In Vitro Drug Release Activity from Core/Shell Electrospun MATS of sPLA-cPEG/GS and sPLA/CA-cPEG/GS

2012 ◽  
Vol 714 ◽  
pp. 263-270 ◽  
Author(s):  
Koravee Vichitchote ◽  
Poonsub Threepopnatkul ◽  
Supakij Suttiruengwong ◽  
Chanin Kulsetthanchalee
Keyword(s):  
Drug Release ◽  
Core Shell ◽  
Immersion Method ◽  
Electrospinning Technique ◽  
The Core ◽  
Buffer Solutions ◽  
Initial Release ◽  
Total Immersion ◽  
Core Section

In this research, the core-shell structured fiber was fabricated by coaxial electrospinning technique. A set of biodegradable polymers namely polylactic acid (PLA) and cellulose acetate (CA) were used as the shell material. Gentamicin sulfate (GS) as antimicrobial drug with polyethylene glycol (PEG) was used as the core structure. PEG formed the core section of the coreshell fibers for GS encapsulation.In-vitrodrug release activity of the core-shell fibers was determined by total immersion method in pH 7.4 phosphate buffer solutions (PBS). It was found that core-shell fibers sPLA-cPEG/GS exhibit higher initial release compared to that of core-shell fibers sPLA/CA-cPEG/GS.

scholarly journals FORMULATION AND IN VITRO–IN VIVO PHARMACOKINETIC EVALUATION OF CARDIOVASCULAR DRUG-LOADED PULSATILE DRUG DELIVERY SYSTEMS

2021 ◽  
pp. 144-151
Author(s):  
KUMAR BABU PASUPULETI ◽  
VENKATACHALAM A. ◽  
BHASKAR REDDY KESAVAN
Keyword(s):  
Drug Release ◽  
Ethyl Cellulose ◽  
Release Kinetic ◽  
In Vitro Drug Release ◽  
The Core ◽  
Coated Tablet ◽  
Tablet Formulations ◽  
Core Tablet

Objective: This study is to formulate Nebivolol into a Pulsatile liquid, solid composite compression coated tablet, which will delay the release of the drug in early morning hypertension conditions. Methods: The liquid, solid composite tablet was formulated and compressed with the ethylcellulose coating polymer. The percent in vitro drug release of the liquid solid composite compressed tablet was tested. Based on disintegration time and wetting time, the LCS2, LCS3, LSC6, LCS7 and LCS12 formulations were found to be the optimized solid-liquid compacts fast-dissolving core tablet formulations, which may be excellent candidates for further coating with polymer to transfer into press coated pulsatile tablet formulations. Coating the core tablet with varying ethyl cellulose concentrations resulted in five different formulations of the pulsatile press-coated tablet (CT1, CT2, CT3, CT4, CT5). In vitro drug release, in vitro release, kinetic studies, in vivo pharmacokinetic and stability tests were all performed for the prepared pulsatile press coated tablet. Results: CT3 tablets are coated with ethyl cellulose polymer, which shows maximum controlled drug release from the core tablet i.e. 96.34±1.2% at 8th h. It shows there was an efficient delay in drug release form core tablet i.e. up to 3 h, followed by the maximum amount of drug release of 96.34±2.4 at 8h. Which shows the core drug will be more efficiently protected from the gastric acid environment 1.2 pH, duodenal environment 4.0 pH and release drug only in the small intestine. Conclusion: According to the findings, CT3 Pulsatile press-coated tablet increased the bioavailability of Nebivolol by 3.11 percent.

scholarly journals In Vitro Double-Stranded RNA Synthesis by Rotavirus Polymerase Mutants with Lesions at Core Shell Contact Sites

2019 ◽  
Vol 93 (20) ◽  
Author(s):  
Courtney L. Steger ◽  
Mackenzie L. Brown ◽  
Owen M. Sullivan ◽  
Crystal E. Boudreaux ◽  
Courtney A. Cohen ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Functional Significance ◽  
Rna Synthesis ◽  
Polymerase Activity ◽  
Core Shell ◽  
Double Stranded Rna ◽  
The Core ◽  
Contact Sites ◽  
Shell Protein

ABSTRACT The rotavirus polymerase VP1 mediates all stages of viral RNA synthesis within the confines of subviral particles and while associated with the core shell protein VP2. Transcription (positive-strand RNA [+RNA] synthesis) by VP1 occurs within double-layered particles (DLPs), while genome replication (double-stranded RNA [dsRNA] synthesis) by VP1 occurs within assembly intermediates. VP2 is critical for VP1 enzymatic activity; yet, the mechanism by which the core shell protein triggers polymerase function remains poorly understood. Structural analyses of transcriptionally competent DLPs show that VP1 is located beneath the VP2 core shell and sits slightly off-center from each of the icosahedral 5-fold axes. In this position, the polymerase is contacted by the core shell at 5 distinct surface-exposed sites, comprising VP1 residues 264 to 267, 547 to 550, 614 to 620, 968 to 980, and 1022 to 1025. Here, we sought to test the functional significance of these VP2 contact sites on VP1 with regard to polymerase activity. We engineered 19 recombinant VP1 (rVP1) proteins that contained single- or multipoint alanine mutations within each individual contact site and assayed them for the capacity to synthesize dsRNA in vitro in the presence of rVP2. Three rVP1 mutants (E265A/L267A, R614A, and D971A/S978A/I980A) exhibited diminished in vitro dsRNA synthesis. Despite their loss-of-function phenotypes, the mutants did not show major structural changes in silico, and they maintained their overall capacity to bind rVP2 in vitro via their nonmutated contact sites. These results move us toward a mechanistic understanding of rotavirus replication and identify precise VP2-binding sites on the polymerase surface that are critical for its enzymatic activation. IMPORTANCE Rotaviruses are important pathogens that cause severe gastroenteritis in the young of many animals. The viral polymerase VP1 mediates all stages of viral RNA synthesis, and it requires the core shell protein VP2 for its enzymatic activity. Yet, there are several gaps in knowledge about how VP2 engages and activates VP1. Here, we probed the functional significance of 5 distinct VP2 contact sites on VP1 that were revealed through previous structural studies. Specifically, we engineered alanine amino acid substitutions within each of the 5 VP1 regions and assayed the mutant polymerases for the capacity to synthesize RNA in the presence of VP2 in a test tube. Our results identified residues within 3 of the VP2 contact sites that are critical for robust polymerase activity. These results are important because they enhance the understanding of a key step of the rotavirus replication cycle.

Drug release profile and reduction in the in vitro burst release from pectin/HEMA hydrogel nanocomposites crosslinked with titania

RSC Advances ◽  
2016 ◽  
Vol 6 (23) ◽  
pp. 19060-19068 ◽  
Author(s):  
Elisangela P. da Silva ◽  
Marcos R. Guilherme ◽  
Francielle P. Garcia ◽  
Celso V. Nakamura ◽  
Lucio Cardozo-Filho ◽  
...  
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Release Profile ◽  
Burst Release ◽  
Drug Release Profile ◽  
Initial Release ◽  
Hydrogel Nanocomposites

Hydrogel nanocomposites of pectin, HEMA and titania for Vit-B12 controlled release with reduced initial release burst were prepared. A reduction of up to ca. 60% was observed.

scholarly journals Design and Development of Antibacterial/Anti-inflammatory Dual Drug-Loaded Nanofibrous Inserts for Ophthalmic Sustained Delivery of Gentamicin and Methylprednisolone: In Vitro Bioassay, Solvent, and Method Effects’ Evaluation

2021 ◽  
Author(s):  
Shahla Mirzaeei ◽  
Donya Barfar
Keyword(s):  
Mechanical Properties ◽  
Sustained Release ◽  
In Vitro Release ◽  
Core Shell ◽  
Solvent Mixtures ◽  
Antibacterial Efficacy ◽  
Electrospinning Technique ◽  
Dual Drug ◽  
Release Profiles

Purpose: To overcome the challenges caused by the use of conventional ophthalmic dosage forms such as the fast elimination of the drug from the surface of the eye, in this study, dual drug-loaded nanofibers were developed for sustained ophthalmic delivery of Gentamicin (GNT) and Methylprednisolone (MP). Moreover, the solvent effects, polymer mixtures, and method of preparation on the release profile of the prepared nanofibers, were evaluated. Methods: The nanofibers were prepared using Polycaprolactone, Poly (lactic-co-glycolic acid), and Polyvinyl alcohol using electrospinning technique. Thereafter, seven optimized formulations were developed with different solvent mixtures and polymer concentrations using various electrospinning methods. The physicochemical and mechanical properties of nanofibers were also evaluated, and the morphology of formulations was observed. The antibacterial efficacy was investigated and the in vitro release amounts of GNT and MP from nanofibers were estimated using the bioassay and Ultraviolet-visible spectroscopy. Results: The developed G1, G4, G5, G6, and G7 had suitable mechanical properties and morphologies with diameter ranging between 70-350 nm. The 1:1 v/v ratio of DMF/DCM in the solvent mixture and using core-shell technique for the preparation, formed nanofibers with more favorable release profiles. The optimized formulations indicated sustained-release manner for both drugs during 3-9 days and the antibacterial efficacy against Staphylococcus aureus. Conclusion: Among all the prepared formulations, the nanofiber with core-shell structure possessed the best sustained-release profiles of GNT and MP. The obtained results suggest that these nanofibers have a potential to be used as an insert in the eye for long-term release of the drug.

scholarly journals Effect of Solution Miscibility on the Morphology of Coaxial Electrospun Cellulose Acetate Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4419
Author(s):  
Ke Yan ◽  
Yao Le ◽  
Hu Mengen ◽  
Li Zhongbo ◽  
Huang Zhulin
Keyword(s):  
Cellulose Acetate ◽  
Shell Structure ◽  
Partial Solution ◽  
Electrospinning Process ◽  
Core Shell ◽  
Electrospinning Technique ◽  
Product Morphology ◽  
The Core ◽  
Core Shell Structure ◽  
Structural Characterizations

Coaxial electrospinning (co-electrospinning) technique has greatly expanded the universality of fabricating core-shell polymer nanofibers. However, the effect of solution miscibility on the morphology of co-electrospun products remains unclear. Herein, different cellulose acetate (CA) solutions with high solution miscibility but distinctly different electrospinnability were used to survey the effect of solution miscibility on the co-electrospinning process. The structural characterizations show that co-electrospun products are composed of nanofibers with and without the core-shell structure. This indicates that partial solution mixing occurred during the co-electrospinning process instead of absolute no-mixing or complete mixing. Importantly, the solution miscibility also shows a significant influence on the product morphology. In particular, the transformation from nanofibers to microparticles was realized with the increase of core-to-shell flow ratio during the co-electrospinning of core electrosprayable CA/dimethylacetamide (DMAc) solution and shell electrospinnable CA/acetone-DMAc (2/1, v/v) solution. Results show that the solution miscibility exerts a significant effect on not only the formation of core-shell structure but also the product morphology. This work provides a new insight for the in-depth understanding of the co-electrospinning process.

Core–shell noble-metal@zeolitic-imidazolate-framework nanocarriers with high cancer treatment efficiency in vitro

2019 ◽  
Vol 7 (7) ◽  
pp. 1050-1055 ◽  
Author(s):  
Liangcan He ◽  
Kanglei Pang ◽  
Wenwen Liu ◽  
Yue Tian ◽  
Lin Chang ◽  
...  
Keyword(s):  
Drug Release ◽  
Cancer Treatment ◽  
Drug Loading ◽  
Controlled Drug Release ◽  
Core Shell ◽  
Treatment Efficiency ◽  
Zeolitic Imidazolate Framework ◽  
High Drug ◽  
High Drug Loading

Core–shell Au@zeolitic-imidazolate-framework nanocarriers with high drug-loading, controlled drug release properties, and high cancer treatment efficiency.

scholarly journals Well Defined Poly(Methyl Methacrylate)-Fe3O4/Poly(Vinyl Pivalate) Core–Shell Superparamagnetic Nanoparticles: Design and Evaluation of In Vitro Cytotoxicity Activity Against Cancer Cells

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2868
Author(s):  
Graciane Resende ◽  
Gabriel V. S. Dutra ◽  
Maria S. B. Neta ◽  
Olacir A. Araújo ◽  
Sacha B. Chaves ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Emulsion Polymerization ◽  
Cell Lines ◽  
Shell Structure ◽  
In Vitro Cytotoxicity ◽  
Core Shell ◽  
Seeded Emulsion Polymerization ◽  
Poly Methyl Methacrylate ◽  
The Core

The objective of this work is to develop and characterize polymeric nanoparticles with core–shell morphology through miniemulsion polymerization combined with seeded emulsion polymerization, aiming at the application in the treatment of vascular tumors via intravascular embolization. The synthesis of the core–shell nanocomposites was divided into two main steps: (i) Formation of the core structure, consisting of poly(methyl methacrylate)/magnetic oxide coated with oleic acid (OM-OA) via miniemulsion and (ii) shell structure produced through seeded emulsion polymerization of vinyl pivalate. Nanocomposites containing about 8 wt.% of OM-OA showed high colloidal stability, mean diameter of 216.8 nm, spherical morphology, saturation magnetization (Ms) of 4.65 emu·g−1 (57.41 emu·g−1 of Fe3O4), preserved superparamagnetic behavior and glass transition temperature (Tg) of 111.8 °C. TEM micrographs confirmed the obtaining of uniformly dispersed magnetic nanoparticles in the PMMA and that the core–shell structure was obtained by seeded emulsion with Ms of 1.35 emu·g−1 (56.25 emu·g−1 of Fe3O4) and Tg of 114.7 °C. In vitro cytotoxicity assays against murine tumor of melanoma (B16F10) and human Keratinocytes (HaCaT) cell lines were carried out showing that the core–shell magnetic polymeric materials (a core, consisting of poly(methyl methacrylate)/Fe3O4 and, a shell, formed by poly(vinyl pivalate)) presented high cell viabilities for both murine melanoma tumor cell lines, B16F10, and human keratinocyte cells, HaCaT.

Facile Synthesis and In Vitro Biological Screening of Pd@SiO2 Core–Shell Nanoparticles

2019 ◽  
Vol 19 (6) ◽  
pp. 3536-3543 ◽  
Author(s):  
K Rajasekar ◽  
A Dinesh ◽  
M Durka ◽  
K Muthukumaravel
Keyword(s):  
Dna Binding ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Core Shell ◽  
Light Illumination ◽  
Shell Nanoparticles ◽  
The Core ◽  
Ft Ir ◽  
Core Shell Nanoparticles

In this study, semiconductor core–shell Pd@SiO2 nanoparticles (NPs) were prepared by Stober’s method. The prepared final products were characterized by XRD, FT-IR, SEM, HR-TEM and EDX techniques. Cell viability of Pd@SiO2 NPs against HeLa cell line was screened by MTT assay. The present study indicates that the core–shell Pd@SiO2 NPs are extremely stable along with very high photodynamic efficiency under LED light illumination. The antibacterial activities of core– shell Pd@SiO2 NPs were determined with Escherichia coli and Staphylococcus aureus by agar diffusion method. DNA binding affinity of the core–shell Pd@SiO2 NPs towards CT-DNA was also investigated. The observed results showed that SiO2 supported on the surface of Pd NPs not only prevented aggregation, but also proved the enhanced antimicrobial and DNA binding propensities than the free Pd NPs.

Phase Inversion Dynamics of PLGA Solutions Related to Drug Delivery

1998 ◽  
Vol 550 ◽  
Author(s):  
A.J. Mchugh ◽  
P.D. Graham ◽  
K.J. Brodbeck
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Release Rate ◽  
Phase Inversion ◽  
In Vitro Drug Release ◽  
Water Influx ◽  
Initial Release ◽  
Dark Ground ◽  
Initial Drug

AbstractDark ground optical microscopy, electron microscopy, and protein release rate studies have been used to quantify the effects of formulation changes on the phase inversion dynamics and in vitro drug release properties of an injectable PLGA-based drug delivery system. Gel growth rates and water influx rates are determined from plots of the square of the respective front with time. Results show that additives that increase the solution gelation rate and produce finger-like void morphologies result in higher initial release rates. Conversely, additives that slow the rate of gelation dramatically reduce the initial drug release rate and lead to a more dense sponge-like morphology.

scholarly journals Fabrication and application of coaxial polyvinyl alcohol/chitosan nanofiber membranes

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 1004-1014 ◽  
Author(s):  
Ting-Yun Kuo ◽  
Cuei-Fang Jhang ◽  
Che-Min Lin ◽  
Tzu-Yang Hsien ◽  
Hsyue-Jen Hsieh
Keyword(s):  
Drug Release ◽  
Polyvinyl Alcohol ◽  
Gum Arabic ◽  
Release Time ◽  
Core Shell ◽  
The Core ◽  
Chitosan Nanofiber ◽  
Application Potential ◽  
Nanofiber Membranes ◽  
Model Drug

AbstractIt is difficult to fabricate chitosan-wrapped coaxial nanofibers, because highly viscous chitosan solutions might hinder the manufacturing process. To overcome this difficulty, our newly developed method, which included the addition of a small amount of gum arabic, was utilized to prepare much less viscous chitosan solutions. In this way, coaxial polyvinyl alcohol (PVA)/chitosan (as core/shell) nanofiber membranes were fabricated successfully by coaxial electrospinning. The core/shell structures were confirmed by TEM, and the existence of PVA and chitosan was also verified using FT-IR and TGA. The tensile strength of the nanofiber membranes was increased from 0.6-0.7 MPa to 0.8-0.9 MPa after being crosslinked with glutaraldehyde. The application potential of the PVA/chitosan nanofiber membranes was tested in drug release experiments by loading the core (PVA) with theophylline as a model drug. The use of the coaxial PVA/chitosan nanofiber membranes in drug release extended the release time of theophylline from 5 minutes to 24 hours. Further, the release mechanisms could be described by the Korsmeyer-Peppas model. In summary, by combining the advantages of PVA and chitosan (good mechanical strength and good biocompatibility respectively), the coaxial PVA/chitosan nanofiber membranes are potential biomaterials for various biomedical applications.

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