N.A. Zakhari

Europium(III) ion probe spectrofluorometric determination of diclofenac sodium

A new method has been devised for the determination of diclofenac sodium in bulk and in pharmaceutical preparations using Eu3+ ions as the Fluorescent probe. The technique was built around the hypersensitive property of the transitions of the fluorescent probe ion, Eu3+, at 616 nm. This is normally a forbidden transition, but the interaction with diclofenac sodium, which contains a carboxylic group, makes the transition allowed and enhances the intensity of its fluorescence emission. The Eu3+ fluorescence emission at 592 nm comes from a non-hypersensitive transition and is not affected by ligation. The intensity ratio, R, defined as I592/I616, was used as a measure of the percentage of bound probe ions. Diclofenac and Eu(III) forms a (1:1) molar complex. The relative stability constant of the complex was found to be 10(5). A linear relationship between bound Eu3+ and the concentration of diclofenac sodium was found for concentrations from 10 to 200 micrograms ml-1, with a recovery percentage of 100.22 +/- 2.27. The method shows a good agreement with a spectrophotometric method.

Fluorimetric determination of aminoglycoside antibiotics using lanthanide probe ion spectroscopy.

The application of probe ion fluorimetry has succeeded in the microdetermination of six aminoglycoside antibiotics: neomycin, streptomycin, gentamicin, tobramycin, amikacin and kanamycin as sulfate salts in pure form and in some pharmaceutical preparations. The method is based on the reaction of Eu(3+) ions with aminoglycosides through amino and hydroxy groups. Such interactions enhance the intensity of the 616 nm fluorescence emission of the Eu(3+) ion. The fluorescence at 592 nm comes from a non-hypersensitive transition and is not affected by the ligand which is bound to the probe ions. The intensity ratio R, defined as I (592)I (616) was used to determine the amount of free and bound europium ions. A linear relationship between bound europium ions and aminoglycoside was found within the concentration ranges 20-100 ppm for neomycin, 5-60 ppm for streptomycin, and 10-70 ppm for gentamicin, tobramycin, amikacin, and kanamycin as sulfate salts. The percentage recoveries ranged from 99.22 to 101.07, with standard deviations ranging from +/- 1.5 to +/- 4.38. The relative stability constants ranged from 5 x 10(3) to 2 x 10(4). The optimum reaction conditions were studied and the results obtained compared favourably with the fluorimetric method using fluorescmine reagent.

Determination of phenothiazines by charge-transfer complex formation with chloranilic acid

A rapid and sensitive spectrophotometrc method has been developed for the microdetermination of some phenothiazine derivatives as the pure substances and in different dosage forms. The method depends on the formation of stable donor-acceptor complexes between phenothiazines and chloranilic acid in an acetonitrile-2-propanol solvent mixture. The resulting intensely purple chloranilic acid radical anion possesses a characteristic absorption maximum at 515 nm. Beers law is obeyed over the concentration ranges 1-6, 1-10 and 5-30 mug ml for prochlorperazine dimaleate, trifluoperazine dihydrochloride and thiethylperazine dihydrochloride, with apparent molar absorptivities of 7.76 x 10(4), 1.95 x 10(4) and 6.64 x 10(3) 1. mole(-1).cm(-1), respectively. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.

Spectrophotometric Assay of Certain Aminoglycosides Using Cyanoacetamide

Abstract A simple and sensitive ultraviolet spectrophotometric method has been devised for the determination of amikacin, kanamycin, neomycin and streptomycin in pure form and in some pharmaceutical preparations. The method depends on the nitrosation of the primary amino groups followed by reaction with cyanoacetamide in ammonia medium at 100°C for 30 min, The reaction products exhibit a characteristic absorption. maximum at 270 nm. Beers law is obeyed within the concentration ranges 4–40 μg ml−1 for amikacin, kanamycin and neomycin and 8–80 μg ml−1 for streptomycin with apparent molar absorptivities of about 1.85 × 104 for the first three compounds and 1.3×104 1. mole−1.cm−1 for streptomycin.

Spectrophotometric Studies On Determination of Some Cephalosporins and Amoxycillin With Chlorobenzotriazole and Sodium Hypochlorite

Abstract Two simple colorimetric methods for the determination of certain cephalosporins (cefaclor and cefadroxil) and amoxycillin sodium are described. The suggested methods depend upon the oxidation of these compounds using sodium hypochlorite (SHC) and 1-chlorobenzotriazole (1-CBT) in alkaline medium and colorimetric measurment of the chromophore formed. The different experimental parameters are studied and incorporated into the procedures. The mean percentages found range from 100.0 ± 0.4 to 100.5 ± 0.9. The proposed methods have been successfully applied to the analysis of some pharmaceutical formulations and the results obtained have been statistically compared with those obtaind using the official methods. The proposed methods are convenient, rapid within the concentration range 15-123 μg. ml−1.

Fluorimetric Determination of Certain Phenothiazine Derivatives Using Eosin

Abstract Eosin reacts with phenothiazine derivatives in dichloroethane to give intense fluorescent compounds having their excitation maximum at 318 nm and emission maxima at 450, 460 and 465 nm for prochlorperazine dimaleate, thiethylperazine dihydrochloride and trifluoperazine dihydrochloride, respectively. Under the optimum conditions, samples of 1-10 μg ml−1 could be determined rapidly with coefficient of variation less than 1.8 %. This fluorescence reaction was also applied successfully to the determination of phenothiazine drugs in some pharmaceutical preparations.

Spectrophotometric determination of aluminum and copper ions using spadns

Aluminum and copper ions are selectively estimated spectrophotometrically. These ions form colored complexes with spadns which have a maximum absorbance at 580 nm. The complexes formed with both cations are stable and pH dependant; aluminum is favorably complexed at pH 5, while copper is complexed at pH 7.The percentage recoveries were found to be 99.69 ± 0.75 and 99.32 ± 0.6 with a minimum detection limit of 0.08 and 0.23 μg ml−1 for aluminum and copper ions respectively. There is insignificant interference from the 10-fold concentrations of other metal ions under the proposed reaction conditions.

Spectrophotometric titration of phenothiazines using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

A specific Spectrophotometric titration method is described for the micro-determination of some phenothiazine derivatives in strong orthophosphoric acid medium using the π-acceptor 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a mild oxidizing titrant. The wavelengths of maximum absorption of the formed phenothiazonium cation radicals are 500, 515, 530, 533 and 650 nm for trifluoperazine dihydrochloride, promethazine hydrochloride, prochlorperazine dimaleate, chlorpromazine hydrochloride and thiethylperazine dihydrochloride, respectively. Quantitative recoveries are reported for pure drugs and their dosage forms. The method is simple and specific for determining phenothiazine derivatives in presence of their induced degraded oxidation products.

Diazotised 4-Nitroaniline as a Chromogenic Reagent for the Determination of Indole Derivatives in Certain Pharmaceutical Preparations

Abstract A sensitive colorimetric method has been devised for microdetermination of six indole derivatives; ergotamine tartrate, methylergometrine maleate, dihydroergocornine methanesulphonate, dihydroergocristine methanesulphonate, dihydroergocryptine methanesulphonate and pindolol, both in pure form and in pharmaceutical preparations. The method is based on the reaction of indole moiety with diazotised 4-nitroaniline in buffer solution of pH 6 to produce a stable yellow monoazo dye. Beers law is obeyed over final concentration ranges 8–32 μgm1−1 for ergotamine tartrate, 4–48 μgml−1 for methylergometrine maleate, 8–56 μgml−1 for dihydro-ergot alkaloids and 1–10 μgml−1 for Pindolol with apparent molar absorptivity range (7.62 × 103−2.61 × 104) 1.mole−1.cm−1. A study has been made to determine the optimum conditions of the colour reaction.

Gas chromatographic assay of methyltestosterone in tablets

A simple gas chromatographic procedure has been developed for the determination of methyltestosterone in bulk powders and in tablets. Two new silyl ether derivatives of methyltestosterone have been prepared using dimethylethylsilylimidazole (DMESI) and dimethylisopropylsilylimidazole (DMiPSI). The method is accurate and selective for methyltestosterone within the concentration range 0.1-1.5 micrograms microliters-1.