A simple RP-HPLC-PDA method for determination of atenolol (ATN) and trimetazidine (TMZ) in human urine and tablets has been developed. Analytes were separated on a Caltrex BI column (125× 4.0 mm, 5 μm) with 25mM potassium dihydrogen phosphate pH 3.3, methanol, and acetonitrile mobile phases. The PDA detector was operated at 210 nm for TMZ and 225 nm for ATN and the flow rate was 1.0 mL/ min. Linearity was obtained over a concentration range of (1.0-100 μg/mL) for both analytes in standard solutions and the method was successfully applied for determination of target analytes in their pharmaceutical tablets. Excellent linearity was also obtained over concentration ranges of (0.25-25 μg/mL) and (0.5-25 μg/mL) in human urine for TMZ and ATN, respectively. A simple liquid-liquid extraction was applied for urine sample clean-up and a gradient method was used for chromatographic separation. The lower limit of quantitation (LOQ) was 0.99 and 0.60 μg/mL for ATN and TMZ, respectively. The limit of detection (LOD) was 0.30 and 0.18 μg/mL for ATN and TMZ, respectively. Inter- and intraday precision and accuracy for ATN were within ±1.89% in pure form and within ±2.85% in urine samples. Inter- and intraday precision and accuracy for TMZ were within ± 3.99% in pure form and within ± 3.19% in urine samples.

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In this work, the application of silver nanoparticles (Ag NPs) for spectrophotometric determination of cefdinir (CFD) and cefepime HCl (CFP) was developed. The method was based on the ability of the alkaline degradation products of the cited drugs to reduce Ag+ ions to silver nanoparticles (Ag-NPs) in the presence of gelatin as a capping agent. The linear concentration ranges were 5.0-40 and 10-100 µg/mL for cefdinir and cefepime HCl, respectively. The lower detection limits were found to be 0.39 and 1.06 µg/mL for CFD and CFP, respectively, while the quantitation limits were found to be 1.18 and 3.21 µg/mL for CFD and CFP, respectively. The formed nanoparticles were characterized by ultraviolet-visible spectroscopy and transmission electron microscopy. The proposed method was applied successfully to determination of CFD and CFP in pure drugs, pharmaceutical preparations and human urine samples.