Papers by K Srinivasa Rao
Journal of Pharmaceutical Research, 2011
DPPH radical, nitric oxide, ABTS radical and hydroxyl radical were obtained to be 2.43 μg/ml, 152... more DPPH radical, nitric oxide, ABTS radical and hydroxyl radical were obtained to be 2.43 μg/ml, 152.76 μg/ml, 14.12 μg/ml and 6.31 μg/ml respectively. However, the IC values for the standard ascorbic acid were noted to be 0.66 μg/ml, 200 μg/ml, 0.7 μg/ml and 1 μg/ml 50 2 beneficial as signal transducers and growth regulators . ROS are regulated by endogenous superoxide dismutase, glutathione peroxidase and catalase but due to overproduction of reactive species, induced by exposure to external oxidant substances or a failure in the defense mechanisms, damage to cell structures, DNA, lipids and 3 proteins occur which increases risk of more than 30 different 4 disease processes . The most notorious among them being 5-6 neurodegenerative conditions like Alzheimer's disease , 7 mild cognitive impairment (MCI) and Parkinson's disease. To circumvent the damage caused ROS, multiple defense systems collectively called antioxidants are present, with protective efficiency depending on th...
A simple, sensitive, accurate and precise LC assay method was developed for the quantitative dete... more A simple, sensitive, accurate and precise LC assay method was developed for the quantitative determination of Ziprasidone Hydrochloride (ZSH) in pharmaceutical dosage form. Chromatographic separation was achieved by use of Lichrospher RP-18 column (250 × 4.0 mm, 5 m), using 20 mM ammonium acetate (pH adjusted to 3.0 with orthophosphoric acid) and methanol (30:70 %v/v) as mobile phase at 25C. The described method was linear over a range of 1-500 g mL-1 for determination of ZSH (r= 0.9998). F-test and t-test at 95% confidence level were used to check the intermediate precision data obtained under different experimental setups; the calculated value was found to be less than critical value. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of ZSH in pharmaceutical formulations.
Indian Journal of Pharmaceutical Education and Research, 2012
Star anise (Illicium verum) was extracted with ethanol using microwave-assisted extraction and so... more Star anise (Illicium verum) was extracted with ethanol using microwave-assisted extraction and soxhlet extraction. Total phenolic content of microwaveassisted extract (MSA) and conventional extract of star anise (SSA) reached 271.2 mg/g and 289 mg/g dry weight, respectively, expressed as gallic acid equivalents, which were quantified using Folin-Ciocalteau reagent. Subsequently, total flavonoids content of MSA and SSA extracts were found to be 14.64 mg/g and 13.98 mg/g dry weight, respectively, expressed as catechin equivalents (P < 0.05). Antioxidant properties of two extracts were investigated employing various established systems in vitro including 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, ABTS assay, total antioxidant activity, hydroxyl radical assay, nitric oxide radical scavenging and total reducing power. MSA and SSA showed excellent antioxidant in all test systems compared to standard ascorbic acid and the antioxidant activities of MSA were all superior to those of SSA. The results obtained in this study clearly indicate that star anise has a significant potential to use as a natural anti-oxidant agent.
Scientia pharmaceutica, 2011
A simple stability indicating reversed-phase HPLC method was developed and subsequently validated... more A simple stability indicating reversed-phase HPLC method was developed and subsequently validated for estimation of Cefpirome sulphate (CPS) present in pharmaceutical dosage forms. The proposed RP-HPLC method utilizes a LiChroCART-Lichrosphere100, C18 RP column (250 mm × 4mm × 5 μm) in an isocratic separation mode with mobile phase consisting of methanol and water in the proportion of 50:50 % (v/v), at a flow rate 1ml/min, and the effluent was monitored at 270 nm. The retention time of CPS was 2.733 min and its formulation was exposed to acidic, alkaline, photolytic, thermal and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. The described method was linear over a range of 0.5-200μg/ml. The percentage recovery was 99.46. F-test and t-test at 95% confidence level were used to check the intermediate precision data obtained under different experimental setups; the calculated value was found to be less than the critical value.
Free Radicals and Antioxidants, 2011
Access Free Rad. Antiox. www.antiox.org mainly due to the findings of the therapeutic effects of ... more Access Free Rad. Antiox. www.antiox.org mainly due to the findings of the therapeutic effects of free radical scavengers on the organism. A great number of plants worldwide showed a strong antioxidant activity [8-9] and a powerful scavenger activity against free radicals. [10-11] Human body posse's defense mechanisms against free radical induced oxidative stress which involves preventive mechanisms, repair mechanisms, physical defenses and antioxidant defenses. Enzymatic antioxidant defenses such as superoxide dismutase (SOD), glutathione peroxidase (GP X), catalase (CAT) etc. Non enzymatic antioxidants are ascorbic acid (vitamin C), α tocopherol (vitamin E), glutathione (GSH), carotenoids, flavanoids etc. All these act by one or more of the mechanisms like reducing activity, free radical Scavenging, potential complexing of pro-oxidant metals and quenching of singlet oxygen. It is possible to reduce the risks of chronic IntroductIon Oxidation is a basic part of the aerobic life and our metabolism. During oxidation, many free radicals are produced which have an unpaired nascent electron. Atoms of oxygen or nitrogen having central unpaired electron are called reactive oxygen or nitrogen species. [1-4] These are harmful to the body and may cause peroxidation of membrane lipids, aggression of tissue membranes and proteins or damage to DNA and enzyme. [5] These can be the cause of some pathology related to arthritis, hemorrhagic shock, coronary artery diseases, cancer as well as age related degenerative brain diseases. [6] Antioxidants are the vital substances which possess the ability to protect the body from damage caused by the free radical induced oxidative stress. [7] There is an increasing interest in the study of antioxidant substances
Indian Journal of Pharmaceutical Sciences, 2010
A simple, specifi c and accurate reverse phase liquid chromatographic method was developed for th... more A simple, specifi c and accurate reverse phase liquid chromatographic method was developed for the simultaneous determination of losartan potassium and ramipril in table dosage forms. A hypersil ODS C18, 4.6×250 mm, 5 µm column in isocratic mode, with mobile phase acetonitrile:methanol:10 mM tetra butyl ammonium hydrogen sulphate in water in the ratio of 30:30:40% v/v/v was used. The fl ow rate was 1.0 ml/min and effl uent was monitored at 210 nm. The retention times of losartan potassium and ramipril were 4.7 and 3.3 min, respectively. The linearity range for losartan potassium and ramipril were in the range of 0.04-100 µg/ml and 0.2-300 µg/ml, respectively. The proposed method was also validated and successfully applied to the estimation of losartan potassium and ramipril in combined tablet formulations.
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Papers by K Srinivasa Rao