Displaying publications 41 - 60 of 78 in total

Abstract:
Sort:
  1. Fulltext Development and Validation of a Stability-Indicating Capillary Electrophoresis Method for the Determination of Zolpidem Tartrate in Tablet Dosage Form with Positive Confirmation using 2D- and 3D-DAD Fingerprints
    Al Azzam KM, Yit LK, Saad B, Shaibah H
    Sci Pharm, 2014;82(2):341-56.
    PMID: 24959406 DOI: 10.3797/scipharm.1401-11
    The aim of the current study was to develop a simple, precise, and accurate capillary zone electrophoresis method for the determination of zolpidem tartrate in tablet dosage form. Separation was conducted in normal polarity mode at 25°C, 22 kV, using hydrodynamic injection for 10 s. Separation was achieved using a background electrolyte of 20 mM disodium hydrogen phosphate adjusted with phosphoric acid (85%), pH at 5.50, and detection at 254 nm. Using the above optimized conditions, complete determination took place in less than 3 min using amiloride HCl as the internal standard. The method was linear over the range of 3-1000 μg mL(-1) with a correlation coefficient of 0.9999. Forced degradation studies were conducted by introducing a sample of zolpidem tartrate standard and pharmaceutical sample solutions to different forced degradation conditions, being neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H2O2), temperature (60°C in oven for 3 days), and photolytic (exposure to UV light at 254 nm for 2 h). Degradation products resulting from the stress studies did not interfere with the detection of zolpidem tartrate and the assay can be considered stability-indicating.
  2. Antimicrobial and self-crosslinking potential of experimentally developed dioctadecyldimethyl ammonium bromide and riboflavin dentin adhesive
    Daood U, Malik AA, Ilyas MS, Ahmed A, Qasim SSB, Banavar SR, et al.
    J Biomed Mater Res A, 2021 Nov;109(11):2392-2406.
    PMID: 34018311 DOI: 10.1002/jbm.a.37221
    The aim of the study is to investigate a new formulation, based on dioctadecyldimethyl ammonium-bromide (QA) and riboflavin (RF), combining antimicrobial activities and protease inhibitory properties with collagen crosslinking without interference to bonding capabilities in a rabbit model. Quaternary ammonium riboflavin (QARF) experimental adhesives modified with dioctadecyldimethyl ammonium-bromide and riboflavin were bonded (0.5/1.0/2.0%) to rabbit dentin to investigate for pulpal-histology, interfacial-morphology, transmission electron microscopy, mechanical properties, collagen crosslinking, micro-Raman analysis, antimicrobial, and anti-protease activities. Collagen type-I molecules were generated using molecular-docking. Odontoblasts appeared with normal histology, were seen in controls with no inflammatory cells detected in 0.5% specimens at day 7 and mild inflammatory response at day 30. In QARF 2.0%, inflammatory cells were not detected at day 7 and 30 (p 
  3. Fulltext In vitro evaluation of the color stability and surface roughness of a new composite flow
    Khazaal G, Daou M, Mahdi SS, Ahmed Z, Maalouf E, Batteni G, et al.
    J Clin Exp Dent, 2023 Jan;15(1):e43-e50.
    PMID: 36755675 DOI: 10.4317/jced.60005
    BACKGROUND: The aim of this study was to evaluate the color stability and the surface roughness of a bulk-fill composite flow (SDR® Plus) by comparison to an ORMOCER-based composite (Ceram.x® Universal SphereTEC™) in order to confirm the validity of using SDR® Plus in the anterior region and to allow the prediction of its long-term results.

    MATERIAL AND METHODS: 35 composite specimens of the same shade (A2), thickness (2mm) and shape of both types of composite were prepared. The specimens were cured and polished according to the manufacturer's instructions. The initial shade of the specimens was measured using a calibrated EasyShade spectrophotometer. The initial surface roughness of the specimens was measured by AFM. Afterwards, the specimens were subjected to an accelerated aging procedure through thermo-cycling, a coffee stain challenge and brushing to simulate two years in the oral environment. The shade and surface roughness of the specimens were measured again after the accelerated aging procedure.

    RESULTS: The mean ΔE was significantly larger than 3.368 in Ceram.x® group (-p-value<0.001) and SDR® Plus group (-p-value<0.001). The mean surface roughness has significantly increased for both groups after aging with no significant difference between the two groups. It however remained clinically acceptable.

    CONCLUSIONS: SDR® Plus and Ceram.x® showed similar surface roughness when subjected to the same testing conditions. Concerning the color stability, both composites displayed noticeable discoloration, with higher ΔE values registered for Ceram.x®. Key words:Composite resins, spectrophotometry, atomic force microscopy, dental material, resin-based material.

  4. Sequential hollow-fiber liquid phase microextraction for the determination of rosiglitazone and metformin hydrochloride (anti-diabetic drugs) in biological fluids
    Ben-Hander GM, Makahleh A, Saad B, Saleh MI, Cheng KW
    Talanta, 2015 Jan;131:590-6.
    PMID: 25281145 DOI: 10.1016/j.talanta.2014.08.037
    A new analytical method for the simultaneous determination of the antidiabetic drugs rosiglitazone (ROS) and metformin hydrochloride (MH) with marked differences in their affinity towards organic solvents (log P of 2.4 and -1.43, respectively) was developed. Prior to the HPLC separation, the drugs were subjected to a sequential hollow fiber liquid phase microextraction (HF-LPME) procedure. Two sequential HF-LPME approaches were considered, the preferred one involves the use of two vials containing solution mixtures for the extraction of ROS (vial 1) and MH (vial 2), respectively, but using the same fiber and acceptor phase. Important parameters that affect the extraction efficiency such as extracting solvent, donor phase conditions, HCl concentration, agitation, extraction time, addition of salt, etc. were studied. Under the optimum conditions, good enrichment factors (EF, 471 and 86.6 for ROS and MH, respectively) were achieved. Calibration curves were linear over the range 1-500 (r(2)=0.998) and 5-2500 ng mL(-1) (r(2)=0.999) for ROS and MH, respectively. The relative standard deviation values (RSD%) for six replicates were below 8.4%. Detection and quantitation limits based on S/N ratio of 3 and 10 were 0.12, 1.0 and 0.36, 3.0 ng mL(-1) for ROS and MH, respectively. The proposed method is simple, sensitive and opens up new opportunities for the microextraction of analytes with contrasting properties.
  5. UPLC method for the determination of vitamin E homologues and derivatives in vegetable oils, margarines and supplement capsules using pentafluorophenyl column
    Wong YF, Makahleh A, Saad B, Ibrahim MN, Rahim AA, Brosse N
    Talanta, 2014 Dec;130:299-306.
    PMID: 25159413 DOI: 10.1016/j.talanta.2014.07.021
    A sensitive and rapid reversed-phase ultra performance liquid chromatographic (UPLC) method for the simultaneous determination of tocopherols (α-, β-, γ-, δ-), tocotrienols (α-, β-, γ-, δ-), α-tocopherol acetate and α-tocopherol nicotinate is described. The separation was achieved using a Kinetex pentafluorophenyl (PFP) column (150 × 2.1mm, 2.6 µm) with both photodiode array (PDA) and fluorescence (FL) detectors that were connected in series. Column was thermostated at 42°C. Under a gradient system consisting of methanol and water at a constant flow rate of 0.38 mL min(-1), all the ten analytes were well separated in less than 9.5 min. The method was validated in terms of linearity, limits of detection and quantitation, precision and recoveries. Calibration curves of the ten compounds were well correlated (r(2)>0.999) within the range of 100 to 25,000 μg L(-1) for α-tocopherol acetate and α-tocopherol nicotinate, 10 to 25,000 μg L(-1) for α-tocotrienol and 5 to 25,000 μg L(-1) for the other components. The method is simple and sensitive with detection limits (S/N, 3) of 1.0 to 3.0 μg L(-1) (FL detection) and 30 to 74 μg L(-1) (PDA detection). Relative standard deviations for intra- and inter-day retention times (<1%) and peak areas (≤ 4%) were obtained. The method was successfully applied to the determination of vitamin E in vegetable oils (extra virgin olive, virgin olive, pomace olive, blended virgin and refined olive, sunflower, soybean, palm olein, carotino, crude palm, walnut, rice bran and grape seed), margarines and supplements.
  6. Micro-solid phase extraction with liquid chromatography-tandem mass spectrometry for the determination of aflatoxins in coffee and malt beverage
    Khayoon WS, Saad B, Salleh B, Manaf NH, Latiff AA
    Food Chem, 2014 Mar 15;147:287-94.
    PMID: 24206720 DOI: 10.1016/j.foodchem.2013.09.049
    A single step extraction-cleanup procedure using porous membrane-protected micro-solid phase extraction (μ-SPE) in conjunction with liquid chromatography-tandem mass spectrometry for the extraction and determination of aflatoxins (AFs) B1, B2, G1 and G2 from food was successfully developed. After the extraction, AFs were desorbed from the μ-SPE device by ultrasonication using acetonitrile. The optimum extraction conditions were: sorbent material, C8; sorbent mass, 20mg; extraction time, 90 min; stirring speed, 1,000 rpm; sample volume, 10 mL; desorption solvent, acetonitrile; solvent volume, 350 μL and ultrasonication period, 25 min without salt addition. Under the optimum conditions, enrichment factor of 11, 9, 9 and 10 for AFG2, AFG1, AFB2 and AFB1, respectively were achieved. Good linearity and correlation coefficient was obtained over the concentration range of 0.4-50 ng g(-1) (r(2) 0.9988-0.9999). Good recoveries for AFs ranging from 86.0-109% were obtained. The method was applied to 40 samples involving malt beverage (19) and canned coffee (21). No AFs were detected in the selected samples.
  7. Micellar electrokinetic chromatography method for the simultaneous determination of furanic compounds in honey and vegetable oils
    Foo Wong Y, Makahleh A, Al Azzam KM, Yahaya N, Saad B, Sulaiman SA
    Talanta, 2012 Aug 15;97:23-31.
    PMID: 22841043 DOI: 10.1016/j.talanta.2012.03.056
    A simple micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of 2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF), 5-hydroxymethylfurfural (5-HMF), 2-furoic acid (2-FA) and 3-furoic acid (3-FA) in honey and vegetable oils is described. Parameters affecting the separation such as pH, buffer and surfactant concentrations, applied voltage, capillary temperature, injection time and capillary length were studied and optimized. The separation was carried out in normal polarity mode at 20 °C, 22 kV and using hydrodynamic injection (17 s). The separation was achieved in a bare fused-silica capillary (46 cm × 50 μm i.d.) with a background electrolyte of 75 mM phosphoric acid (pH 7.3), containing 200 mM of sodium dodecyl sulphate (SDS). The detection wavelengths were at 200 nm (2-FA and 3-FA) and 280 nm (2-F, 3-F, 5-MF, 5-HMF). The furfurals were well separated in less than 20 min. The method was validated in terms of linearity, limit of detection and quantitation, precision and recoveries. Calibration curves of the six furfurals were well correlated (r(2)>0.991) within the range 1-25 μg mL(-1). Relative standard deviations of intra- and inter-day migration times and corrected peak areas ≤9.96% were achieved. The limit of detection (signal:noise, 3) was 0.33-0.70 μg mL(-1) whereas the limit of quantitation (signal:noise, 10) was 1.00-2.12 μg mL(-1). The method was applied to the determination of furanic compounds in honeys and vegetable oils (palm, walnut, grape seed and rapeseed). The effects of thermal treatment and gamma irradiation on the formation of the furanic compounds in honey were also investigated.
  8. A synthetic hydrazone derivative acts as an apoptotic inducer with chemopreventive activity on a tongue cancer cell line
    Zulkepli NA, Rou KV, Sulaiman WN, Salhin A, Saad B, Seeni A
    Asian Pac J Cancer Prev, 2011;12(1):259-63.
    PMID: 21517268
    One of the main aims of cancer chemopreventive studies is to identify ideal apoptotic inducers, especially examples which can induce early apoptotic activity. The present investigation focused on chemopreventive effects of a hydrazone derivative using an in vitro model with tongue cancer cells. Alteration in cell morphology was ascertained, along with stage in the cell cycle and proliferation, while living-dead status of the cells was confirmed under a confocal microscope. In addition, cytotoxicity test was performed using normal mouse skin fibroblast cells. The results showed that the compound inhibited the growth of tongue cancer cells with an inhibitory concentration (IC₅₀) of 0.01 mg/ml in a dose and time-dependent manner, with a two-fold increase in early apoptotic activity and G0G1 phase cell cycle arrest compared to untreated cells. Exposure to the compound also resulted in alterations of cell morphology including vacuolization and cellular shrinkage. Confocal microscope analysis using calcein and ethidium staining confirmed that the compound caused cell death, whereas no cytotoxic effects on normal mouse skin fibroblast cells were observed. In conclusion, the findings in this study suggested that the hydrazone derivative acts as an apoptotic inducer with anti-proliferative chemopreventive activity in tongue cancer cells.
  9. Stability-indicating micellar electrokinetic chromatography method for the analysis of sumatriptan succinate in pharmaceutical formulations
    Al Azzam KM, Saad B, Tat CY, Mat I, Aboul-Enein HY
    J Pharm Biomed Anal, 2011 Dec 15;56(5):937-43.
    PMID: 21873014 DOI: 10.1016/j.jpba.2011.08.007
    A micellar electrokinetic chromatography method for the determination of sumatriptan succinate in pharmaceutical formulations was developed. The effects of several factors such as pH, surfactant and buffer concentration, applied voltage, capillary temperature, and injection time were investigated. Separation took about 5 min using phenobarbital as internal standard. The separation was carried out in reversed polarity mode at 20 °C, 26 kV and using hydrodynamic injection for 10s. Separation was achieved using a bare fused-silica capillary 50 μm×40 cm and background electrolyte of 25 mM sodium dihydrogen phosphate-adjusted with concentrated phosphoric acid to pH 2.2, containing 125 mM sodium dodecyl sulfate and detection was at 226 nm. The method was validated with respect to linearity, limits of detection and quantification, accuracy, precision and selectivity. The calibration curve was linear over the range of 100-2000 μg mL(-1). The relative standard deviations of intra-day and inter-day precision for migration time, peak area, corrected peak area, ratio of corrected peak area and ratio of peak area were less than 0.68, 3.48, 3.28, 2.97 and 2.83% and 2.01, 5.50, 4.46, 4.92 and 4.07%, respectively. The proposed method was successfully applied to the determinations of the analyte in tablet. Forced degradation studies were conducted by introducing a sample of sumatriptan succinate standard solution to different forced degradation conditions using neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H(2)O(2)) and photolytic (exposure to UV light at 254 nm for 2 h). It is concluded that the stability-indicating method for sumatriptan succinate can be used for the analysis of the drug in various samples.
  10. A reversed phase high performance liquid chromatography method for the determination of fumonisins B1 and B2 in food and feed using monolithic column and positive confirmation by liquid chromatography/tandem mass spectrometry
    Khayoon WS, Saad B, Salleh B, Ismail NA, Abdul Manaf NH, Abdul Latiff A
    Anal Chim Acta, 2010 Oct 29;679(1-2):91-7.
    PMID: 20951862 DOI: 10.1016/j.aca.2010.09.008
    The development of a reversed phase high performance liquid chromatography fluorescence method for the determination of the mycotoxins fumonisin B(1) and fumonisin B(2) by using silica-based monolithic column is described. The samples were first extracted using acetonitrile:water (50:50, v/v) and purified by using a C(18) solid phase extraction-based clean-up column. Then, pre-column derivatization for the analyte using ortho-phthaldialdehyde in the presence of 2-mercaptoethanol was carried out. The developed method involved optimization of mobile phase composition using methanol and phosphate buffer, injection volume, temperature and flow rate. The liquid chromatographic separation was performed using a reversed phase Chromolith(®) RP-18e column (100 mm × 4.6 mm) at 30 °C and eluted with a mobile phase of a mixture of methanol and phosphate buffer pH 3.35 (78:22, v/v) at a flow rate of 1.0 mL min(-1). The fumonisins separation was achieved in about 4 min, compared to approximately 20 min by using a C(18) particle-packed column. The fluorescence excitation and emission were at 335 nm and 440 nm, respectively. The limits of detections were 0.01-0.04 μg g(-1) fumonisin B(1) and fumonisin B(2), respectively. Good recoveries were found for spiked samples (0.1, 0.5, 1.5 μg g(-1) fumonisins B(1) and B(2)), ranging from 84.0 to 106.0% for fumonisin B(1) and from 81.0 to 103.0% for fumonisin B(2). Fifty-three samples were analyzed including 39 food and feeds and 14 inoculated corn and rice. Results show that 12.8% of the food and feed samples were contaminated with fumonisin B(1) (range, 0.01-0.51 μg g(-1)) and fumonisin B(2) (0.05 μg g(-1)). The total fumonisins in these samples however, do not exceed the legal limits established by the European Union of 0.8 μg g(-1). Of the 14 inoculated samples, 57.1% contained fumonisin B(1) (0.16-41.0 μg g(-1)) and fumonisin B(2) (range, 0.22-50.0 μg g(-1)). Positive confirmation of selected samples was carried out using liquid chromatography-tandem mass spectrometry, using triple quadrupole analyzer and operated in the multiple reaction monitoring mode.
  11. Determination of underivatized long chain fatty acids using RP-HPLC with capacitively coupled contactless conductivity detection
    Makahleh A, Saad B, Siang GH, Saleh MI, Osman H, Salleh B
    Talanta, 2010 Apr 15;81(1-2):20-4.
    PMID: 20188881 DOI: 10.1016/j.talanta.2009.11.030
    A reversed-phase high-performance liquid chromatographic method with capacitively coupled contactless conductivity detector (C(4)D) has been developed for the separation and the simultaneous determination of five underivatized long chain fatty acids (FAs), namely myristic, palmitic, stearic, oleic, and linoleic acids. An isocratic elution mode using methanol/1mM sodium acetate (78:22, v/v) as mobile phase with a flow rate of 0.6 mL min(-1) was used. The separation was effected by using a Hypersil ODS C(18) analytical column (250 mm x 4.6 mm x 5 microm) and was operated at 45 degrees C. Calibration curves of the five FAs were well correlated (r(2)>0.999) within the range of 5- 200 microg mL(-1) for stearic acid, and 2-200 microg mL(-1) for the other FAs. The proposed method was tested on four vegetable oils, i.e., pumpkin, soybean, rice bran and palm olein oils; good agreement was found with the standard gas chromatographic (GC) method. The proposed method offers distinct advantages over the official GC method, especially in terms of simplicity, faster separation times and sensitivity.
  12. In situ derivatization hollow fibre liquid-phase microextraction for the determination of biogenic amines in food samples
    Saaid M, Saad B, Ali AS, Saleh MI, Basheer C, Lee HK
    J Chromatogr A, 2009 Jul 3;1216(27):5165-70.
    PMID: 19481215 DOI: 10.1016/j.chroma.2009.04.091
    Hollow fibre liquid-phase microextraction with in situ derivatization using dansyl chloride has been successfully developed for the high-performance liquid chromatography-ultraviolet (HPLC-UV) determination of the biogenic amines (tryptamine, putrescine, cadaverine, histamine, tyramine, spermidine) in food samples. Parameters affecting the performance of the in situ derivatization process such as type of extraction solvent, temperature, extraction time, stirring speed and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; acceptor phase, 0.1M HCl; extraction time, 30 min; extraction temperature, 26 degrees C; without addition of salt), enrichment factors varying from 47 to 456 were achieved. Good linearity of the analytes was obtained over a concentration range of 0.1-5 microg mL(-1) (with correlation coefficients of 0.9901-0.9974). The limits of detection and quantification based on a signal-to-noise ratio of 3-10, ranged from 0.0075 to 0.030 microg mL(-1) and 0.03 to 0.10 microg mL(-1), respectively. The relative standard deviations based on the peak areas for six replicate analysis of water spiked with 0.5 microg mL(-1) of each biogenic amine were lower than 7.5%. The method was successfully applied to shrimp sauce and tomato ketchup samples, offering an interesting alternative to liquid-liquid extraction and solid phase extraction for the analysis of biogenic amines in food samples.
  13. Simultaneous determination of ofloxacin and ornidazole in pharmaceutical preparations by capillary zone electrophoresis
    See KL, Elbashir AA, Saad B, Ali AS, Aboul-Enein HY
    Biomed Chromatogr, 2009 Dec;23(12):1283-90.
    PMID: 19488980 DOI: 10.1002/bmc.1251
    A simple, rapid and validated capillary electrophoretic method has been developed for the separation and determination of ofloxacin and ornidazole in pharmaceutical formulations with detection at 230 nm. Optimal conditions for the quantitative separations were investigated. Analysis times shorter than 4 min were obtained using a background electrolyte solution consisting of 25 mmol/L phosphoric acid adjusted with 1 M Tris buffer to pH 8.5, with hydrodynamic injection of 5 s and 20 kV separation voltage. The validation criteria for accuracy, precision, linearity and limits of detection and quantitation were examined and discussed. An excellent linearity was obtained in concentration range 25-250 microg/mL. The detection limits for ofloxacin and ornidazole were 1.03 +/- 0.11 and 1.80 +/- 0.06 microg/mL, respectively. The proposed method has been applied for the analysis of ofloxacin and ornidazole both individually and in a combined dosage tablet formulation. The proposed validated method showed recoveries between 96.16 and 105.23% of the nominal contents.
  14. Extraction of biogenic amines using sorbent materials containing immobilized crown ethers
    Saaid M, Saad B, Rahman IA, Ali AS, Saleh MI
    Talanta, 2010 Jan 15;80(3):1183-90.
    PMID: 20006072 DOI: 10.1016/j.talanta.2009.09.006
    Three sorbent materials (A18C6-MS, DA18C6-MS and AB18C6-MS) based on the crown ether ligands, 1-aza-18-crown-6, 1,4,10,13-tetraoxa-7,16-diazacyclo octadecane and 4'-aminobenzo-18-crown-6, respectively, were prepared by the chemical immobilization of the ligand onto mesoporous silica support. The sorbents were characterized by FT-IR, scanning electron microscopy-energy dispersive X-ray microanalysis, elemental analysis and nitrogen adsorption-desorption test. The applicability of the sorbents for the extraction of biogenic amines by the batch sorption method was extensively studied and evaluated as a function of pH, biogenic amines concentration, contact time and reusability. Under the optimized conditions, all the sorbents exhibited highest selectivity toward spermidine (SPD) compared to other biogenic amines (tryptamine, putrescine, histamine and tyramine). Among the sorbents, AB18C6-MS offer the highest capacity and best selectivity towards SPD in the presence of other biogenic amines. The AB18C6-MS sorbent can be repeatedly used three times as there was no significant degradation in the extraction of the biogenic amines (%E>85). The optimized procedure was successfully applied for the separation of SPD in food samples prior to the reversed-phase high performance liquid chromatography separation.
  15. Assay and stability-indicating micellar electrokinetic chromatography method for the simultaneous determination of valacyclovir, acyclovir and their major impurity guanine in pharmaceutical formulations
    Al Azzam KM, Saad B, Makahleah A, Aboul-Enein HY, Elbashir AA
    Biomed Chromatogr, 2010 May;24(5):535-43.
    PMID: 19739243 DOI: 10.1002/bmc.1323
    A micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of the antiviral drugs acyclovir and valacyclovir and their major impurity, guanine, was developed. The influences of several factors (surfactant and buffer concentration, pH, applied voltage, capillary temperature and injection time) were studied. Using tyramine hydrochloride as internal standard, the analytes were all separated in about 4 min. The separation was carried out in reversed polarity mode at 28 degrees C, 25 kV and using hydrodynamic injection (15 s). The separation was effected in a fused-silica capillary 100 microm x 56 cm and a background electrolyte of 20 mM citric acid-1 M Tris solution (pH 2.75), containing 125 mM sodium dodecyl sulphate and detection at 254 nm. The method was validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. Calibration curves were linear over the range 0.1-1 microg/mL (guanine) and from 0.1 to 120 microg/mL for both valacyclovir and acyclovir. The relative standard deviations of intra- and inter-day migration times and corrected peak areas were less than 5.0%. The proposed method was successfully applied to the determination of the analytes in tablets and creams. From the previous study it is concluded that the stability-indicating method developed for acyclovir and valacyclovir can be used for analysis of the drug in various stability samples.
  16. Enantioselective analysis of primaquine and its impurity quinocide by capillary electrophoresis
    Elbashir AA, Saad B, Ali AS, Saleh MI, Aboul-Enein HY
    Biomed Chromatogr, 2009 Mar;23(3):295-301.
    PMID: 18816453 DOI: 10.1002/bmc.1113
    A capillary electrophoretic (CE) method for the baseline separation of the enantiomers of primaquine diphosphate (PQ) and quinocide (QC) (a major contaminant) in pharmaceutical formulations is proposed. Both components were separated under the following conditions: 50 mm tris phosphate buffer (pH 3.0) containing 15 mm hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as background electrolyte; applied voltage, 16 kV; capillary temperature, 25 degrees C; detection wavelength, 254 nm; hydrostatic injection, 10 s. The separations were conducted using a 35 cm length and 50 microm i.d. uncoated fused silica capillary column. Under the optimized conditions, the components were successfully separated in about 5 min. Intraday precision of migration time and corrected peak areas when expressed as relative standard deviation ranged from 0.17 to 0.45 and 2.60 to 3.94%, respectively, while the interday precision ranged from 2.59 to 4.20 and 3.15 to 4.21%, respectively. After the validation exercise, the proposed method was applied for the determination of QC impurity in PQ formulations.
  17. Determination of quinocide as impurity in primaquine tablets by capillary zone electrophoresis
    Elbashir AA, Saad B, Ali AS, Saleh MI, Aboul-Enein HY
    Biomed Chromatogr, 2009 May;23(5):464-71.
    PMID: 19016231 DOI: 10.1002/bmc.1137
    A capillary zone electrophoretic method has been developed and validated for the determination of the impurity quinocide (QC) in the antimalarial drug primaquine (PQ). Different buffer additives such as native cyclodextrins and crown ethers were evaluated. Promising results were obtained when either beta-cyclodextrin (beta-CD) or 18-crown-6 ether (18C6) were used. Their separation conditions such as type of buffer and its pH, buffer additive concentration, applied voltage capillary temperature and injection time were optimized. The use of 18C6 offers slight advantages over beta-CD such as faster elution times and improved resolution. Nevertheless, migration times of less than 5 min and resolution factors (R(s)) in the range of 2-4 were obtained when both additives were used. The method was validated with respect to selectivity, linearity, limits of detection and quantitation, analytical precision (intra- and inter-day variability) and repeatability. Concentrations of 2.12 and 2.71% (w/w) of QC were found in pharmaceutical preparations of PQ from two different manufacturers. A possible mechanism for the successful separation of the isomers is also discussed.
  18. Simultaneous determination of preservatives (benzoic acid, sorbic acid, methylparaben and propylparaben) in foodstuffs using high-performance liquid chromatography
    Saad B, Bari MF, Saleh MI, Ahmad K, Talib MK
    J Chromatogr A, 2005 May 06;1073(1-2):393-7.
    PMID: 15909546
    A reversed-phased HPLC method that allows the separation and simultaneous determination of the preservatives benzoic (BA) and sorbic acids (SA), methyl- (MP) and propylparabens (PP) is described. The separations were effected by using an initial mobile phase of methanol-acetate buffer (pH 4.4) (35:65) to elute BA, SA and MP and changing the mobile phase composition to methanol-acetate buffer (pH 4.4) (50:50) thereafter. The detector wavelength was set at 254 nm. Under these conditions, separation of the four components was achieved in less than 23 min. Analytical characteristics of the separation such as limit of detection, limit of quantification, linear range and reproducibility were evaluated. The developed method was applied to the determination of 67 foodstuffs (mainly imported), comprising soft drinks, jams, sauces, canned fruits/vegetables, dried vegetables/fruits and others. The range of preservatives found were from not detected (nd)--1260, nd--1390, nd--44.8 and nd--221 mg kg(-1) for BA, SA, MP and PP, respectively.
  19. Flow-through chloroquine sensor and its applications in pharmaceutical analysis
    Saad B, Zin ZM, Jab MS, Rahman IA, Saleh MI, Mahsufi S
    Anal Sci, 2005 May;21(5):521-4.
    PMID: 15913140
    Poly (vinyl chloride) membrane electrodes that responded selectively towards the antimalarial drug chloroquine are described. The electrodes were based on the use of the lipophilic potassium tetrakis(4-chlorophenyl)borate as ion-exchanger and bis(2-ethylhexyl)adipate (BEHA), or trioctylphosphate (TOP) or dioctylphenylphosphonate (DOPP) as plasticizing solvent mediator. All electrodes produced good quality characteristics such as Nernstian- and rapid responses, and are minimally interfered with by the alkali and alkaline earth metal ions tested. The membranes were next applied to a flow-through device, enabling it to function as flow-injection analysis (FIA) detector. The performance of the sensor after undergoing the FIA optimization was further evaluated for its selectivity characteristics and lifetime. Results for the determination of chloroquine in synthetic samples that contained common tablet excipients such as glucose, starch, and cellulose, and other foreign species such as cations, citric acid or lactic acid were generally satisfactory. The sensor was also successfully used for the determination of the active ingredients in mock tablets, synthetic fluids and biological fluids. The sensor was applied for the determination of active ingredients and the dissolution profile of commercial tablets was also established.
  20. Ion-pair vortex assisted liquid-liquid microextraction with back extraction coupled with high performance liquid chromatography-UV for the determination of metformin in plasma
    Alshishani A, Makahleh A, Yap HF, Gubartallah EA, Salhimi SM, Saad B
    Talanta, 2016 Dec 01;161:398-404.
    PMID: 27769423 DOI: 10.1016/j.talanta.2016.08.067
    A new sample preparation method, ion-pair vortex assisted liquid-liquid microextraction (VALLME-BE), for the determination of a highly polar anti-diabetic drug (metformin) in plasma sample was developed. The VALLME-BE was performed by diluting the plasma in borate buffer and extracted to 150µL 1-octanol containing 0.2M di-(2-ethylhexyl)phosphoric acid as intermediate phase. The drug was next back-extracted into 20µL of 0.075M HCl solution. The effects of pH, ion-pair concentration, type of organic solvent, volume of extraction phases, ionic strength, vortexing and centrifugation times on the extraction efficiency were investigated. The optimum conditions were at pH 9.3, 60s vortexing and 2min centrifugation. The microextract, contained metformin and buformin (internal standard), was directly injected into a HPLC unit using C1 column (250mm×4.6mm×10µm) and detected at 235nm. The method was validated and calibration curve was linear with r2>0.99 over the range of 20-2000µgL-1. The limits of detection and quantitation were 1.4 and 4.1µgL-1, respectively. The accuracy was within 94.8-108% of the nominal concentration. The relative standard deviation for inter- and intra-day precision was less than 10.8%. The method was conveniently applied for the determination of metformin in plasma samples.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator ([email protected])

External Links