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P. Nagaraju ¹, M. V. L. Ramanakanth ¹

Affiliations
1 Department of Pharmaceutical Analysis, Hindu College of Pharmacy, Amaravathi Road, Guntur - 522 002, Andhra Pradesh, IN

Abstract

The current work explains simple, accurate, rapid and precise isocratic reverse-phase high-performance liquid chromatographicstability indicating method for simultaneous determination of metformin HCl and acarbose in bulk and combined dosage form. The chromatographic separation was carried out on Zorbax C-18 analyticalcolumn (4.6×250 mm; 5 μm) with a mixture of methanol: 0.1% O-phosphoric acid 60:40(v/v) as mobile phase; at a flow rate of 1.2 ml/min. UV detection was performed at 239 nm. The retention times were 2.218 min and 2.972 min for metformin HCl and acarbose respectively. Calibration plots were linear over the concentration range of 400-1200 μg/ml for metformin HCl and 40-120 μg/ml for acarbose. The method was validated for accuracy, precision, linearity and sensitivity. The proposed method was successfully used for quantitative analysis of tablets. No interference from any component of pharmaceutical dosage form was observed. Degradation studies were performed by subjecting the sample to various stressed conditions of acid, alkali, peroxide, thermal and photolytic studies.

Keywords

Metformin Hcl, Acarbose, RP-HPLC, Stability Indicating Method.

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P. Nagaraju ¹, B. Sridhar ², P. Jitendra Kumar ³, U. Upendra Rao ¹, K. Hanumantha Rao ², P. N. V. Gopal ¹

Affiliations
1 Hindu College of Pharmacy, Amaravathi Road, Guntur – 522 002, Andhra Pradesh, IN
2 DCRM Pharmacy College, Inkollu, Andhra Pradesh, IN
3 Siddhartha Institute of Pharmacy, Sattenapalli, Andhra Pradesh, IN

Abstract

The present work describes a simple reverse phase HPLC method for the estimation of Atorvastatin calcium in bulk and pharmaceutical formulations. The estimation was carried out on phenomenex C₁₈ (250 × 4.6 mm, 5μ) column using a mobile phase containing of Acetonitrile: Ortho-phosphoric acid (0.1%): Tetrahydrofuran (48:0.04:52). The eluent was monitored at 244 nm. The results have been validated statistically and recovery studies confirmed the accuracy of proposed method.

Keywords

HPLC, Validation, Atorvastatin Calcium and Pharmaceutical Formulation.

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B. Bhavya ¹, P. Nagaraju ¹, V. Mounika ¹, G. Indira Priyadarshini ¹

Affiliations
1 Department of Pharmaceutical Analysis, Hindu College of Pharmacy, Amaravathi Road, Guntur 522002, Andhra Pradesh, IN

Abstract

A new simple, precise, selective, accurate and rapid reverse phase high performance liquid chromatographic stability indicating method had been developed and validated for simultaneous quantitative determination of Albendazole and Ivermectin in pharmaceutical dosage form. The chromatographic separation was achieved with Inertsil ODS 150×4.6 mm, 5μm particle size column. The optimized mobile phase consisting of pH 3.5 sodium phosphate buffer: Methanol (25:75v/v) in isocratic mode. The flow rate was 1.0 mL/min and eluents were detected at 245 nm using DAD (or) UV detector. The retention time of Albendazole and Ivermectin were found to be 1.974 and 2.897 mins respectively. The percentage recoveries for Albendazole and Ivermectin were found to be in the range of 98.67 -100.84%,and 101.46 - 100.26%. The calibration curve was constructed between peak area Vs concentration and demonstrated good linear in the range of 40 -200 μg/ml for Albendazole and 0.6-3 μg/ml for Ivermectin. Degradation studies were studied for Albendazole and Ivermectin under various stress conditions such as acid hydrolysis, base hydrolysis, oxidation, and thermal. All the degradation peaks were resolved effectively using developed method with different retention times. The developed method was validated according to ICH guidelines. As the method could effectively separate the degradation products from active ingredient, it can be used for routine analysis of drug in pharmaceutical dosage form.

Keywords

Albendazole and Ivermectin, pH 3.5 Sodium Phosphate Buffer, Methanol, RP-HPLC.

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P. Nagaraju ¹, M. K. Naik ²

Affiliations
1 Department of Plant Pathology, AICRP on Groundnut, University of Agricultural Sciences, Dharwad (Karnataka), IN
2 Department of Plant Pathology, University of Agricultural Sciences, Raichur (Karnataka), IN

Abstract

The study was conducted to know the field efficacy of different fungicides, botanicals and bio-agents against sheath blight of rice under irrigated eco-system. Among the different treatments, the least per cent disease index (17.00 PDI) was recorded in Hexaconazole (Contaf 5 EC) with the highest grain yield (81.02 q/ha). This was followed by Validamycin 3L (21.60 PDI and grain yield 73.83 q/ha) and Carbendazim 50 WP (24.80 PDI and grain yield 69.21 q/ha). Among the botanicals and bio-agents, the least disease incidence was noticed in Tricure (Azadirachtin @ 0.03%) with 30.50 PDI and grain yield of 61.43 q per ha and P. fluorescens (Pfr-l) with 36.20 PDI with a grain yield of 54.02 q per ha. The C:B ratio was high in Hexaconazole (1:2.5) followed by Propiconazole (1:2.3).

Keywords

Sheath Blight, Rice, Rhizoctonia solani, Hexaconazole, Botanicals, Bio-Agents.

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P. Nagaraju ¹, V. D. N. Srinivas ¹, S. V. N. Padma ¹, P. N. V. Gopal ¹, D. Mallikarjuna Rao ¹

Affiliations
1 Department of Pharmaceutical Analysis, Hindu College of Pharmacy, Amaravathi Road, Guntur, IN

Abstract

Over the past decade, cavity ring down spectroscopy has emerged as a powerful technique for performing direct absorption measurements using pulsed lasers. Cavity ring down spectroscopy has since been used from the ultraviolet to the mid-infrared. It is a direct absorption technique, which can be performed with pulsed or continuous light sources and has a significantly higher sensitivity than obtainable in conventional absorption spectroscopy. It can be used to measure the concentration of some light-absorbing substances. Typically, the substances to be measured are in gaseous form. This technique is most widely known as cavity ring-down spectroscopy, although the alternative, but more cumbersome, cavity ring-down laser absorption spectroscopy is preferred by some authors. Here we discuss about the experimental implementation of Cavity ring down spectroscopy and its application to a number of areas of research including laser diagnostics of hostile environments, reaction kinetics and spectroscopy, with particular emphasis on our ongoing studies of the fast (sub-nanosecond) pre dissociation of electronically excited states of small molecules and radicals.

Keywords

Cavity Ring Down Spectroscopy, Absorption Spectroscopy.

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P. Nagaraju ¹, Z. Vishnu Vardhan ², J. V. L. N. Seshagiri Rao ³

Affiliations
1 Hindu College of Pharmacy, Amaravathi Road, Guntur-522002 (Andhra Pradesh), IN
2 Department of Environmental Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, IN
3 University College of Pharmaceutical Sciences, Andhra University, Visakhapatnam, IN

Abstract

A simple, sensitive and precise reverse phase high performance liquid chromatographic method has been developed for the simultaneous estimation of Atorvastatin calcium and Ezetimibe in pharmaceutical dosage forms. The mobile phase consisted of Acetonitrile: buffer (0.1% v/v ortho phosphoric acid, P^H-6) in the ratio 60:40 delivered at a flow rate of 1 ml/min and wavelength of detection at 232 nm. The retention times of Atorvastatin calcium and Ezetimibe were 3.7 min and 6.1 min respectively. The developed method was validated according to ICH guidelines. The proposed method can be used for determination of these drugs in combined dosage forms.

Keywords

Atorvastatin Calcium, Ezetimibe, RP-HPLC.

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P. Nagaraju ¹, D. Narendra ¹, P. Jitendra Kumar ¹, V. D. N. Srinivas ¹, S. V. N. Padma ¹

Affiliations
1 Hindu College of Pharmacy, Amaravathi Road, Guntur-522002, IN

Abstract

A reverse phase high performance liquid chromatographic method (HPLC) has been developed for the estimation of entacapone in its dosage forms using C₁₈ column. The mobile phase (acetonitrile and 20 mM potassium dihydrogen phosphate, P^H 3.5) was pumped at a flow rate of 1 ml/min in the ratio of 80:20 and the eluents were monitored at 320 nm. The intra- and inter- day variation was found to be less than 2% showing high precision of the assay method. The mean recovery of the drug from the solution containing 200 or 300 μg/ml was 99.66±1.20% indicating high accuracy. The proposed HPLC method may be used for determining entacapone in bulk drug samples or in pharmaceutical dosage forms.

Keywords

Estimation, Entacapone, Tablets and HPLC.

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P. Nagaraju ¹, M. K. Naik ²

Affiliations
1 AICRP on Groundnut, University of Agricultural Sciences, Dharwad (Karnataka), IN
2 Department of Plant Pathology, University of Agricultural Sciences, Raichur (Karnataka), IN

Abstract

The study was conducted to know the influence of nitrogenous fertilizer levels, planting density and integrated disease management (IDM) on the severity of sheath blight of rice in northern Karnataka. The results indicated that, application of 200 kg N per ha recorded higher per cent disease index (PDI) of 40.37 per cent. However, increased N application from 100 kg N to 350 kg N per ha resulted in increased PDI from 17.04 to 62.60%, respectively. Minimum PDI (23.33%) and higher grain yield (67.80 q/ha) were recorded at 150 kg N per ha which is the recommended N dosage in Thunga Bhadra Project command area of Karnataka state. Among different planting densities, the system of rice intensification (SRI) method (16 hills/m²) recorded least PDI (5.00%) and highest grain yield (67.16 q/ha) whereas increased planting density from 20 to 70 hills per m² resulted in higher PDI from 6.86 to 45.18 per cent, respectively. However, at 50 hills per m², 16.12 PDI was recorded with a grain yield of 60.53 q per ha which is the recommended planting density. In the integrated disease management (IDM) trial, wherein, use of cultivar, IR-64 (moderately resistant variety) with foliar application of fungicide hexaconazole (@0.1%) resulted in minimum PDI of 21.26% with higher grain yield of 71.74 q per ha as against 34.73 PDI and 56.87 q per ha grain yield in Samba mahsuri (susceptible variety).

Keywords

Nitrogen Fertilizer, Planting Density, IDM, Sheath Blight, Rice.

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P. Nagaraju ¹, Labani Ray ¹, G. Ravi ¹, Vyasulu V. Akkiraju ¹, Sukanta Roy ¹

Affiliations
1 CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad - 500 606, IN

Abstract

Heat flow has been determined by combining temperature measurements in 7 boreholes with thermal conductivity measurements in the Upper Vindhyan sedimentary rocks of Shivpuri area, central India. The boreholes are distributed at 5 sites within an area of 15 × 10 km²; their depths range from 174 to 268 m. Geothermal gradients estimated from borehole temperature profiles vary from 8.0-12.7 mK m^-1 in the sandstone-rich formations to 25.5-27.5 mK m^-1 in the shale-rich formations, consistent with the contrast in thermal conductivities of the two rock types. Heat flow in the area ranges between 45 and 61 mW m^-2, with a mean of 52±6 mW m^-2. The heat flow values are similar to the >50 mW m^-2 heat flow observed in other parts of the northern Indian shield. The heat flow determinations represent the steady-state heat flow because, the thermal transients associated with the initial rifting, convergence and sedimentation in the basin as well as the more recent Deccan volcanism that affected the region to the south of the basin would have decayed, and therefore, the heat flow is in equilibrium with the radiogenic heat production of the crust and the heat flow from the mantle. The present study reports the heat flow measurements from the western part of the Vindhyan basin and provides heat flow information for the Bundhelkhand craton for the first time. Radioelement (Th, U and K) abundances have been measured both in the sedimentary rocks exposed in the area as well as in the underlying basement granite-gneiss of Bundelkhand massif exposed in the adjacent area. Radioactive heat production, estimated from those abundances, indicate mean values of 0.3 μW m^-3 for sandstone with inter-bands of shale and siltstone, 0.25 μW m^-3 for sandstone with inter-bands siltstone, 0.6 μW m^-3 for quartzose sandstone, and 2.7 μW m^-3 for the basement granitoids. With a total sedimentary thickness not exceeding a few hundred metres in the area, the heat production of the sedimentary cover would be insignificant. The radioactive heat contribution from the basement granitoids in the upper crust is expected to be large, and together with the heat flow component from the mantle, would control the crustal thermal structure in the region.

Keywords

Heat Flow, Geothermal Gradient, Thermal Conductivity, Vindhyan Basin, Central India.

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