379 research outputs found
Brief Effect of a Small Hydrophobic Drug (Cinnarizine) on the Physicochemical Characterisation of Niosomes Produced by Thin-Film Hydration and Microfluidic Methods
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Open AccessArticle
Brief Effect of a Small Hydrophobic Drug (Cinnarizine) on the Physicochemical Characterisation of Niosomes Produced by Thin-Film Hydration and Microfluidic Methods
by Li Key YeoOrcID,Temidayo O. B. Olusanya,Cheng Shu Chaw andAmal Ali Elkordy *OrcID
School of Pharmacy and Pharmaceutical Sciences, University of Sunderland, Sunderland SR1 3SD, UK
*
Author to whom correspondence should be addressed.
Pharmaceutics 2018, 10(4), 185; https://doi.org/10.3390/pharmaceutics10040185
Received: 20 July 2018 / Revised: 5 October 2018 / Accepted: 9 October 2018 / Published: 13 October 2018
(This article belongs to the Special Issue Non-Ionic Surfactant Vesicles for Drug Delivery)
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Abstract
Novel niosomal formulations containing cinnarizine were developed to enhance its drug characteristics. In this work, niosomes (non-ionic surfactant vesicles) were prepared by conventional thin-film hydration (TFH) and microfluidic (MF) methods with sorbitan monostearate (Span® 60), cholesterol, and co-surfactants (Cremophor® ELP, Cremophor® RH40 and Solutol® HS15) as key excipients. The aim was to study the effect of cinnarizine on the characteristics of different niosomal formulations manufactured by using different methods. For effective targeted oral drug delivery, the efficacy of niosomes for therapeutic applications is correlated to their physiochemical properties. Niosome vesicles prepared were characterised using dynamic light scattering technique and the morphology of niosomes dispersion was characterised using optical microscopy. Dialysis was carried out to purify niosome suspensions to determine drug loading and drug release studies was performed to study the potential use of niosomal systems for cinnarizine
Integrating new assessment strategies into mathematics classrooms: an exploratory study in Singapore primary and secondary schools
No full textEducational researchers and practitioners have in recent years paid mounting attention to the importance of new assessment (or the so-called alternative assessment) strategies in Mathematics instruction to better reflect the new desired educational goals and shifted values in education. However, research is wanting in this area, particularly in Singapore's educational setting. This project seeks to investigate the influence of using new assessment strategies in Mathematics teaching and learning on students' achievements, in both the cognitive and affective domains, in our local school settings. A quasi-experimental study with about 15-20 teachers at primary and lower secondary levels will be carried out to assess the impact of using a variety of strategies (e.g., projects, journal writing, oral presentation, performance tasks, student self-assessment, classroom observation and interview, etc.) for three school semesters on students' learning. The project will also look into issues concerning how to use new assessment strategies effectively in classrooms in local schools. For this purpose, data will be collected from classroom observation, interviews with teachers and students, and questionnaire surveys. It is hoped that the project will provide research-based evidence and practical suggestions for promoting the effective use of alternative assessment in Singapore Mathematics classrooms. <br/
Evaluation of niosome formulations containing methylene blue and cinnarizine manufactured by thin film hydration and microfluidic methods
No full textEnabling formulations has been emerging in formulation development owing to their characteristics to improve critical quality attributes of the drug delivery systems. This study focused on the preparation of niosome formulation as nanocarrier drug delivery system for the delivery of small drug molecules. This study was aimed to prepare niosome formulations to encapsulate cinnarizine, a poorly water-soluble drug with narrow absorption window in the stomach using the conventional thin film hydration (TFH) method and microfluidic (MF) method. Small drug molecule methylene blue was used as a model hydrophilic drug for optimisation of manufacturing and formulation parameters in order to pave the way for cinnarizine-containing niosome formulations.
The self-assembled niosomes were based on a 45/45/10 molar ratio of Span® 60 surfactant, cholesterol, and co-surfactant, respectively. Different drug-excipient ratios and different co-surfactant types (i.e. Cremophor® ELP, Cremophor® RH40 and Solutol® HS15) were investigated. Manufacturing variables in thin film hydration method were investigated, such as the hydration time and hydration volume. The effect of sonication on TFH-based niosomes was investigated. On the other hand, in microfluidic method, investigated manufacturing variables were total flow rate (mL/min) and flow rate ratio of the aqueous to organic solvents of the system parameters. Formulation parameters were drug concentration and total surfactant/lipid concentration. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were used to analyse the interactions between the model drug and formulation excipients. Additionally, the shape and size of all prepared niosome formulations were analysed using transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The drug release characteristics of the formulations were evaluated using dialysis technique in 0.1M hydrochloric acid (pH1.2) at 37±1 °C under agitation. Determination and quantification of drug were obtained using high-performance liquid chromatography (HPLC) for encapsulation efficiencies and release data. Release data were analysed by fitting to release kinetic model to describe drug release behaviour. Stability studies of niosome formulations at a refrigeration temperature (2-8 °C) and room temperature (21-25 °C) for one month were evaluated for their size and distribution. The incorporation of different mucoadhesive polymers (chitosan solution and alginate-based Gaviscon® suspension) with MF-based niosomes were prepared to study their feasibility to adhere to gastric mucosa for prolonged retention of the formulation system containing drug with an absorption window in the stomach, in order to enhance drug absorption and bioavailability. A modified HPLC with evaporative light scattering detection (HPLC-ELSD) method was employed in the direct quantification of Span® 60 and cholesterol recovery of the MF-based niosomes before and after purification process (gel chromatography filtration), in order to understand the applicability on preparation of niosomes using microfluidics.
Generally, based on the size and distribution data, it was found that TFH-based niosome formulations showed large and highly polydisperse, comparing to MF-based niosome formulations. Niosome formulations released entrapped drug in a slow release pattern, offering a more consistent drug absorption with a prolonged gastric retention time. At the same time, mucoadhesive formulations have shown adhesion to the stomach mucosa, showing retentive potential for drug absorption. This study demonstrated and evaluated both the conventional TFH-based niosome and advanced MF-based niosome formulations encapsulating small drug molecules – cinnarizine (poorly water-soluble) and methylene blue (hydrophilic), offers insights on controlling manufacturing parameters to produce niosome formulations for their applicability as dosage forms.
Keywords: Niosome, methylene blue, cinnarizine, thin film hydration, microfluidic
Pathways to high-impact journal publication: mastering bibliometric analysis in four steps / Yii Ming Leong and Yeo Jiin Yih
No full textBibliometric analysis is a research method that summarises extensive bibliometric data. It enables scholars to identify emerging trends in article and journal performance, collaboration patterns, publication trend analysis, author productivity, citation analysis and predicting emerging trends. Mastering bibliometric analysis involves four key steps. Firstly, identify the topic of interest; secondly, narrow down the scope; thirdly, download the dataset;and finally, conduct the bibliometric analysis and present the results. Bibliometric analysis enables academicians to excel in their Key Performance Indicators (KPIs) by publishing high-impact journals. It also increases their visibility and global recognition as well as creating avenues for securing funding opportunities. Furthermore, bibliometric analysis showcases the novelty of its usefulness in research. First, datasets are readily available and many research analytical tools are openly accessible, making it applicable across a broad spectrum of academic disciplines. Additionally, simplicity in analysis, minimal resource requirements and methodological transparency further enhance its practicality, providing a cost-effective and efficient approach for researchers. In terms of commercialization potential, empowering the application of bibliometric analysis leads to ncome generation avenues. This encompasses organizing paid workshops and training sessions to educate researchers on effective use of bibliometric insights. Additionally, offering paid consultation services aids researchers and institutions in strategically leveraging bibliometric data for planning, while providing paid research evaluation packages supports funding agencies and
institutions in assessing research impact
Reducing the Key Size of McEliece Cryptosystem from Automorphism-induced Goppa Codes via Permutations
No full textIn this paper, we propose a new general construction to reduce the public key size of McEliece cryptosystems constructed from automorphism-induced Goppa codes. In particular, we generalize the ideas of automorphism-induced Goppa codes by considering nontrivial subsets of automorphism groups to construct Goppa codes with a nice block structure. By considering additive and multiplicative automorphism subgroups, we provide explicit constructions to demonstrate our technique. We show that our technique can be applied to automorphism-induced Goppa codes based cryptosystems to further reduce their key sizes
Microfluidic-based preparations of novel niosomal formulations for entrapment of cinnarizine as a model poorly water soluble drug
No full textA key interaction with RPA orients XPA in NER complexes
No full text© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.The XPA protein functions together with the single-stranded DNA (ssDNA) binding protein RPA as the central scaffold to ensure proper positioning of repair factors in multi-protein nucleotide excision repair (NER) machinery. We previously determined the structure of a short motif in the disordered XPA N-terminus bound to the RPA32C domain. However, a second contact between the XPA DNA-binding domain (XPA DBD) and the RPA70AB tandem ssDNA-binding domains, which is likely to influence the orientation of XPA and RPA on the damaged DNA substrate, remains poorly characterized. NMR was used to map the binding interfaces of XPA DBD and RPA70AB. Combining NMR and X-ray scattering data with comprehensive docking and refinement revealed how XPA DBD and RPA70AB orient on model NER DNA substrates. The structural model enabled design of XPA mutations that inhibit the interaction with RPA70AB. These mutations decreased activity in cell-based NER assays, demonstrating the functional importance of XPA DBD-RPA70AB interaction. Our results inform ongoing controversy about where XPA is bound within the NER bubble, provide structural insights into the molecular basis for malfunction of disease-associated XPA missense mutations, and contribute to understanding of the structure and mechanical action of the NER machinery11Nsciescopu
The Effects of Hydration Parameters and Co-Surfactants on Methylene Blue-Loaded Niosomes Prepared by the Thin Film Hydration Method
No full textAbstract: This work aimed to investigate and optimise the effects of co-surfactants, hydration volume, and time on the entrapment of methylene blue (MB) within niosomes and the vesicle sizes of MB-loaded niosomes upon different storage temperatures. Niosomes were prepared by the thin film hydration method followed by gel permeation chromatography to obtain purified niosome suspensions. The probe sonication method was used to reduce the niosome vesicle size and distribution. Highest entrapment efficiencies (%EE) were determined for niosomal formulations containing Span® 60, cholesterol, and Cremophor® ELP (E2 and E3), which were prepared with a hydration volume of 5 mL. The hydration time was 15 min for E2 and 60 min for E3 (%EE = 40.1 ± 7.9% and 32.9 ± 10.1% for E3 and E2, respectively). The final lipid contents in the formulations were shown to have an impact on %EE
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