oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Quantitation of artemether in pharmaceutical raw material and injections by high performance liquid chromatography
César, Isabela da Costa;Pianetti, Gerson Ant?nio;
Brazilian Journal of Pharmaceutical Sciences , 2009, DOI: 10.1590/S1984-82502009000400018
Abstract: the quantitation of artemether in both pharmaceutical raw material and injections was carried out by high performance liquid chromatography (hplc) with ultraviolet detection. a zorbax c18 column (150 x 4.6 mm; 5 μm), at 30 °c, and a mobile phase composed of acetonitrile and water (70:30), at a flow rate of 1ml/min, were used. the detection wavelength was 216 nm and the injection volume was 20 μl. the method proved to be linear (r2=0.9999), precise (rsd < 20% for intra-day and inter-day precision), accurate and selective regarding possible impurities and excipients of the samples. the detection and quantitation limits were 8 μg/ml and 25 μg/ml, respectively. the artemether content obtained in the raw material analysis was 99.26% and in the injections, 102.08%. the optimized and validated method may be successfully employed to perform routine quality control analyses.
Simultaneous quantitation and monitoring of rosuvastatin with NSAIDs by liquid chromatography with UV detection
Arayne MS, Sultana N, Tabassum A
Research and Reports in Medicinal Chemistry , 2012, DOI: http://dx.doi.org/10.2147/RRMC.S32238
Abstract: ltaneous quantitation and monitoring of rosuvastatin with NSAIDs by liquid chromatography with UV detection Original Research (805) Total Article Views Authors: Arayne MS, Sultana N, Tabassum A Published Date October 2012 Volume 2012:2 Pages 19 - 29 DOI: http://dx.doi.org/10.2147/RRMC.S32238 Received: 12 July 2012 Accepted: 05 September 2012 Published: 24 October 2012 Muhammad Saeed Arayne,1 Najma Sultana,2 Arman Tabassum1 1Department of Chemistry; 2Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Karachi, Karachi, Pakistan Overview and methods: A simple, accurate, and sensitive high-performance liquid chromatography-ultraviolet detection method was developed for simultaneous determination of rosuvastatin with co-administered nonsteroidal anti-inflammatory drugs (meloxicam, ibuprofen, and mefenamic acid) in active pharmaceutical ingredient (API), pharmaceutical formulations, and human serum. Isocratic separation was employed on prepacked Purospher Star C18 (5 μm, 25 × 0.46 cm) columns at ambient temperature. The mobile phase consisted of methanol:water:acetonitrile (80:17.5:2.5 v/v), pH adjusted to 3.0 with o-phosphoric acid at 1 mL min-1. The drugs in the eluant were monitored at isosbestic point of drugs at 230 nm. The method was compared by programming the detector adjusting the wavelength with time to match the individual analyte's chromophore which enhanced sensitivity with linear range. Results: Linear behavior was observed between 0.1 and 2.5 μgmL–1 for rosuvastatin, 0.4 and 10 μgmL-1 for meloxicam, 0.25 and 6.25 μgmL-1 for ibuprofen, and 0.15 and 3.75 μgmL-1 for mefenamic acid, with r2 > 0.998. The relative standard deviation for inter-day precision was <2 in API, formulations, and human serum. Percent recovery for all drugs was 97.3%–100.89% in API and formulations and 99.3%–100.4% in human serum. Wavelength-programmed analysis made the method more sensitive, where 4 < limit of quantification (LOQ) < 11 and 1 < limit of detection (LOD) < 4 ngmL-1 for API; 6 < LOQ < 10 and 2 < LOD < 3 ngmL-1 for pharmaceutical formulations; and 3 < LOQ < 10 and 1 < LOD < 3 ngmL-1 in human serum, reduced from 9 < LOQs < 23 and 3 < LODs < 7 ngmL–1 for all drug analytes in API; and 4 < LOQs < 17 and 1 < LODs < 6 ngmL-1 in human serum recorded at isosbestic point for rosuvastatin, meloxicam, ibuprofen, and mefenamic acid, respectively. Recovery of drugs was 99.998%–104.000% in all API, formulations, and serum samples. Conclusion: The proposed method can be used for the quantitative analysis of these drugs in raw materials, in bulk drugs, dosage formulations and in human serum and for clinical studies even when the drug is present in low amounts.
Effects of Taurine on Glutathione Peroxidase, Glutathione Reductase and Reduced Glutathione Levels in Rats  [PDF]
P. Anand,D. Rajakumar,Mathew Jeraud,A. John William Felix
Pakistan Journal of Biological Sciences , 2011,
Abstract: The aim of the present study is to investigate the effects of oral administration of taurine on endogenous glutathione peroxidase (GPx) and Glutathione Reductase (GR) activities and reduced glutathione (GSH) level in normal rats. Normal saline (Group I) or 5% taurine in normal saline was administered in dose of 50 mg (Group II), 250 mg (Group III) or 500 mg kg-1 of body weight (Group IV) through intragastric intubation for 60 days. GPx and GR enzyme activities and GSH and taurine levels were determined in liver, heart, stomach, kidney and plasma of normal Wistar rats. GPx activity showed an increase in liver, heart, stomach and plasma. GR activity increased in kidney and decreased in liver and plasma. GSH levels increased in liver, stomach and decreased in kidney. Liver showed an increase and heart, stomach and kidney a decrease in taurine level in taurine administered rats when compared to control rats. The results varied from organ to organ and the observed variations among organs might be related to their respective enzymatic, non-enzymatic antioxidant potential and its functions. From the present study it may be concluded that long term oral administration of taurine affects GPx, GR and GSH levels in normal rats.
Protection against Oxidative Stress in Beta Thalassemia/Hemoglobin E Erythrocytes by Inhibitors of Glutathione Efflux Transporters  [PDF]
Chatchai Muanprasat, Chokdee Wongborisuth, Nutthapoom Pathomthongtaweechai, Saravut Satitsri, Suradej Hongeng
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0055685
Abstract: In beta thalassemia/hemoglobin E (Hb E), abnormally high levels of oxidative stress account for accelerated senescence and increased destruction of erythrocytes. The present study aimed to investigate the role of glutathione efflux transporters, namely cystic fibrosis transmembrane conductance regulator (CFTR) and multidrug resistance-associated protein 1 (MRP1), in the control of glutathione levels and protection against oxidative challenges in beta thalassemia/Hb E erythrocytes. We found that CFTR protein was expressed in the erythrocytes of beta thalassemia/Hb E patients. Treatments with GlyH-101 (50 μM), a small molecule CFTR inhibitor, and MK571 (50 μM), an MRP1 inhibitor, reduced H2O2-induced free radical generation in the erythrocytes by ~80% and 50%, respectively. Furthermore, combined treatment with GlyH-101 and MK571 completely abolished the induction of reactive oxygen radicals. Increased oxidative stress in the erythrocytes following H2O2 challenges was accompanied by a decrease in intracellular level of reduced glutathione (GSH), which was prevented by treatments with GlyH-101 and MK571. CMFDA-based assays revealed that GlyH-101 and MK571 reduced H2O2-induced glutathione efflux from the erythrocytes by 87% and 66%, respectively. Interestingly, H2O2-induced osmotic tolerance of erythrocytes, a sign of erythrocyte aging, was ameliorated by treatment with GlyH-101. Our study indicates that oxidative stress induces glutathione efflux via CFTR and MRP1 in beta thalassemia/Hb E erythrocytes. Pharmacological inhibition of glutathione efflux represents a potential therapy to delay aging and premature destruction of erythrocytes in beta thalassemia/Hb E.
Quantitation of 6-, 8- and 10-Gingerols and 6-Shogaol in Human Plasma by High-Performance Liquid Chromatography with Electrochemical Detection  [cached]
Suzanna M. Zick,Mack T. Ruffin,Zora Djuric,Daniel Normolle
International Journal of Biomedical Science , 2011,
Abstract: Zingiber officinale is one of the most commonly used spices. We developed a method to determine the main pungent ginger constituents, 6-, 8- and 10-gingerols and 6-shogaol in human plasma. Quantitation was achieved using a reversed-phase C18 column using high-performance liquid chromatography with electrochemical detection. The assay was linear from 0.1 to 5.0 μg/mL. The within-day coefficients of variation for the assay at 5.0 μg/mL were ≤ 5% for all analytes. The recovery of all four analytes was > 99% for at 5.0 μg/mL. The lower limit of quantitation was 0.1 μg/mL except for 10-gingerol which was 0.25 μg/mL. Currently, there is no analytical method for detecting pungent ginger constituents in human plasma. This HPLC method allows for the detection of all four of ginger’s pungent constituents simultaneously in a relatively short run time of 25 minutes. This method should be useful for determining plasma levels of 6-, 8-, 10-gingerol and 6-shogaol in phase I clinical trials.
Reduced PKC Activity Induces Senescent Phenotype in Erythrocytes
Rukmini B. Govekar,Poonam D. Kawle,Suresh H. Advani,Surekha M. Zingde
Anemia , 2012, DOI: 10.1155/2012/168050
Abstract: The molecular mechanism mediating expression of senescent cell antigen-aggregated or cleaved band 3 and externalized phosphatidylserine (PS) on the surface of aged erythrocytes and their premature expression in certain anemias is not completely elucidated. The erythrocytes with these surface modifications undergo macrophage-mediated phagocytosis. In this study, the role of protein kinase C (PKC) isoforms in the expression of these surface modifications was investigated. Inhibition of PKC by 30 μM rottlerin (R30) and 2.3 nM Gö 6976 caused expression of both the senescent cell marker-externalized PS measured by FACS analysis and aggregated band 3 detected by western blotting. In contrast to this observation, but in keeping with literature, PKC activation by phorbol-12-myristate-13-acetate (PMA) also led to the expression of senescence markers. We explain this antithesis by demonstrating that PMA-treated cells show reduction in the activity of PKC , thereby simulating inhibition. The reduction in PKC activity may be attributed to the known downregulation of PMA-activated PKC , caused by its membrane translocation and proteolysis. We demonstrate membrane translocation of PKC in PMA-treated cells to substantiate this inference. Thus loss of PKC activity either by inhibition or downregulation can cause surface modifications which can trigger erythrophagocytosis.
The levels of glutathione and hemoglobin in sheep erythrocytes as a function of age
Mario Annunziata,Mario Iorio
Italian Journal of Animal Science , 2010, DOI: 10.4081/ijas.2004.283
Abstract: The behaviour of the levels of glutathione (GSH) and hemoglobin (Hb) was studied in blood samples from 126 one- to seven-year-old sheep reared in the province of Salerno, Italy. Negative and significant correlation with age both for hemoglobin and glutathione has been reported. A significant difference, on the basis of age, is evidenced only in males (n=24) for Hb (P = 0.001) and only in females (n=102) for GSH (P = 0.001). These results indicate a greater presence of Hb in young sheep and a greater demand for GSH in adult sheep. Moreover, the lowering of GSH and Hb with respect to age may have caused a reduction of the organism defense to environmental stress factors. Therefore, it would be useful, at least in productive animals, to use feed with a high content of polyphenolic compounds that increase the GSH concentration. The aim of the present work was to study the behaviour of the levels of glutathione and hemoglobin in sheep at different ages.
Liquid Chromatography/Tandem Mass Spectrometry Method for Quantitation of Cremophor EL and Its Applications  [PDF]
V. Vijaya Bhaskar,Anil Middha
International Journal of Analytical Chemistry , 2013, DOI: 10.1155/2013/135613
Abstract: A rapid sensitive and selective MRM based method for the determination of Cremophor EL (CrEL) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC-MS/MS). CrEL and polypropylene glycol (internal standard) were extracted from rat plasma with acetonitrile and analysed on C18 column (XBridge, 50 × 4.6?mm, 3.5?μm). The most abundant molecular ions corresponding to PEG oligomers at m/z 828, 872, 916 and 960 with daughter ion at m/z 89 were selected for multiple reaction monitoring (MRM) in electrospray mode of ionisation. Plasma concentrations of CrEL were quantified after administration through oral and intravenous routes in male sprague dawley rats at a dose of 0.26?g/kg. The standard curve was linear (0.9972) over the concentration range of 1.00 to 200?μg/mL. The lower limit of quantitation for CrEL was 1.00?μg/mL using 50?μL plasma. The coefficient of variation and relative error for inter and intra assay at three QC levels were 0.69 to 9.21 and ?7.60 to 4.74 respectively. A novel proposal was conveyed to the scientific community, where formulation excipient can be analysed as qualifier in the analysis of NCEs to address the spiky plasma concentration profiles. 1. Introduction In early stages of drug discovery, pharmacokinetic and drug metabolism and disposition studies were conducted in rodents, as they were relatively inexpensive and can be easily acquired and handled [1]. In a typical pharmacokinetic (PK) study, new chemical entities (NCEs) are administered to rats via intravenous and oral routes. Serial blood samples are collected and analysed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Few NCEs have spiky plasma concentration profiles and various reasons for such profiles could be due to enterohepatic circulation or discrepancies in sample collection/sample processing. Spiky profiles in elimination phase will lead to inaccurate quantification of PK parameters. Extensive studies needed to be carried to characterize enterohepatic circulation behavior of test compounds. Drugs that undergo enterohepatic cycling to a significant extent include colchicine, phenytoin, leflunomide, and tetracycline antibiotics. As formulation excipients have fixed plasma concentration profiles irrespective of NCEs dosed, monitoring the plasma concentration levels of excipient along with NCEs will help to take a decision on the spiky plasma concentration profiles of NCEs. A thoroughly developed and validated bioanalytical method is required to fix the plasma concentration profile and understand the pharmacokinetic disposition
Activities of Antioxidant Scavenger Enzymes (Superoxide Dismutase and Glutathione Peroxidase) in Erythrocytes in Adult Women With and Without Type II Diabetes  [PDF]
Eli Carmeli,Raymond Coleman,Yitshal N. Berner
Experimental Diabetes Research , 2004, DOI: 10.1080/15438600490451659
Abstract: It is widely believed that oxidative stress plays an important role in the pathogenesis of type II diabetes. The present study was undertaken to examine the functioning of two antioxidant scavenger enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), in erythrocytes in a population of healthy aging adult women compared with a similar population with type II diabetes. Blood samples were examined from 42 female adult healthy subjects at different ages and from 59 female patients with type II diabetes. A significant increase in SOD activities was correlated with aging in erythrocytes of the healthy control subjects (r = .550, P = .001); however, this correlation was not found in subjects with type II diabetes (r = .250, P < .07). A trend showing a reduction in glutathione peroxidase activities was demonstrated with aging (r = ?.331, P = .228); however, this trend was not found in diabetic subjects (r = .031, P < .820). The results indicate a possible imbalance in the antioxidant system in erythrocytes of aging adult women, which is even more pronounced in cases of type II diabetes. This study may indicate possible therapeutic treatment or preventive measures to limit oxidative damage and reduce complications of diabetes.
Role of nitric oxide and reduced glutathione and their implication on typhoid  [cached]
Syed Haque
Journal of Biology and Earth Sciences , 2012,
Abstract: Typhoid one of the most important causes of illness and death, particularly among children and adolescents in south-central and Southeast Asia, due to poor sanitation and unsafe food and drinking water. Nitric oxide (NO) is a versatile molecules produced in a biological system. Reduced glutathione (GSH) is the most abundant cytosolic thiol that easily reacts with NO and forms S-nitrosoglutathione (GS-NO) these thiol compounds might decrease the levels of free forms of NO, thereby affecting its fate and biological activity. Infection with bacteria to control mice resulted in significant decrease in the GSH level by 10% at day 8 of infection and after treatment with formulated drugs significant increment was observed.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.