Browsing by Author "Fawaz E.M."

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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.
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.
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.