scholarly journals Extraction of Parquat from Blood by Clinoptilolite

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad-Amin Aghaii-Afshar ◽  
Seyed Vahid Shetab-Boushehri
Keyword(s):  
Water Solubility ◽  
Limit Of Detection ◽  
High Surface ◽  
High Surface Area ◽  
Sodium Dithionite ◽  
Exchange Property ◽  
Color Test ◽  
Limit Of Quantification ◽  
Saturated Sodium Chloride Solution ◽  
Laboratory Error

Paraquat is a bipyridyl herbicide and organic divalent cation which due to its high polarity and water solubility cannot be readily extracted by common organic solvents from body fluids. Dithionite color test for qualitative and quantitative determination of paraquat in urine has been proposed and used for many years. Although some methods were proposed for solvent extraction of paraquat from blood, they are less practical in clinical laboratories and lack high extraction recovery. Clinoptilolite is a highly porous natural zeolite with cation-exchange property and high surface area. In the present work, extraction of paraquat from human blood by clinoptilolite was investigated and compared with Amberlite CG-50 I, a well-known weak cation-exchanger. Blood paraquat was adsorbed by adsorbents (clinoptilolite or Amberlite) and extracted from them by saturated sodium chloride solution. Extracted paraquat was spectrophotometrically measured by means of sodium dithionite reagent at 394.5 nm. Recovery, limit of detection, considering signal-to-noise (S/N) ratio of 3, and limit of quantification, regarding S/N of 10, of paraquat extraction by clinoptilolite and Amberlite CG-50 were 81.7% ± 3.4%, 0.58 μg, and 1.93 μg and 83.6% ± 3.2%, 0.49 μg, and 1.63 μg, respectively. Repeatabilities (within-laboratory error) of paraquat extraction by clinoptilolite and Amberlite CG-50 I were 7.1% and 6.3%, respectively.

Porous Silicas for Enhanced Drug Release

2014 ◽  
Vol 91 ◽  
pp. 79-81
Author(s):  
Abina M. Crean ◽  
Robert J. Ahern ◽  
Rakesh Dontireddy ◽  
Walid Faisil ◽  
John P. Hanrahan ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Solubility ◽  
Solid Dispersions ◽  
High Surface ◽  
High Surface Area ◽  
Porous Silica ◽  
High Energy ◽  
Drug Dissolution ◽  
Drug Candidates ◽  
Drug Molecules

Low drug water-solubility is a major challenge to overcome in the development of tablet or capsule dosage forms for a large number of promising drug candidates. Strategies to improve drug solubility and dissolution involve chemical, physical and formulation approaches. An emerging formulation approach to increase drug dissolution and solubility involves the creation of solid dispersions of drug molecules on to a high surface area inorganic carrier, such as porous silica. The combined benefits of a hydrophilic inorganic substrate, increased drug surface area and a high-energy drug form facilitate rapid drug dissolution into aqueous based media and can create supersaturated drug solutions. The work presented provides a brief overview of the silica grades investigated, processes employed to load drugs onto the silica substrates, provide some examples of the ability of silica to enhance drug dissolution and highlight some of the challenges in the development of these novel drug delivery systems.

scholarly journals Silica-Based Stimuli-Responsive Systems for Antitumor Drug Delivery and Controlled Release

Pharmaceutics ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Avelino Corma ◽  
Pablo Botella ◽  
Eva Rivero-Buceta
Keyword(s):  
Water Solubility ◽  
High Surface ◽  
High Surface Area ◽  
Membrane Receptors ◽  
Specific Cell ◽  
Stimuli Responsive ◽  
Precise Control ◽  
Good Biocompatibility ◽  
Near Future ◽  
Real Patients

The administration of cytotoxic drugs in classical chemotherapy is frequently limited by water solubility, low plasmatic stability, and a myriad of secondary effects associated with their diffusion to healthy tissue. In this sense, novel pharmaceutical forms able to deliver selectively these drugs to the malign cells, and imposing a space-time precise control of their discharge, are needed. In the last two decades, silica nanoparticles have been proposed as safe vehicles for antitumor molecules due to their stability in physiological medium, high surface area and easy functionalization, and good biocompatibility. In this review, we focus on silica-based nanomedicines provided with specific mechanisms for intracellular drug release. According to silica nature (amorphous, mesostructured, and hybrids) nanocarriers responding to a variety of stimuli endogenously (e.g., pH, redox potential, and enzyme activity) or exogenously (e.g., magnetic field, light, temperature, and ultrasound) are proposed. Furthermore, the incorporation of targeting molecules (e.g., monoclonal antibodies) that interact with specific cell membrane receptors allows a selective delivery to cancer cells to be carried out. Eventually, we present some remarks on the most important formulations in the pipeline for clinical approval, and we discuss the most difficult tasks to tackle in the near future, in order to extend the use of these nanomedicines to real patients.

scholarly journals A highly sensitive safrole sensor based on polyvinyl acetate (PVAc) nanofiber-coated QCM

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kuwat Triyana ◽  
Aditya Rianjanu ◽  
Doni Bowo Nugroho ◽  
Ahmad Hasan As’ari ◽  
Ahmad Kusumaatmaja ◽  
...  
Keyword(s):  
Response Time ◽  
Polyvinyl Acetate ◽  
Limit Of Detection ◽  
High Surface ◽  
High Surface Area ◽  
Average Diameter ◽  
Promising Alternative ◽  
Force Microscopy ◽  
Atomic Force ◽  
Highly Sensitive

Abstract A novel, highly sensitive and selective safrole sensor has been developed using quartz crystal microbalance (QCM) coated with polyvinyl acetate (PVAc) nanofibers. The nanofibers were collected on the QCM sensing surface using an electrospinning method with an average diameter ranging from 612 nm to 698 nm and relatively high Q–factors (rigid coating). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the PVAc nanofiber surface morphology, confirming its high surface area and roughness, which are beneficial in improving the sensor sensitivity compared to its thin-film counterpart. The as-spun PVAc nanofiber sensor could demonstrate a safrole limit of detection (LOD) of down to 0.7 ppm with a response time of 171 s and a sensitivity of 1.866 Hz/ppm. It also showed good reproducibility, rapid response time, and excellent recovery. Moreover, cross-interference of the QCM sensor response to non-target gases was investigated, yielding very low cross-sensitivity and high selectivity of the safrole sensor. Owing to its high robustness and low fabrication cost, this proposed sensing device is expected to be a promising alternative to classical instrumental analytical methods for monitoring safrole-based drug precursors.

scholarly journals Product Innovations from Electrospun Nanofibers

2020 ◽  
Vol 5 (1) ◽  
Keyword(s):  
Water Solubility ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Electrospun Nanofibers ◽  
Silver Ions ◽  
Solvent System ◽  
Cellulose Microfibrils ◽  
Poly Lactic Acid ◽  
Innovative Products

The article reviews some significant research trends in the development of innovative products from electrospun nanofibers. In one area of investigation, high surface area poly (lactic acid) (PLA)/tea polyphenols (TPs) porous composite nanofiber membranes (CNFMs) were prepared successfully by electrospinning and applied to adsorption of silver ions. In another area of research electrospun PVA/SiO2 separator membranes were presented and their electrochemical performance was evaluated for use in Li-ion batteries. Polyvinyl alcohol (PVA) was used to prepare nanofiber based membranes due to advantages such as low cost, water solubility, and biodegradability. In yet another work, a mixture of formic acid (FA), acetic acid (AA), and acetone was used, for the first time, as a ternary solvent system to dissolve poly(E-caprolactone) (PCL). In addition, as a biomaterial reinforcement, various amounts of cellulose microfibrils (CMF) (1.5, 3, and 5wt. %), extracted from rice husk, were added to PCL solution, and subsequently the prepared suspensions were individually electrospun.

scholarly journals Breaking the barrier to biomolecule limit-of-detection via 3D printed multi-length-scale graphene-coated electrodes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Md. Azahar Ali ◽  
Chunshan Hu ◽  
Bin Yuan ◽  
Sanjida Jahan ◽  
Mohammad S. Saleh ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
High Surface ◽  
High Surface Area ◽  
Length Scale ◽  
Graphene Nanoflakes ◽  
Sensing Platform ◽  
Low Concentrations ◽  
Ultralow Concentrations ◽  
3D Printed ◽  
Coated Electrodes

AbstractSensing of clinically relevant biomolecules such as neurotransmitters at low concentrations can enable an early detection and treatment of a range of diseases. Several nanostructures are being explored by researchers to detect biomolecules at sensitivities beyond the picomolar range. It is recognized, however, that nanostructuring of surfaces alone is not sufficient to enhance sensor sensitivities down to the femtomolar level. In this paper, we break this barrier/limit by introducing a sensing platform that uses a multi-length-scale electrode architecture consisting of 3D printed silver micropillars decorated with graphene nanoflakes and use it to demonstrate the detection of dopamine at a limit-of-detection of 500 attomoles. The graphene provides a high surface area at nanoscale, while micropillar array accelerates the interaction of diffusing analyte molecules with the electrode at low concentrations. The hierarchical electrode architecture introduced in this work opens the possibility of detecting biomolecules at ultralow concentrations.

scholarly journals The Promising Role of Chitosan–Poloxamer 188 Nanocrystals in Improving Diosmin Dissolution and Therapeutic Efficacy against Ferrous Sulfate-Induced Hepatic Injury in Rats

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2087
Author(s):  
Neamet S. Lotfy ◽  
Thanaa M. Borg ◽  
Elham A. Mohamed
Keyword(s):  
Water Solubility ◽  
Chemical Interaction ◽  
High Surface ◽  
High Surface Area ◽  
Dissolution Enhancement ◽  
Hepatic Tissue ◽  
Poloxamer 188 ◽  
Ft Ir ◽  
Electrostatic And Steric Stabilization ◽  
Oxide Synthase

Diosmin (DSN) exhibits poor water solubility and low bioavailability. Although nanocrystals (NCs) are successful for improving drug solubility, they may undergo crystal growth. Therefore, DSN NCs were prepared, employing sonoprecipitation utilizing different stabilizers. The optimum stabilizer was combined with chitosan (CS) as an electrostatic stabilizer. NCs based on 0.15% w/v poloxamer 188 (PLX188) as a steric stabilizer and 0.04% w/v CS were selected because they showed the smallest diameter (368.93 ± 0.47 nm) and the highest ζ-potential (+40.43 ± 0.15 mV). Mannitol (1% w/v) hindered NC enlargement on lyophilization. FT-IR negated the chemical interaction of NC components. DSC and XRD were performed to verify the crystalline state. DSN dissolution enhancement was attributed to the nanometric rod-shaped NCs, the high surface area, and the improved wettability. CS insolubility and its diffusion layer may explain controlled DSN release from CS-PLX188 NCs. CS-PLX188 NCs were more stable than PLX188 NCs, suggesting the significance of the combined electrostatic and steric stabilization strategies. The superiority of CS-PLX188 NCs was indicated by the significantly regulated biomarkers, pathological alterations, and inducible nitric oxide synthase (iNOS) expression of the hepatic tissue compared to DSN suspension and PLX188 NCs. Permeation, mucoadhesion, and cellular uptake enhancement by CS may explain this superiority.

scholarly journals Fate of β-Carotene within Loaded Delivery Systems in Food: State of Knowledge

2021 ◽  
Author(s):  
Vaibhav Maurya ◽  
Amita Shakya ◽  
Manjeet Aggarwal ◽  
K.M. Gothandam ◽  
Torsten Bohn ◽  
...  
Keyword(s):  
Oral Delivery ◽  
Water Solubility ◽  
High Surface ◽  
High Surface Area ◽  
Research Area ◽  
Delivery Systems ◽  
Preparation Methods ◽  
Bioactive Agents ◽  
Unique Composition ◽  
Β Carotene

Accruing evidence on the influence of β-carotene regarding the prevention of several chronic diseases - in addition to its well-acknowledged role in vision has been a strong driver for developing alternative delivery systems. Though oral delivery is accepted as the most fitting, mild and safe path for delivering bioactive agents, β-carotene delivery via food items poses challenges due to its lipophilic nature, poor water-solubility, high chemical/photochemical instability and poor oral bioavailability. Nanotechnology has opened new windows for delivering bioactive agents. Their physiochemical characteristics, i.e. small size, high surface area, unique composition, biocompatibility and biodegradability make these nanomaterials an attractive tool for β-carotene delivery. Delivering β-carotene through nanoparticles does not only improve its bioavailability/bioaccumulation in target tissues, but also lessens its sensitivity against environmental factors during processing. Regardless of these benefits, nanocarriers inherit some limitations, such as variations in sensory quality, modification of the food matrix, increasing costs, as well as limited consumer acceptance and regulatory challenges. This research area has been rapidly evolved, with a plethora of innovative nano-engineered materials, including micelles, nano/microemulsion, liposomes, niosomes, solid-lipid nanoparticles and nanostructured lipid carriers. These nano-delivery systems make conventional delivery systems appear archaic and promise better solubilization, protection during processing, improved shelf-life, higher bioavailability as well as controlled and targeted release. This review provides information on the state of knowledge on β-carotene nano-delivery systems adopted for developing functional foods: depicting their classification, composition, preparation methods, challenges, release-and absorption of β-carotene in the GIT and possible risks and future prospects.

A bifunctional adsorbent with high surface area and cation exchange property for synergistic removal of tetracycline and Cu2+

2014 ◽  
Vol 258 ◽  
pp. 26-33 ◽  
Author(s):  
Yan Ma ◽  
Qing Zhou ◽  
Sicong Zhou ◽  
Wei Wang ◽  
Jing Jin ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Exchange Property

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

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