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.
Authors:N. Kumar, D. Sangeetha, R. Goyal, and P. S. Reddy
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.
Authors:R. Singhal, P. Sharma, M. Bassan, H. Basu, and A. Reddy
During this work selective separation of uranium from rock phosphate and columbite mineral was done before its quantitative
estimation by using Inductively Coupled Plasma Optical Emission Spectrometery (ICP-OES). Uranium from the rock phosphate and
columubite was extracted by sodium peroxide fusion followed by leaching in 2 M HNO3. To avoid spectral interference in the estimation of uranium by ICP-OES, the selective separation of uranium from the leachate
was carried out by using two different extractants, 30% Tributyl Phophates (TBP) in CCl4 and a equi-volume mixture of Di(2-ethylhexyl) phosphoric acid (D2EHPA) & TBP in petrofin. Uranium was stripped from the organic
phase by using 1 M ammonium carbonate solution. Determination of uranium by ICP-OES was done after dissolving the residue
left after evaporation of ammonium carbonate solution in 4% HNO3. The concentration of the uranium observed in the rock phosphates samples was 40–200 μg g−1 whereas in columbite samples the concentration range was 100–600 μg g−1. Uranium concentration evaluated by ICP-OES was complimented by gamma & alpha spectrometry. Concentration of uranium evaluated
by gamma spectrometry in case of rock phosphate and coulmbite was in close agreement with the uranium content obtained by
ICP-OES. Uranium determination by alpha spectrometry showed only minor deviation (1–2%) from the results obtained by ICP-OES
in case of rock phosphates whereas in case of coulmbites results are off by 20–30%.
Authors:R. Acharya, P. Burte, A. Nair, A. Reddy, and S. Manohar
Multielement analysis was carried out in two samples of natural rubies obtained from Kenya and Tanzania and a synthetic ruby obtained locally. The trace element profile was used to characterise the ruby samples. Instrumental Neutron Activation Analysis (INAA) by the single comparator (K0 method) was used to determine the concentrations of 22 elements with gold as the comparator. High resolution -ray spectrometry was employed for radiometric assay of the activation products. The accuracy and precision were evaluated by analysing standard reference materials such as USGS-W-1 and AGV-1 and were found to be satisfactory.
Authors:P. Sarita, G. Naga Raju, A. Pradeep, Tapash Rautray, B. Seetharami Reddy, S. Bhuloka Reddy, and V. Vijayan
Trace elemental imbalance in human beings is postulated to exert action, directly or indirectly, on the carcinogenic process.
The objective of this study was to evaluate the levels of trace elements in blood sera of breast cancer patients and analyze
their alteration with respect to healthy controls. This work was also intended to establish the role played by the trace elements
in carcinogenic process. Particle induced X-ray emission (PIXE) technique was used for trace elemental analysis of blood sera
of breast cancer patients and healthy controls. The PIXE measurements were carried out using a 2.5 MeV collimated proton beam
from the 3 MV Tandem Pelletron accelerator at Institute of Physics, Bhubaneswar, India. On comparing the trace elemental content
in the sera of breast cancer patients with those of control subjects, significant variations were observed in the levels of
most of the trace elements. The serum levels of almost all the elements except Fe and Cu were observed to be depressed in
cancer patients with respect to normal subjects. However, this variation was significant only for Ti (P < 0.00005), Cr (P < 0.005), Mn (P < 0.0005), Ni (P < 0.01), Zn (P < 0.000001), and Se (P < 0.05). On the other hand, significant elevations were observed in serum Fe (P < 0.05) and Cu (P < 0.005) levels in cancer patients. The findings presented in this paper give guidelines for future study into the possible
roles and interactions of essential trace elements in the breast carcinogenic process.
Authors:M. Vamsi Krishna, R. N. Dash, B. Jalachandra Reddy, P. Venugopal, P. Sandeep, and G. Madhavi
An isocratic ion-pair reversed phase high-performance liquid chromatography-ultraviolet (RP-HPLC-UV) method for analysis of eberconazole nitrate in bulk and in pharmaceutical dosage forms has been developed and validated. Best separation was achieved on Lichrospher C18 column (250 mm × 4.6 mm, 5 μm) using a mobile phase of 10 mM potassium dihydrogen phosphate containing 10 mM tetra-butyl ammonium hydroxide (pH adjusted to 2.8 with ortho phosphoric acid) and methanol (75:25, v/v) at a flow rate of 1.0 mL min−1. UV detection was performed at 220 nm. The method was validated for specificity, linearity, precision, accuracy, limit of detection, limit of quantification, robustness, and solution stability. The calibration plot was linear over the concentration range of 10–80 μg mL−1 (r2 = 0.999) and the limits of detection and quantification were 0.3 and 0.9 μg mL−1, respectively. Intra-day and inter-day precisions were 1.13% and 1.67%, respectively. Experimental design was employed to optimize the method. The method was successfully used for analysis of eberconazole nitrate in commercially available cream (Ebernet).
Authors:P. Ramanjaneyulu, Y. Sayi, T. Newton Nathaniel, A. Reddy, and K. Ramakumar
Boron concentration has been determined in groundwater samples, collected from Khuchch, Gujarat, India, by prompt gamma neutron
activation analysis (PGNAA) after selective separation and pre-concentration by solvent extraction with 10% 2-ethyl hexane
1,3-diol in CHCl3. Solvent extraction separation helped to eliminate the interfering elements in PGNAA determination of boron. The sensitivity
of PGNAA is found to be 18.83 cps/mg B based on the slope of a calibration plot obtained by carrying out measurements on synthetic
boric acid samples containing boron in the range of 30–150 μg. Detection limit of the method is 0.2 μg/g counted for 35,000
seconds at a sample size of 15 gram. The precision (relative standard deviation at 1σ level) and accuracy of the method is
5%. The analytical results of the present method agreed well with well-established spectrophotometric determination of boron
as boron-curcumin complex and inductively coupled plasma atomic emission spectroscopy (ICP-AES).
Authors:S. Bhade, P. Reddy, A. Narayanan, K. Narayan, D. Babu, and D. Sharma
Simultaneous measurement of gross alpha and gross beta activities by liquid scintillation counting technique using LKB Wallac
Quantulus 1220 liquid scintillation counter (LSC) equipped with Pulse Shape Analyzer (PSA) is described. Three sets of pure
alpha and pure beta standards simulating the activity concentration values of real samples in terms of α/β activity ratios
were used to calibrate the LSC. Calibration methodology for the Quantulus 1220 with respect to the above measurements using
241Am and 90Sr/90Y standards of respective activity concentrations of ~25 dpm and ~104 dpm is described in detail. Also highlighted the need to calibrate the LSC using another set of 241Am and 90Sr/90Y standards of low and high activity concentrations respectively. The practicability and working performance of these calibration
plots was checked by the validation trials with test samples spiked with 241Am and 90Sr/90Y covering range of α/β activity ratios from 1:1 to 1:50.
Authors:R. Singhal, H. Basu, M. Bassan, M. Pimple, V. Manisha, D. Avhad, P. Sharma, and A. Reddy
Direct determination of uranium in the concentration range of 8 μg L−1 to mg L−1 in water samples originating from different geochemical environments has been done using Inductively Coupled Plasma-Optical
Emission Spectroscopy (ICP-OES). Uranium detection with 2–3% RSD (relative standard deviation) has been achieved in water
samples by optimizing the plasma power, argon and sheath gas flow. These parameters were optimized for three different emission
lines of uranium at 385.958, 409.014 and 424.167 nm. Interference arising due to the variation in concentration of bicarbonate,
sodium chloride, calcium chloride, Fe and dissolved organic carbon (DOC) on the determination of uranium in water samples
was also cheeked as these are the elements which vary as per the prevailing geochemical environment in groundwater samples.
The concentration of NaHCO3, CaCl2 and NaCl in water was varied in the range 0.5–2.0%; whereas Fe ranged between 1 and 10 μg mL−1 and DOC between 0.1–1%. No marked interference in quantitative determination of uranium was observed due to elevated level
of NaHCO3, CaCl2 and NaCl and Fe and DOC in groundwater samples. Concentration of uranium was also determined by other techniques like adsorptive
striping voltametry (AdSv); laser fluorimetry and alpha spectrometry. Results indicate distinct advantage for uranium determination
by ICP-OES compare to other techniques.