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Optimizing SIC assay method for acetyl salicylic acid and rosuvastatin and adapting to HPLC with performance comparison

Idris A. M., Alnajjar A. O.

Acta Chromatographica

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2015

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Vol. 27, no. 1

111--125

EN

Acetyl salicylic acid (ASA), as the major drug consumed in the world, has been combined with other various drugs. In this regard, ASA-rosuvastatin is the most recent combination. The current article reported the first two separation methods for the assay of that combination utilizing sequential injection chromatography (SIC) and high-performance liquid chromatography (HPLC). The optimization process was conducted for SIC, and the optimum conditions were then adapted to HPLC. Both methods, SIC and HPLC, were validated and successfully applied to tablet formulation. In both methods, the analytes were chromatographed onto a short C18 monolithic column (4.6 × 25 mm) by a mobile phase composition of 10 mmol L -1 phosphate:acetonitrile: methanol (50:30:20, v/v/v at pH 3.0). The performances of both methods were compared. The remarkable advantages of the SIC method over HPLC method were the reduction in reagent consumption and instrumentation simplicity and cost-effectiveness. The total volume of mobile phase consumed is three orders of magnitude larger in HPLC than that in SIC. Other analytical features of the SIC and HPLC methods were comparable and acceptable for pharmaceutical analysis. Accordingly, the SIC method could be more suitable for routine analysis of simple matrices after examining the capability of the technique to work under industrial conditions.

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Capillary electrophoresis with fluorescence detection for sensitive analysis of morphine and 6-acetylmorphine in human urine

Alnajjar A. O.

Acta Chromatographica

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2008

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Vol. 20, no. 2

227-238

EN

Capillary electrophoresis with fluorescence detection has been investigated for simple, sensitive, and selective analysis of morphine and 6-acetylmorphine (6-AM) in human urine. The method is based on the reaction of morphine and 6-AM with the freshly prepared diazonium salt of aniline at 0°C. The method is selective in the presence of codeine. Conditions that affect derivatization (diazonium concentration and reaction time) and separation (electrolyte concentration, pH, β-cyclodextrin concentration, organic additives, and separation potential) were studied. When fluorescence detection was used with an excitation wavelength of 350 nm and an emission cutoff filter of 500 nm, good linearity was obtained in the range of 50-2000 ng mL-1 with limits of detection and quantification below 1.0 and 3.3 ng mL-1, respectively. The method was applied to human urine and validated by comparison with previously established capillary electrophoretic methods. Accuracy, repeatability, and intermediate precision of results were comparable. The method is suitable for application in forensic cases for initial screening, and in clinical analysis to prevent overdose-induced toxicity.

3

Multi-response optimization of a capillary electrophoretic method for determination of vardenafil in the bulk drug and in a tablet formulation

Idris A. M., Alnajjar A. O.

Acta Chromatographica

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2007

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No. 19

97-109

EN

Capillary electrophoresis (CE) with diode-array detection has been used to develop a simple and rapid method for assay of vardenafil in the bulk drug and in a tablet formulation. Multi-response optimization of sensitivity, speed, repeatability of peak height and migration time, and their relative standard deviation (RSD; n = 5), was performed. Electrophoretic factors assumed to be independently affecting the analysis were optimized by use of factorial design and response-surface methods. Other factors were optimized by the univariant method. The optimum conditions were: running buffer 100 mM phosphate, pH 6, injection time 8 s, column temperature 25°C, separating potential 25 kV, column length 31.2 cm, and detection at 222 nm. The method was validated in the presence of the excipients iden-tified by the manufacturer of the tablets (Levitra). Good analytical data were obtained, including linear range 0.5–75 µg mL.1, recovery 98.8%, re-peatability (as RSD) 1.3% (seven consequent injections on the same day), intermediate precision (as RSD) 3.4% (five injections over a week), and li-mits of detection and quantification 0.042 and 0.140 µg mL.1, respectively. Selectivity was assessed in relation to the other, structurally related, drug commonly used to treat erectile dysfunction (sildenafil); sufficient separation was achieved.