1,721,023 research outputs found
Micronized carvedilol SR matrix tablet for improved dissolution
No full textSustained release (SR) matrix formulation can overcome the disadvantages of frequent dosing of conventional tablet. Poor soluble drugs (BCS class II) suffer from low bioavailability due to low dissolution rate. Micronization is one of the easiest approaches to enhance solubility of drugs. Formulation of a SR matrix tablet with micronized drug particle will help to enhance dissolution as well as prolong the duration of drug release. In the research work entitled “micronized carvedilol SR matrix tablet for improved dissolution”, Carvedilol, a BCS class II β blocker drug is formulated as a SR matrix tablet with micronized drug particle. Direct compression method was applied to prepare tablet using PEO 301 as a release retardant polymer. The formulation was optimized by a 3 level factorial design considering amount of PEO 301 and hardness of tablet as dependent variables. In-vitro release study showed near about 100% of drug release in 12 hrs. for lowest particle size drug whereas for non-micronized drug it was less than 80%. The developed tablet showed desired stability for 3 months in accelerated conditions. The developed micronized carvedilol SR matrix tablet can be proposed for in-vivo assessment after relevant toxicity studies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Improved dissolution, flow property and compressibility of poor soluble API by co-grinding with fine silica
No full textObjective:The objective of this work was to enhance dissolution and tableting property of a poor soluble API which also has poor flow property. If flowability and compressibility of the API can be improved, the drug powder would be suitable to direct compression method of tableting.
Methods:Ibuprofen is chosen as a model poor soluble and poor flowable API. Ibuprofen is mixed with 1 wt% of hydrophobic and hydrophilic silica (particle size < 40 nm) separately by a ‘V’ blender. The mixture was then subjected to milling by a simple lab scale ball mil. The co-milled ibuprofen-silica mixture is then formulated as tablet using 30, 50 and 70% drug loading. Before tableting flow property and bulk density of all the tableting mixtures containing co-milled ibuprofen as well as blended ibuprofen (before milling) along with other inactive excipients were studied by various approaches such as angle of repose (AOR), Carr index (CI) and powder flow tester. The tablets are tested for physico-chemical characteristics and in-vitro dissolution.
Results:Tableting mixture of 30% and 50% drug (co milled mixture with hydrophobic silica) loading showed ‘excellent’ flow property by AOR (<30̊), CI (<10) and flow function co-efficient (ffc) (<12). However 70% drug loaded mixture showed ‘poor’ flowability by AOR and CI but comparable flowability by ffc. The compressibility result was superior in 50% co-milled ibuprofen loaded tableting mixture than other mixtures. The simple blended ibuprofen tableting mixture also showed acceptable flowability for 30% and 50% drug loaded mixture. Hydrophilic silica mixed ibuprofen in all cases resulted in ‘fair’ flowability but poor compressibility. Out of the entire tablets 50% co-milled drug loaded tablet showed better dissolution profile by releasing more than 90% of drug within 1 hour which is significantly higher than normal blended ibuprofen loaded tablet. However 70% drug loaded tablet resulted in slow drug release (<59.34% in 1 hour).
Conclusion:Co-milling of silica-ibuprofen might be a good strategy to improve flowability and dissolution of the drug. This approach may help preparing tablet by direct compression using high dose poor flowable drug
Nose to brain drug delivery: a recent update
No full textDrugs used to treat brain or central nervous system disorder suffer from shortfall of absorption and reaching brain due to blood
brain barrier and cerebro spinal fluid barrier. Intra nasal administration of brain targeted drug delivery system is gaining popularity
to circumvent blood brain barrier and enhance drug availability in brain. It also shows promising reduction of systemic adverse
effect incurred by the drug. However there are major limitation of this route which restrict its success of application. Despite
different dosage forms such as micro or nano emulsion, gel, in situ gel etc the intra nasal route is still lacking wide applicability. This
short review aims to highlight some important features related to nose to brain drug delivery along with its potential challenges that
need to overcome. It has focused on few interesting or significant articles on the matter published within last 4-5 years
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