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Altagamoa Al Khames, Main centre of town, end of 90th Street
New Cairo
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Mohamed Mohamed

Basic information

Name : Mohamed Mohamed
Title: Professor of Analytical Chemistry
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Personal Info: Professor Mohamed Abdelkawy, professor of Analytical chemistry - Department of Pharmaceutical Chemistry. he has a PH.D and MSC degree in Analytical Chemistry from Cairo university. View More...

Education

Certificate Major University Year
PhD Pharmaceutical Sciences Analytical Chemistry Cairo University 1987
Masters Pharmaceutical Sciences Analytical Chemistry Cairo University 1980
Bachelor Pharmaceutical Sciences Cairo University 1973

Researches /Publications

Potentiometric Method to Determine Montelukast Sodium in its Tablets with In-line Monitoring of its Dissolution Behaviour. - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

T Soudi A, G Hussein O, S Elzanfaly E, E Zaazaa H

01/04/2020

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Simultaneous determination of meclizine hydrochloride in its mixtures with pyridoxine hydrochloride, caffeine or nicotinic acid Using HPLC and TLC-densitometric methods, - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Hassib ST, El-Bagary RI, Taha EA, Barakat GH.

01/01/2020

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• Different aspects in manipulating overlapped spectra used for the analysis of trimebutine maleate and structure elucidation of its degradation products. - 01/1

Mohamed Abdelkawy Mohammad Ibrahim

Morgan EM, Fayez YM

01/12/2019

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Spectral analysis of overlapped absorption bands of binary mixtures—an application on combination of pseudoephedrine sulphate and loratadine mixture. - 01/1

Mohamed Abdelkawy Mohammad Ibrahim

El-Hanboushy S, Fayez YM

01/12/2019

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Comparison of two augmented classical least squares algorithms and PLS for determining nifuroxazide and its genotoxic impurities using UV spectroscopy. - 01/1

Mohamed Abdelkawy Mohammad Ibrahim

Hegazy MA, Abdelwahab NS, Ali NW, Sharkawi MM, El‐Saadi MT.

01/12/2019

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Spectral analysis of overlapped absorption bands of binary mixture-an application on combination of Pseudoephedrine Sulfate and Loratadine mixture - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Yasmin M. Fayez

01/09/2019

Background Simple, specific, accurate, and precise spectrophotometric methods are progressed and validated for concurrent analysis of pseudoephedrine sulphate (PSE) and loratadine (LOR) in their combined dosage form depending on spectral analysis procedures. In this binary mixture, pseudoephedrine (PSE) could be determined by using its resolved spectrum of zero-order absorption at 256.8 nm after subtraction of the spectrum of LOR, and also it could be determined in existence of the spectrum of LOR by different methods including absorption correction method (AC) at 256.8 nm and 280 nm, dual wavelength method (DW) at 254 nm and 273 nm, induced dual-wavelength method (IDW) at 230 nm and 263 nm, and ratio difference method (RD) at 256.8 nm and 270 nm. Loratadine (LOR) in the binary mixture could be determined either by direct analysis at 280 nm without any contribution from the spectrum of PSE or through its recovered spectrum of zero-order absorption via constant multiplication method (CM) using plateau region (277–326 nm). Also, concurrent determination for PSE and LOR in their overlapped binary mixture could be achieved by applying induced amplitude modulation (IAM) method. Results Specificity of the proposed spectrophotometric methods was examined by the analysis of prepared mixtures in laboratory and was applied successfully for pharmaceutical dosage form analysis which has the cited drugs without additive contribution. The proposed spectrophotometric methods were also validated as per the guidelines of ICH. Statistical comparison was performed between the obtained results with those from the official methods of the cited drugs, using one-way ANOVA, F test, and Student’s t test, and the results exhibit insignificant difference concerning precision and accuracy. Conclusions The previously proposed spectrophotometric methods could be easily used accurately and precisely for simultaneous determination of the studied binary mixture with simple manipulation procedures.

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Potentiometric sensing of Valaciclovir Hydrochloride in the presence of its acid induced degradation product with real time acquisition of the dissolution profile from its pharmaceutical formulations - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Yasmin Mohammed Fayez, Mohamed K. Abd El-Rahman

01/07/2019

The possibility of obtaining continuous analytical signal excluding any pre-treatment of sample is the most environmental friendly method of analysis. In the current manuscript, a solid contact sensor was fabricated for dual purpose; firstly, determination of valaciclovir hydrochloride (VAL) in existence of its acid induced degradation product, Guanine (GUA) and secondly, real time acquisition of the dissolution profile from its pharmaceutical formulations (Valtrex) and (Valysernex). The sensing membrane was fabricated using a polyvinyl chloride (PVC), sodium tetraphenyl borate as a cation exchanger with bis (2-ethylhexyl) sebacate as a plasticizer. The proposed sensor displayed fast, stable Nernstian responses across VAL concentration range (1 × 10−5 M to 1 × 10−2 M). The opportunities of the proposed sensor with respect to other off-line classical techniques originates from being in-line, time saving, cost-effective, green and simple. ICH guidelines were followed to ensure validation of the proposed method concerning accuracy and precision.

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Potentiometric sensing of Valaciclovir Hydrochloride in the presence of its acid induced degradation product with real time acquisition of the dissolution profile from its pharmaceutical formulations - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Yasmin Mohammed Fayez, Mohamed K. Abd El-Rahman

01/07/2019

The possibility of obtaining continuous analytical signal excluding any pre-treatment of sample is the most environmental friendly method of analysis. In the current manuscript, a solid contact sensor was fabricated for dual purpose; firstly, determination of valaciclovir hydrochloride (VAL) in existence of its acid induced degradation product, Guanine (GUA) and secondly, real time acquisition of the dissolution profile from its pharmaceutical formulations (Valtrex) and (Valysernex). The sensing membrane was fabricated using a polyvinyl chloride (PVC), sodium tetraphenyl borate as a cation exchanger with bis (2-ethylhexyl) sebacate as a plasticizer. The proposed sensor displayed fast, stable Nernstian responses across VAL concentration range (1 × 10−5 M to 1 × 10−2 M). The opportunities of the proposed sensor with respect to other off-line classical techniques originates from being in-line, time saving, cost-effective, green and simple. ICH guidelines were followed to ensure validation of the proposed method concerning accuracy and precision.

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Real time selective monitoring of the dissolution behavior of Pseudoephedrine Sulfate and Loratadine in their binary and ternary dosage form by utilization of In-line potentiometric sensor - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Yasmine M. Fayez

01/05/2019

An electro-analytical procedure was progressed for quantitative determination and monitoring the dissolution behavior of both cationic pseudoephedrine sulfate (PSE sulfate) and loratadine (LOR) drugs in their binary mixture with each other and ternary mixture with paracetamol (PAR) by in-line potentiometric analysis system without a need for pre-treatment or derivatization of the sample. This approach is performed by measuring continuously the increase in the generated emf over time by incorporating an in-site selective electrode for PSE sulfate and LOR fabricated utilizing polymeric membrane of poly (vinyl chloride) (PVC), tetraphenyl borate (TPB) and potassium tetrakis (4-chlorohenyl) borate (KTCPB) as a cation exchanger, Bis(2-ethylhexyl) sebacate and nitrophenyl octyl ether (NPOE), were utilized as plasticizers for determination of PSE sulfate and LOR, conjointly. The proposed sensors for both drugs exhibited stable and fast responses over wide PSE sulfate and LOR concentration range (2 × 10−5 to 2 × 10−2 mol/L regarding PSE sulfate while 1 × 10−5 to 1 × 10−2 mol/L regarding LOR). Afterwards, the proposed potentiometric method's validation was performed, and it is supposed to be eco-friendly and green technique in which consumption of solvents and sample pre-treatment were not mandatory for its application.

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Simultaneous Determination of Thalidomide and Dexamethasone in Rat Plasma by Validated HPLC and HPTLC With Pharmacokinetic Study - 01/1

Mohamed Abdelkawy Mohammad Ibrahim

Marco M Zaki, Souty M Z Sharkawi, Nada S Abdelwahab , Nouruddin W Ali

01/10/2018

Two validated chromatographic methods have been developed for the simultaneous determination of thalidomide (THD) and dexamethasone (DEX) in rat plasma using paracetamol (PAR) as an internal standard (IS). Chromatographic analysis was achieved firstly by HPLC method on C18 column (150 × 4.6 mm2 i.d., 5 μm) and a mobile phase composed of ethanol:water (containing 0.1% acetic acid) (70:30, v/v) at the flow rate of 0.6 mL min−1. The second method was HPTLC method which depended on using a developing system of methylene chloride:acetone:ethyl acetate (7:4:1, by volume). In both methods, PAR was used as an IS. The developed methods have been validated as per FDA guidelines. All parameters were tested using quality control samples (LQC, MQC and HQC). All the obtained parameters were within the acceptance criteria. In the same way, the two methods were successfully used to study the pharmacokinetic parameters of both THD and DEX after their intra-peritoneal administration. Moreover, results obtained after administration of each drug alone were compared to those obtained after their administration together. The drugs showed drug–drug interactions when administered in combination, meaning that monitoring of such combination is very important

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Validated stability-indicating spectrophotometric methods for the determination of Silodosin in the presence of its degradation products - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Shereen A. Boltia, Taghreed A. Mohammed, Nahla N. Mostafa

01/09/2018

Five simple, rapid, accurate, and precise spectrophotometric methods are developed for the determination of Silodosin (SLD) in the presence of its acid induced and oxidative induced degradation products. Method A is based on dual wavelength (DW) method; two wavelengths are selected at which the absorbance of the oxidative induced degradation product is the same, so wavelengths 352 and 377 nm are used to determine SLD in the presence of its oxidative induced degradation product. Method B depends on induced dual wavelength theory (IDW), which is based on selecting two wavelengths on the zero-order spectrum of SLD where the difference in absorbance between them for the spectrum of acid induced degradation products is not equal to zero so through multiplying by the equality factor, the absorption difference is made to be zero for the acid induced degradation product while it is still significant for SLD. Method C is first derivative (1D) spectrophotometry of SLD and its degradation products. Peak amplitudes are measured at 317 and 357 nm. Method D is ratio difference spectrophotometry (RD) where the drug is determined by the difference in amplitude between two selected wavelengths, at 350 and 277 nm for the ratio spectrum of SLD and its acid induced degradation products while for the ratio spectrum of SLD and its oxidative induced degradation products the difference in amplitude is measured at 345 and 292 nm. Method E depends on measuring peak amplitudes of the first derivative of the ratio (1DD) where peak amplitudes are measured at 330 nm in the presence of the acid induced degradation product and measured by peak to peak technique at 326 and 369 nm in the presence of the oxidative induced degradation product. The proposed methods are validated according to ICH recommendations. The calibration curves for all the proposed methods are linear over a concentration range of 5–70 μg/mL. The selectivity of the proposed methods was tested using different laboratory prepared mixtures of SLD with either its acid induced or oxidative induced degradation products showing specificity of SLD with accepted recovery values. The proposed methods have been successfully applied to the analysis of SLD in pharmaceutical dosage forms without interference from additives.

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Chemometric assisted solid-phase extraction for the simultaneous determination of some anti-inflammatory drug residues in pharmaceutical industrial wastewater - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Mohamed A. R. Korashy , Ahmed S. Saad, Sherif A. Abdel Gawad , , Medhat A. Al-Ghobashy, Nagiba Y. Hassan

01/07/2018

Development of analytical methods capable of selective determination and quantification of chemical compounds in industrial wastewater have become essential as these compounds lead to alteration of the ecosystem causing serious effects on public health; thereby, development of a sensitive and selective method for the simultaneous determination of four commonly used non-steroidal antiinflammatory drugs, namely; paracetamol, diclofenac sodium, ibuprofen and indomethacin in wastewater. Solid phase extraction (SPE) was carried out for the selective extraction and preconcentration of the drugs from the water samples. Multivariate calibration of spectrophotometric absorbance data using Partial Least Squares (PLS) regression analysis. As per the multilevel multifactor design, calibration and validation sets were fabricated and the model was constructed using mean centered data of the calibration set, leaving out one mixture at a time for cross-validation, then, the method was applied blindly for determination of the four drugs in the validation set. The method was validated according to the ICH guidelines, and the mentioned chemometric method were successfully applied for the selective determination of the four mentioned drugs in real wastewater samples. Prior to the application of chemometric technique the actual wastewater samples were subjected to SPE for pretreatment and preconcentration.

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Real-time potentiometric sensor; an innovative tool for monitoring hydrolysis of chemo/bio-degradable drugs in pharmaceutical sciences - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Ahmed Ma’mun, Mohamed K. Abd El-Rahman

01/05/2018

In recent years, the whole field of ion-selective electrodes(ISEs) in pharmaceutical sciences has expanded far beyond its original roots. The diverse range of opportunities offered by ISEs was broadly used in a number of pharmaceutical applications, with topics presented ranging from bioanalysis of drugs and metabolites, to protein binding studies, green analytical chemistry, impurity profiling, and drug dissolution in biorelevant media. Inspired from these advances and with the aim of extending the functional capabilities of ISEs, the primary focus of the present paper is the utilization of ISE as a tool in personalized medicine. Given the opportunity to explore biological events in real-time (such as drug metabolism) could be central to personalized medicine. (ATR) is a chemo-degradable and bio-degradable pharmaceutically active drug. Laudanosine (LDS) is the major degradation product and metabolite of ATR and is potentially toxic and reported to possess epileptogenic activity which increases the risk of convulsive effects. In this work, ATR have been subjected to both chemical and biological hydrolysis, and the course of the reactions is monitored by means of a ISE. In this study, we have designed an efficient real-time tracking strategy which substantially resolve the challenges of the ATR chemical and biological degradation kinetics. By utilizing a potentiometric sensor, tracking of ATR chemical and biological degradation kinetics can be performed in a very short time with excellent accuracy. The LOD was calculated to be 0.23 μmol L−1, the potential drift was investigated over a period of 60 min and the value was 0.25 mV h−1. Real serum samples for measurement the rate of in vitro metabolism of ATR was performed. Furthermore, a full description of the fabricated screen-printed sensor was presented

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Spectrofluorimetric determination of Bisoprolol fumarate and Rosuvastatin calcium in a novel combined formulation and in human spiked plasma - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

NS Abdelwahab, NW Ali, MM Zaki, AA Ali

01/02/2018

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Simultaneous determination of hyoscine N-butyl bromide and paracetamol in their binary mixture by RP-HPLC method - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nouruddin W.Ali, Mohammed Gamal

01/05/2017

RP-HPLC chromatographic method was developed for the determination of hyoscine N-butyl bromide (HBB) and Paracetamol (PAR). In this chromatographic method, HBB and PAR were separated using C18 (25 cm × 4.6 mm i.d. 5 μm particle size) column as a stationary phase and water: methanol (50:50, V/V pH adjusted to 3.9 with CF3COOH acid) as a mobile phase, maintaining the flow rate at 1.0 mL min−1 with UV detection at 210 nm. The proposed method was successfully applied for the determination of HBB and PAR in pure form over a concentration range of 2.0–50.0 μg mL−1 for HBB with mean percentage recovery of 100.10 ± 0.475 and over a concentration range of 5.0–200.0 μg mL−1 for PAR with mean percentage recovery of 99.87 ± 0.942 and in their pharmaceutical formulations (Buscopan plus® tablets, Buscamol® tablets and Buscopan plus® suppositories).

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Validated electrochemical and chroma-tographic quantifications of some antibiotic residues in pharmaceutical industrial waste water. - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Heba K. Ibrahim, Mona M. Abdel-Moety, Sherif A. Abdel-Gawad , Medhat A. Al-Ghobashy

01/01/2017

Realistic implementation of ion selective electrodes (ISEs) into environmental monitoring programs has always been a challenging task. This could be largely attributed to difficulties in validation of ISE assay results. In this study, the electrochemical response of amoxicillin trihydrate (AMX), ciprofloxacin hydrochloride (CPLX), trimethoprim (TMP), and norfloxacin (NFLX) was studied by the fabrication of sensitive membrane electrodes belonging to two types of ISEs, which are polyvinyl chloride (PVC) membrane electrodes and glassy carbon (GC) electrodes. Linear response for the membrane electrodes was in the concentration range of 10−5–10−2 mol/L. For the PVC membrane electrodes, Nernstian slopes of 55.1, 56.5, 56.5, and 54.0 mV/decade were achieved over a pH 4–8 for AMX, CPLX, and NFLX, respectively, and pH 3–6 for TMP. On the other hand, for GC electrodes, Nernstian slopes of 59.1, 58.2, 57.0, and 58.2 mV/decade were achieved over pH 4–8 for AMX, CPLX, and NFLX, respectively, and pH 3–6 for TMP. In addition to assay validation to international industry standards, the fabricated electrodes were also cross-validated relative to conventional separation techniques; high performance liquid chromatography (HPLC), and thin layer chromatography (TLC)-densitometry. The HPLC assay was applied in concentration range of 0.5–10.0 μg/mL, for all target analytes. The TLC-densitometry was adopted over a concentration range of 0.3–1.0 μg/band, for AMX, and 0.1–0.9 μg/band, for CPLX, NFLX, and TMP. The proposed techniques were successfully applied for quantification of the selected drugs either in pure form or waste water samples obtained from pharmaceutical plants. The actual waste water samples were subjected to solid phase extraction (SPE) for pretreatment prior to the application of chromatographic techniques (HPLC and TLC-densitometry). On the other hand, the fabricated electrodes were successfully applied for quantification of the antibiotic residues in actual waste water samples without any pretreatment. This finding assures the suitability of the fabricated ISEs for environmental analysis.

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Comparative study of the spectral resolution efficiency of the recently developed and conventional spectrophotometric methods in the analysis of severely overlapped zero-order absorption spectra with the same geometrical features - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Yasmin Mohamde Fayez

01/09/2016

Simple, cost-effective, safe, accurate, precise and environmentally friendly spectro-photometric methods were developed and validated for the quantitative determination of valaciclovir (VAL) in the presence of its related impurity in bulk powder and in its pharmaceutical preparation. This related impurity namely guanine (GUA) is the potential and synthesis impurity of VAL. The spectra of VAL and GUA show the same geometrical features with different absorptivities, so their resolution is very challengeable. A Comparative study was conducted for the results of the conventional methods namely, dual wavelength (DW), first derivative of ratio spectra (1DD) and mean centering of ratio spectra (MCR) versus the recently developed methods namely, induced dual wavelength (IDW), ratio difference (RD) and constant center (CC). The optimized methods allow the estimation of VAL in the concentration range 5-50 μg/mL. The methods were validated as per ICH guidelines and the specificity was assessed by analyzing synthetic mixtures containing different percentages of the related impurity with the drug. The obtained results were compared with that of the official HPLC method by using one-way analysis of variance (ANOVA) and proved to be suitable for quality control laboratories.

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Simultaneous Determination of Aspirin, Dipyridamole and Two of Their Related Impurities in Capsules by Validated TLC-Densitometric and HPLC Methods - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nariman A. El-Ragehy, Nagiba Y. Hassan, Mahmoud A.Tantawy

01/08/2016

Aspirin (ASP) and dipyridamole (DIP) are widely used as a combination in pharmaceutical formulations for treatment of strokes. Many of these formulations are containing tartaric acid as an excipient (in DIP pellets formulation for sustained release), which increases the probability of formation of dipyridamole tartaric acid ester impurity (DIP-I). On the other hand, salicylic acid (SAL) is considered to be one of the synthesis impurities and a degradation product of ASP. In this work, two chromatographic methods, namely, TLC-densitometry and HPLC, have been established and validated for simultaneous determination of ASP, DIP, SAL and DIP-I. Good separation was achieved by using silica gel as stationary phase and toluene-methanol-ethyl acetate (2:3:5, by volume) as mobile phase in the case of TLC-densitometry and Zorbax ODS column with mobile phase consisting of phosphate buffer (pH 3.3)-acetonitrile-triethylamine (40:60:0.03, by volume) for HPLC. Influence of different organic solvents in mobile phase composition has been studied to optimize the separation efficiency in TLC densitometry. Moreover, factors affecting the efficiency of HPLC, like pH of the buffer used, organic solvent ratio in the mobile phase and flow rate, have been carefully studied using one variable at a time approach. Finally, the proposed methods were validated as per ICH guidelines

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Chemometrics Tools in Detection and Quantitation of the Main Impurities Present in Aspirin/Dipyridamole Extended-Release Capsules - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

El-Ragehy NA, Yehia AM, Hassan NY, Tantawy MA

01/07/2016

Aspirin (ASP) and dipyridamole (DIP) in combination is widely used in the prevention of secondary events after stroke and transient ischemic attack. Salicylic acid is a well-known impurity of ASP, and the DIP extended-release formulation may contain ester impurities originating from the reaction with tartaric acid. UV spectral data analysis of the active ingredients in the presence of their main impurities is presented using multivariate approaches. Four chemometric-assisted spectrophotometric methods, namely, partial least-squares, concentration residuals augmented classical least-squares (CRACLS), multivariate curve resolution (MCR) alternating least-squares (ALS), and artificial neural networks, were developed and validated. The quantitative analyses of all the proposed calibrations were compared by percentage recoveries, root mean square error of prediction, and standard error of prediction. In addition, r(2) values between the pure and estimated spectral profiles were used to evaluate the qualitative analysis of CRACLS and MCR-ALS. The lowest error was obtained by the CRACLS model, whereas the best correlation was achieved using MCR-ALS. The four multivariate calibration methods could successfully be applied for the extended-release formulation analysis. The application results were also validated by analysis of the stored dosage-form solution, which showed a susceptibility of DIP esterification in the extended-release formulation. Statistical comparison between the proposed and official methods showed no significant difference.

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Validated UPLC and TLC-Densitometry Stability Indicating Methods for the Determination of Rafoxanide in Presence of Its Degradation products - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Ahmad S. Saad, Abdallah M. Hamdy, Fathy M. Salama

01/07/2016

Two sensitive and accurate stability-indicating chromatographic methods were developed and validated for the determination of rafoxanide (RFX). Degradation products were identified by mass spectrometry and IR spectroscopy. The first is ultra-performance liquid chromatography method where separation was performed using acetonitrile:0.005 M potassium dihydrogen orthophosphate (pH 3.5) in a ratio of 80:20 by volume as a mobile phase using a Hypersil GOLD™ C8 column 1.9 mm (50 × 2.1 mm), UV detection was adjusted at 220 nm and the flow rate was 0.6 mL min-1 The other is a thin-layer chromatography-densitometry method where separation was achieved using a mobile phase composed of chloroform:ethyl acetate:toluene:ammonia (5:4:3:0.1 by volume) on silica gel 60 F254 plates, and densitometric detection was done at 280 nm. Validation was achieved as per the ICH guidelines. The proposed methods proved to be accurate, robust, specific and suitable for application as stability-indicating methods for routine analysis of RFX in quality control laboratories.

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Enhancing prediction power of chemometric models through manipulation of the fed spectrophotometric data: A comparative study - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Ahmed S. Saad AbdallahM. Hamdy, Fathy M. Salama

01/05/2016

Effect of data manipulation in preprocessing step proceeding construction of chemometric models was assessed. The same set of UV spectral data was used for construction of PLS and PCR models directly and after mathematically manipulation as per well known first and second derivatives of the absorption spectra, ratio spectra and first and second derivatives of the ratio spectra spectrophotometric methods, meanwhile the optimal working wavelength ranges were carefully selected for each model and the models were constructed. Unexpectedly, number of latent variables used for models' construction varied among the different methods. The prediction power of the different models was compared using a validation set of 8 mixtures prepared as per the multilevel multifactor design and results were statistically compared using two-way ANOVA test. Root mean squares error of prediction (RMSEP) was used for further comparison of the predictability among different constructed models. Although no significant difference was found between results obtained using Partial Least Squares (PLS) and Principal Component Regression (PCR) models, however, discrepancies among results was found to be attributed to the variation in the discrimination power of adopted spectrophotometric methods on spectral data.

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Stability-indicating chromatographic methods for determination of flecainide acetate in the presence of its degradation products; isolation and identification of two of its impurities - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nariman A. El-Ragehya, Nagiba Y. Hassana, Mahmoud A. Tantawya

01/04/2016

In this work, two stability-indicating chromatographic methods have been developed and validated for determination of flecainide acetate (an antiarrhythmic drug) in the presence of its degradation products (flecainide impurities; B and D). Flecainide acetate was subjected to a stress stability study including acid, alkali, oxidative, photolytic and thermal degradation. The suggested chromatographic methods included the use of thin layer chromatography (TLC-densitometry) and high-performance liquid chromatography (HPLC). The TLC method employed aluminum TLC plates precoated with silica gel G.F254 as the stationary phase and methanol-ethyl acetate-33% ammonia (3:7:0.3, by volume) as the mobile phase. The chromatograms were scanned at 290 nm and visualized in daylight by the aid of iodine vapor. The developed HPLC method used a RP-C18 column with isocratic elution. Separation was achieved using a mobile phase composed of phosphate buffer pH 3.3-acetonitrile-triethylamine (53:47:0.03, by volume) at a flow rate of 1.0 mL/min and UV detection at 292 nm. Factors affecting the efficiency of HPLC method have been studied carefully to reach the optimum conditions for separation. The developed methods were validated according to the International Conference on Harmonization guidelines and were applied for bulk powder and dosage form.

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Stability-indicating spectrophotometric methods for determination of the anticoagulant drug apixaban in the presence of its hydrolytic degradation product - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Tantawy MA, El-Ragehy NA, Hassan NY

01/01/2016

Apixaban (a novel anticoagulant agent) was subjected to a stress stability study including acid, alkali, oxidative, photolytic, and thermal degradation. The drug was found to be only liable to acidic and alkaline hydrolysis. The degradation product was then isolated and identified by IR and GC-mass spectrometry. Four spectrophotometric methods, namely; first derivative (D(1)), derivative ratio (DR), ratio difference (RD) and mean centering of ratio spectra (MCR), have been suggested for the determination of apixaban in presence of its hydrolytic degradation product. The proposed methods do not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated as per ICH guidelines and the specificity was assessed by analyzing synthetic mixtures containing different percentages of the degradation product with the drug. The developed methods were successfully applied for the determination of apixaban in bulk powder and its tablet dosage form

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Simultano određivanje metokarbamola i ibuprofena ili diklofenak kalija metodom centriranja srednjih vrijednosti spektralnih omjera (mean centering of the ratio spectra method) - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

NOURUDDIN WAGEIH ALI, MAHA AHAMD HEGAZY, EGLAL ABDELAHAMID ABDELALEEM

01/01/2015

Sažetak U radu su opisane točne i osjetljive metode za simultano određivanje metokarbamola i ibuprofena ili diklofenak kalija u njihovim binarnim smjesama, te u prisutnosti gvajfenezina, supstancije srodne metokarbamolu koristeći metodu centriranja srednjih vrijednosti spektralnih omjera. Dobiveni rezultati su statistički uspoređeni s objavljenim HPLC metodama. Nije pronađena značajna razlika u točnosti i preciznosti između predložene metode i objavljenih metoda.

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LC-MS as a Stability-Indicating Method for Analysis of Hyoscine N-Butyl Bromide under Stress Degradation Conditions with Identification of Degradation Products - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

NW Ali, M Gamal

01/01/2015

Abstract Hyoscine N-Butyl Bromide (HBB) was subjected to different ICH prescribed stress conditions. It showed extensive decomposition under base hydrolytic conditions, while it was less liable to stress acid hydrolytic conditions. It showed also moderate degradation in response to oxidation stress of hydrogen peroxide. The drug showed no changes under photolysis conditions.

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Spectrofluorimetric Determination of Diiodohydroxyquinoline in Presence of Metronidazole in Pharmaceutical Formulation and Spiked Human Plasma - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Y ABOUL-ENEIN, Mohammed GAMAL

01/01/2015

ABSTRACT Accurate and sensitive spectrofluorimetric method was developed for determination of diiodohydroxyquinoline in presence of metronidazole. In this method the native fluorescence of diiodohydroxyquinoline in water solvent at λ= 495 nm when excitation was at 250 nm is used for its determination. Linear correlation was obtained in the concentration range of 400 to 900 ng mL-1. The proposed method was successfully applied for determination of diiodohydroxyquinoline in bulk powder with mean accuracy of 100.21 ...

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Two validated liquid chromatographic methods for the simultaneous determination of flumethasone pivalate, its related substance (flumethasone), and clioquinol - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nour Sayed, Maha Hegazy, Eglal Abdel-Aleem, Rehab Abdelfatah

01/01/2015

Two liquid chromatographic methods were developed and validated. Simple and sensitive thin-layer chromatography (TLC)-densitometric and high-performance liquid chromatographic (HPLC) methods were used for the simultaneous determination of flumethasone pivalate (FP), flumethasone pivalate related substance and impurity, flumethasone (FL), and clioquinol (CL). The proposed TLC-densitometric method has been developed using silica gel plates 60 F254 as a stationary phase with benzene-hexane- ...

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Validated RP-HPLC and TLC-Densitometric Methods for Analysis of Ternary Mixture of Cetylpyridinium Chloride, Chlorocresol and Lidocaine in Oral Antiseptic Formulation - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nada S Abdelwahab, Nouruddin W Ali,Aml A Emam

01/01/2015

Abstract This work was concerned with development, optimization, application and validation of reversed phase high performance liquid chromatography (RP-HPLC) and thin layer chromatography (TLC)-densitometric methods for analysis of cetylpyridinium chloride, chlorocresol and lidocaine in Canyon® gel. The first developed RP-HPLC method depended on chromatographic separation on a ZORBAX Eclipse Plus C 8 column, with elution with a mobile phase consisting of 0.05% phosphoric acid solution: acetonitrile: ...

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Determination of nifuroxazide and drotaverine hydrochloride in pharmaceutical preparations by three independent analytical methods - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Fadia H Metwally, Mohammed Abdelkawy, Ibrahim A Naguib

01/01/2015

Three new, different, simple, sensitive, and accurate methods were developed for quantitative determination of nifuroxazide (I) and drotaverine hydrochloride (II) in a binary mixture. The first method was spectrophotometry, which allowed determination of I in the presence of II using a zero-order spectrum with an analytically useful maximum at 364.5 nm that obeyed Beer's law over a concentration range of 210 g/mL with mean percentage recovery of 100.08 0.61. Determination of II in presence of I was obtained by second ...

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Different spectrophotometric and TLC-densitometric methods for determination of Lidocaine HCl and Cetylpyridinum Chloride - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nourddin W Ali, Nada S Abdelwahab, M Abdelkawy, Ahmed M Elgebaly

01/01/2014

Abstract Lidocaine HCl (LID) and Cetylpyridinum Chloride (CPC) formulated as oral gels used to alleviate the painful and inflammatory lesions of the oral mucosa and gums. In this work, three accurate, precise and specific spectrophotometric and chromatographic methods have been developed and validated for determination of these drugs in their bulk powder and pharmaceutical dosage form. Method (I) is dual wavelength method at which two wavelengths were selected for each drug in such a way that the difference in absorbance ...

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Different Spectrophotometric and TLC-Densitometric Methods for Determination of Two Analgesic Drugs - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Nourddin Wageh Ali

01/01/2014

Abstract Different Spectrophotometric and TLC-Densitometric Methods for Determination of Two Analgesic DrugsNada sayed Abdelwahab, Nourddin Wageh Ali, Mohammed Mohammed Abdelkawy, Ahmed mohammed gebalyDiclofenac sodium (DIC) and Diflunisal (DIF) are two widely used analgesic drugs formulated in combined dosage form to treat inflammation and relive pain in many conditions. In this work, four accurate, precise and specific spectrophotometric and chromatographic methods have been developed and ...

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Simultaneous determination of diloxanide furoate and metronidazole in presence of diloxanide furoate degradation products - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Samah S Abbas, Nour E Wagieh, Maha M Abdelrahman

01/01/2011

Three methods are presented for the simultaneous determination of diloxanide furoate (DLX) and metronidazole (MTR), used for their antiprotozoal and antiamoebic effect, in the presence of DLX alkaline degradates and in pharmaceutical formulations, without previous separation. The first method is chemometric-assisted spectrophotometry, in which principal component regression and partial least squares were applied. These two approaches were successfully applied to quantify each drug in the mixture using the information included in ...

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DRUG FORMULATIONS AND CLINICAL METHODS-Simultaneous Determination of Diloxanide Furoate and Metronidazole in Presence of Diloxanide Furoate Degradation Products - 01/0

Mohamed Abdelkawy Mohammad Ibrahim

Samah S Abbas, Nour E Wagieh, Maha M Abdelrahman

01/01/2011

Three methods are presented for the simultaneous determination of diloxanide furoate (DLX) and metronidazole (MTR), used for their antiprotozoal and antiamoebic effect, in the presence of DLX alkaline degradates and in pharmaceutical formulations, without previous separation. The first method is chemometric-assisted spectrophotometry, in which principal component regression and partial least squares were applied. These two approaches were successfully applied to quantify each drug in the mixture using the information included in the absorption spectra in the range of 225–320 nm. The second method is TLC-densitometry, in which the binary mixture and degradates were separated on silica gel plates using a chloroform–acetone–glacial acetic acid (9.5 + 0.5 + 0.07, v/v/v) mobile phase and the bands were scanned at 254 nm. The last method is HPLC, in which DLX, MTR, and degradates were separated using the mobile phase acetonitrile–0.05 M dibasic potassium phosphate (25 + 75, v/v), adjusted to pH 4 with orthophosphoric acid, at a flow rate of 1 mL/min, on a C18 analytical column. Detection was at 254 nm. The proposed methods were successfully applied for the analysis of DLX and MTR in pharmaceutical formulations, and the results were statistically compared with a reported spectrophotometric method.

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