scholarly journals The state of cognitive functions after angioreconstructive operations on the carotid arteries

2019 ◽  
pp. 65-71
Author(s):  
M.M. Tanashyan ◽  
R.B. Medvedev ◽  
O.V. Lagoda ◽  
E.S. Berdnikovich ◽  
S.I. Skrylev ◽  
...  
Keyword(s):  
Gel Filtration ◽  
Chemical Properties ◽  
Drug Carriers ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Drug Manufacturing ◽  
Major Trend ◽  
Pharmaceutical Agents ◽  
Process Controls ◽  
Resonance Laser

The use of nanostructured components in drug manufacturing and, more specifically, targeted drug delivery has recently become a major trend in the pharmaceutical industry. Nanodrugs encompass a wide range of pharmaceutical agents containing dendrimers, nanocrystals, micelles, liposomes, and polymer nanoparticles. Liposomes are the most well-studied nanoparticles and effective drug carriers. However, the more complex their structure is, the more process controls are needed and the more quality attributes have to be monitored, including the chemical properties of the liposomal fraction such as the shape, size and charge of the nanoparticle, conjugation efficacy, and distribution of the active ingredient. We believe that quality control of key liposome characteristics should rely on dynamic and laser light scattering coupled with electrophoresis, differential scanning calorimetry, cryo-electron microscopy, nuclear magnetic resonance, laser diffraction analysis, and gel filtration chromatography.

scholarly journals Development of liposomal drug formulations: quality attributes and methods for quality control

2018 ◽  
pp. 33-39
Author(s):  
E.V. Melnikova ◽  
D.V. Goryachev ◽  
A.A. Chaplenko ◽  
M.A. Vodyakova ◽  
A.R. Sayfutdinova ◽  
...  
Keyword(s):  
Quality Control ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Drug Carriers ◽  
Quality Attributes ◽  
Scanning Calorimetry ◽  
Liposomal Drug ◽  
Wide Range ◽  
Drug Manufacturing ◽  
Major Trend

The use of nanostructured components in drug manufacturing and, more specifically, targeted drug delivery has recently become a major trend in the pharmaceutical industry. Nanodrugs encompass a wide range of pharmaceutical agents containing dendrimers, nanocrystals, micelles, liposomes, and polymer nanoparticles. Liposomes are the most well-studied nanoparticles and effective drug carriers. However, the more complex their structure is, the more process controls are needed and the more quality attributes have to be monitored, including the chemical properties of the liposomal fraction such as the shape, size and charge of the nanoparticle, conjugation efficacy, and distribution of the active ingredient. We believe that quality control of key liposome characteristics should rely on dynamic and laser light scattering coupled with electrophoresis, differential scanning calorimetry, cryo-electron microscopy, nuclear magnetic resonance, laser diffraction analysis, and gel filtration chromatography.

scholarly journals Functional Protein-Based Bioinspired Nanomaterials: From Coupled Proteins, Synthetic Approaches, Nanostructures to Applications

2019 ◽  
Vol 20 (12) ◽  
pp. 3054
Author(s):  
Dong Zhang ◽  
Yi Wang
Keyword(s):  
Smart Materials ◽  
Organic Dyes ◽  
Drug Loading ◽  
Chemical Properties ◽  
Water Source ◽  
Drug Carriers ◽  
Functional Protein ◽  
Wide Range ◽  
Bioinspired Nanomaterials ◽  
Synthetic Approaches

Protein-based bioinspired nanomaterials (PBNs) combines the advantage of the size, shape, and surface chemistry of nanomaterials, the morphology and functions of natural materials, and the physical and chemical properties of various proteins. Recently, there are many exciting developments on biomimetic nanomaterials using proteins for different applications including, tissue engineering, drug delivery, diagnosis and therapy, smart materials and structures, and water collection and separation. Protein-based biomaterials with high biocompatibility and biodegradability could be modified to obtain the healing effects of natural organisms after injury by mimicking the extracellular matrix. For cancer and other diseases that are difficult to cure now, new therapeutic methods involving different kinds of biomaterials are studied. The nanomaterials with surface modification, which can achieve high drug loading, can be used as drug carriers to enhance target and trigger deliveries. For environment protection and the sustainability of the world, protein-based nanomaterials are also applied for water treatment. A wide range of contaminants from natural water source, such as organic dyes, oil substances, and multiple heavy ions, could be absorbed by protein-based nanomaterials. This review summarizes the formation and application of functional PBNs, and the details of their nanostructures, the proteins involved, and the synthetic approaches are addressed.

The Synthesis of High Molecular Weight Partially Hydrolysed Poly(vinyl alcohol) Grades Suitable for Nanoparticle Fabrication

2008 ◽  
Vol 8 (11) ◽  
pp. 5739-5747 ◽  
Author(s):  
Jasminder Chana ◽  
Ben Forbes ◽  
Stuart Allen Jones
Keyword(s):  
Vinyl Alcohol ◽  
High Probability ◽  
Chemical Properties ◽  
Synthetic Polymer ◽  
Partial Hydrolysis ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Manufacture Process ◽  
Wide Range ◽  
Hydrolysis Of

Poly(vinyl alcohol) (PVA) is a highly versatile synthetic polymer that is formed by full or partial hydrolysis of poly(vinyl acetate) (PVAc). A wide range of PVA partially hydrolysed grades are commercially available, but the amphiphilic grades of the polymer (30–60% hydrolysis), which probably the most interesting in terms of drug delivery, are not readily available. As a consequence few studies have assessed the application of low hydrolysis PVA polymers to form nanocarriers. The aims of this study were to synthesise amphiphilic grades of PVA on a laboratory scale, analyse their chemical properties and determine whether these grades could be used to form nanoparticles. PVA 30%, PVA 40%, PVA 50% and PVA 60% were synthesised via direct saponification of PVAc. All grades of PVA synthesised had degrees of hydrolysis close to those predicted from the stoichiometry of the saponification reaction. The PVA grades displayed <1.5% batch to batch variability (n = 3) in terms of percentage hydrolysis, demonstrating the manufacture process was both reproducible and predictable. Analysis of the polymer characteristics using 13C nuclear magnetic resonance and differential scanning calorimetry revealed that all PVA grades contained block distributions (i.e., η < 1) of vinyl alcohol monomers (η ranged from 0.33–0.45) with a high probability of adjacency calculated for the hydroxylated units (POH ranged 0.926–0.931). All the grades of PVA formed nanoparticles using a precipitation technique with a trend towards smaller particle size with increasing degree of PVA hydrolysis; PVA 30% resulted in significantly larger nanoparticles (225 nm) compared to PVA 40–60% (137–174 nm).

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

PLGA+HA/βTCP scaffold incorporating simvastatin: a promising biomaterial for bone tissue engineering

2020 ◽  
Author(s):  
Mariane Beatriz Sordi ◽  
Ariadne Cristiane Cabral da Cruz ◽  
Águedo Aragones ◽  
Mabel Mariela Rodríguez Cordeiro ◽  
Ricardo de Souza Magini
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Thermal Analyses ◽  
Chemical Properties ◽  
Biological Properties ◽  
Scanning Calorimetry ◽  
Evaporation Technique ◽  
Porosity Analysis ◽  
Biphasic Ceramic

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite / β-tricalcium phosphate (PLGA+HA/βTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% βTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m:m) of this medication. Scaffolds were synthesized in a cylindric-shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in PBS at 37 °C under constant stirring for 7, 14, 21, and 28 days. Non-degraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro, meso, and micropores in the polymer structure with HA/βTCP particles homogeneously dispersed. Chemical and thermal analyses presented very similar results for both PLGA+HA/βTCP and PLGA+HA/βTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/βTCP and PLGA+HA/βTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/βTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.

An Overview of Optimization of Spherical Crystallisation Process

2013 ◽  
Vol 6 (4) ◽  
pp. 2203-2209
Author(s):  
N B Bhagat ◽  
A V Yadav ◽  
P R Mastud ◽  
R A Khutale
Keyword(s):  
Physical Phenomenon ◽  
Chemical Properties ◽  
Spherical Shape ◽  
Particle Engineering ◽  
Spherical Crystallization ◽  
Stirring Rate ◽  
Physico Chemical ◽  
Rate Selection ◽  
Pharmaceutical Agents ◽  
Spherical Crystals

In this article we describe the optimizing parameters in the process of spherical crystallisation. Particle engineering of active pharmaceutical agents is an innovative area of research in pharmaceutical industry because of several advantages. Spherical crystallization is one of the particle engineering technique in which drug directly gets crystallized and agglomerated into spherical shape. The spherical crystals can be obtained by different methods like solvent change, Quasi-emulsion droplet, ammonia diffusion and neutralisation. The optimization of process of spherical crystallization is important for obtaining the ideal spherical crystal agglomerates. It includes stirring rate, selection of solvent, pH, temperature etc. which affects on the physico-chemical properties of crystals. These optimizing parameters play its specific role in formation of spherical crystals. Stirring rate affects the shape as well as size of the final agglomerates and solvent selection helps in the formation of maximum amount of agglomerates in the system. The factors like pH and temperature should be maintained in case of drugs which show polymorphism. Apart from this, several others physical phenomenon or parameters like interfacial tension and rate of crystallisation are also important for thorough optimization of process.  

pH-Dependent Thermal Stability of Vibrio cholerae L-asparaginase

2019 ◽  
Vol 26 (10) ◽  
pp. 743-750 ◽  
Author(s):  
Remya Radha ◽  
Sathyanarayana N. Gummadi
Keyword(s):  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Kinetic Studies ◽  
Structural Features ◽  
Structure Stability ◽  
Kcal Mole ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Ph Dependent ◽  
Ph Range

Background:pH is one of the decisive macromolecular properties of proteins that significantly affects enzyme structure, stability and reaction rate. Change in pH may protonate or deprotonate the side group of aminoacid residues in the protein, thereby resulting in changes in chemical and structural features. Hence studies on the kinetics of enzyme deactivation by pH are important for assessing the bio-functionality of industrial enzymes. L-asparaginase is one such important enzyme that has potent applications in cancer therapy and food industry.Objective:The objective of the study is to understand and analyze the influence of pH on deactivation and stability of Vibrio cholerae L-asparaginase.Methods:Kinetic studies were conducted to analyze the effect of pH on stability and deactivation of Vibrio cholerae L-asparaginase. Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) studies have been carried out to understand the pH-dependent conformational changes in the secondary structure of V. cholerae L-asparaginase.Results:The enzyme was found to be least stable at extreme acidic conditions (pH< 4.5) and exhibited a gradual increase in melting temperature from 40 to 81 °C within pH range of 4.0 to 7.0. Thermodynamic properties of protein were estimated and at pH 7.0 the protein exhibited ΔG37of 26.31 kcal mole-1, ΔH of 204.27 kcal mole-1 and ΔS of 574.06 cal mole-1 K-1.Conclusion:The stability and thermodynamic analysis revealed that V. cholerae L-asparaginase was highly stable over a wide range of pH, with the highest stability in the pH range of 5.0–7.0.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

scholarly journals Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1891
Author(s):  
Antonio Reina ◽  
Trung Dang-Bao ◽  
Itzel Guerrero-Ríos ◽  
Montserrat Gómez
Keyword(s):  
Chemical Properties ◽  
Added Value ◽  
Solid Supports ◽  
Nanosized Materials ◽  
Nano Structures ◽  
Liquid Phases ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Physical And Chemical ◽  
A Current

Metal nanoparticles have been deeply studied in the last few decades due to their attractive physical and chemical properties, finding a wide range of applications in several fields. Among them, well-defined nano-structures can combine the main advantages of heterogeneous and homogenous catalysts. Especially, catalyzed multi-step processes for the production of added-value chemicals represent straightforward synthetic methodologies, including tandem and sequential reactions that avoid the purification of intermediate compounds. In particular, palladium- and copper-based nanocatalysts are often applied, becoming a current strategy in the sustainable synthesis of fine chemicals. The rational tailoring of nanosized materials involving both those immobilized on solid supports and liquid phases and their applications in organic synthesis are herein reviewed.

scholarly journals Mesoporous Silica Nanoparticles for Targeting Subcellular Organelles

2020 ◽  
Vol 21 (24) ◽  
pp. 9696
Author(s):  
Miguel Gisbert-Garzarán ◽  
Daniel Lozano ◽  
María Vallet-Regí
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
State Of The Art ◽  
Mesoporous Silica Nanoparticles ◽  
Drug Distribution ◽  
Chemical Properties ◽  
Drug Carriers ◽  
Subcellular Organelles ◽  
Physico Chemical ◽  
Tumoral Cells

Current chemotherapy treatments lack great selectivity towards tumoral cells, which leads to nonspecific drug distribution and subsequent side effects. In this regard, the use of nanoparticles able to encapsulate and release therapeutic agents has attracted growing attention. In this sense, mesoporous silica nanoparticles (MSNs) have been widely employed as drug carriers owing to their exquisite physico-chemical properties. Because MSNs present a surface full of silanol groups, they can be easily functionalized to endow the nanoparticles with many different functionalities, including the introduction of moieties with affinity for the cell membrane or relevant compartments within the cell, thus increasing the efficacy of the treatments. This review manuscript will provide the state-of-the-art on MSNs functionalized for targeting subcellular compartments, focusing on the cytoplasm, the mitochondria, and the nucleus.

Sign in / Sign up

Export Citation Format

Share Document