scholarly journals Determination of the Raman polarizability tensor in the optically anisotropic crystal potassium dihydrogen phosphate and its deuterated analog

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
T. Z. Kosc ◽  
H. Huang ◽  
T. J. Kessler ◽  
R. A. Negres ◽  
S. G. Demos

Abstract The Raman tensor of the dominant A1 modes of the nonlinear optical crystalline material potassium dihydrogen phosphate and its 70% deuterated analog have been ascertained. Challenges in determining the A1 mode tensor element values based on previous reports have been resolved using a specially designed experimental setup that makes use of spherical crystal samples. This novel experimental design enabled the determination of measurement artifacts, including polarization rotation of the pump and/or scattered light propagating through the sample and the contribution of additional overlapping phonon modes, which have hindered previous efforts. Results confirmed that the polarization tensor is diagonal, and matrix elements were determined with high accuracy.

INDIAN DRUGS ◽  
2018 ◽  
Vol 55 (02) ◽  
pp. 44-49
Author(s):  
P Choksi ◽  
◽  
F. Shaikh ◽  
D. A. Shah ◽  
K. Agarwal ◽  
...  

A simple, specific, accurate, precise and reproducible method has been developed and validated for the estimation of bromhexine hydrochloride and enrofloxacin in fixed dose combination using RP-HPLC. The separation was achieved using stationary phase ODS Hypersil C18 column (250 mm× 4.6 mm i.d.) in isocratic mode, with mobile phase containing 0.05 M potassium dihydrogen phosphate buffer (pH 4 by o-phosphoric acid) : methanol: acetonitrile : triethylamine (40:20:40:01), at a flow rate of 1.0mL/min and eluents were monitored at 256 nm. The retention time of enrofloxacin and bromhexine HCl were found to be 3.00 min and 5.1 min respectively. The linearity for bromhexine HCl and enrofloxacin was in the range of 2-15 μg/mL and 20-150 μg/mL, respectively. The method was validated as per ICH guideline. The recoveries of bromhexine HCl and enrofloxacin were found in the range of 99.61-101.65% and 99.52-100.13 %, respectively. The method was successfully applied for the determination of both the drugs in combined dosage form.


2015 ◽  
Vol 98 (6) ◽  
pp. 1496-1502 ◽  
Author(s):  
Ramzia I El-Bagary ◽  
Ehab F Elkady ◽  
Shereen Mowaka ◽  
Maria Attallah

Abstract Two simple, accurate, and precise chromatographic methods have been developed and validated for the determination of dronedarone (DRO) HCl and amiodarone (AMI) HCl either alone or in binary mixtures due to the possibility of using AMI as a counterfeit of DRO because of its lower price. First, an RP-HPLC method is described for the simultaneous determination of DRO and AMI. Chromatographic separation was achieved on a BDS Hypersil C18 column (150 × 4.6 mm, 5 μm). Isocratic elution based on potassium dihydrogen phosphate buffer with 0.1% triethylamine pH 6–methanol (10 + 90, v/v) at a flow rate of 2 mL/min with UV detection at 254 nm was performed. The second method is RP ultra-HPLC in which the chromatographic separation was achieved on an AcclaimTM RSLC 120 C18 column (100 × 2.1 mm, 2.2 μm) using isocratic elution with potassium dihydrogen phosphate buffer with 0.1% triethylamine pH 6–methanol (5 + 95, v/v) at a flow rate of 1 mL/min with UV detection at 254 nm. Linearity, accuracy, and precision of the two methods were found to be acceptable over the concentration ranges of 5–80 μg/mL for both DRO and AMI. The results were statistically compared using one-way analysis of variance. The optimized methods were validated and proved to be specific, robust, precise, and accurate for the QC of the drugs in their pharmaceutical preparations.


2017 ◽  
Vol 100 (6) ◽  
pp. 1869-1878 ◽  
Author(s):  
Bixia Yang ◽  
Lian Wang ◽  
Chunying Luo ◽  
Xixi Wang ◽  
Chengjun Sun

Abstract An analytical method was developed for the simultaneous determination of 11 aminoglycoside (AG) antibiotics, including amikacin, paromomycin, dihydrostreptomycin, gentamicin C1a, hygromycin, kanamycin, netilmicin, spectinomycin, sisomicin, streptomycin, and tobramycin in honey, milk, and pork samples by LC with tandem MS and molecularly imprinted polymer (MIP) SPE. The AG antibiotics in milk and homogenated meat samples were extracted with a solution composed of 10 mmol/L potassium dihydrogen phosphate, 0.4 mmol/L EDTA-Na2, and 2% trichloroacetic acid. For honey samples, the extractant was 50 mmol/L potassium dihydrogen phosphate. The extracts were cleaned up with MIP SPE cartridges. The separation was performed on a zwitter ionic-HILIC column (50 × 2.1 mm, 3.5 μm), with the mobile phase consisting of methanol, 0.3% formic acid, and 175 mmol/L ammonium formate at 0.50 mL/min in gradient elution. A triple-quadrupole mass spectrometer equipped with an electrospray ionization source, which was operated in positive mode, was used for detection. The quantification was based on matrix-matched calibration curves. The method was applied to real samples with three different matrixes. The LODs of the method were 2–30 μg/kg and the LOQs were 7–100 μg/kg; the average recovery ranged from 78.2 to 94.8%; intraday RSDs and interday RSDs were ≤15 and ≤18%, respectively; and the absolute values of matrix effect for all AGs were RSDs ≤23%.


2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Laura D. Simionato ◽  
Leonardo Ferello ◽  
Sebastián Stamer ◽  
Patricia D. Zubata ◽  
Adriana I. Segall

Simple, sensitive, and economical simultaneous volumetric and HPLC methods for the determination of pridinol mesylate in raw material have been developed. The volumetric method is based on the reaction of pridinol with sodium lauryl sulphate in diluted sulphuric acid. Dimethyl yellow was used as indicator to detect the end point of the titration in aqueous/organic layer. The HPLC method for the determination of pridinol mesylate employs a reverse phase C18 column at ambient temperature with a mobile phase consisting of acetonitrile: 0.05 M potassium dihydrogen phosphate, pH adjusted to 5.0 (1 : 2, v/v). The flow rate was 0.8 mL/min. Quantitation was achieved with UV detection at 258 nm based on peak area. Both methods were found to be suitable for the quality control of pridinol mesylate in raw material.


2022 ◽  
Vol 2152 (1) ◽  
pp. 012016
Author(s):  
Yun Yun ◽  
Mingshi Lin

Abstract Objective “To establish an HPLC method for the determination of metronidazole and chlorhexidine gluconate in metronidazole and chlorhexidine lotion. Method Using Agilent Eclipse-XDB-C18 chromatographic column, with 0.05 mol·L-1 potassium dihydrogen phosphate solution 1000 ml plus 13.2 ml 10% tetrabutylammonium hydroxide aqueous solution (pH adjusted to 3.5 by phosphoric acid)-acetonitrile (77:23) as Mobile phase, detection wavelength 230 nm. Results The two components could be separated well. The linear ranges of metronidazole and chlorhexidine acetate were 36.33~59.04 μg·ml-1 (r = 0.9994) and 35.45~220.11 μg·ml-1 (r = 1).); The average recoveries were 100.6% and 100.5 %, and the RSD were 0.42% and 0.58%. Conclusion: The method is simple and specific, and the result is more accurate and reliable. Which is suitable for simultaneous determination of two components in compound preparations.


2017 ◽  
Vol 100 (4) ◽  
pp. 992-999 ◽  
Author(s):  
Ramzia I El-Bagary ◽  
Ehab F Elkady ◽  
Shereen Mowaka ◽  
Maria A Attallah

Abstract A simple, accurate, and precise LC method with a reversed stationary phase was developed and validated for the determination of perindopril (PER) arginine, amlodipine (AML), and indapamide (IND) alone and in binary mixtures (PER arginine is found in two dosage forms, i.e., with either AML or IND). Chromatographic separation was carried out on a BDS Hypersil® C18 column (100 × 3 mm, 5 μm). The mobile phase, consisting of 0.05 M potassium dihydrogen phosphate buffer (pH 2.6)–methanol (50 + 50, v/v), was pumped through the column whose temperature was maintained at 50°C at a flow rate of 0.6 mL/min using isocratic elution, and UV detection at 215 nm was performed. Acceptable values of linearity, accuracy, and precision of the method were found over the concentration ranges of 5–80 μg/mL PER, 2.5–80 μg/mL AML, and 0.5–20 μg/mL IND. The proposed chromatographic method was statistically compared to that of reference methods using one-way analysis of variance. The results showed that there was no significant difference between the methods. The developed method proved reliable for use in accurate QC of the drugs in their pharmaceutical preparations.


2018 ◽  
Vol 101 (2) ◽  
pp. 401-409 ◽  
Author(s):  
Asmaa A El-Zaher ◽  
Ehab F Elkady ◽  
Hanan M Elwy ◽  
Mahmoud Abo El Makarim Saleh

Abstract A new LC method is introduced with the concept of its versatile application to widely used drugs from different pharmacological classes. Metformin hydrochloride (MTF), sitagliptin phosphate (SIT), simvastatin (SIM) and ezetimibe (EZB) were simultaneously determined with a simple reversed-phase LC method in which a SIT–SIM binary mixture, present in a dosage form brand, was considered central for its development. Chromatographic separation was achieved with a mobile phase of acetonitrile and 0.02 M potassium dihydrogen phosphate (pH 5.2) (77 + 23, v/v) flowing through a C18 column (BDS Hypersil, 250 × 4.6 mm, 5 µm) at 1.2 mL/min at ambient temperature. UV detection was programmed to be carried out at 210 nm for EZB, SIT, and MTF, whereas SIM was detected at 240 nm. The method was validated according to International Conference on Harmonization guidelines. Linearity, accuracy, and precision were satisfactory over concentration ranges 4–40 µg/mL for EZB and SIM, 0.5–50 µg/mL for SIT, and 5–500 µg/mL for MTF. Coefficients of determination were >0.99 for the four drugs. LOQs found were 0.01 µg/mL for EZB, 0.02 µg/mL for SIT, 0.2 µg/mL for MTF, and 0.02 µg/mL for SIM. The developed method is simple, rapid, accurate, precise, and suitable for the routine QC analysis of the cited drugs in pharmaceutical products by conventional HPLC systems.


INDIAN DRUGS ◽  
2015 ◽  
Vol 52 (11) ◽  
pp. 24-28
Author(s):  
S.B Rohith ◽  
◽  
B.M Gurupadayya ◽  
R.S Chandan

A novel ultra-fast liquid chromatography (RP- UFLC) analytical method has been developed to quantify opipramol in tablet formulations. The determination was carried out by means of a Phenomenex Luna C8 Column (250×4.60mm, 5μ); potassium dihydrogen phosphate buffer of pH 2.4 and acetonitrile was used as a mobile phase in the ratio of 60:40 V/V with a flow rate of 1.00 mL/min. The photo diode array (PDA) detector was operated at wavelength of 253nm. The retention time for opipramol was found to be 2.72min. The validation studies were carried out according to ICH guidelines with a specific aim to establish that the new analytical method developed complied with the validation guidelines. The main parameters for validation study are specificity, linearity, accuracy, precision, LOD, LOQ and robustness. This method can be used for quality control analysis of opipramol in pure and marketed formulation.


2016 ◽  
Vol 99 (4) ◽  
pp. 957-963 ◽  
Author(s):  
Asmaa A El-Zaher ◽  
Ehab F Elkady ◽  
Hanan M Elwy ◽  
Mahmoud A Saleh

Abstract A rapid, simple, and precise RPLC method was developed for the simultaneous determination of the widely used oral antidiabetic, metformin hydrochloride (MTF), with some commonly coadministered oral antidiabetics from different pharmacological classes—glipizide (GPZ), pioglitazone hydrochloride (PGZ), glimepiride (GLM), and repaglinide (RPG)—in bulk, laboratory-prepared mixtures and pharmaceutical formulations in the presence of metformin-reported impurity [1-cyanoguanidine (CNG)]. Chromatographic separation was achieved using isocratic elution mode with a mobile phase of acetonitrile: 0.02 M potassium dihydrogen phosphate (pH 3.17; 50–50, v/v) flowing through a CN Phenomenex column (Phenosphere Next, 250 × 4.6 mm, 5 μm) at a rate of 1.5 mL/min at ambient temperature. UV detection was carried out at 220 nm. The method was validated according to International Conference on Harmonization guidelines. Linearity, accuracy, and precision were satisfactory for concentration ranges: 0.175–350 μg/mL for MTF, 0.0525–105 μg/mL for GPZ, 0.125–250 μg/mL for PGZ, and 0.05–100 μg/mL for GLM and RPG. Correlation coefficients were >0.99 for all analytes. LOQs were 0.009 μg/mL for MTF, 0.009 μg/mL for GPZ, 0.04 μg/mL for GLM, 0.124 μg/mL for PGZ, and 0.044 μg/mL for RPG. The developed method is specific, accurate, and suitable for the QC and routine analysis of the cited drugs in their pharmaceutical products.


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