Spectrophotometric microdetermination of phenylephrine hydrochloride in pure and in pharmaceutical formulations using haematoxylin

A new voltammetric platform for reliable determination of the sport performance-enhancing stimulant synephrine in dietary supplements using a boron-doped diamond electrode

For the first time, we propose a new modification-free voltammetric platform for simple, fast and reliable quantification of the sport performance-enhancing stimulant synephrine (SYN) based on the usage of a commercial screen-printed boron-doped diamond (BDD) electrochemical sensor. Applying cyclic voltammetry, SYN exhibited one well-shaped, irreversible and diffusion-driven oxidation peak at a peak potential of +1.45 V (vs. the silver pseudoreference electrode) in the presence of 2 M HClO₄. Under the selected experimental conditions, the following analytical parameters for determination of SYN were obtained: linear concentration ranges from 19.6 up to 1000 μM and from 9.9 up to 1000 μM for differential pulse (DPV) and square-wave voltammetry (SWV), respectively, detection limits at micromolar concentration levels and intra-day repeatability with a relative standard deviation below 4% for both pulse techniques. The interference study revealed fair selectivity when considering the target dietary supplements. The feasibility of the developed voltammetric platform was verified in the analysis of commercially available dietary supplements and reasonable recovery values were achieved by DPV and SWV, respectively. In addition, the method can be performed directly without higher consumption of chemicals, waste generation, complex sample extraction and higher instrumentation cost. The advanced BDD electrochemical sensor has appeared to be a suitable competitor for efficient applications in food quality control analysis.

Quantitative estimation of trimazolin hydrochloride in pharmaceutical preparation by RP-HPLC method

A sensitive and selective RP-HPLC method was developed and validated for the quantitative determination of trimazolin hydrochloride in nasal drops formulations. The mobile phase composition was water-acetonitrile (50:50, v/v) and the UV detection was carried out at 270 nm. Linearity range in the concentration range of 10 to 110 ?g cm-3. The method was tested and validated for various parameters according to ICH guidelines. The detection and quantization limits were found to be 1.45 and 4.8 ?g cm-3, respectively. The results demonstrated that the procedure for estimation of trimazolin hydrochloride in nasal drops formulations was accurate, precise and reproducible.