Browsing by Author "Mohamed, Dalia"

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ANALYSIS OF PARACETAMOL, PSEUDOEPHEDRINE AND BROMPHENIRAMINE IN COMTREX® TABLETS USING CHEMOMETRIC METHODS
(2017) Hosam Youssef, Souha; Abdel MoneimHegazy, Maha; Mohamed, Dalia; Mohamed Badawey, Amr
Paracetamol (PAR), pseudoephedrine hydrochloride (PSE)and brompheniramine maleate (BRM) are co-formulated drugs that are widely used in the Egyptian market for the reliefof symptoms associated with common cold. Their severely overlapped spectra were resolved by two simple,accurate and precise chemometric techniques, principal component regression method (PCR) and partial Least Squares methods(PLS).The proposed methods were rapid, cost effective and were successfully applied for the analysis of laboratory prepared mixtures andthecombined dosage form. Good recoveries were obtained for PCR method, 100.42, 100.05 and 98.96%and for PLS method 100.04, 99.95 and 100.36%for PAR, PSE and BRM, respectively. Themethods were validated according to the ICH guidelines. Comparison of the applied methods with the reportedmethod was done and no significant difference was found regardingaccuracy and precision
Analytical methods for the determination of paracetamol, pseudoephedrine and brompheniramine in Comtrex tablets
(BMC, CAMPUS, 4 CRINAN ST, LONDON N1 9XW, ENGLAND, 2019-07) Youssef, Souha H; Mohamed, Dalia; Hegazy, Maha Abdel Monem; Badawey, Amr
Comtrex (R) tablets composed of paracetamol, pseudoephedrine and brompheniramine are widely used for relieving symptoms related to common cold. This study has overcome the challenging dosage form ratio (250:15:1) and proposed chromatographic methods for analyzing the ternary combination were utilized displaying different apparatus, solvents and sensitivity ranges. Three chromatographic methods namely thin layer chromatography (TLC), high performance liquid chromatography with ultra-violet detection (HPLC-UV) and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) were developed and validated for the simultaneous determination of the three drugs. Concerning the TLC method, aluminum TLC plates pre-coated with silica gel 60F(254) were used and methanol:water:ammonia (9:1:0.1, v/v/v) was applied as a mobile phase; scanning of the plates was carried out at 254 nm. For the HPLC-UV method C-18 column was used with an isocratic elution mobile phase composed of water:acetonitrile (75:25, v/v; pH 3.2) and the detection was at 210 nm. For the UPLC-MS/MS method; separation was performed on a UPLC-BEH C-18 column with methanol: 0.1% ammonium formate (60:40, v/v) as the mobile phase utilizing diphenhydramine as an internal standard and mass spectrometry was used for detection. The methods were simple, sensitive, accurate and precise. Statistical analysis revealed no significant difference from the reported methods in regard to accuracy and precision.
Application of NEMI, Analytical Eco-Scale and GAPI tools for greenness assessment of three developed chromatographic methods for quantification of sulfadiazine and trimethoprim in bovine meat and chicken muscles: Comparison to greenness profile of reported HPLC methods
(Elsevier Inc., 3/26/2020) Mohamed, Dalia; Fouad, Manal M
Employing green analytical chemistry approaches to newly developed methods has extremely gained the interest of the analytical community and was intensely established in the past few years. The utilized solvents as well as the amount of produced waste have the chief impact on evaluating the greenness of the method. The present work is devoted to the development and the assessment of the greenness profile of three developed chromatographic methods for the quantitative estimation of sulfadiazine (SDZ) and trimethoprim (TMP) in bovine meat and chicken muscles using three evaluation tools; the “National Environmental Method Index” (NEMI), the “Analytical Eco-Scale” and the “Green Analytical Procedure Index” (GAPI). The developed methods have employed a variety of mobile and stationary phases and offered different quantification ranges. Conventional RP-HPLC with green aqueous-organic mobile phase was applied in Method I with the composition of water: ethanol (90: 10 v/v, pH = 5.5) utilizing a Gemini C18 column (150 × 4.6 mm, 5 µm) with linear ranges of 1–60 μg/mL for SDZ and 1–50 μg/mL for TMP. Micellar liquid chromatography (MLC) as an efficient green alternate was used in Method II with mobile phase composition of 0.1 M SDS, 12% isopropanol in 0.1 N citric acid buffered at pH 5.5 while utilizing an XTerra RP18 column (150 × 3.9 mm, 5 µm) and resulting in a linear range of 0.5–100 μg/mL for both drugs. UPLC-MS/MS as a high throughput analytical technique was utilized in Method III with a mobile phase composed of ammonium acetate: acetonitrile (80: 20 v/v, pH = 5.5) and an Acquity UPLC-BEH C18 column (50 × 2.1 mm, 1.7 μm), where the linear range was 0.1–2 μg/mL for both drugs. Thus, Methods II and III have permitted the estimation of the residues of SDZ and TMP at levels equivalent to their maximum residue limits. The three assessment tools have agreed that Methods II and III are the greenest developed methods, thus, recommending the utilization of MLC and UPLC-MS/MS as green, safe practice for estimating the drugs’ residues in food of animal origin.
Chlorambucil-adducts in DNA analyzed at the oligonucleotide level using HPLC-ESI MS.
(American Chemical Society, 2009) Mohamed, Dalia; Mowaka, Shereen; Jürgen, Thomale; Michael, W Linscheid
Chlorambucil (N,N-bis(2-chloroethyl)-p-aminophenylbutyric acid) is a bifunctional alkylating drug belonging to the nitrogen mustard group and is widely used as an anticancer agent. As the antitumor activity of the nitrogen mustards is based on the formation of adducts with genomic DNA, calf thymus DNA-Chlorambucil adducts were the major target in this study. Calf thymus DNA was incubated with Chlorambucil to induce the formation of a wide variety of adducts. Subsequently, enzymatic digestion of the DNA was performed using Benzonase and Nuclease S1 aiming at the production of oligonucleotides. Separation and structure elucidation of the individual DNA-Chlorambucil adducts was achieved using HPLC interfaced to electrospray ionization ion trap mass spectrometry. Both trinucleotide and tetranucleotide Chlorambucil adducts were detected. The majority of the detected trinucleotide adducts involved monofunctional alkylation with guanine being the hotspot for alkylation. Only a few bifunctional trinucleotide adducts both intra- and interstrand cross-links were found. On the contrary, cross-linked adducts were the major detected tetranucleotides in which the intrastrand cross-links predominated over the interstrand cross-links. To a lesser extent, monofunctional guanine alkylated tetranucleotides were detected as well. With MS(n) experiments, the detailed structures of Chlorambucil adducts of the tri- and tetranucleotides were determined.
A Comparative Study of Smart Spectrophotometric Methods and a Densitometric Method for Simultaneous Determination of Binary Mixture of Canagliflozin and Metformin Hydrochloride
(TAYLOR & FRANCIS LTD, 2018) S Elshahed, Mona; Mohamed, Dalia; Nasr, Tamer; Aboutaleb, Nageh; Zakaria, Ola
Simple and sensitive Spectrophotometric methods and a densitometric thin layer chromatographic method (TLC) are developed and validated for simultaneous determination of binary mixture of metformin hydrochloride (MET) and canagliflozin (CFZ) in combined dosage form. Three spectrophotometric methods manipulating ratio spectra namely ratio subtraction, ratio difference and derivative ratio are used for the determination of MET in the presence of CFZ without preliminary separation, while CFZ is directly determined by measuring its absorbance at λmax 290 nm. The calibration curves follow Beer's law in the concentration range of 1 - 20 and 1 - 30 μg/mL for MET and CFZ respectively. A simple TLC method is developed where separation is performed on TLC silica gel plates 60F254 using toluene: Methylene chloride: methanol: water: glacial acetic acid in the volume ratio (20:15:15:1:0.25) as a mobile phase. Rf values are 0.55 ± 0.05 for CFZ and 0.21 ± 0.03 for MET, the linearity ranges are 0.3-4.5 and 0.5-5.5 μg/band for CFZ and MET respectively. The developed methods are successfully applied for the simultaneous determination of MET and CFZ in bulk and pharmaceutical formulation.
The concept of Relative Absorptivity Distribution for enhancing disbanding power of spectrophotometric technique to resolve co-formulated tablets: A tool for purity index and uniformity assessment
(Elsevier B.V., 10/05/2020) M.Lotfy, Hayam; Elshahed, Mona S; Mohamed, Dalia
Resolving the spectral bands of the drugs into their discrete constituents is critical for an effective mathematical spectrophotometric method. The spectral resolution is ordinarily affected by the required application. In the current work an innovative, simple and green Relative Absorptivity Distribution (RAD) concept was established for the successful assay and assessing of content uniformity and purity index of tablet co-formulation which is recommended for lowering the blood glucose level and is comprised of Cangliflozin (CGF) and Metformin CGF and MTF. From the spectrophotometric perspective, the investigation of this combination is challenging as the composition of the tablets is CGF:MTF (1:17), where CGF is not only the minor analyte but also the one of lower absorptivity. The RAD concept is based on the production of master Resolving Spectra (RS). Within the RAD concept and according to the manipulation used for the generation of the RS, three different univariate mathematic methods via spectrophotometer software were developed. The proposed methods are characterized by the ability of extracting the raw spectra of each investigated analyte separately, consequently, enabling each analyte to be determined at its λmax without the contribution of the other. The proposed methods had analyzed CGF in the range 1.0–30.0 μg/mL and MTF within the range 1.0–20.0 μg/mL. The guidelines of the ICH were performed for the complete validation of all methods and the results confirmed satisfactory accuracy, precision and selectivity. The accomplished results together with the simplicity and low-cost of all methods suggested their suitability for the routine quality control analysis of bulk materials, assay of the pharmaceutical formulations and evaluating the content uniformity. Statistical comparison of the results with those of reported HPLC method showed good agreement. In addition, the environmental impact of the proposed methods was assessed by utilizing the National Environmental Methods Index (NEMI), the Analytical Eco-Scale and the Green Analytical Procedure Index (GAPI) where the three tools confirmed the environmentally friendly nature of all proposed methods.
Determination of Itraconazole in Bulk and Human Plasma by High Performance Liquid Chromatographic-Electrospray Ionization-Tandem Mass Spectrometry
(TAYLOR & FRANCIS LTD, 2016) M Abou El Alamin, Maha; MM Azab, Marwa; Mohamed, Dalia
A fast, sensitive and selective high performance liquid chromatography-electron spray ionization-tandem mass spectrometry method (HPLC-ESI-MS/MS) was produced and validated for the determination of itraconazole (ITC) in bulk and human plasma on an intersil, ODS-3, C18 column using a mobile phase consisting of acetonitrile: ammonium formate (80:20, v/v)(pH 3.5) with flow rate 0.5 ml/min. Detection was carried out on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode utilizing m/z 705.3 → m/z 392.3 for ITC and m/z 559.3 → m/z 440.3 for atorvastatin as an internal standard (IS). Different parameters were discussed, e.g: type of columns, mobile phase pH, mobile phase composition, rate of fragmentation, and rate of collision. .The mass detection was performed using electrospray ionization in the positive mode (ESI +). The method was linear over the concentration range 4- 1000 ng/ml for ITC with r2 = 0.99 . The limit of detection and limit of quantification were 1.17 and 3.54 ng/ml in human plasma, respectively. Intra-and between day accuracy demonstrated % RSD < 1.50%. The outcome acquired by the proposed strategy was contrasted and that got by the reference LC-MS method. The technique demonstrated great selectivity, repeatability, linearity and affectability as indicated by the assessment of the validation parameters.
Downregulation of MMP1 expression mediates the anti-aging activity of Citrus sinensis peel extract nanoformulation in UV induced photoaging
(Elsevier, 2021-03) Amer, Reham I; Ezzat, Shahira M; Aborehab, Nora M; Ragab, Mai F; Mohamed, Dalia; Hashad, Amira; Attia, Dalia; Salama, Maha M; El Bishbishy, Mahitab H
Aging of the skin is a complicated bioprocess that is affected by constant exposure to ultraviolet irradiation. The application of herbal-based anti-aging creams is still the best choice for treatment. In the present study, Citrus sinensis L. fruit peels ethanolic extract (CSPE) was formulated into lipid nanoparticles (LNPs) anti-aging cream. Eight different formulations of CSEP-LNPs were prepared and optimized using 23 full factorial designs. In vivo antiaging effect of the best formula was tested in Swiss albino mice where photo-aging was induced by exposure to UV radiation. HPLC-QToF-MS/MS metabolic profiling of CSPE led to the identification of twenty-nine me- tabolites. CSPE was standardized to a hesperidin content of 15.53 ± 0.152 mg% using RP-HPLC. It was suggested that the optimized formulation (F7) had (245 nm) particle size, (91.065%) EE, and (91.385%) occlusive effect with a spherical and smooth surface. The visible appearance of UV-induced photoaging in mice was significantly improved after topical application on CSPE-NLC cream for 5 weeks, levels of collagen and SOD were significantly increased in CSPE- NLC group, while levels of PGE2, COX2, JNK, MDA, and elastin was reduced. Finally, The prepared anti-aging CSPE-NLC cream represents a safe, convenient, and promising skincare cosmetic product.
Fluorimetric determination of diosmin and hesperidin in combined dosage forms and in plasma through complex formation with terbium
(ELSEVIER, 2013) Mohamed, Dalia
A sensitive and simple fluorimetric method was developed for the determination of diosmin and hesperidin. The proposed method involves the formation of ternary complex with Tb3+ in the presence of Tris buffer. The fluorescence quenching of Tb3+ at 549 and 494 nm (λex at 275 and 248 nm) due to the complex formation was quantitatively measured for diosmin and hesperidin, respectively. The reaction conditions and the fluorescence spectral properties of the complexes have been investigated. Under the described conditions, the proposed method was applicable over the concentration range (4.93 × 10−6–1.81 × 10−5 mol) and (3.28 × 10−6–1.64 × 10−5 mol) with mean percentage recoveries 100.22 ± 0.89 and 99.13 ± 0.72 for diosmin and hesperidin, respectively. The proposed method was applied successfully for the determination of studied drugs in bulk powder, dosage forms and plasma samples. The results obtained by applying the described method were statistically analyzed and compared with those obtained by applying a reported method. The method was validated according to ICH recommendations
Greenness evaluation of different chromatographic approaches for the determination of dextromethorphan, phenylephrine & brompheniramine in their pharmaceutical formulation
(Elsevier Inc., 2020-09) Mohamed, Dalia; Hegazy, Maha A; El-Sayed, Ghada M; Youssef, Souha H.
View references (19) The effect of analytical procedures on the environment is a major concern nowadays. Scientists are trying to contribute to eco-friendly practices to reduce the negative impact of chemicals and solvents on the environment and analysts working on the field. This work demonstrates three chromatographic methods for the determination of a cold medication composed of dextromethorphan (DEX), phenylephrine (PHN) and brompheniramine (BRM) in their dosage form. Thin layer chromatography (TLC) was attempted using methanol: methylene chloride: water: acetic acid (7:1:1.5:0.5, v/v/v/v) as a mobile phase and detection carried out at 254 nm. The drugs were separated with good resolution at retention factors 0.54, 0.66 and 0.78 for BRM, DEX and PHN, respectively. Two high performance liquid chromatographic (HPLC) methods were also applied; method A utilized a mobile phase made up of acetonitrile, phosphate buffer and methanol (gradient elution) and green solvents were applied in method B namely; ethanol: water (15:85, v/v). Peaks were detected at 270 nm and the retention times for method A were 2.02, 7.59 and 8.43 min and for method B were 2.04, 4.25 and 4.91 min for PHN, BRM and DEX, respectively. Greenness profiles using three approaches; national environmental method index (NEMI), analytical ecoscale and green analytical procedure index (GAPI) were used to evaluate and compare the developed methods. Finally, statistical analysis was applied and no significant difference regarding accuracy and precision was noted
Guidelines for Accurate Application of Green and White Analytical Concepts: Merits Vs Demerits with Insights of Significant Milestones of Assessment Tools Applied for Antiviral Drugs
(Elsevier Inc, 2024-01) Saleh, Sarah S; Obaydo, Reem H; El Hamd, Mohamed A; Rostom, Yasmin; Mohamed, Dalia; Lotfy, Hayam M
In recent years, there has been a growing focus in analytical research on the ecological and sustainable aspects of analytical methodologies. However, it is necessary to apply the relevant metrics to evaluate the effectiveness of certain analytical methods. The present study aims to conduct a thorough analysis of the major turning points, merits, and demerits of some reported methods carried out to determine anti-viral drugs. Since the COVID-19 pandemic in 2020, researchers have become interested in antiviral drugs because it was the class of interest for facing the challenges of this pandemic. That’s why, a comprehensive application of several relevant green metrics has been reviewed. Additionally, the study intends to choose tools that have been reported as being green to use, explain the data that has been gathered, compare the data to one another, and highlight the benefits of particular features in each tool based on the timeline progress of using these tools. In addition, suggestions were made for adapting each tool to the recommended guidelines. Case studies were presented to highlight the proper application of each assessment tool.
Guidelines for accurate application of green and white analytical concepts: Merits Versus demerits with insights of significant milestones of assessment tools applied for antiviral drugs
(Elsevier Inc, 2024-01) Saleh, Sarah S; Obaydo, Reem H; El Hamd, Mohamed A; Rostom, Yasmin; Mohamed, Dalia; Lotfy, Hayam M
In recent years, there has been a growing focus in analytical research on the ecological and sustainable aspects of analytical methodologies. However, it is necessary to apply the relevant metrics to evaluate the effectiveness of certain analytical methods. The present study aims to conduct a thorough analysis of the major turning points, merits, and demerits of some reported methods carried out to determine anti-viral drugs. Since the COVID-19 pandemic in 2020, researchers have become interested in antiviral drugs because it was the class of interest for facing the challenges of this pandemic. That’s why, a comprehensive application of several relevant green metrics has been reviewed. Additionally, the study intends to choose tools that have been reported as being green to use, explain the data that has been gathered, compare the data to one another, and highlight the benefits of particular features in each tool based on the timeline progress of using these tools. In addition, suggestions were made for adapting each tool to the recommended guidelines. Case studies were presented to highlight the proper application of each assessment tool.
The Impact of Audit Committee Characteristics on Audit Quality Using Audit Fees as a Mediating Variable
(October University For Modern Sciences and Arts, 2022) Amr Al-antably, Yasmin; Mohamed, Dalia; Adel, Manar; Tageldien, Mohamed
This research aims to examine and investigate the independent variable, which is the audit committee characteristics on the dependent variable, which is audit quality taking Audit fees as a mediating, and a control variable is firm performance. This research applied investigation on a time period from 2018 to 2020 which is three years. Using 50 listed companies in EGX as a sample with 150 observations. This research use regression and correlation model to measure the variables. Adding, the empirical studies show that audit committee characteristics has no relation with audit quality. In addition, the relation between audit committee characteristics and audit fees is not significant. Although, by taking audit fees as a mediating variable .it was found that it has a positive significant impact on Audit quality
Kinetic spectrophotometric determination of flavonoids using alka-line potassium permanganate
(Analytical Chemistry An Indian Journal, 2013) Mowaka, Shereen; Mohamed, Dalia
Two simple and sensitive kinetic methods were developed for the determination of diosmin and hesperidin in bulk and pharmaceutical preparations. The proposed methods are based on kinetic investigation of the oxidation reaction of the drugs with alkaline potassium permanganate at room temperature for a fixed time of 20 min and 15 min for the first and second methods, respectively. In the first method the absorbance of the green colored manganate ion produced by diosmin and hesperidin was measured at 610 nm. Alternatively in the second method, the decrease in the absorbance of permanganate ion after addition of diosmin was measured at 525 nm. Calibration graphs were linear over the concentration range 5.0- 25.0 and 1.0-20.0 ìg/mL for diosmin using the two methods, respectively and 1.10-2.77 ìg/mL for hesperidin, using the first method. The results obtained were compared statistically with those obtained by a reported method and showed no significant differences regarding accuracy and precision. In addition, the activation parameters such as Ea, ï H, ï S and ï G were also evaluated for the reaction and found to be 15.85 KJ mol-1, 40.79 KJmol-1, 25.59 JK-1mol-1 and -7.63 KJmol-1, respectively.
A new potentiometric sensor based on molecularly imprinted polymer for analysis of a veterinary drug imidocarb dipropionate
(2014) Rizk, Mohamed; Shafik Toubar, Safaa; Ezz El-Din Sayour, Hossam; Mohamed, Dalia; Moussa Tony, Rehab
A new potentiometric sensor based on molecularly imprinted polymer (MIP) was fabricatedfor the recognition and determination of imidocarb dipropionate. The MIP was synthesizedusing imidocarb as the template material, methacrylic acid as a functional monomer, andethylene glycol dimethacrylate as a cross linking agent. The sensor showed a high selectivityand a sensitive response to the template molecule in aqueous solution. The MIP‐electrodeexhibited a near‐Nernstian response in a wide concentration range 10‐5 ‐ 10‐2 M with a lowerdetection limit of 2×10‐6 M. The potentiometric conditions were carefully studied and allmeasuring parameters were optimized including pH, buffer type, plasticizer type, responsetime and stability. The applicability of the sensor was tested through potentiometricdetermination of imidocarb dipropionate in pure drug as well as in pharmaceuticalformulation. The proposed method was statistically compared with a reported one showingno significant difference regarding accuracy and precision, which assured a good reliablenovel sensor for imidocarb estimation.
Novel LC-MS/MS method for analysis of metformin and canagliflozin in human plasma: application to a pharmacokinetic study
(BMC, 2019-07) Mohamed, Dalia; Elshahed, Mona S; Nasr, Tamer; Zakaria, Ola
Highly sensitive and selective liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous estimation of the recently approved oral hypoglycemic mixture; metformin (MET) and canagliflozin (CFZ) in human plasma using propranolol HCl (PPL) and tadalafil (TDF) as internal standards (IS), respectively. Analytes were extracted using protein precipitation induced by acetonitrile then liquid-liquid extraction was performed using ethyl acetate. Reversed phase HPLC was carried out using C18 analytical column (50 mm x 4.6 mm i.d., 5 mu m) with a simple isocratic mobile phase composed of 0.1% formic acid and acetonitrile (60:40, v/v). Detection was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM), with the transitions of m/z 130.2 -> 60.1, m/z 462.3 -> 191.0, m/z 260.2 -> 183.0 and m/z 390.2 -> 268.2 for MET, CFZ, PPL and TDF, respectively, in the positive ion mode. The analysis was carried out within 5 min over a linear concentration range of 50-5000 ng/mL for MET and 10-1000 ng/mL for CFZ. The method was validated in accordance with the FDA guidelines for bioanalytical method. All obtained recoveries were higher than 90.0% while the accuracy was in the range of 88.14-113.05% and the relative standard deviation was below 10.0% for all investigated drugs by the proposed method. The achieved promising results has allowed for the successful application of the developed LC-MS/MS method to a pharmacokinetic study of the target drugs after their oral administration to Egyptian healthy volunteers. The pharmacokinetic study was accomplished after the agreement of the ethics committee.
Separation and identification of trinucleotide–melphalan adducts from enzymatically digested DNA using HPLC–ESI–MS
(Springer-Verlag, 2008) Mohamed, Dalia; Linscheid, Michael
Melphalan is a bifunctional alkylating agent that covalently binds to the nucleophilic sites present in DNA. In this study we investigated oligonucleotides prepared enzymatically from DNA modified with melphalan. Calf thymus DNA was incubated in-vitro with melphalan and the resulting modifications were enzymatically cleaved by means of benzonase and nuclease S1. Efficient sample preconcentration was achieved by solid-phase extraction, in which phenyl phase cartridges resulted in better recovery of the modified species than C18. The applied enzymatic digestion time resulted in production of trinucleotide adducts which were efficiently separated and detected by use of reversed-phase HPLC coupled to an ion-trap mass spectrometer with electrospray ionization. It was assumed that melphalan could act as both a monofunctional and bifunctional alkylating agent. Mono-alkylated adducts were much more abundant, however, and the alkylation site was located on the nucleobases. On the other hand, we unequivocally identified cross-link formation in DNA, even though at low abundance and only a few adduct types were detected.
Simultaneous determination of Dantrolene and Paracetamol in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry
(Elsevier, 07/06/2021) Rizk, Mohammed Salem; Sultan, Maha; Mohamed, Dalia; Tony, Rehab Moussa
A simple, sensitive, rapid and specific method based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) for the simultaneous quantification of dantrolene (DAN) and paracetamol (PAR) in real human plasma was developed and validated. The preparation of sample was achieved by liquid–liquid extraction with tertiary butyl methyl ether. The analysis was performed on a reversed-phase C18column (1.7 µm, 2.1 × 30 mm) using acetonitrile: 0.1% formic acid (80:20, v/v) as the mobile phase and pumped in an isocratic mode at a flow rate of 0.3 mL/min using citalopram (CIT) as an internal standard. Tandem mass spectrometric detection was carried out by both positive and negative electrospray ionization (ESI) in the multiple-reaction monitoring mode (MRM). The analysis was carried out within 1 min for each sample which made it possible to analyze more than 350 human samples per day. Validation of the method was performed according to FDA guidelines for bio-analytical method. The method was found to be linear in the range of 25 – 2500 ng/mL and 100 – 10000 ng/mL for DAN and PAR, respectively. The method was applied successfully for the determination of the two analytes in the plasma after oral administration of Dantrelax® compound capsules to healthy volunteers. The study was accomplished after approval of the ethics committee
Simultaneous Determination of Levonorgestrel and Ethinyl Estradiol in Combined Dosage form Utilizing Spectrophotometric Methods and High Performance Thin Layer Chromatographic Method on Nanosilica Gel Plates
(eurjchem, 2017) Moussa Tony, Rehab; Mohamed, Dalia; Sultan, Maha; Salem Rizk, Mohammed
Simultaneous quantification of levonorgestrel (LEV) and ethinyl estradiol (EE) was performed utilizing five different spectrophotometric methods and a high performance thin layer chromatographic method (HPTLC). The applied spectrophotometric methods were based on either ratio spectra namely; ratio difference, ratio subtraction and derivative ratio or the presence of isosbestic point specifically; absorbance subtraction and amplitude modulation. The proposed methods had the ability to resolve the overlapped spectra of the drugs with a linear relationship in the concentration range 1-65 µg/mL and 1-95 µg/mL for LEV and EE, respectively. The developed HPTLC method has revealed a good separation of the drugs upon utilizing Nano Silica Gel on TLC plates with fluorescent indicator 254 nm glass plates as the stationary phase and chloroform: methanol (99:1, v:v) as the mobile phase. The proposed HPTLC method has shown high sensitivity, where the linearity range was 0.02-3.00 µg/band and 0.5-20.0 µg/band, for LEV and EE, respectively. The proposed methods were successfully applied for the analysis of laboratory prepared mixtures as well as combined dosage form. Validation for all methods was conducted in compliance with the ICH guidelines proving the methods to be selective, linear, precise and accurate. The proposed methods were statistically compared with the pharmacopoeial method, where the obtained results showed no significant difference regarding accuracy and precision.
Simultaneous determination of pamabrom and paracetamol in bulk powders and womankit tablets using spectrophotometric and chemometric-assisted spectrophotometric methods
(2013) Salem, Hesham; Mohamed, Dalia
Fivemethodswere developed for simultaneous determination of pamabrom and paracetamol without previous separation. In the first and second methods pamabrom and paracetamol were determined using second and third derivative UV spectrophotometry with zero crossing measurement at 301 and 265 nm for second derivative method and at 290 and 257 nm for third derivative method, for pamabromand paracetamol, respectively. The third method depends on first derivative of the ratios spectra by measurements of the amplitudes at 271 nmfor pamabromand at 258 nm for paracetamol. The fourth one depends on two wavelength measurement for the total content of the two drugs at 222 and 265 nm, while the content of paracetamol was determined by measuring the absolute value of the first derivative curve at 243 nm. The fifth method describes the use of multivariate spectrophotometric calibration for the simultaneous determination of the analyzed binarymixture where the resolution is accomplished by using classical least squares regression analysis. All the proposed methods were extensively validated and the results obtained were statistically analyzed and compared with those obtained by official methods. The results obtained were statistically analyzed and proved to be precise and accurate.