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Development and validation of a stability-indicating RP-LC method for the estimation of process-related impurities and degradation products of oxcarbazepine in pharmaceutical formulation

Reddy P. S., Babu K. S., Kumar N.

Acta Chromatographica

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2014

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Vol. 26, no. 2

267--282

EN

A stability-indicating gradient reverse-phase liquid chromatographic method was developed for the quantitative determination of process-related impurities and forced degradation products of oxcarbazepine in pharmaceutical formulation. The method was developed by using Inertsil cyano (250 × 4.6 mm) 5 μm column with mobile phase containing a gradient mixture of solvent A (0.01 M sodium dihydrogen phosphate, pH adjusted to 2.7 with orthophosphoric acid and acetonitrile in the ratio of 80:20 v/v) and B (50:40:10 v/v/v mixture of acetonitrile, water, and methanol). The flow rate of mobile phase was 1.0 mL min−1. Column temperature was maintained at 25°C and detection wavelength at 220 nm. Developed reverse-phase high-performance liquid chromatography (RP-HPLC) method can adequately separate and quantitate five impurities of oxcarbazepine, namely imp-A, imp-B, imp-C, imp-D, and imp-E. Oxcarbazepine was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation. Oxcarbazepine was found to degrade significantly in acid, base, and oxidative stress conditions. The degradation products were well resolved from oxcarbazepine and its impurities. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.

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A validated stability-indicating RP-LC method for the estimation of process-related impurities and degradation products of quetiapine fumarate in solid oral dosage form

Kumar N., Sangeetha D, Goyal R, Reddy P. S.

Acta Chromatographica

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2013

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Vol. 25, no. 2

393--409

EN

A simple, selective, and stability-indicating reverse phase liquid chromatographic method has been developed and validated for the simultaneous determination of impurities and forced degradation products of quetiapine fumarate. The chromatographic separation was achieved on Inertsil-3 C8, 150 mm × 4.6 mm, 5 μm column at 35°C with UV detection at 217 nm using gradient mobile phase at a flow rate of 1.0 mL/min. Mobile phase A contains a mixture of 0.01 M di-potassium hydrogen orthophosphate (pH 6.8) and acetonitrile in the ratio of 80:20 (v/v), respectively, and mobile phase B contains a mixture of 0.01 M di-potassium hydrogen orthophosphate (pH 6.8) and acetonitrile in the ratio of 20:80 (v/v), respectively. The drug product was subjected to the stress conditions of oxidative, hydrolysis (acid and base), hydrolytic, thermal, and photolytic degradation. Quetiapine fumarate was found to degrade significantly in acid, base, and oxidative stress conditions. The degradation products were well resolved from main peak and its impurities. The mass balance was found to be in the range of 96.6–102.2% in all the stressed conditions, thus proved the stability-indicating power of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.

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A novel method for high temperature measurements using fiber Bragg grating sensor

Reddy P. S., Sai Prasad R. L. N., Srimannarayana K., Sai Shankar M., Sen Gupta D.

Optica Applicata

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2010

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Vol. 40, nr 3

685--692

EN

This paper reports the simulation, design and experimental analysis of a fiber Bragg grating (FBG) temperature sensor, making use of chemical composition grating (CCG), which ranges from room temperature to over 900 °C. The interrogation system of the sensor proposed is simple, effective and of low cost. The sensor head comprises FBG attached to a metal plate that will be strained due to change in the length of the plate with increase in temperature. The temperature is measured on the basis of the reflected Bragg wavelength shifts from the FBG. The dynamic range of the sensor is about 30 °C to 900 °C. The proposed sensor can be employed for monitoring the health of structural members at elevated temperatures. The dynamic range of the sensor can be increased to beyond 1500 °C by making use of FBG made up of sapphire instead of silicon fiber.