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ABSTRACT: A new highly sensitive and specific spectrofluorimetric method has been developed to determine a sympathomimetic drug pseudoephedrine hydrochloride. The present method was based on derivatization with 4-chloro-7-nitrobenzofurazan in phosphate buffer at pH 7.8 to produce a highly fluorescent product which was measured at 532 nm (excitation at 475 nm). Under the optimized conditions a linear relationship and good correlation was found between the fluorescence intensity and pseudoephedrine hydrochloride concentration in the range of 0.5-5 µg mL(-1). The proposed method was successfully applied to the assay of pseudoephedrine hydrochloride in commercial pharmaceutical formulations with good accuracy and precision and without interferences from common additives. Statistical comparison of the results with a well-established method showed excellent agreement and proved that there was no significant difference in the accuracy and precision. The stoichiometry of the reaction was determined and the reaction pathway was postulated.
Luminescence 11/2011; 26(6):510-7. · 1.73 Impact Factor
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ABSTRACT: Two new simple, sensitive, accurate, and precise spectrophotometric methods have been developed and validated for the determination of cefdinir (CFD) in bulk drug and in its pharmaceutical formulations. The first method was based on the reaction of CFD with 1, 2- napthaquinone-4- sulfonic acid sodium (NQS) in an alkaline medium (pH 11) to form an orange-coloured product that was measured at 490 nm. The second method depends on hydrolysis of CFD using 0.5 M NaOH at 100 °C and subsequent reaction of the formed sulfide ions with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) to form a yellow-coloured chromogen measured at 390 nm. Different variables affecting the reactions of CFD with both NQS and NBD-Cl (e.g. NaOH concentration, hydrolysis time, NQS or NBD-Cl concentration and diluting solvent) were studied and optimized. Under optimum conditions, good linear relationships with good correlation coefficients (0.9990-0.9999) were found in the range of 10-80 and 5.0-30 µg ml(-1) for NQS and NBD-Cl, respectively. The limits of assay detection and quantitation ranged from 1.097 and 0.280 and 3.656 and 0.934 µg ml(-1) for NQS and NBD-Cl, respectively. The accuracy and precision of the proposed methods were satisfactory. The proposed method is simple, rapid, precise and convenient and was successfully applied for analysis of CFD in its pharmaceutical formulations and the recovery percentages ranged from 99.25 to 100.20%. Copyright © 2011 John Wiley & Sons, Ltd.
Drug Testing and Analysis 04/2011; · 2.54 Impact Factor
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ABSTRACT: Non-steroidal anti-inflammatory drugs (NSAIDs) are the group most often used in human and veterinary medicine, since they are available without prescription for treatment of fever and minor pain. The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control and pharmacodynamic and pharmacokinetic studies. An extensive survey of the literature published in various analytical and pharmaceutical chemistry related jour-nals has been conducted and the instrumental analytical methods which were developed and used for determination of some non-steroidal anti-inflammatory, coxibs, arylalkanoic acids, 2-arylpropi-onic acids (profens) and N-arylanthranilic acids (fenamic acids) in bulk drugs, formulations and biological fluids have been reviewed. This review covers the time period from 1985 to 2010 during which 145 spectrophotometric methods including UV and derivative; visible which is based on for-mation of metal complexation, redox reactions, ion pair formation, charge-transfer complexation and miscellaneous; flow injection spectrophotometry as well as spectrofluorometric methods were
Arabian Journal of Chemistry 01/2011; · 1.37 Impact Factor
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ABSTRACT: Three rapid, simple, reproducible and sensitive spectrophotometric methods (A, B and C) are described for the determination of two organophosphorus pesticides, (malathion and dimethoate) in formulations and vegetable samples. The methods A and B involve the addition of an excess of Ce4+ into sulphuric acid medium and the determination of the unreacted oxidant by decreasing the red color of chromotrope 2R (C2R) at a suitable lmax = 528 nm for method A, or a decrease in the orange pink color of rhodamine 6G (Rh6G) at a suitable lmax = = 525 nm. The method C is based on the oxidation of malathion or dimethoate with the slight excess of N-bromosuccinimide (NBS) and the determination of unreacted oxidant by reacting it with amaranth dye (AM) in hydrochloric acid medium at a suitable lmax = 520 nm. A regression analysis of Beer-Lambert plots showed a good correlation in the concentration range of 0.1-4.2 μg mL−1. The apparent molar absorptivity, Sandell sensitivity, the detection and quantification limits were calculated. For more accurate analysis, Ringbom optimum concentration ranges are 0.25-4.0 μg mL−1. The developed methods were successfully applied to the determination of malathion, and dimethoate in their formulations and environmental vegetable samples.
Chemical Industry and Chemical Engineering Quarterly. 01/2010;
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Ayman A Gouda
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ABSTRACT: Studies were carried out, for the first time, to investigate the charge-transfer reactions of ganciclovir as n-electron donor with the sigma-acceptor iodine and various pi-acceptors: 7,7,8,8-tetracyanoquinodimethane; tetracyanoethylene; 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; p-chloranilic acid; 2,3,5,6-tetrabromo-1,4-benzoquinone; 2,3,5,6-tetrachloro-1,4-benzoquinone and 2,4,7-trinitro-9-fluorenone. The formation of the colored charge-transfer complexes was utilized in the development of simple, rapid and accurate spectrophotometric methods for the analysis of ganciclovir in pure form as well as in its pharmaceutical formulation (capsules). Different variables affecting the reactions were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9993-0.9998) were found between the absorbance and the concentration of ganciclovir in the range of 2.0-240 microg mL(-1). For more accurate analysis, Ringbom optimum concentration range was found to be between 5.0 and 225 microg mL(-1). The limits of detection ranged from 0.36 to 2.45 microg mL(-1) and the limits of quantification ranged from 1.20 to 8.17 microg mL(-1). A Job's plot of the absorbance versus the molar ratio of ganciclovir to each of acceptors under consideration indicated (1:1) ratio. The proposed methods were applied successfully for simultaneous determination of ganciclovir in capsules with good accuracy and precision and without interferences from common additives. The recovery percentages ranged from 99.45+/-0.73% to 100.35+/-1.40%. The results were compared favourably with the reported method.
Talanta 11/2009; 80(1):151-7. · 3.79 Impact Factor
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ABSTRACT: A simple, rapid, and extractive spectrophotometric method was developed for the determination of hyoscine butylbromide (HBB) and famciclovir (FCV) in pure and pharmaceutical formulations. These methods are based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug and four sulphonphthalein acid dyes, namely; bromocresol green (BCG), bromothymol blue (BTB), bromocresol purple (BCP) and bromophenol blue (BPB) in phthalate buffer of pH range (3.0-3.5). The formed complexes were extracted with chloroform and measured at 420, 412, 409 and 415nm for HBB and at 418, 412, 407 and 414nm for FCV using BCG, BTB, BCP and BPB, respectively. The analytical parameters and their effects on the reported systems are investigated. Beer's law was obeyed in the range 1.0-20microgmL(-1) with correlation coefficient (n=6)> or =0.9997. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. The composition of the ion pairs was found 1:1 by Job's method in all cases and the conditional stability constant (Kf) of the complexes have been calculated. The free energy changes (DeltaG) were determined for all complexes formed. The proposed methods have been applied successfully for the analysis of the studied drugs in pure and pharmaceutical formulations with percentage recoveries ranges from 99.84 to 100.26. The results were in good agreement with those obtained by the official methods.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 10/2008; 70(4):785-92. · 2.10 Impact Factor
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ABSTRACT: A new simple, very sensitive, selective and accurate procedure for the determination of trace amounts of iron(II) by solid-phase spectrophotometry (SPS) has been developed. The procedure is based on fixation of iron(II) as 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline on a styrene-divinylbenzene anion-exchange resin. The absorbance of resin sorbed iron(II) complex is measured directly at 743 and 830nm. Iron(III) was determined by difference measurements after reduction of iron(III) to iron(II) with hydroxylamine hydrochloride. Calibration is linear over the range 1.0-20 microgL(-1) of Fe(II) with relative standard deviation (R.S.D.) of 1.65% (n=10.0). The detection and quantification limits for 100mL sample system are 280 and 950 ngL(-1) using 0.5 g of the exchanger. The molar absorptivity and Sandell sensitivity are also calculated and found to be 2.86 x 10(6)Lmol(-1)cm(-1) and 0.0196 ngcm(-2), respectively. The proposed procedure has been successfully applied to determine iron(II) and iron(III) in tap, mineral and well water samples.
Talanta 10/2008; 76(5):1241-5. · 3.79 Impact Factor
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ABSTRACT: Etodolac (ETD) is a non-steroidal anti-inflamatory antirheumatic drug. A survey of the literature reveals that there is no method available for the determination of ETD in pure form and pharmaceutical formulations by oxidation-reduction reactions.
We describe three simple, sensitive and reproducible spectrophotometric assays (A-C) for the determination of etodolac in pure form and in pharmaceutical formulations. Methods A and B are based on the oxidation of etodolac by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of the tris-complex on reaction with Fe3+-o-phen and/or Fe3+-bipy mixtures in acetate buffer solution at optimum pH was demonstrated at 510 and 520 nm with o-phen and bipy. Method C is based on the oxidation of etodolac by Fe3+ in acidic medium, and the subsequent interaction of iron(II) with ferricyanide to form Prussian blue, with the product exhibiting an absorption maximum at 726 nm. The concentration ranges are 0.5-8, 1.0-10 and 2-18 microg mL(-1) respectively for methods A, B and C. For more accurate analysis, Ringbom optimum concentration ranges were calculated, in addition to molar absorptivity, Sandell sensitivity, detection and quantification limits.
Our methods were successfully applied to the determination of etodolac in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were <or= 0.76 %, with recoveries of 99.87 % - 100.21 %.
Chemistry Central Journal 02/2008; 2:7. · 3.28 Impact Factor
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ABSTRACT: Two rapid, simple and sensitive extractive specrophotometric methods has been developed for the determination of three histamine H1-antagonists drugs, e.g., chlorphenoxamine hydrochloride (CPX), diphenhydramine hydrochloride (DPH) and clemastine (CMT) in bulk and in their pharmaceutical formulations. The first method depend upon the reaction of molybdenum(V) thiocyanate ions (Method A) with the cited drugs to form stable ion-pair complexes which extractable with methylene chloride, the orange red color complex was determined colorimetrically at lambda(max) 470nm. The second method is based on the formation of an ion-association complex with alizarin red S as chromogenic reagents in acidic medium (Method B), which is extracted into chloroform. The complexes have a maximum absorbance at 425 and 426nm for (DPH or CMT) and CPX, respectively. Regression analysis of Beer-Lambert plots showed a good correlation in the concentration ranges of 5.0-40 and 5-70microgmL(-1) for molybdenum(V) thiocyanate (Method A) and alizarin red S (Method B), respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, detection and quantification limits were calculated. Applications of the procedure to the analysis of various pharmaceutical preparations gave reproducible and accurate results. Further, the validity of the procedure was confirmed by applying the standard addition technique and the results obtained in good agreement well with those obtained by the official method.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 02/2008; 69(1):245-55. · 2.10 Impact Factor
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ABSTRACT: Three simple, sensitive, and reproducible spectrophotometric methods (A-C) for the determination of pipazethate hydrochloride (PiCl) in pure form and in pharmaceutical formulations are described. The first and second methods, A and B, are based on the oxidation of the drug by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of tris-complex upon reactions with Fe3+-o-phen and/or Fe3+-bipy mixture in an acetate buffer solution of the optimum pH values was demonstrated at 510 and 522 nm, respectively, with o-phen and bipy. The third method, C, is based on the reduction of Fe(III) by PiCl in acid medium and subsequent interaction of Fe(II) with ferricyanide to form Prussian blue, which exhibits an absorption maximum at 750 nm. The concentration ranges are from 0.5 to 8, 2 to 16, and 3 to 15 microg/mL for Methods A-C, respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, and detection and quantitation limits were calculated. The developed methods were successfully applied to the determination of PiCl in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were < or =0.83% with recoveries of 98.9-101.15%.
Journal of AOAC International 90(3):686-92. · 1.20 Impact Factor
