In this work, a fast, versatile, and convenient dispersive solid-phase micro-extraction (DSPME) method is combined with a spectro-densitometric technique for the analysis of zolmitriptan (ZOLM) in biologi- cal fluids. Fe 3 O 4 /FeOOH magnetic nanocomposites (MNCs) were prepared by a co-precipitation method in aqueous solutions and utilized subsequently as a sorbent in DSPME. By coupling DSPME with high- performance thin-layer chromatography (HPTLC) with fluorescence detection, the preconcentration and determination of (ZOLM) in presence of metoclopramide (MET) and paracetamol (PARA), which are pre- scribed as an adjuvant therapy with ZOLM, was accomplished. Adsorption capability was assessed using both Langmuir and Freundlich adsorption isotherm models. The adsorption data was fitted to Langmuir adsorption isotherm model as reflected by high determination coefficient (R 2 = 0.9944). Moreover, ad- sorption kinetics was assessed by pseudo-first and pseudo-second order kinetic models. The data was fitted to pseudo-second order kinetics, which proves that ZOLM interaction with the adsorbent is a chemisorption process. Surface complexation with MNCs was suggested to explain the pH dependence of ZOLM sorption. The key parameters of extraction and desorption steps (including pH, extraction time, sample volume, magnetic adsorbent amount, and desorption circumstances) were evaluated. Optimized conditions for solid phase microextraction of ZOLM were pH 2.9, 5.0 mg Fe 3 O 4 /FeOOH MNCs, 15 min vortex-assisted extraction time and 3 ×200 μL of methanol: 33% ammonia; 4:1 as eluent. The analysis was achieved using ACN: dichloromethane: 33% ammonia (22.5: 6.0: 1.5, v/v/v) as a mobile phase and the fluorescence detection was carried out at 223 nm. The proposed DSPME method was successfully ap- plied for trace quantification of ZOLM in rabbits’ plasma ( n = 6) after oral administration with a linearity range of 50.0 –400.0 ng mL −1 (R 2 = 0.9931), a detection limit of 12.0 ng mL −1 and extraction recovery of 97.27–99.89% with an RSD < 2% ( n = 9). Moreover, the selectivity of the proposed approach for analysis of ZOLM in the presence of MET and PARA is demonstrated

A selective and simple salting-out-assisted thin-layer chromatographic methodology
was developed for the simultaneous determination of two oral hypoglycemic drugs,
dapagliflozin (DAPA) and metformin (MET) in their pure forms, tablets and spiked
human plasma samples. Silica gel 60 F254 plates were used in the separation of the
two drugs using a mobile phase consisting of 0.5 M (NH4)2SO4 and methanol
(3:7, v/v). The plates were scanned in the reflectance mode at λmax = 237 nm. The
obtained retardation factor (Rf) values for DAPA and MET were 0.77 ± 0.02 and 0.25
± 0.02, respectively. The thin-layer chromatography method was validated according
to International Conference on Harmonization guidelines. The peak areas were linearly
increased with the increases in concentrations of 45–1,000 and 50–1,500 ng/band
for DAPA and MET, respectively. Moreover, the method was applied to estimate the
molecular lipophilicity parameters of DAPA and MET via retention data. The
suggested method was efficiently utilized for the analysis of DAPA and MET in
pharmaceutical tablets and plasma samples with recoveries 98.4–100.4 and RSDs in
the ranges of 1.4–2.6 and 2.2–3.0% for DAPA and MET, respectively.