Sonia Z. El-khateeb

Application of proton magnetic resonance spectrometry in the analysis of diclofenac sodium and its tablets

Abstract A new simple and rapid quantitative proton magnetic resonance method has been developed for the determination of diclofenac sodium in pure and tabler forms. Among other peaks, the PMR spectrum of diclofenac has a well defined sharp singlet (at ≃ 3.62 ppm) which is chosen for quantitative measurements. The method involves co-paring the integral of this signal to that of a sharp singlet of anhydrous sodium acetate (at ≃ 1.85 ppm) which is used as internal standard. The proposed procedure gives accurate and reproducible results when applied for the analysis of authentic drug and its tablets. In addition, the PMR um obtained helps in confirming the identity and purity of the drug.

Determination of metformin hydrochloride in tablets by nuclear magnetic resonance spectrometry

Abstract The 1H-n.m.r. signal of the drug (10–35 mg ml−1) in deuterium oxide, with maleic acid as internal reference standard, is used. The integral of the peak at 3.06 ppm with respect to 3-trimethylsilylpropionic acid is compared with that at 6.3 ppm for the internal standard. The method is quantitative and free from interference by tablet excipients.

Development of membrane electrodes for the selective determination of hyoscine butylbromide

Four polyvinyl chloride (PVC) membrane sensors for the determination of hyoscine butylbromide are described and characterized. The sensors are based on the use of the ion association complexes of hyoscine cation with ammonium reineckate counter anions as ion exchange sites in the PVC matrix. The membranes incorporate ion association complexes of hyoscine with dibutylsebathete (sensor 1), dioctylphthalate (sensor 2), nitrophenyl octyl ether (sensor 3) and beta-cyclodextrin (sensor 4). The performance characteristics of these sensors were evaluated according to IUPAC recommendations, which reveal a fast, stable and linear response for hyoscine over the concentration range of 10(-5)-10(-2)M for sensors 1 and 2 and 10(-6)-10(-2) for sensors 3 and 4 with cationic slopes of -53.19, -55.17, -51.44 and -51.51mV per concentration decade for the four sensors, respectively. The direct potentiometric determination of hyoscine butylbromide using the proposed sensors gave average recoveries % of 99.92+/-1.11, 99.93+/-1.00, 99.94+/-1.18 and 99.87+/-1.39 for the four sensors, respectively. The sensors are used for determination of hyoscine butylbromide in laboratory prepared mixtures, pharmaceutical formulations in combination with ketoprofen and in plasma. Validation of the method shows suitability of the proposed sensors for use in the quality control assessment of hyoscine butylbromide. The developed method was found to be simple, accurate and precise when compared with a reported HPLC method.

Determination of quaternary ammonium surfactants in pharmaceutical formulations by the hypochromic effect

A spectrophotometric procedure for determination of the quaternary ammonium salts cetrimide (N,N,N-trimethyl-l-hexadecylammonium bromide), cetylpyridinium chloride (l-hexadecyl-pyridinium chloride) and sapamine [N-(2-dimethylaminoethyl)oleamide acetate] in bulk form and some pharmaceutical formulations, such as eye-drops, disinfectant solutions, creams and tablets, is described. Following TLC separation when necessary, addition of an aqueous solution of the active surfactant to a standard amount of Bromothymol Blue, buffered at pH 7.5, leads to an equivalent decrease of the absorbance at 610 nm, which can be taken as an analytical measure of the drug concentration. Good mean recoveries have been obtained for standard additions of these analytes to pharmaceutical formulations containing them.

Stability indicating method for determination of nortriptyline hydrochloride using 3-methyl-2-benzothiazolinone hydrazone (MBTH).

A spectrophotometric procedure is described for determination of nortriptyline hydrochloride in pure and dosage form as well as in the presence of its degradate. 3-Methyl-2-benzothiazolinone hydrazone (MBTH) has been used as the chromogenic reagent, where aqueous solutions of the drug and reagent are treated with cerium(IV) ammonium sulphate in an acidic medium. Nortriptyline hydrochloride reacts to give a blue coloured product having two absorption maxima at 619 and 655 nm. Various parameters affecting the reaction have been studied. Beers law is obeyed in the concentration range of 24-216 microg ml(-1) of nortriptyline hydrochloride, with mean percentage recoveries of 100.22+/-0.870 and 100.66+/-0.642% for both maxima, 619 and 655 nm, respectively. Results were statistically analyzed and compared with those obtained by applying the British Pharmacopoeia (1993) method.

Sepectrometric Determination of Madopar Capsules

Abstract Levodopa is determined in the presence of benserazide hydrochloride by a sensitive, simple and precise ultraviolet absorption method, recording absorbance in 0.05 M borax solution at 281, 287 and 293 nm. An equation has been used to obtain the correct absorbance at 287 nm. An accurate and specific proton magnetic resonance (PMR) procedure is proposed to quantify benserazide hydrochloride in admixture with levodopa using dimethylsulfoxide to separate the two components, and for quantitative measurements. The estimation of both drugs in Madopar capsules can be achieved successfully using the methods presented.

SPECTROPHOTOMETRIC AND STABILITY INDICATING HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC DETERMINATION OF NORTRIPTYLINE HYDROCHLORIDE AND FLUPHENAZINE HYDROCHLORIDE

ABSTRACT Spectrophotometric and high performance liquid chromatographic procedures are described for determination of nortriptyline hydrochloride and fluphenazine hydrochloride. The first procedure is based on application of first derivative of ratio spectra (1DD) for quantitative determination of nortriptyline hydrochloride in presence of fluphenazine hydrochloride. Secondly, an accurate, sensitive and stability indicating method has been introduced for determination of nortriptyline hydrochloride and fluphenazine hydrochloride in both bulk powder and in dosage form. In the derivative ratio method, Beers law is obeyed in the concentration ranges of 8–32 µg mL−1 and 4–32 µg mL−1 of nortriptyline hydrochloride at wavelengths 271.4 and 284.2 nm, respectively. In high performance liquid chromatographic method, linear relationship in the range of 0.6–3.6 µg mL−1 and 1.2–4.2 µg mL−1 for nortriptyline hydrochloride and fluphenazine hydrochloride, respectively, was obtained. The mobile phase used was 0.05 M ammonium acetate : methanol : acetonitrile (4 : 1 : 5 v/v/v), and detection was done spectrophotometrically at 254 nm. Results were statistically analyzed and compared with those obtained by applying the British Pharmacopoeia (2000) method.

Spectrophotometric Determination of Triamterene Using Some Acid Dyes

Abstract Two acid dye reagents have been utilized for spectrophotometric determination of triamterene in pure form and in pharmaceutical preparations. The dyes used are bromophenol blue (B. P. B), and bromothymol blue (B. T. S. They form a chloroform-soluble, coloured ion association complex with triamterene, at pH 3.4 and 3.2 using B. P. B and B. T. B, respectively. The formed complex could be extracted and measured spectrophotometrically at 417 nm for both dyes. The molar ratio of the formed drug-dye ion association complex is found to be 1:1 for both dyes used, as deduced by applying Jobs method. Linearity was obtained using concentration ranges of 2.5–10 μg, and 2.5–15 μg. ml−1 of triamterene with B. P. B. and B. T. B. respectively. The validity of the procedure was assessed by applying the standard addition technique. Results obtained by using the proposed procedure were statistically analysed and compared with those obtained by adopting the pharmacopoeial method.

Utility of p-chloranilic Acid and 2,3 Dichloro-5,6-dicyano p-Benzoquinone (DDQ) for the Spectrophotometric Determination of Triamterene

Abstract Two simple and sensitive spectrophotometric procedures are suggested for analysis of triamterene. The first procedure is based on the reaction of triamterene with p-chloranilic acid (p-CA) in methylene chloride to form a highly stable coloured product, exhibiting maximum absorbance at λ 530 nm. Beers law is obeyed in the range of 40–220 μg.ml−1 with a mean percentage accuracy of 99.98 ± 0.446. Limit of determination is 20 μg.ml−1. In the second procedure, the drug is determined via charge transfer complex formation with 2,3 dichloro-5,6-dicyano p-benzoquinone (DDQ) using methylene chloride as a solvent. Here the reaction product has two well defined maxima at 460 nm and 530 nm where each has been utilized for quantitative determination. Beers law is obeyed in concentration ranges of 25–125 μg.ml−1 and 25–150 μg.ml−1 with mean percentage accuracies of 99.92 ± 0.449 and 100.00 ± 0.511 for both maxima. 460 and 530 nm. respectively. Limit of determination is 12.5 μg.ml−1 at both maxima. Optimum con...

Application of Proton Magnetic Resonance Spectrometry in the Analysis of Piroxicam and its Pharmaceutical Formulations

Abstract A new simple and rapid quantitative proton magnetic resonance method has been developed for the determination of piroxicam in pure form and in pharmaceutical dosage forms. Among other peaks, the PMR spectrum of piroxicam has a well defined sharp singlet (at ≃ 3.00 p.p.m.) which is chosen for quantitative measurements. The method involves comparing the integral of this signal to that of a sharp singlet of maleic acid (6.3 p.p.m.) which is used as internal standard. The proposed procedure gives accurate and reproducible results when applied for the analysis of authentic drug, its tablets and capsules. In addition, the PMR spectrum obtained helps in confirming the identity and purity of the drug.