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1

Validated stability-indicating HPLC method for analysis of gemifloxacin in tablet formulations

Sharif S, Khan I. U., Sheikh T. A, Sharif Y, Ashfaq M.

Acta Chromatographica

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2011

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Vol. 23, no. 1

95--107

EN

A stability-indicating reversed-phase high-performance liquid chromatographic method has been developed for analysis of gemifloxacin in tablet formulations. When the drug was subjected to forced degradation under acidic, basic, thermal, oxidative, and photolytic conditions, the degradation products produced were successfully separated on a 250 mm × 4.6 mm, 5-μm particle, C18 column with ammonium acetate buffer (pH 2.7; 0.05 M)-acetonitrile 70:30 (υ/υ) as mobile phase at a flow rate of 0.7 mL min-1. Diode-array detection was performed at 272 nm. The method was validated in accordance with ICH guidelines. Response was a linear function of concentration over the range 0.256–128 μg mL-1 (correlation coefficient 0.9990). The limits of detection and quantification were 10 and 30 ng mL-1, respectively. Separation of gemifloxacin from its stress-induced degradation products and excipients was adequate; resolution was >1.5 within 11 min. The purity index for the gemifloxacin peak after all types of stress was >0.999, indicating complete separation of the analyte peak from the degradation products. The method can therefore be regarded as stability-indicating. It is rapid, and suitable for purity and assay determination not only for routine quality control but also in stability studies.

2

Simple and sensitive LC-UV method for simultaneous analysis of hydrochlorothiazide and candesartan cilexetil in pharmaceutical formulations

Qutab S. S., Razzaq S. N., Ashfaq M., Shuja Z. A., Khan I. U.

Acta Chromatographica

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2007

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No. 19

119-129

EN

A simple, sensitive, and inexpensive high-performance liquid-chromatographic method has been developed for simultaneous determination of hydrochlorothiazide and candesartan cilexetil in pharmaceutical formulations. Chromatographic separation was achieved on a Phenyl-2 column with a 25:75:0.2 mixture of 0.02 M potassium dihydrogen phosphate, methanol, and triethylamine, final pH 6.0 š 0.1, as mobile phase. Detection was at 271 nm. Response was a linear function of concentration in the range 5–45 µg mL-1 for hydrochlorothiazide and 12–56 µg mL-1 for candesartan cilexetil; the correlation coefficients were 0.9993 and 0.9991, respectively. Total elution time for the two components was less than 5 min.

3

Determination of atenolol in pure substance and pharmaceutical preparations applying first order derivative spectrophotometry

Khan I. U., Yaqoob N., Ahmad M.

Chemia Analityczna

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2005

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Vol. 50, No. 5

951-955

EN

The improved first order derivative spectrophotometric method for the determination of atenolol in pure substance and pharmaceutical preparations has been proposed. The first order derivative spectrum of the coloured complex of atenolol with phenolsulfothaline exhibited maximum absorbance at 558.4 nm. The proposed approach allowed one to eliminate spectral interferences. The measured analytical signal changed linearly within the analyte concentration range: from 0.05 to 0.4 mg mL-1. Coefficient of variation was 0.854%. Detection limit was found to be 0.05 mg mL-1.

PL

Zaproponowano ulepszoną metodę spektrofotometrii pochodnej do oznaczania atenololu w substancji farmaceutycznej i w postaci leku. Pierwsza pochodna widma barwnego kompleksu atenololu 7. fenolosulfotalinąwykazaia maksimum absopcji przy 558,4 nm. Proponowana metoda pozwala na wyeliminowanie interferencji spektralnych. Sygnał analityczny miał liniowy przebieg w zakresie stężeń od 0,05 do 0,4 mg L-1. Współczynnik zmienności wynosił 0,854%. Granicę wykrywalności określono na 0,05 mg L-1.