protonation of functional groups in the main macromolecule in an acidic medium leads to a value of zeta potential of 40÷80 mV on the surface of chitosan-based gel and others. Although the chemical structure is different, the isoelectric point is set around pH=6÷8 for all three hydrogels. The dependences of the sorption process on the amount of gels, antibiotic concentration, temperature, and pH medium were studied. The experimental data were analyzed using two adsorption models, Langmuir and Freundlich, with the later system providing the best fit. Doxycycline is adsorbed on the surface of chitosan, gummiarabic and polyacrylic acid based hydrogel composite through by physical interactions. Also, the results of thermodynamic parameters ΔG40 kJ/mol show that the nature of the adsorption process is physical, and spontaneous, too. Keywords: Chitosan, Gummiarabic-arabinogalactane, polyacrylic acid, hydrogel, sorption isoterms, doxycycline, thermodynamica.

scholarly journals DEVELOPMENT OF MICROEMULSION FORMULATION FOR ORAL DELIVERY OF ROSUVASTATIN CALCIUM

2020 ◽  
pp. 35-39
Author(s):  
Himanshu Paliwal ◽  
Ram Singh Solanki ◽  
Chetan Singh Chauhan
Keyword(s):  
Zeta Potential ◽  
Droplet Size ◽  
Oral Delivery ◽  
Water Solubility ◽  
Tween 80 ◽  
In Vitro Dissolution ◽  
Microemulsion Formulation ◽  
Polyethylene Glycol 400 ◽  
Rosuvastatin Calcium

The purpose of conducting this study was to prepare an oral microemulsion formulation of Rosuvastatin calcium (RC) to improve its water solubility. Oil in water microemulsion was formulated using Oleic acid, Tween 80 and Polyethylene Glycol-400(PEG-400) as oil, surfactant and co-surfactant, respectively. The ideal proportion of surfactant: co-surfactant (Smix) was chosen by constructing pseudoternary diagrams. The microemulsion formulations which proved to be stable after thermodynamic stability testing were further evaluated for physical characteristics. Selected formulations were evaluated for droplet size, zeta potential, polydispersity index, viscosity and % drug content. The results were suggestive that optimized microemulsion formulation (F2) was thermodynamically stable and clear having a droplet size of 74.29 nm and zeta potential of -18.44.  In vitro dissolution study for optimized microemulsion was performed using a dialysis bag method and cumulative % drug release was determined. The result from the release study was indicative of improved solubility of Rosuvastatin calcium which may serve to boost up the oral bioavailability of drug.

scholarly journals A novel method to extract juglone from Juglans mandshurica waste branches using a water-in-oil microemulsion

2021 ◽  
Author(s):  
Chunying Li ◽  
Xianming Meng ◽  
Mengfei Tian ◽  
Shen Li ◽  
Yao Tian ◽  
...  
Keyword(s):  
Operating Time ◽  
Tween 80 ◽  
Microemulsion System ◽  
Microwave Assisted Extraction ◽  
Juglans Mandshurica ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Low Efficiency ◽  
Ethanol Ethanol ◽  
First Time

Abstract Pruning of Juglans mandshurica produces a lot of waste branches which are potentially rich source of juglone. However, they are usually discarded as waste. Given that, the water-in-oil microemulsion was proposed, aiming at developing a novel and efficient microemulsion-based microwave-assisted extraction（MBMAE）method. By which juglone in the Juglans mandshurica waste branches could be obtained. In our experiment, the waste branches powder was added to the MBMAE system. Under the best microemulsion system: (tween 80: n-propanol : n-hexane : water＝27% : 13.5% : 4.5% : 55%), the PH of the microemulsion solution of 5.6, microemulsion - Juglans mandshurica branches powder of 20:1 (mL/g), operating temperature of 40°C and operating time of 63 s, operating power of 400 W, the juglone yield was 4.58 mg/g. The results were that the extraction yield applying the MBMAE method were 1.86-fold and 6.65-fold that of microwave-assisted extraction applying ethanol (Ethanol-MAE) and heat reflux extraction by ethanol (Ethanol-HRE), respectively. Obviously, the MBMAE method could be used as an alternative to traditional extraction methods to extract juglone.Statement of Novelty A large number of waste branches from Juglans mandshurica pruning are often discarded as waste. Based on the concept of green development, this work proposes for the first time the extraction and utilization of juglone from the waste branches of Juglans mandshurica. However, a certain problem such as low efficiency, high cost, and complicated operation is existing in traditional extraction method for juglone. Consequently, a special microemulsion system for juglone was established for the first time, and on this basis, the application of MBMAE method to the extraction of juglone was also proposed for the first time. It provides data support for the extraction of juglone from other materials or plants.

scholarly journals Formulation, Development and Evaluation of Ibuprofen Loaded Nano-transferosomal Gel for the Treatment of Psoriasis

2019 ◽  
pp. 1-8
Author(s):  
Marwa H. Abdallah ◽  
Amr S. Abu Lila ◽  
Md. Khalid Anwer ◽  
El-Sayed Khafagy ◽  
Muqtader Mohammad ◽  
...  
Keyword(s):  
Drug Release ◽  
Zeta Potential ◽  
Drug Loading ◽  
Entrapment Efficiency ◽  
Tween 80 ◽  
Formulation Development ◽  
In Vitro Drug Release ◽  
Vesicle Size

The present work was aimed to develop a transferosomal gel of ibuprofen (IBU) for the amelioration of psoriasis like inflammation. Three formulation of IBU loaded transferosomes (TFs1-TFs3) were prepared using different proportions of lipid (phospholipon 90H) and surfactant (tween 80) and further evaluated for vesicle size, zeta potential (ZP), entrapment efficiency and in vitro drug release. The IBU loaded transferosomes (TFs2) was optimized with vesicle size (217±8.4 nm), PDI (0.102), ZP (-31.5±4.3 mV), entrapment efficiency (88.4±6.9%) and drug loading (44.2±2.9%). Further, the optimized IBU loaded transferosomes (TFs2) was incorporated into 1% carbopol 934 gel base and characterized for homogeneity, extrudability, viscosity and drug content. The in vivo pharmacodynamic study of gel exhibited reduction in psoriasis like inflammation in mice. The ibuprofen loaded transferosomal gel was successfully developed and has shown the potential to be a new therapy against psoriasis like inflammation.

Controllable Preparation of Silver Orthophosphate@Carbon Layer Core/Shell Heterostructure with Enhanced Visible Photocatalytic Properties and Stability

NANO ◽  
2015 ◽  
Vol 10 (02) ◽  
pp. 1550022 ◽  
Author(s):  
Yangcun Xie ◽  
Xiuwen Wang ◽  
Xu Wen
Keyword(s):  
High Stability ◽  
Separation Efficiency ◽  
Visible Region ◽  
Carbon Layer ◽  
Core Shell ◽  
Photogenerated Electrons ◽  
First Time ◽  
Fabrication Parameters ◽  
Controllable Preparation ◽  
High Separation

In this study, silver orthophosphate@carbon layer ( Ag 3 PO 4@ C ) core/shell heterostructure photocatalyst was prepared for the first time. The results showed that a uniform carbon layer was formed around the Ag 3 PO 4. By adjusting the hydrothermal fabrication parameters, the thickness of carbon layer could be easily controlled. Furthermore, the Ag 3 PO 4@ C had remarkable light absorption in the visible region. Photocatalytic tests displayed that the Ag 3 PO 4@ C heterostructures possessed a much higher degradation rate of phenol than pure Ag 3 PO 4 under visible light. The enhanced photocatalytic activity could be attributed to high separation efficiency of photogenerated electrons and holes based on the synergistic effect between carbon as a sensitizer and Ag 3 PO 4. Recycle tests showed that the Ag 3 PO 4@ C core/shell heterostructures maintained high stability over several cycles. The good stability could be attributed to the protection of insoluble carbon layer on the surfaces of Ag 3 PO 4 crystals in aqueous solution.

scholarly journals Preparation of Stable Cross-Linked Enzyme Aggregates (CLEAs) of a Ureibacillus thermosphaericus Esterase for Application in Malathion Removal from Wastewater

Catalysts ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 154 ◽  
Author(s):  
Yuliya Samoylova ◽  
Ksenia Sorokina ◽  
Alexander Piligaev ◽  
Valentin Parmon
Keyword(s):  
Response Surface Methodology ◽  
Bovine Serum Albumin ◽  
High Stability ◽  
Municipal Wastewater ◽  
Maximal Activity ◽  
Cross Linking ◽  
Soluble Enzyme ◽  
Initial Activity ◽  
E Coli ◽  
Ureibacillus Thermosphaericus

In this study, the active and stable cross-linked enzyme aggregates (CLEAs) of the thermostable esterase estUT1 of the bacterium Ureibacillus thermosphaericus were prepared for application in malathion removal from municipal wastewater. Co-expression of esterase with an E. coli chaperone team (KJE, ClpB, and ELS) increased the activity of the soluble enzyme fraction up to 200.7 ± 15.5 U mg−1. Response surface methodology (RSM) was used to optimize the preparation of the CLEA-estUT1 biocatalyst to maximize its activity and minimize enzyme loss. CLEA-estUT1 with the highest activity of 29.4 ± 0.5 U mg−1 (90.6 ± 2.7% of the recovered activity) was prepared with 65.1% (w/v) ammonium sulfate, 120.6 mM glutaraldehyde, and 0.2 mM bovine serum albumin at 5.1 h of cross-linking. The biocatalyst has maximal activity at 80 °С and pH 8.0. Analysis of the properties of CLEA-estUT1 and free enzyme at 50–80 °C and pH 5.0–10.0 showed higher stability of the biocatalyst. CLEA-estUT1 showed marked tolerance against a number of chemicals and high operational stability and activity in the reaction of malathion hydrolysis in wastewater (up to 99.5 ± 1.4%). After 25 cycles of malathion hydrolysis at 37 °С, it retained 55.2 ± 1.1% of the initial activity. The high stability and reusability of CLEA-estUT1 make it applicable for the degradation of insecticides.

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