Abdel Kader S. Ahmad

Spectrophotometric and Spectrofluorimetric Determination of Famotidine and Ranitidine Using 1,4-Benzoquinone Reagent

ABSTRACT Spectrophotometric and spectrofluorimetric methods were adopted for the analysis of Famotidine and Ranitidine depending on their reaction with 1,4 Benzoquinone reagent at pH 5.2 and 5.6, respectively. The absorbances of the resulting condensation products were measured at 502 and 508 nm for Famotidine and Ranitidine, respectively. Concentrations adhering to Beers law were from 40-160 μg.ml− for Famotidine and from 20-100 μg.ml− for Ranitidine. Furthermore the resulting condensation products exhibited fluorescence at 665 nm when excited at 290 nm and the calibration graphs were rectilinear from 0.4-1.4 μg.ml− for Famotidine and from 0.21 μg.ml− for Ranitidine. Different parameters affecting these reactions were thoroughly studied. Also these methods were applied to the pharmaceutical preparations and the results were satisfactory. The validities of the methods were ascertained by the standard addition technique revealing fine results in consideration to the mean recovery percent and standard devi...

First derivative ratio spectrophotometric, HPTLC-densitometric, and HPLC determination of nicergoline in presence of its hydrolysis-induced degradation product.

Three methods are presented for the determination of Nicergoline in presence of its hydrolysis-induced degradation product. The first method was based on measurement of the first derivative of ratio spectra amplitude of Nicergoline at 291 nm. The second method was based on separation of Nicergoline from its degradation product followed by densitometric measurement of the spots at 287 nm. The separation was carried out on HPTLC silica gel F(254) plates, using methanol-ethyl acetate-glacial acetic acid (5:7:3, v/v/v) as mobile phase. The third method was based on high performance liquid chromatographic (HPLC) separation and determination of Nicergoline from its degradation product on a reversed phase, nucloesil C(18) column using a mobile phase of methanol-water-glacial acetic acid (80:20:0.1, v/v/v) with UV detection at 280 nm. Chlorpromazine hydrochloride was used as internal standard. Laboratory prepared mixtures containing different percentages of the degradation product were analysed by the proposed methods and satisfactory results were obtained. These methods have been successfully applied to the analysis of Nicergoline in Sermion tablets. The validities of these methods were ascertained by applying standard addition technique, the mean percentage recovery +/- R.S.D.% was found to be 99.47 +/- 0.752, 100.01 +/- 0.940, 99.75 +/- 0.740 for the first derivative of ratio spectra method, the HPTLC method and the HPLC method, respectively. The proposed methods were statistically compared with the manufacturers HPLC method of analysis of Nicergoline and no significant difference was found with respect to both precision and accuracy. They have the advantage of being stability indicating. Therefore, they can be used for routine analysis of the drug in quality control laboratories.

Thermal analysis of urea, fatty acids, and their adducts

Abstract The thermal analysis of urea and its decomposition product, biuret, was achieved. The calorimetric method was found to be suitable for the determination of the purity of urea. Some selected fatty acids varying in chain length and saturation (butyric, caproic, lauric, myristic, palmitic, stearic and oleic acid) were also examined. Attempts at their characterization and identification were successful. Determination of their boiling or melting points was possible by thermal analysis. The possibility of adduct formation between urea and fatty acid was also studied using either the dissolved urea technique or simply by physical mixing. The stability of the formed adducts, mechanism of dissociation, their dissociation temperatures and heat of reaction (Δ H ) were also investigated. The boiling point, melting point, Δ H values and decomposition temperatures for each series studied were found to increase with chain length and decrease with unsaturation. Various thermal analysis techniques were used, namely, diferential thermal analysis (DTA), differential scanning calorimetry (DSC), thermogravimetry (TG) and derivative thermogravimetry (DTG).

Spectrophotometric and spectrofluorimetric determination of pefloxacin

Abstract Two methods were adopted for the analysis of Pefloxacin. The first was a spectrophotometric determination of the substance in 0.1N H2SO4 measuring the absorbance at λ 276 nm. Concentrations adhering to Beers law were from 2.0–10.0 μg ml−1. The method gave satisfactory results when applied on Peflacine tablets after extracting the active substance completely with alcohol. The validity of this method was ascertained by standard addition technique, the mean percentage recovery ± S.D. was found to be [99.87 ± 0.96]. The second was a spectrofluorimetric method in which samples of Pefloxacin in 0.1N H2SO4 showed native fluorecence at λ 445 nm when excitation was at λ 282 nm. The calibration graph was rectilinear from 0.2–1.2 μg ml−1. The method was applied to Peflacine tablets after complete extraction of Pefloxacin with alcohol and the results were satisfactory. The validity of the method was ascertained by the standard addition technique, the mean percentage recovery ± S.D. was found to be [100.14 ±...

Potentiometric titration of reducing carbohydrates

ZusammenfassungDie Veränderungen der Redoxpotentiale einer alkalischen Hg(II)-EDTat-Lösung wurden in Abhängigkeit zur Zugabe won Glucoselösung verfolgt. Die Titrationen wurden bei 70–80° C durchgeführt, ohne daß sich Luftausschluß als nötig erwiesen hätte. Daneben wurden die Reduktionswerte anderer wichtiger Zucker angegeben. Mit dieser Methode können 1,5 bis 6%ige Zuckerlösungen mit einem Fehler won etwa 0,5–1,5% bestimmt werden.SummaryThe work to be described consists of following the changes in oxidation reduction potential as glucose solutions is progressively added to an alkaline solution of Hg(II)-EDTate. Preliminary work appears to show that normal sodium hydroxide provides the best alkaline medium for the purpose. The titrations are carried out at 70–80° C. It was also found that there was no need for rigid exclusion of air. The response of the more important carbohydrates upon titration with this reagent are studied and their reduction values ascertained.The method can be used to determine from 1.5–6% sugar solutions with an average error of about 0.5–1.5%.