Mohamed El-Sadek

Spectrophotometric determination of ciprofloxacin, enrofloxacin and pefloxacin through charge transfer complex formation

A spectrophotometric method was described for the determination of the antibacterial quinolone derivatives, ciprofloxacin, enrofloxacin and pefloxacin through charge transfer complex formation with three different acceptors. Chloranilic acid (CL) was utilized for their determination, forming charge transfer complex with lambdamax 520 nm. The proposed method was applied for determination of Ciprocin tablets, Enroxil oral solution, Peflacin ampoules and Peflacin tablets, with mean percentage accuracies, 99.58+/-1.25,99.94+/-0.96,100.91+/-1.59 and 99.86+/-1.003. Also, tetracyanoethylene (TCNE) was utilized in the determination of the concerned compounds forming charge transfer complexes with maximum absorbances at lambdamax 335 nm for ciprofloxacin and at lambdamax 290 nm for both enrofloxacin and pefloxacin. The procedure was applied for determination of Ciprocin tablets, Enroxil 10% oral solution, Peflacine tablets and Peflacine ampoules with mean percentage accuracies 99.40+/-1.27,99.95+/-0.90,98.98+/-1.565 and 99.88+/-0.998, respectively. Also, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) was utilized for determination of pefloxacin forming charge transfer complex with maximum absorbance at lambdamax 460 nm. The procedure was applied for determination of peflacine tablets and peflacine ampoules with mean percentage accuracies 100.40+/-0.76 and 99.91+/-0.623, respectively. Statistical analysis of the obtained results showed no significant difference between the proposed method and other official and reported methods as evident from the t-test and variance ratio.

Spectrophotometric determination of enrofloxacin and pefloxacin through ion-pair complex formation.

Two simple, quick and sensitive spectrophotometric methods are described for the determination of enrofloxacin and Pefloxacin. The methods are based on the reaction of these drugs with bromophenol blue (BPB) and methyl orange (MO) in buffered aqueous solution at pH 2.3-2.5 in case of bromophenol blue and at pH 3.6 with MO to give highly coloured complex species, extractable with chloroform. The coloured products are quantitated spectrophotometrically at 420 and 424 nm for BPB and MO, respectively. Optimisation of the different experimental conditions is described. Beers law is obeyed in the concentration ranges 2-12 and 2-18 microg ml(-1) with BPB and in the ranges 1-12 and 4-40 microg ml(-1)with MO for enrofloxacin and pefloxacin, respectively. The proposed methods are applied for determination of Enroxil oral solution, Peflacine tablets and Peflacine ampoules with mean percentage accuracies 99.5+/-0.99, 99.39+/-1.05 and 100.02+/-0.895, respectively, with BPB and 100.30+/-0.89, 100.25+/-0.98 and 100.20+/-0.72, respectively, with MO.

Synchronous Spectrofluorimetric Determination of Famotidine, Fluconazole and Ketoconazole in Bulk Powder and in Pharmaceutical Dosage Forms

Abstract The aim of this work was to investigate a simple and reliable method for the determination of trace amounts of famotidine, fluconazoie and ketoconazole in bulk powder and in their pharmaceutical dosage forms. Also to study the different factors affecting the sensitivity of the synchronous technique in order to improve the measurement The sample was prepared in methanol in case of famotidine and ketoconazole, and in water, after dissolution in methanol, in case of fluconazoie. The fluorescence intensity was recorded at 384 (ex. at 284 nm), 285 (ex. at 255 nm) and 364 nm(ex. at 239 nm) for famotidine, fluconazole and ketoconazole respectively. The calibration curves were linear over the concentration ranges 15 50, 0. 20–10 and 0. 02–0. 4 μg/ml for famotidine, fluconazole and ketoconazole respectively.

U.V. AND U.V. DERIVATIVE SPECTROPHOTOMETRIC DETERMINATION OF TWO-COMPONENT MIXTURES

Abstract In this paper, two-component mixtures (spironolactone with hydrochlorothiazide, captopril with hydrochlorothiazide, and spironolactone with furosemide) were assayed by U.V. (A), first derivative (dA/dlD) and second derivative (d2A/dlD2) spectrophotometric methods, applying “Zero-Crossing” technique of measurement. The methods were proved using laboratory prepared mixtures. The utility of the methods in assay of dosage forms is also presented.

Spectrophotometric method for the determination of flufenamic and mefenamic acids

A spectrophotometric method was developed for the determination of flufenamic and mefenamic acids both in the pure form and in pharmaceutical dosage forms. The method depends on their complexation with copper(II) ammine sulphate. The complex is extracted with chloroform and treated with diethyldithiocarbamate solution, whereupon another copper(II) complex (λmax. 430 nm) is formed. Beers law is followed over the concentration ranges 6–60 µg ml–1 for flufenamic acid and 6–48 µg ml–1 for mefenamic acid.

HPLC and Chemometric Methods for the Simultaneous Determination of Miconazole Nitrate and Nystatin

High-performance liquid chromatography (HPLC) and chemometric methods were applied to the simultaneous determination of the two nonsteroidal antifungal drugs, miconazole (MIC) and nystatin (NYS). The applied chemometric techniques are multivariate methods including classical least squares, principal component regression and partial least squares methods. The ultraviolet (UV) absorption spectra of the standard solutions of the training and validation sets in methanol are recorded in the range of 280-320 nm at 0.2-nm intervals. The HPLC method depends on reversed-phase separation using a C18 column. The mobile phase consists of a mixture of methanol-acetonitrile-ammonium acetate buffer (pH 6; 50 mM) (60:30:10 v/v/v). The UV detector was set at 230 nm. The developed methods were validated and successfully applied to the simultaneous determination of MIC and NYS in their tablets. The assay results obtained using the chemometric methods were statistically compared to those of the HPLC method and good agreement was observed.

Spectrophotometric determination of ketoprofen in pharmaceutical preparations by means of charge transfer complex formation

A spectrophotometric determination of ketoprofen based upon oxime formation followed by charge transfer complexation with o-chloranil has been developed. Different variables affecting the complexation process have been studied. Beers law is obeyed in the concentration range 10-80 microg/ml. The method has been successfully applied to the determination of ketoprofen in pure form and in pharmaceutical dosage forms in the presence of its impurities.

Synthesis, Characterization, and Nanoencapsulation of Tetrathiatriarylmethyl and Tetrachlorotriarylmethyl (Trityl) Radical Derivatives—A Study To Advance Their Applicability as in Vivo EPR Oxygen Sensors

Tissue oxygenation plays an important role in the pathophysiology of various diseases and is often a marker of prognosis and therapeutic response. EPR (ESR) is a suitable noninvasive oximetry technique. However, to reliably deploy soluble EPR probes as oxygen sensors in complex biological systems, there is still a need to investigate and improve their specificity, sensitivity, and stability. We reproducibly synthesized various derivatives of tetrathiatriarylmethyl and tetrachlorotriarylmethyl (trityl) radicals. Hydrophilic radicals were investigated in aqueous solution mimicking physiological conditions by, e.g., variation of viscosity and ionic strength. Their specificity was satisfactory, but the oxygen sensitivity was low. To enhance the capability of trityl radicals as oxygen sensors, encapsulation into oily core nanocapsules was performed. Thus, different lipophilic triesters were prepared and characterized in oily solution employing oils typically used in drug formulations, i.e., middle-chain triglycerides and isopropyl myristate. Our screening identified the deuterated ethyl ester of D-TAM (radical 13) to be suitable. It had an extremely narrow single EPR line under anoxic conditions and excellent oxygen sensitivity. After encapsulation, it retained its oxygen responsiveness and was protected against reduction by ascorbic acid. These biocompatible and highly sensitive nanosensors offer great potential for future EPR oximetry applications in preclinical research.

RP-HPLC/Pre-Column Derivatization for Analysis of Omeprazole, Tinidazole, Doxycycline and Clarithromycin

A validated, reliable and accurate reversed-phase high performance liquid chromatographic method using pre-column derivatization was adopted for the simultaneous determination of two ternary mixtures containing omeprazole, tinidazole and doxycycline hyclate or clarithromycin. Separation was achieved on a C18 column, through a gradient elution system using acetonitrile-methanol-water adjusted to pH = 6.60. Drugs were detected at 277 nm over concentration ranges of 1-112, 5-125, 2.5-550 and 2.5-100 µg/mL for omeprazole, tinidazole, doxycycline hyclate and clarithromycin, respectively. This is the first method that has isolated and identified clarithromycin derivative by infrared and mass spectroscopy. This method is the first study for the simultaneous determination of omeprazole, tinidazole, doxycycline hyclate and clarithromycin in combined mixtures and pharmaceutical formulations.

Synthesis and evaluation of 3-(benzylthio)-5-(1H-indol-3-yl)-1,2,4-triazol-4-amines as Bcl-2 inhibitory anticancer agents

A series of substituted 3-(benzylthio)-5-(1H-indol-3-yl)-4H-1,2,4-triazol-4-amines has been synthesised and tested in vitro as potential pro-apoptotic Bcl-2-inhibitory anticancer agents. Synthesis of the target compounds was readily accomplished in good yields through a cyclisation reaction between indole-3-carboxylic acid hydrazide and carbon disulfide under basic conditions, followed by S-benzylation. Active compounds, such as the nitrobenzyl analogue 6c, were found to exhibit sub-micromolar IC50 values in Bcl-2 expressing human cancer cell lines. Molecular modelling and ELISA studies further implicated anti-apoptotic Bcl-2 as a candidate molecular target underpinning anticancer activity.