Browsing by Author "Mowaka S."

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A comparative study of smart spectrophotometric methods for simultaneous determination of sitagliptin phosphate and metformin hydrochloride in their binary mixture
(Elsevier, 2015) Lotfy H.M.; Mohamed D.; Mowaka S.; Analytical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr-El Aini Street; Cairo; 11562; Egypt; Pharmaceutical Chemistry Department; Faculty of Pharmaceutical Sciences and Pharmaceutical Industries; Future University; Cairo; 12311; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Helwan University; Ein Helwan; Cairo; 11795; Egypt; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts; October City; 117876; Egypt; Department of Analytical Chemistry; Faculty of Pharmacy; British University in Egypt; El-Sherouk City; 11837; Egypt
Simple, specific, accurate and precise spectrophotometric methods were developed and validated for the simultaneous determination of the oral antidiabetic drugs; sitagliptin phosphate (STG) and metformin hydrochloride (MET) in combined pharmaceutical formulations. Three methods were manipulating ratio spectra namely; ratio difference (RD), ratio subtraction (RS) and a novel approach of induced amplitude modulation (IAM) methods. The first two methods were used for determination of STG, while MET was directly determined by measuring its absorbance at ?max 232 nm. However, (IAM) was used for the simultaneous determination of both drugs. Moreover, another three methods were developed based on derivative spectroscopy followed by mathematical manipulation steps namely; amplitude factor (P-factor), amplitude subtraction (AS) and modified amplitude subtraction (MAS). In addition, in this work the novel sample enrichment technique named spectrum addition was adopted. The proposed spectrophotometric methods did not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined. The selectivity of the developed methods was investigated by analyzing laboratory prepared mixtures of the drugs and their combined pharmaceutical formulations. Standard deviation values were less than 1.5 in the assay of raw materials and tablets. The obtained results were statistically compared to that of a reported spectrophotometric method. The statistical comparison showed that there was no significant difference between the proposed methods and the reported one regarding both accuracy and precision. � 2015 Elsevier B.V. All rights reserved.
Lanthanide-DNA probe for spectrofluorimetric determination of some 6-fluoroquinolones in eye-ear pharmaceutical preparations
(Elsevier Inc., 2019) Rizk M.; Habib I.H.I.; Mohamed D.; Mowaka S.; El-Eryan R.T.; Department of Analytical Chemistry; Faculty of Pharmacy; Helwan University; Ein-Helwan; 11745; Egypt; Department of Applied Organic Chemistry; Microanalytical Chemistry Laboratory; National Research Centre; Dokki; Giza; 12622; Egypt; Department of Pharmaceutical Analytical Chemistry; Faculty of Pharmacy; October University for Modern Sciences and Arts; October City 6; 11787; Egypt; Department of Analytical Chemistry; Faculty of Pharmacy; British University in Egypt; El-Sherouk City; 11837; Egypt
A sensitive, accurate and precise spectrofluorimetric method was established for the quantification of ciprofloxacin HCl and norfloxacin drugs. The spectrofluorimetric method has involved the development of a ternary complex between the investigated drugs and Tb3+ in presence of Calf thymus DNA which was used as a fluorescence enhancing agent causing reduction in the non-radiative energy loss produced by O[sbnd]H vibration of H2O in the original Tb3+�drug complex. Thus, the fluorescence of the system (Tb3+�drug�DNA) at ?em of 545 nm for ?ex of 272 nm was enhanced. Investigation of all the conditions that could affect the reaction as well as the formed complexes' spectral properties was performed. Upon utilization of the optimum reaction conditions; the spectrofluorimetric method was highly sensitive and showed linearity over the concentration range of 40�700 ng/mL for both ciprofloxacin and norfloxacin with a correlation coefficient of 0.9998 and 0.9997, respectively. The limit of detection was 12.56 ng/mL and 11.44 ng/mL, while the limit of quantification was 38.06 ng/mL and 34.66 ng/mL for ciprofloxacin and norfloxacin, respectively. The developed method was effectively utilized for the estimation of the studied drugs in eye-ear pharmaceutical dosage forms. The achieved results were compared statistically with those of the pharmacopoeial method where no significant difference was perceived concerning both accuracy and precision. 2019 Elsevier B.V.
Novel contribution to the simultaneous analysis of certain hypoglycemic drugs in the presence of their impurities and degradation products utilizing UPLC-MS/MS
(Royal Society of Chemistry, 2015) Mowaka S.; Mohamed D.; Analytical Chemistry Department; Faculty of Pharmacy; Helwan University; Cairo; Ein Helwan; 11795; Egypt; Department of Analytical Chemistry; Faculty of Pharmacy; British University in Egypt; El-Sherouk City; 11837; Egypt; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts; 6 October City; 11787; Egypt
A novel ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method was established for simultaneous determination of three hypoglycemic drugs namely; sitagliptin (STG), vildagliptin (VLG) and metformin (MET) in the presence of their degradation products and STG related impurities. Chromatographic separation was accomplished on a Hypersil gold 50 mm � 2.1 mm (1.9 ?m) column, using acetonitrile and 0.2% formic acid aqueous solution as the mobile phase with a gradient elution. Electrospray ionization (ESI) source was operated in the positive ion mode. The selected reaction monitoring (SRM) mode on a triple quadrupole mass spectrometer was used to quantify the drugs utilizing the transitions of 408.12 ? 235.24 (m/z), 304.33 ? 154.32 (m/z), 130.12 ? 71.32 (m/z) and 255.75 ? 166.15 (m/z), for STG, VLG, MET and diphenhydramine (IS), respectively. The method has displayed a lower limit of detection of 1.50 ng mL-1, 1.50 ng mL-1 and 3.00 ng mL-1 for STG, VLG and MET, respectively. The drugs were subjected to forced degradation where it was concluded that STG, VLG and MET were highly susceptible for alkaline stress conditions. In addition, the study of the degradation kinetics of the drugs has proved that the degradation follows a pseudo-first-order reaction. The proposed method was effectively applied for the analysis of laboratory prepared mixtures as well as combined pharmaceutical formulations. No significant difference was found regarding accuracy and precision upon statistical comparison of the obtained results with those of the reported method. Validation was conducted in compliance with the ICH guidelines proving the method to be selective, linear, precise and accurate. The simplicity and sensitivity of this method allows its use in the quality control of the cited drugs. � The Royal Society of Chemistry 2015.
Square wave voltammetric determination of rasagiline mesylate on hanging mercury drop electrode and its application in dosage form and biological fluids
(Institute of Electrical and Electronics Engineers Inc., 2016) Habib I.H.I.; Rizk M.; Mohamed D.; Mowaka S.; El-Eryan R.T.; Microanalytical Chemistry Laboratory; Applied Organic Chemistry Department; National Research Centre; Dokki; Giza; 12622; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Helwan University; Cairo; 11745; Egypt; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts; 6 October City; 11787; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; British University in Egypt; El-Sherouk City; 11837; Egypt
A new square wave voltammetric (SWV) method has been developed and validated for the determination of Rasagiline mesylate in bulk, dosage form and human plasma due to a cathodic behaviour of its acetylene group at Hanging Mercury Drop Electrode (HMDE). Many facts such as different supporting electrolytes, scan rate, pulse amplitude, accumulation time and accumulation potential were studied. A good linearity was obtained over a concentration range of (2.8 x10-8 to1.4 x10-7mol L-1) with 99.78% as mean recovery and 1.09%, as the relative standard deviation and limits of detection and quantification were found to be (2.7 x10-9 and 9.24 x1 0-9mol L-1), respectively. The accuracy and precision of the method were within acceptable limits. The method was applied for determining the active ingredients in its tablets with % recoveries � relative standard deviation of 95.46 � 3.7 6 and in spiked human plasma with 94.3 � 2.8 9%, respectively. � 2016 The Authors.
UPLC-MS/MS estimation of paracetamol, pseudoephedrine hydrochloride and brompheniramine maleate in plasma: Application to a pharmacokinetic study on healthy Egyptian volunteers based on ethnic difference
(Elsevier Inc., 2019) Mohamed D.; Hassan O.; Bahnasawy N.; Elnoby A.S.; Mowaka S.; Analytical Chemistry Department; Faculty of Pharmacy; Helwan University; EinHelwan; Cairo 11795; Egypt; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); October City 6; 11787; Egypt; Pharmacology Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); October City 6; 11787; Egypt; Pharmaceutics Department; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); October City 6; 11787; Egypt; Clinical Pharmacy Department; Children's Cancer Hospital Egypt (57357)Cairo 11617; Egypt; Pharmaceutical Chemistry Department; Faculty of Pharmacy; British University in Egypt; El-Sherouk City; Cairo 11837; Egypt
The current study was focused on establishing a novel ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method for the quantitative estimation of the co-formulated drugs; paracetamol (PAR), pseudoephedrine hydrochloride (PSD) and brompheniramine maleate (BRP) in human plasma to Egyptian volunteers. Additionally, the study aimed to recognize whether the co-administration of the target drugs to different ethnic population affects their pharmacokinetics. The drugs extraction involved liquid-liquid extraction technique with the aid of ethyl acetate. Reversed phase UPLC separation was accomplished on Agilent Zorbax SB C18 (50 mm � 2.1 mm, 1.8 ?m) column using acetonitrile: 0.1% formic acid (70: 30 v/v) as the mobile phase. Positive electrospray ionization and multiple reaction monitoring were employed. The short analysis time (1 min/sample) was promising as it has allowed the analysis of many human plasma samples per day. The developed method displayed linear ranges of 0.05�20.0 ?g/mL for PAR, 1.0�500.0 ng/mL for PSD and 0.1�50.0 ng/mL for BRP. A detailed validation of the developed method was performed in compliance with the FDA guidelines where all the validation parameters results were satisfactory. The UPLC-MS/MS method was utilized for studying the pharmacokinetics of the three drugs after the oral administration of their combined dosage form to Egyptian healthy volunteers. The pharmacokinetic study was accomplished after agreement of the ethics committee. The achieved pharmacokinetic results by the newly developed method were; Cmax (ng/mL) 8001.77, 127.76, 1.92, tmax (h) 0.75, 1.5, 4.0 and t� (h) 3.3, 4.65, 16.26 for PAR, PSD and BRP, respectively, these results were compared with those obtained from other reported clinical trials done on other races. It was clear that the pharmacokinetic parameters of PAR and PSD were not affected when the same dose was given to volunteers from different ethnic populations. Additionally, the co-administration of PSD and BRP with PAR has not altered the pharmacokinetics of PAR. The pharmacokinetics of PSD when it was co-administered with PAR and BRP was almost similar to that when it was co-administered with benorylate and chlorpheniramine, however, the Cmax of PSD was greatly affected when it was co-administered with caffeine, chlorpheniramine and cloperastine. � 2019 Elsevier B.V.