10 research outputs found
Authors, authorship order, the moving finger writes
No full textThere has been a phenomenal increase in the number of research papers with multiple authors. Increasing academic pressures and halo around individuals with prolific publications have made many aspirants to claim authorship. Increasing number of authors has brought its own issues of author credits, disputes, rivalry, and a degree of unwelcome scramble for credit sharing. Many unresolved issues about authorship and various guidelines and admonitions are more often infringed than adhered to. The position of the first and last author seem to be well recognized in medical and dental journals, but the fate of middle authors is left to guessing and often of inconsequential importance. Most of these issues, as well as fraud, misconduct in medical research publications, have been discussed amply but too of no avail. It is comforting to know that except for small shouts and whispers, dental research has been relatively free from scams and frauds. The complacency, however, needs to be tempered with constant vigil against fraud, falsification and fabrication of research reports. Honest authorship, vigilant editors, robust peer review, and a discerning readership are the sine qua non for a good research paper. Academic institutions and selection committees should be concentrating on the quality of research papers and not enamored of their number
Female Leaders and Pandemic Response: Analysis of Gender Stereotypes in Media
No full textMedia coverage of female politicians can affect how the public perceives them as leaders. The language used by the media to portray female leaders is crucial in constructing their image as politicians. This study explored how female national leaders were represented by the global media during the pandemic and how it resulted in enhancing their stereotypical image. Social constructionism was used as the theoretical framework as the study focused on the gender representations of leaders and the language used by the media, both of which are social constructs.
News articles from the top 25 English-language news websites in the years 2020 and 2021 were selected to collect the data for the research. A combination of quantitative and qualitative assessment was done as part of the content analysis. 78 news articles were analyzed in total on the basis of nine attributes mentioned in the articles: age, professional background, family background, dressing style, characteristics associated with femininity, characteristics associated with masculinity, gender, details on personal lives, and sentiments expressed by the leaders. These attributes were formulated by the author on the basis of knowledge gathered from previous academic research. The results from the quantitative analysis were further evaluated in reference to the findings of previous research to gain a comprehensive understanding of the topic.
The results of the study suggest that the gender of the leader plays a crucial role in their media portrayal. Feminine traits are often associated with female leaders rather than their competency as leaders. Moreover, irrelevant aspects such as personal details, family, and professional background are given importance while covering news related to female leaders. While, initially, the thesis was also interested to explore whether the stereotypes were challenged, the findings of this study confirms that the language used by the media to represent female national leaders during the pandemic reiterated their stereotypical image as politicians. The results also cite the importance of media representations of female leaders and how present concept of leadership needs to improvise
Reimagining Spiritual Horizons: Critical Reflections on Reinventing Sanatana Dharma
No full textThis commentary critically examines Mukundan P.R\u27s significant work Reinventing Sanatana Dharma: The Spiritual Movement of Navajyoti Sree Karunakara Guru for a New India and a New World Order, New Delhi, India, Authors Press, 2024, Pages: 212, Rs. 500, Paperback, ISBN: 97-93-5529-976-5. The book critically reinterprets the Indian philosophical concept of Sanatana Dharma through the teachings of Navajyoti Sree Karunakara Guru, a spiritual visionary born in Kerala, India. The book challenges the traditional perceptions of Hindu philosophy, presenting Sanatana Dharma as a universal, non-discriminatory spiritual science. It explores key distinctions between Sanatana Dharma and mainstream Hinduism, addressing themes such as the spiritual evolution of consciousness, the significance of a true guru, and the reinterpretation of certain key Upanishadic concepts. While the book’s non-linear structure challenges narrative flow, its interdisciplinary approach—bridging Indian scriptures and contemporary scientific insights—offers a fresh perspective on spirituality. This review, therefore, highlights the book’s contribution to spiritual discourse and its potential to inspire a re-examination of Indian philosophy. In addition, the commentary also hints at what the author names a ‘syncretic monotheism’, which integrates the most profound principles of various religions into the overarching framework of Sanatana Dharma, contributing to sustainable development, making it an engaging resource for scholars, seekers, and readers interested in the intersection of religion and spirituality
Sol–gel derived ZnO thin film as a transparent counter electrode for WO3 based electrochromic devices
No full textPlease cite this article in press as: A.H. Haritha, et al., Sol–gel derived ZnO thin film as a transparent counter electrode for WO3 based elec trochromic devices, Bol. Soc. Esp. Cerám. Vidr. (2023), https://doi.org/10.1016/j.bsecv.2023.08.002[EN] Electrochromic devices (ECDs) have the ability to show color even when electrical power is disconnected. However, challenges such as simple and cost-effective electrochromic material preparation, insufficient coloration, slow switching times, and poor cycling stability have yet to be overcome. The paper describes an electrochromic device with WO3 thin film as the electrochromic material for the working electrode and ZnO thin film as a counter electrode fabricated on FTO glass substrates by a simple sol–gel spin coating method. The optical contrast at 600 nm of ZnO counter electrode based ECD (12.4%) is almost double that of graphite counter electrode based ECD (6.5%), showing higher efficiency and better electrochromic response. The properties of ECD devices were also examined using cyclic voltammetry and chronoamperometry measurements with results showing that the devices were stable and the charge required to tint the device (5.6 mA s) is reduced compared to typical graphite-coated counter electrode. These types of devices are promissing candidates to be used as smart windows.[ES] Los dispositivos electrocrómicos (ECD) tienen la capacidad de mostrar color incluso cuando se desconectan de la energía eléctrica. Sin embargo, para su implantación total deben superarse importantes desafíos como la preparación de materiales electrocrómicos simples y rentables, la coloración insuficiente, los tiempos de conmutación que son lentos y la mala estabilidad del ciclo. En este artículo se describe la preparación de un dispositivo electrocrómico basado en una película delgada de WO3 como electrodo de trabajo y una película delgada de ZnO obtenida por sol-gel como contra-electrodo, todo fabricado sobre sustratos de vidrio FTO mediante un método simple de centrifugado. Como resultados destacar que el contraste óptico a 600 nm del ECD basado en el contra-electrodo de ZnO (12,4%) es casi el doble que el del sistema ECD basado en el contra-electro de grafito (6,5%), mostrando una mayor eficiencia y una mejor respuesta electrocrómica. Las propiedades del dispositivo ECD de ZnO también se examinaron mediante voltametría cíclica y cronoamperometría y los resultados mostraron que los dispositivos eran estables y la carga necesaria para teñir el dispositivo (5,6 mAs) se reducía comparado con el dispositivo ECD de grafito. Este tipo de dispositivos son candidatos prometedores para ser utilizados como ventanas inteligentes.This work is a part of the activities of the FunGlass project. This project has received funding from the European Union Horizon 2020 Research and Innovation Program under Grant 739566. This work was also supported by the Grant VEGA 1/0844/21 of the Grant Agency of the Slovak Republic and the authors are grateful to the JECS Trust for funding (contract No. 2022301).Peer reviewe
Banishayban in the Islamic era
No full textGenealogists have related BaniShayban origin from Mosni-bin HarithaShaybani to prophet’s 19th ancestor called Nazar. Mosni-bin HarithaShaybani was a significant character who played a basic role in the events of early Islam. He managemd to earn reputation among Arabs due to his victory over the army of Iran in Zuqar battle, so that the first and second caliphs let him attack Iranian borders with other Islamic commanders.In addition to Zuqar battle under commandment of Mosni-bin HarithaShaybani, BaniShayban tribe had several battles with Shahrbaraz, Iranian self-styled king, including battle of chains and battle of Ullais during 11 to 14 A.H years. They participated in battle of the bridge with Abu Obadiah, another commander of the Muslim Arabs. They were also present at the battle of Boveib. The commander of Shaybanis attended the battle of al-Qādisiyyah with several injuries on his body and wished to participate in the battle of Jalula, but his life came to its end before that.In the days of Imam Ali, Shaybanis helped him and were his commanders, particularly in the battle of Siffin, because of being allied with the descendants of Abu Talib. Although some of them stood against Imam Ali, some others lost their lives guilty of friendship with him. They acquired high positions at the time of Umayyad and Bani Abbas and were even appointed in Armenia.The most important question is whether Shaybanis had any relationships with caliphs in early Islam; what role did they play in early Muslim conquests; and what positions were they assigned in the early centuries of Islam? The present study investigates the role of Shaybanis in Islamic era, particularly during early Islam as well as Umayyad and Bani Abbas reign.Keywords: BaniShayban, Mosni-bin Haritha, Iranian army, Umayyad, Bani Abba
Influence of annealing temperature on the photocatalytic efficiency of sol-gel dip-coated ZnO thin films in methyl orange degradation
No full textZnO thin films on glass substrates and silicon wafers were prepared by the sol-gel dipcoating technique and annealed at temperatures ranging from 300 - 550 °C. X-ray diffraction (XRD) and Raman analysis confirm the hexagonal wurtzite structure of ZnO. Scanning electron microscopy (SEM) examination confirmed that the films were homogeneous, crack-free and with a uniform distribution of nano-sized spherical grains. The decomposition of methyl orange (MO) using a solar simulator was used to determine the photocatalytic activity of the thin films. The annealing temperature was found to have a significant influence on the structure, morphology, and photocatalytic performance of ZnO thin films. The best photocatalytic activity under solar irradiation was shown by the ZnO thin film annealed at 450 °C. The enhanced photocatalytic performance of the films can be attributed to their optimized crystallinity, surface roughness and morphology, which provide more active sites for the photocatalytic reactions
Literary Review of Poorva Karma in Shalya Karma
No full textAcharya Sushruta is credited with inventing the notion of Trividha Karma and mentioned Trividha Chikitsha Karma in Agropharniya Adhyaya viz; - Poorva Karma, Pradhana Karma, and Paschata Karma. Poorva Karma is derived from the words Poorva (foremost) and Karma (action). In the Ayurvedic tradition, there are two methods of treatment for all diseases: Aushadhi Chikitsa or Shastra Chikitsa. In Shayla Tantra, there are descriptions of Yanta, Shastra, Kshara, and Agni Karmas for performing Shayla Karma (surgical and para surgical procedure), but Poorva Karma should be given importance in any surgical treatment, and this Poorva Karma is recognized as pre-operative care. Poorva Karma is crucial to a successful and complication-free operation
Time-dependent Mechanical Properties and Structural Behaviour of Graphene Nanoplatelet-reinforced Concrete
No full textConcrete with high volumes of supplementary cementitious materials often have lower early age compressive strength and slower strength gain with time. It has been reported that the addition of graphene nanoplatelets (GNPs) enhances concrete compressive strength. However, the ability of GNPs to increase the early age concrete compressive strength has not been investigated, and there has been limited testing of structural elements of GNP-containing concrete. This study examines the mechanical properties of low cement concrete between 1- and 28-days of curing with varying GNP concentrations. Furthermore, reinforced concrete beams with GNPs were tested at 3 and 28 days to investigate their structural behaviour. The results show compressive strength increases of up to 31% at early ages for a GNP concentration of 0.15 wt% of cement, but no overall changes in the structural behaviour.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
High performance double layer hydrophobic antireflective coatings on glass prepared by sol–gel method
No full textA double layer coating was designed and fabricated on glass surfaces by sol-gel method using a silica-titania (SiO2–TiO2) thin film as the bottom layer and an inorganic-organic (triethoxy(octyl)silane (OTES) modified SiO2) upper layer. SiO2 and TiO2 sols were prepared using tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TIP) as precursors and nitric acid (HNO3) as catalyst. The refractive index of the SiO2–TiO2 and OTES modified SiO2 layers were 1.79 and 1.45, and their thicknesses were approximately 76.8 nm and 94.2 nm, respectively. The results show an increase of 7% in transmittance respect to the uncoated glass substrate. At the same time, OTES-modified SiO2 top layer significantly improved the hydrophobicity of the system; the water contact angle of film increased from 56° for system without the OTES modified SiO2 layer to 102° for the system with OTES-modified SiO2 top layer
Validation of Dissolution Method of Levofloxacin 750 mg Tablet by High Performance Liquid Chromatography
No full textAbstract
Dissolution test is required to study the drug release from the dosage form and it’s in vivo performance. Dissolution test is used to assess the lot to lot quality of drug product. The development and validation of dissolution procedures is of paramount importance during development of new formulation and in quality control. The dissolution procedure must be properly developed and validated. The objective of this paper is to review the development and validation of dissolution procedure(s) and to provide practical approaches for determining specificity, linearity, range, accuracy, precision, limit of detection and limit of quantitation of methods. Developing and validating dissolution test procedures can be a challenging process, on multiple fronts. Methods must be developed and validated not just for the dissolution test procedure itself, but also for any assay used to evaluate the test results.
1.1 Levofloxacin:
Levofloxacin is an antibiotic. It is used to treat a number of bacterial infections, such as bacterial sinusitis, pneumonia, urinary tract infection, chronic prostatitis, and some types of gastroenteritis. Along with other antibiotics it may be used to treat tuberculosis, meningitis, pelvic inflammatory diseases. Use is generally recommended only when other options are not available. It available by mouth, intravenously and in eye drop form. Common side effects include nausea, diarrhea and troubling sleeping. Serious side effects may include tendon rupture, tendon inflammation, seizure, psychosis and potentially permanent peripheral nerve damage. Tendon damage may appear month after treatment is completed. People may also sunburn more easily. In people with myasthenia gravis, muscle weakness and breathing problem may worsen. While use during pregnancy is not recommended, risk appears to be low. The use of other medications in this class appears to be safe while breast feeding; however, the safety of Levofloxacin is unclear. Levofloxacin is a broad-spectrum antibiotic of the fluroquinolone drug class. It is usually results in death of the bacteria. It is the left sided isomer of the medication ofloxacin.
Levofloxacin was patented in 1985 and approved for medical use in the United States in 1996. It is on the World Health Organization’s list of essential medicines, the most effected and safe medicines needed in the health system. It available as generic medication. The wholesale cost in the developing world is about 50-100. In 2016 it was the 161st most prescribed medication in the United States with more than 3 million prescriptions.
Fig 1: Structure of Levofloxacin
Levofloxacin is used to treat infections including: respiratory tract infection, cellulities, urinary tract infection, anthrax, endocardities, menengities, pelvic inflammatory diseases, traveler’s diarrhoea, tuberculosis and plague. It is available by mouth, intravenously and in the eye drop form.
Levofloxacin is broad-spectrum antibiotic that is active against both gram-positive and gram-negative bacteria. Like all quinolones, it function may inhibiting the DNA gyrase and topoisomerase IV which is necessary to separate DNA that has been replicated prior to bacterial cell division. With the DNA not being separated, the process is stopped and the bacteria cannot be divided. DNA gyrase, on the other hand, is responsible for supercoiling the DNA, so that it will fit in the newly formed cells. Both mechanisms amount to killing the bacterium. Levofloxacin acts as a bactericide.
1.2 HPLC
1.2.1 Principle:
High performance liquid chromatography (HPLC; formally referred to as High pressure liquid chromatography) is a technique in analytical chemistry used to separate, identify and quantify each component in a mixture. It relies on pumps to pass the pressurized liquid solvent containing the sample mixture through a column filled with a solid adsorbent material, causing different flow rates for the different components and leading to the separation of the components as they flow out of the column.
1.2.2 Major components:
Pump
Column
Detector
Injector
HPLC Accessories
1.2.2.1 Pump:
The role of pump is to force liquid (called the mobile phase) through the chromatography at a specific flow rate, express in ml/min. High-pressure pumps are needed to push the mobile phase through the packed stationary phase. A steady pump pressure (Usually about 1000-2000 psi) is needed to ensure reproducibility and accuracy.
1.2.2.2 Injector:
The injector serves to introduce the liquid sample into the flow stream of the mobile phase. An injector for an HPLC system should provide an injection of the liquid sample within the range of 0.1-100 ml of volume with high reproducibility and under high pressure (Up to 4000 psi). For liquid chromatography, liquid samples can be directly injected and solid samples need only to be diluted in the appropriate solvent.
Types:
• Manual Injector: For manual injector, a syringe 22-gauge blunt tip needle is used to introduce the sample into the sample loop at load position.
• Auto sampler: An auto sampler allows the automatic sample injection from sample vial or
• 96-well microplates.
1.2.2.3 Column:
The column is the heart of the HPLC system. A typical column is a stainless-steel tube filled with small-particle packing used for sample separation.
Types:
HPLC columns can be categorized in a number of ways:
• By Column Hardware: Standard or cartridge, stainless steel, PEEK, titanium.
• By Chromatographic Modes: Normal-phase (NPC), Reversed-phase (RPC), ion exchanged (IEC), size-exclusion (SEC).
• By Dimensions: Prep, semi prep, analytical, Fast LC, micro, nano.
• By Support Types: Silica, polymer, zirconia, hybrid.
Guard Column:
A guard column is a protective column or cartridge installed between the injector and the analytical column. It serves to remove the impurities and suspended solids from reaching the analytical column. Typically, it has a length of about 2 cm and internal diameter of 4.6 mm. Guard column are packed with pellicular particles of around 40 μm size to offer negligible pressure drop.
1.2.2.4 Detector:
The detector detects the individual molecules that come out (elute) from the column. A detector serves to measure the amount of those molecules so that the analyst can quantitatively analyze the sample components. The detector provides an output to a recorder or computer those results in the liquid chromatogram (i.e., the graph of the detector response).
There are different types of detectors:
UV visible detector
Photodiode Array (PDA) Detector
Fluorescence Detector
Mass Spectroscopic detector
Refractive Index Detector
Electrochemical Detector
Conductivity Detector
1.2.2.4.1 UV visible detector:
HPLC UV detectors are used with high performance liquid chromatography to detect and identify analysis in the sample. A UV visible HPLC detector uses light to analyze samples. By measuring the samples absorption of light at different wavelengths, the analyze can be identified. HPLC UV detector can be used by any lab using HPLC, including genomic, biology, and biochemistry laboratories, to analyses nucleic acids, proteins, and to do toxic and therapeutic drug testing. Two types of HPLC UV detectors are single and variable wavelength detectors measure the sample absorption of a single wavelength, while variable wavelength detector measure absorption of multiple wavelengths and are therefore more sensitive. When deciding on a HPLC UV detector, consider whether a single wavelength will be sufficient or if a variable wavelength detector is needed. The wavelength range that can be used and the sensitivity of the detector should also be factored into the decision.
1.2.2.4.2 Photodiode Array detector:
Photodiode Array HPLC Detector are most commonly used to record the ultraviolet and visible (UV-visible) absorption spectra of samples that are passing through a high-pressure liquid chromatograph. This enables qualitative information to be pharmaceuticals and life sciences, chemistry, energy and pharmaceutical industry, environment and agriculture. An advantage to diode array HPLC detector is the ability to select the best wavelength for analysis. Some feature to consider when choosing a diode array HPLC detector include resolution, wavelength range, NIR (Near Infrared) ranges, low noise, baseline stability, peak integration and an interchangeable flow cell design. Some vendors also offer detection done with a configurable fiber optic light path. Be sure to inquire about features that may be an advantage in your application field.
1.2.2.4.3 Fluorescence detectors:
Fluorescence detectors are probably the most sensitive among the existing modern HPLC detectors. It is possible to detect even a presence of a single analyte molecule in the flow cell. Typically, fluorescence sensitivity is 10 -1000 times higher than that of the UV detector for strong UV absorbing materials. Fluorescence detectors are very specific and selective among the others optical detectors. This is normally used as an advantage in the measurement of specific fluorescent species in samples. When compounds having specific functional groups are excited by shorter wavelength energy and emit higher wavelength radiation which called fluorescence. Usually, the emission is measured at right angles to the excitation.
1.2.2.4.4 Mass spectroscopic detectors:
Liquid chromatography–mass spectrometry (LC-MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (or HPLC) with the mass analysis capabilities of mass spectrometry (MS). Coupled chromatography - MS systems are popular in chemical analysis because the individual capabilities of each technique are enhanced synergistically. While liquid chromatography separates mixtures with multiple components, mass spectrometry provides structural identity of the individual components with high molecular specificity and detection sensitivity. This tandem technique can be used to analyze biochemical, organic, and inorganic compounds commonly found in complex samples of environmental and biological origin. Therefore, LC-MS may be applied in a wide range of sectors including biotechnology, environment monitoring, food processing, and pharmaceutical, agrochemical, and cosmetic industries
1.2.2.4.5 Refractive Index Detectors:
HPLC Refractive Index Detectors (HPLC RI Detectors) are used with high-pressure liquid chromatographs when detecting substances with limited or no UV absorption. These chemical components included alcohols, sugars, fatty acids, polymers and carbohydrates. Applications where HPLC RI detectors are used include polymer analysis. RI detectors are considered universal detectors. A limitation of HPLC RI detectors may be their lack in sensitivity; they are also temperature dependent and are not suitable for gradient elution. Some features to consider in a HPLC RI detector include dual temperature control, improved baseline stability, low noise, software compatibility and automated sequences. HPLC RI detectors can be a simple and effective way to detect analytes that do not absorb UV light. Some vendors may even offer RI detectors that are bundled with other HPLC detectors.
1.2.2.4.6 Electrochemical detector:
The electrochemical detector is also a popular liquid chromatographic detector. It should be considered by the chromatographer because of the additional selectivity and sensitivity for some compounds. This detector is based on the measurements of the current resulting from oxidation/reduction reaction of the analyte at a suitable electrode. Since the level of the current is directly proportional to the analyte concentration, this detector could be used for quantification.
1.2.2.4.7 Conductivity Detector:
A conductivity detector measures the electrical conductivity of the HPLC eluent streams and is amenable to ppm-ppb levels analysis of ions, organic, acids, and surfactants. It is the primary detection mode for ion chromatography.
1.2.3 Separation Modes:
Most HPLC separations are performed under isocratic conditions in which the same mobile phase is used throughout the elution of the entire sample. Although isocratic analysis is good for simple mixtures, gradient analysis, in which the strength of the mobile phase is increased with the time during sample elution, is preferred for more complex sample containing analysis of diverse polarities. There are four major modes that are used to separate most compound.
1.2.3.1 Normal Phase Chromatography:
Aqueous normal-phase chromatography (ANP) is a chromatographic technique that involves the mobile phase region between reverse-phase chromatography (RP) and organic normal phase chromatography. In normal-phase chromatography, the stationary phase is polar and the mobile phase is nonpolar. Typical stationary phases for normal-phase chromatography are silica or organic moieties with cyano and amino functional groups.
1.2.3.2 Reversed-phase chromatography:
Reversed-phase chromatography (also called RPC, reverse-phase chromatography, or hydrophobic chromatography) includes any chromatographic method that uses a hydrophobic stationary phase. RPC refers to liquid (rather than gas) chromatography.
Stationary Phase: Common stationary phase is silica which has been surface modified with RMe2SiCl. Where R is the straight chain of alkyl group.
C8[Octyl]: Si (CH3)2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
Mobile Phase: The mobile phase is the solvent that moves the analyses(solute) through the column. In HPLC, the mobile phase interacts with body the solute and stationary phase and a powerful influence on solute retention and separation. Common mobile phase solvents are:
Methanol (CH3OH)
Acetonitrile (CH3CN)
Tetrahydrofuran (CH2)4O
Water (H2O)
1.2.3.3 Ion-exchange chromatography:
Ion chromatography (or ion-exchange chromatography) is a chromatography process that separates ions and polar molecules based on their affinity to the ion exchanger. It works on almost any kind of charged molecule—including large proteins, small nucleotides, and amino acids. However, ion chromatography must be done in condition that are one unit away from the isocratic point of a protein.
1.2.3.4 Size Exclusion chromatography:
Size-exclusion chromatography (SEC), also known as molecular sieve chromatography, is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers. Typically, when an aqueous solution is used to transport the sample through the column, the technique is known as gel-filtration chromatography, versus the name gel permeation chromatography, which is used when an organic solvent is used as a mobile phase. The chromatography column is packed with fine, porous beads which are composed of dextran polymers (Sephadex), agarose (Sepharose), or polyacrylamide (Sephacryl or Bio Gel P). The pore sizes of these beads are used to estimate the dimensions of macromolecules. SEC is a widely used polymer characterization method because of its ability to provide good molar mass distribution (Mw) results for polymers.
1.2.4: Significance of HPLC:
Speed, efficiency and accuracy: Compared to other chromatographic techniques, such as TLC, HPLC is extremely quick and efficient. It uses a pump, rather than gravity, to force a liquid solvent through a solid adsorbent material, with different chemical components separating out as they move at different speeds. The process can be completed in roughly 10 to 30 minutes, and it delivers high resolution. It is accurate and highly reproducible. Because it is largely automated, basic HPLC runs can be performed with minimal training.
Sensitivity and Resolution: In general, HPLC is versatile and extremely precise when it comes to identifying and quantifying chemical components. With many steps involved, the precision of HPLC is largely down to the process being automated and therefore highly reproducible.
Compound stability: In gas chromatography, the sample injected into the system is vaporized at about 4000 F before it is carried through the column. Thus the compound must be able to withstand heat at high temperatures without breaking down or degrading into another molecule. When using liquid chromatography, the sample remains in its liquid state and is pushed through the column under high pressure by various solvents such as water, methanol or acetonitrile. Different concentration of each solvent will affect the chromatography of each compound differently. Having the sample remain in its liquid state increases the stability of the compound.
Column: HPLC columns are silica based and have a thick metal casing to withstand high amounts of internal pressure. These columns operate under room temperature and range from 50 to 250 centimeters in length.
1.3 Dissolution Tester:
In the pharmaceutical industry, drug dissolution testing is routinely used to provide critical in vitro drug release information for both quality control purposes, i.e., to assess batch-to-batch consistency of solid oral dosage forms such as tablets, and drug development, i.e., to predict in vivo drug release profiles. There are three typical situations where dissolution testing plays a vital role:
i) formulation and optimization decisions: during product development, for products where dissolution performance is a critical quality attribute, both the product formulation and the manufacturing process are optimized based on achieving specific dissolution targets.
ii) Equivalence decisions: during generic product development, and also when implementing post-approval process or formulation changes, similarity of in vitro dissolution profiles between the reference product and its generic or modified version are one of the key requirements for regulatory approval decisions.
iii) Product compliance and release decisions: during routine manufacturing, dissolution outcomes are very often one of the criteria used to make product release decisions.
The vessels of the dissolution method are usually either partially immersed in a water bath solution or heated by a jacket. An apparatus is used on solution within the vessels for a predetermined amount of time which depends on the method for the particular drug. The dissolution medium within the vessels are heated to 37°C with an acceptable difference of ± 0.5°C.
Chapter 2:
Literature review
Literature Review:
Journal Name Internal Journal of Advances in Pharmacy, Biology and Chemistry
Author Name K. Srinivas, Rama Prasad Padhy, Subhash Chandra Dinda
Method Name Novel Validated RP-HPLC Method for Simultaneous estimation of Levofloxacin and Cefodoxime Proxitil in Bulk and Tablet Dosage Form.
Column Name Phenomenex column 250 x 4.6 mm, 5μm
Mobile Phase Orthophosphoric acid: Methanol (70:30)
Wave Length 230 nm
Run Time 30 min
Flow Rate 1 ml /min
Journal Name International Journal of Pharmaceutical and Clinical Research
Author Name Shafrose Syed, Haritha Pavani
Method Name Validated Simultaneous Estimation and Development of Levofloxacin and Ornidazole by RP-HPLC Method
Column Name Hypersil BDS C18 Column 150 x 4.6mm, 5μm
Mobile Phase Phosphate Buffer: Acetonitrile (75:25)
Wave Length 315 nm
Run Time 8 min
Flow Rate 1 ml /min
Journal Name International Journal of Pharmacy and Pharmaceutical analysis
Author Name Vaddeswarapu Madhavi and Mandalapu Neehanika
Method Name RP-HPLC Method for Simultaneous estimation of Levofloxacin and Ambroxol HCl in Pharmaceutical Dosage Forms
Column Name Intersil ODS C18 column 150 x 4.6mm, 5μm
Mobile Phase Phosphate Buffer: CAN: Methanol (40:20:20, v/v/v)
Wave Length 223 nm
Run Time 6 min
Flow Rate 1 ml /min
Journal Name International Journal of Chemical Science
Author Name CH. Narasimha Raju Bh, K. V. Ramana. G. Devala Raoand Parthasarathi Ramamoorthy Thoddi
Method Name Simultaneous RP-HPLC Method Development and Validation of Levofloxacin and Ornidazole in Combined Pharmaceutical Dosage Forms
Column Name Phenomenex column 250 x 4.6 mm, 5μm
Mobile Phase Phosphate Buffer: ACN: Methanol (70:10:20, v/v/v)
Wave Length 295 nm
Run Time 110 min
Flow Rate 1 ml /min
Journal Name Research Gate Journal
Author Name Krupa Kothekar, Balasundaram Jayakar, Amit Khandar, Rajnish Mishra
Method Name Quantitative Determination of Levofloxacin and Ambroxol Hydrochloride in Pharmaceutical Dosage Forms by reverse phase High Performance Liquid Chromatography.
Column Name Hypersil BDS C18 Column 150 x 4.6mm, 5μm
Mobile Phase Buffer: ACN: Methanol (650:250:100)
Wave Length 220 nm
Run Time 10 min
Flow Rate 1 ml /min
Journal Name Research Gate Journal
Author Name Suyog Chepurwar, S S Shirkhedkar, Sanjay Kumar bari,RA Fursule
Method Name Validated HPTLC Method for Simultaneous Estimation of Levofloxacin Hemihydrate and Ornidazole in Pharmaceutical Dosage Form
Column Name N/A
Mobile Phase Butanol: Methanol: Ammonia (5:1:1.5)
Wave Length 298 nm
Run Time N/A
Flow Rate N/A
Journal Name Research Gate Journal
Author Name E Reddy, Raghuram Reddy
Method Name Development and Validation of RP-HPLC for the Method for Simultaneous Estimation of Azithromycin and Levofloxacin in combined tablet dosage form.
Column Name Hypersil BDS C18 Column 120 A (250 x 4.6mm), 5μm
Mobile Phase Acetonitrile and Methanol (60:40)
Wave Length 285 nm
Run Time 5 min and 3 min
Flow Rate 1 ml /min
Chapter 3:
Aim and Objectives
Aim:
The objective of validation of dissolution procedure is to demonstrate that it is suitable for its intended purpose. D
