Browsing by Author "Riad S.M."

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Chemometrics for resolving spectral data of cephalosporines and tracing their residue in waste water samples
(Elsevier B.V., 2019) Yehia A.M.; Elbalkiny H.T.; Riad S.M.; Elsaharty Y.S.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini 13 Street; Cairo; 11562; Egypt; Chemistry Department; School of Pharmacy and Pharmaceutical Industries; Badr University in Cairo; Badr City; Cairo 11829; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); 6th of October City; 11787; Egypt
Chemometrics approaches have been used in this work to trace cephalosporins in aquatic system. Principal component regression (PCR), partial least squares (PLS), multivariate curve resolution-alternating least squares (MCR-ALS), and artificial neural networks (ANN) were compared to resolve the severally overlapped spectrum of three selected cephalosporins; cefprozil, cefradine and cefadroxil. The analytical performance of chemometric methods was compared in terms of errors. Artificial neural networks provide good recoveries with lowest error. Satisfactory results were obtained for the proposed chemometric methods whereas ANN showed better analytical performance. The qualitative meaning in MCR-ALS transformation provided very well correlations between the pure and estimated spectra of the three components. This multivariate processing of spectrophotometric data could successfully detect the studied antibiotics in waste water samples and compared favorably to alternative costly chromatographic methods. � 2019
A comparative study between three stability indicating spectrophotometric methods for the determination of diatrizoate sodium in presence of its cytotoxic degradation product based on two-wavelength selection
(Elsevier, 2015) Riad S.M.; El-Rahman M.K.A.; Fawaz E.M.; Shehata M.A.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini Street; Cairo; 11562; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October for Modern Sciences and Arts University; 6th of October City; Egypt
Abstract Three sensitive, selective, and precise stability indicating spectrophotometric methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA) in the presence of its acidic degradation product (highly cytotoxic 3,5-diamino metabolite) and in pharmaceutical formulation, were developed and validated. The first method is ratio difference, the second one is the bivariate method, and the third one is the dual wavelength method. The calibration curves for the three proposed methods are linear over a concentration range of 2-24 ?g/mL. The selectivity of the proposed methods was tested using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed. 2015 Elsevier B.V. All rights reserved.
Comparison of Two Stability-Indicating Chromatographic Methods for the Determination of Mirabegron in Presence of Its Degradation Product
(Friedr. Vieweg und Sohn Verlags GmbH, 2017) Yehia A.M.; Sami I.; Riad S.M.; El-Saharty Y.S.; Department of Analytical Chemistry; Faculty of Pharmacy; Cairo University; Kasr El-Aini Street; Cairo; 11562; Egypt; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts; 6 October City; 11787; Egypt
Mirabegron is a novel ?3-adrenoceptor agonist containing an amide group. It was subjected to stress conditions of acidic and alkaline hydrolyses. The hydrolytic degradation product was isolated and its structure was confirmed using mass and IR spectrometry. Two stability-indicating chromatographic methods have been proposed for the determination of mirabegron. TLC method was applied using silica gel as stationary phase and chloroform methanol ammonia (9.0:1.0:0.1 by volume) as the mobile phase, and chromatograms were scanned at 250. nm. Accurate determination of the drug was achieved over the concentration range of 2. 1. g per band. In addition, an isocratic HPLC method was developed on Agilent C18 column (150. mm. נ4.5.mm I.D., particle size 5.m) using ethanol-phosphate buffer pH 2.5 (30:70, by volume) as a mobile phase with flow rate of 1.mL.min?1.The intact drug was detected at 255.nm with running time less than 5.min. Mirabegron was determined accurately in a concentration range of 1.25.g.mL?1. The proposed chromatographic methods were applied successfully for the assay of mirabegron in pharmaceutical dosage form and both methods were validated as per the International Conference on Harmonization guidelines and statistically compared with a reported gradient HPLC method. 2016, Springer-Verlag Berlin Heidelberg.
Derivative constant wavelength synchronous fluorescence spectrometry for the simultaneous detection of cefadrine and cefadroxil in water samples
(Elsevier B.V., 2020) Elbalkiny H.T.; Yehia A.M.; Riad S.M.; Elsaharty Y.S.; Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); 6th October City; 11787; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini 13 Street; Cairo; 11562; Egypt; Chemistry Department; School of Pharmacy and Pharmaceutical Industries; Badr University in Cairo; Badr City; Cairo 11829; Egypt
A sensitive accurate spectrofluorimetric technique was developed to detect cefadroxil and cefradine traces in water samples simultaneously, by applying a procedure based on the formation of hydrolysis products corresponding to these compounds by sodium hydroxide (1 N NaOH) treatment. The conventional and the synchronous fluorescence spectra of these hydrolyzed products were totally overlapped making resolving of this mixture impossible. The second-derivative constant-wavelength synchronous fluorescence spectra allowed their detection simultaneously in a single scan after experimental conditions optimization, which was measured at 390 nm and 379 nm for cefadroxil and cefradine, respectively at ?? = 30.0. The calibration curves between derivative synchronous fluorescence intensity and drugs concentration showed suitable linear correlation in the range of 0.1 to 5 ?g.mL? 1 for cefadroxil and 0.5�10 ?g.mL? 1 for cefradine. The proposed fluorimetric method is superior in being simple, environmental friendly and cost effective in comparison to the previously published reported methods. � 2019 Elsevier B.V.
Determination of fluoroquinolone antibiotics in industrial wastewater by high-pressure liquid chromatography and thin-layer chromatography-densitometric methods
(Akademiai Kiado Rt., 2014) Khattab F.I.; Salem H.; Riad S.M.; Elbalkiny H.T.; Cairo University; Analytical Chemistry Department; Faculty of Pharmacy; Kasr-El Aini Street; 11562 Cairo; Egypt; October University for Modern Sciences and Arts (MSA); Analytical Chemistry Department; Faculty of Pharmacy; 11787 6th October City; Egypt
Two methods were described for the simultaneous determination of ciprofloxacin HCl (CIP) and moxifloxacin HCl (MOX) in their binary mixture present in industrial wastewater. A solid-phase extraction procedure (SPE) based on retention on HLB OASIS cartridges and elution with a mixture of methanol-water in acidic medium was preformed, and then both fluoroquinolones were separated using two chromatographic methods. The first method was based on high-performance liquid chromatographic separation of the two drugs on reversed-phase Zorbax C18 column. The mobile phase consisted of monobasic potassium phosphate (50 mM, pH 2.5, adjusted with phosphoric acid) and acetonitrile (80:20, v/v). Flow rate was 1 mL min-1. Quantitation was achieved with ultraviolet (UV) detection at 278 nm. Linearity was found to be over the concentration range of 1-50 ?g mL-1 for both CIP and MOX. The second method was based on the thin-layer chromatographic (TLC) separation of the two drugs followed by densitometric measurements of their bands at 278 nm. The separation was carried out on silica gel 60 F254 plates, using methanol, ammonia, and methylene chloride (55:35:20, v/v) as a developing system. The linearity was found to be in the range of 0.25-2.5 ?g band -1 for both CIP and MOX. Both methods were optimized and validated as per International Conference on Harmonization (ICH) guidelines. Separation was developed on spiked water samples and checked on process wastewaters of industrial origin after SPE sample pretreatment.
Ion-Selective membrane sensors for the determination of ciprofloxacin hydrochloride in water and pharmaceutical formulation
(Center of Excellence in Electrochemistry, Univ. of Tehran, 2014) Riad S.M.; Khattab F.I.; Salem H.; Elbalkiny H.T.; Analytical Chemistry Department; Cairo University; Kasr-El Aini Street; Cairo; 11562; Egypt; Analytical Chemistry Department; October University for Modern Sciences and Arts (MSA); 6th October City; 11787; Egypt
The construction and electrochemical response characteristics of six Ciprofloxacin-selective electrodes were investigated using precipitation based technique with sodium tetraphenyl borate (TPB), phosphomolybdate (PMA) and phosphotungstate (PTA); respectively upon using polyvinyl chloride (PVC) matrix and dibutyl phthalate (DBP) as a plasticizer. The resultant sensors have different forms, either as membrane electrodes (sensors 1, 3 and 5) or as coated wire electrodes (sensors 2, 4 and 6). Linear responses of CIP within the concentration ranges of 10?6 to 10?2 mol/L for sensors 1, 2 and 5 while for sensors 3 and 4, the linear responses were within the concentration ranges of 10?5 to 10?2 mol/L and for sensor 6 it shows linear responses within the concentration ranges of 10?7 to 10?2 mol/L. Nernstian slopes of 51.7, 50.7, 58.3, 57.7, 44 and 41.8 mV/decade were observed over the pH range of (5�9) for sensors 1, 2, 5 and 6 and over range of (5-7) for sensor 3 and 4 respectively. The selectivity coefficients of the developed sensors indicated excellent selectivity for CIP. The proposed sensors displayed useful analytical characteristics for the determination of CIP in water samples and pharmaceutical preparation. 2014 by CEE.
Ion-selective membrane sensors for the determination of tinidazole and clarithromycin in bulk powder and pharmaceutical formulation
(Center of Excellence in Electrochemistry, Univ. of Tehran, 2014) Riad S.M.; Rezk M.R.; Ahmed K.; Salem H.; Analytical Chemistry Department; Cairo University; Kasr El-Aini Street; Cairo; 11562; Egypt; Pharmaceutical and Analytical Chemistry Department; University for Modern Sciences and Arts; 6th of October city; Egypt; Pharmaceutical and Analytical Chemistry Department; Deraya University; Egypt
The construction and electrochemical response characteristics of three selective electrodes were investigated using precipitation based technique with phosphotungstate and phosphomolybdate; respectively upon using polyvinyl chloride (PVC) matrix and dioctyl phthalate (DOP) as a plasticizer. The resultant membrane sensors were tinidazole phosphotungestate (TND-PTA) electrode (sensors 1), tinidazole phosphomolybdate (TNDPMA) electrode (sensors 2) and clarithromycin phosphotungestate (CLR-PTA) electrode (sensors 3). Linear responses of TND and CLR within the concentration ranges of 10?6to 10?2mol/L for sensors 1, 2 and 3 were observed. Nernstian slopes of 58.3, 57.1 and 58.8 mV/decade were observed over the pH range of 3-7 for sensors 1and 2 and over range of 3-8 for sensor 3, respectively. The selectivity coefficients of the developed sensors indicated excellent selectivity for TND and CLR. The proposed sensors displayed useful analytical characteristics for the determination of TND and CLR in bulk powder and pharmaceutical formulation (Helicure. tablets). 2014 by CEE.
Monitoring and optimization of diclofenac removal by adsorption technique using in-line potentiometric analyzer
(Elsevier Inc., 2019) Yehia A.M.; Elbalkiny H.T.; Riad S.M.; Elsaharty Y.S.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini 13 Street; Cairo; 11562; Egypt; Chemistry Department; School of Pharmacy and Pharmaceutical Industries; Badr University in Cairo; Badr City; Cairo 11829; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); 6th October City; 11787; Egypt
Diclofenac (DICLO) is one of the most prescribed non-steroidal anti-inflammatory drugs worldwide. The presence of DICLO residues in aquatic environment either from industrial or hospital wastewater has harmful effects on many organisms. In this contribution, the adsorption of DICLO on granulated active carbon and mesoporous silica nanoparticles was optimized in order to remove those residues from water. The tracking of DICLO was done using in-line potentiometric ion-selective electrodes (ISE) through the whole experiments. The constructed electrode allows tracking of DICLO residues in real time. A central composite design was applied, inspecting the pH, initial concentration, adsorbent loading concentration and adsorbent type effects on the adsorption process, the results showed that the pH effect was most significant; pH 5 gave best results. The adsorption kinetics of these adsorbents have been investigated and the results indicated that the adsorption process followed the pseudo-second-order kinetic model. The adsorption isotherm data were analyzed by both Langmuir and Freundlich models and later provides better fit of the experimental data. The removal efficiency was about ~89% upon applying the optimum set of experimental conditions in time < 60 min. In-line monitoring is considered a green protocol, that should be carried out also at the pharmaceutical industry scale due to the high selectivity, lack of harmful waste generation and minimal solvent use. � 2019 Elsevier B.V.
Monitoring of the degradation kinetics of diatrizoate sodium to its cytotoxic degradant using a stability-indicating high-performance liquid chromatographic method
(John Wiley and Sons Ltd, 2017) Fawaz E.M.; El-Rahman M.K.A.; Riad S.M.; Shehata M.A.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini Street; Cairo; 11562; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October for Modern Sciences and Arts University; 6th of October City; Egypt
The X-ray diagnostic agent sodium diatrizoate (DTA) was studied for chemical degradation. The 3,5-diamino derivative was found to be the alkaline and acidic degradation product. The 3,5-diamino degradate is also the synthetic precursor of DTA and it is proved to have cytotoxic and mutagenic effects. A sensitive, selective and precise high-performance liquid chromatographic stability-indicating method for the determination of DTA in the presence of its acidic degradation product and in pharmaceutical formulation was developed and validated. Owing to the high toxicity of the degradation product, the kinetics of the acidic degradation process was monitored by the developed RP-HPLC method. The reaction was found to follow pseudo-first order kinetics. The kinetic parameters such as rate constant (K) and half-life (t�) were calculated under different temperatures and acid concentrations; activation energy was estimated from the Arrhenius plot. The developed RP-HPLC method depends on isocratic elution of a mobile phase composed of methanol�water (25:75 v/v; pH adjusted with phosphoric acid), and UV detection at 238 nm. The method showed good linearity over a concentration range of 2�100 ?g/mL with mean percentage recovery of 100.04 � 1.07. The selectivity of the proposed method was tested using laboratory-prepared mixtures. The proposed method has been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives and the results were statistically compared with the official USP method. Validation of the proposed method was performed according to International Conference on Harmonization guidelines. Copyright � 2016 John Wiley & Sons, Ltd.
A new platform for profiling degradation-related impurities via exploiting the opportunities offered by ion-selective electrodes: Determination of both diatrizoate sodium and its cytotoxic degradation product
(AOAC International, 2018) Riad S.M.; Abd El-Rahman M.K.; Fawaz E.M.; Shehata M.A.; Cairo University; Faculty of Pharmacy; Analytical Chemistry Department; Kasr-El Aini St; Cairo; 11562; Egypt; October University for Modern Sciences and Arts; Faculty of Pharmacy; Analytical Chemistry Department; 6th of October City; Egypt
Although the ultimate goal of administering active pharmaceutical ingredients (APIs) is to save countless lives, the presence of impurities and/or degradation products in APIs or formulations may cause harmful physiological effects. Today, impurity profiling (i.e., the identity as well as the quantity of impurity in a pharmaceutical) is receiving critical attention from regulatory authorities. Despite the predominant use of spectroscopic and chromatographic methods over electrochemical methods for impurity profiling of APIs, this work investigates the opportunities offered by electroanalytical methods, particularly, ion-selective electrodes (ISEs), for profiling degradation-related impurities (DRIs) compared with conventional spectroscopic and chromatographic methods. For a meaningful comparison, diatrizoate sodium (DTA) was chosen as the anionic X-ray contrast agent based on its susceptibility to deacetylation into its cytotoxic and mutagenic degradation product, 3,5-diamino-2,4,6 triiodobenzoic acid (DTB). This cationic diamino compound can be also detected as an impurity in the final product because it is used as a synthetic precursor for the synthesis of DTA. In this study, four novel sensitive and selective sensors for the determination of both DTA and its cytotoxic degradation products are presented. Sensors I and II were developed for the determination of the anionic drug, DTA, and sensors III and IV were developed for the determination of the cationic cytotoxic impurity. The use of these novel sensors not only provides a stability-indicating method for the selective determination of DTA in the presence of its degradation product, but also permits DRI profiling. Moreover, a great advantage of these proposed ISE systems is their higher sensitivity for the quantification of DTB relative to other spectroscopic and chromatographic methods, so it can measure trace amounts of DTB impurities in DTA bulk powder and pharmaceutical formulation without a need for preliminary separation. � 2018 AOAC International. All rights reserved.
Potentiometric diclofenac detection in wastewater using functionalized nanoparticles
(Elsevier Inc., 2019) Elbalkiny H.T.; Yehia A.M.; Riad S.M.; Elsaharty Y.S.; Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); 6th October City; 11787; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini 13 Street; Cairo; 11562; Egypt; Chemistry Department; School of Pharmacy and Pharmaceutical Industries; Badr University in Cairo; Badr City; Cairo; 11829; Egypt
Ion selective electrodes for diclofenac monitoring in both pharmaceutical wastewater and dosage form were described; that are considered environmental friendly analytical method. The sensors development depended on comparative performance evaluation of membranes that were based on functionalized magnetite nanoparticles with the classical sensors; this approach provided that nanoparticles in the inner solution of sensor membrane were highly dispersed and coated with ionophore to enhance a complete ion-pairing interaction between the ionophore and the analyte. The optimum membrane was that containing ??cyclodextrin coupled with magnetite ferric oxide as inner filling solution, dibutylphthalate as plasticizer and crystal violet as ion exchanger in poly (vinylchloride) matrix. This sensor (CV-Fe-?-CD) exhibited high sensitivity, Nernstian slope of the calibration curve, as well as fast, stable response and good selectivity. The sensor exhibits a Nernstian slope of ?58.7 � 1 mV/decade over the concentration range 1.0 � 10?7 to 1.0 � 10?2 M of Diclofenac with a minimal limit of detection of 1.1 � 10?7 M. The electrode showed a good potentiometric selectivity for diclofenac with respect to a number of interfering ions and organic species. The membrane sensor was successfully applied for the determination of diclofenac in wastewater samples and dosage form without sample pretreatment steps prior to its analysis. � 2018 Elsevier B.V.
Qualitative and quantitative chemometry as stability-indicating methods for determination of dantrolene sodium and paracetamol
(Bentham Science Publishers B.V., 2018) Yehia A.M.; Sami I.; Riad S.M.; El-Saharty Y.S.; Cairo University; Faculty of Pharmacy; Department of Analytical Chemistry; Kasr El-Aini Street; Cairo; ET 11562; Egypt; October University for Modern Sciences and Arts; Faculty of Pharmacy; Pharmaceutical Analytical Chemistry Department; 6 October City; 11787; Egypt
Background: Simultaneous determination of binary mixtures with simple and cost effective analysis is always of interest. Progressive advancement in chemometrics enables spectral resolution of drugs in the presence of their degradation products or impurities. Methods and Result: Three stability indicating chemometric methods are applied for the simultaneous determination of Dantrolene sodium (DNT) and Paracetamol (PAR). Partial Least Squares (PLS), Concentration Residuals Augmented Classical Least Squares (CRACLS) and Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) were selected for that purpose. DNT and PAR were determined in the linearity range of (2 � 10 ?g mL-1) and (12 � 28 ?g mL-1), respectively, in the presence of their degradation products. The presented methods were compared for their qualitative and quantitative analyses and validated according to the ICH guidelines. Furthermore, statistical comparison between the results obtained by the proposed methods and the reported chromatographic method showed no significant differences. Conclusion: The proposed multivariate calibrations were accurate and specific for quantitative analysis of the studied components. Furthermore, CRACLS and MCR-ALS methods succeeded in both quantitative and qualitative of the studied components and their degradation products. � 2018 Bentham Science Publishers.
Removal and tracing of cephalosporins in industrial wastewater by SPE-HPLC: optimization of adsorption kinetics on mesoporous silica nanoparticles
(Springer, 2019) Elbalkiny H.T.; Yehia A.M.; Riad S.M.; Elsaharty Y.S.; Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); 6th of October City; 11787; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini 13 Street; Cairo; 11562; Egypt; Chemistry Department; School of Pharmacy and pharmaceutical industries; Badr University in Cairo; Badr City; Cairo 11829; Egypt
Cephalosporins are ?-lactam antibiotics which are considered the most widely used for humans and animals in many countries. Solid phase extraction was applied using Oasis HLB cartridges for tracing three cephalosporins (cefadroxil, cefprozil, and cefradine) in industrial wastewater samples. Sample extraction was followed by chromatographic analysis. The developed high-performance liquid chromatographic method was used for the determination of these selected cephalosporins. Separation was achieved on a Hypersil C18 column with an isocratic elution of acidified water (pH 2.5) to methanol to acetonitrile (82:12:6 per volume) at a flow rate of 1.5 mL min?1 and UV detection at 254 nm. Moreover, the proposed extraction and analysis procedures were applied to study the ability of mesoporous silica nanoparticles to remove cephalosporin residues from water by adsorption technique. A factorial design was applied to investigate the effect of pH, initial cephalosporins concentration, and adsorbent concentration on the adsorption process using removal percentage as a response. The prediction model fit well to experimental data based on statistical analysis. Adsorption kinetics and isotherm have been also studied, and the experimental results indicated that the adsorption process followed the pseudo-second-order kinetic model and Freundlich isotherm. � 2019, The Author(s).
Screen printed ion selective electrodes as a fully integrated PAT tool: Application to the analysis and impurity profiling of diatrizoate sodium
(Electrochemical Society Inc., 2018) Fawaz E.M.; Abd El-Rahman M.K.; Riad S.M.; Shehata M.A.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Cairo; 11562; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October for Modern Sciences and Arts University; Cairo; Egypt
Conventional pharmaceutical manufacturing is generally accomplished via batch processing followed by laboratory testing conducted on some representative samples collected to evaluate batch quality. However, today significant opportunities exist for improving pharmaceutical quality assurance through innovation in process development and analysis. FDA's guidance for pharmaceutical industry has defined Process Analytical Technology (PAT) as a system for designing, analyzing, and controlling manufacturing through timely measurements,with the goal of ensuring final product quality.Nevertheless, pharmaceutical companies are encouraged to develop and implement innovative PAT tools for designing, analyzing, and controlling manufacturing through real-time strategies (i.e., during processing) of critical quality attributes of raw and final product. The goal of PAT is that quality cannot be tested into products; it should be built-in or should be by design. Furthermore, FDA stated that sensor-based measurements could pave the way to built-in product quality assurance which is the key to PAT development. From this perspective, this scientific approach presents screen-printed ISEs (SPEs) as a potential real-time analyzer and PAT-tool. Diatrizoate sodium (DTA) was chosen as a model analyte, it is a widely used X-ray contrast agent that is susceptible to degradation into a cytotoxic and mutagenic compound, that can be also used as its precursor. Two SPEs were fabricated and used successfully in the analysis of both DTA and its potential impurity. The proposed SPEs have the advantage of being real-time analyzers that could be fully integrated into the production cycle giving a key to a promising competent PAT-tool. � 2018 The Electrochemical Society.
Three different spectrophotometric methods exploiting ratio spectra for the selective determination of iohexol in the presence of its acidic degradate
(Bentham Science Publishers B.V., 2018) El-Rahman M.K.A.; Riad S.M.; Fawaz E.M.; Shehata M.A.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini Street; Cairo; 11562; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October for Modern Sciences and Arts University; 6th of October city; Egypt
Background: Non-ionic X-ray contrast agents constitute a very important class of pharmaceutical compounds produced in large quantities. Iohexol is an important example of such compounds. Objective: Three simple and selective stability indicating spectrophotometric methods utilizing ratio spectra were proposed for the determination of the widely used X-ray contrast medium, iohexol in the presence of its acidic degradate and in its pharmaceutical formulation. Methods: The first method is the first derivative of ratio spectra method (DD 1 ), the second is the Ratio Difference Method (RD), and the last one is the Mean Centering method (MC). Results: The three proposed methods showed a good linearity over the concentration range of 4-40 ?g.mL -1 . The selectivity of the three developed methods was evaluated by analyzing different laboratory-prepared mixtures and satisfactory results were obtained. Conclusion: Iohexol has been successfully determined in its pure form and pharmaceutical formulation (Omnipaque vials) utilizing the proposed methods with no interference from the present additives. The results obtained by each of the proposed methods were statistically compared to the official United States pharmacopeial method and non-significant difference was obtained regarding accuracy or precision. 2018 Bentham Science Publishers.
Validated univariate and multivariate spectrophotometric methods for the determination of pharmaceuticals mixture in complex wastewater
(Blackwell Publishing Ltd, 2015) Riad S.M.; Salem H.; Elbalkiny H.T.; Khattab F.I.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini Street; Cairo; 11562; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Deraya University; Menia; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); October City; 11787 6th; Egypt
Five, accurate, precise, and sensitive univariate and multivariate spectrophotometric methods were developed for the simultaneous determination of a ternary mixture containing Trimethoprim (TMP), Sulphamethoxazole (SMZ) and Oxytetracycline (OTC) in waste water samples collected from different cites either production wastewater or livestock wastewater after their solid phase extraction using OASIS HLB cartridges. In univariate methods OTC was determined at its ?max 355.7 nm (0D), while (TMP) and (SMZ) were determined by three different univariate methods. Method (A) is based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method followed by ratio difference method for determination of TMP and SMZ. Method (B) is successive derivative ratio technique (SDR). Method (C) is mean centering of the ratio spectra (MCR). The developed multivariate methods are principle component regression (PCR) and partial least squares (PLS). The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs. The obtained results are statistically compared with those obtained by the official methods, showing no significant difference with respect to accuracy and precision at p = 0.05. � 2015 Elsevier B.V. All rights reserved.