Finnigan surveyor lc pump plus system

HPLC was employed to quantify the amount of QCT remaining unchanged in the synthesized NPs. Analysis was performed using a Finnigan Surveyor LC Pump Plus system (Thermo Fisher Scientific, Waltham, MA, USA) equipped with an autosampler and a photodiode array detector. Samples were eluted on a C18 UniverSil column (5 μm, 150 × 4.6 mm; Fortis Technologies Ltd., Cheshire, UK) using a mobile phase composed of 0.1% aqueous formic acid and methanol (60:40 v/v) at a flow rate of 1 mL/min, and the detection wavelength was 370 nm. QCT serial dilutions (0.16–5 μg/mL) were prepared in the mobile phase and used to construct the calibration curve. One milligram of each NP was dissolved in 1 mL of mobile phase and injected into the column. The concentration of QCT remaining in each NP was calculated based on a calibration curve of QCT standards’ peak area versus concentration. The results were expressed as % QCT content by weight.

The amount of TQ loaded in NPs and the amount released during in vitro release studies was analyzed by HPLC. The setup was composed of a Finnigan Surveyor LC Pump Plus system (Thermo Fisher Scientific, Waltham, MA, USA) equipped with an autosampler and a photodiode array UV detector. The mobile phase consisted of 0.1% formic acid, methanol, and isopropanol (50:45:5, v/v/v) at an isocratic flow rate of 1 mL min⁻¹. Elution was performed on a C18 UniverSil column (5 μm, 150 × 4.6 mm; Fortis Technologies Ltd., Cheshire, UK) and the detection wavelength was set to 260 nm. TQ serial dilutions (0.16–20 μg mL⁻¹) were prepared in the mobile phase and were used to construct the calibration curve, which was linear over the range of concentrations used (y = 218378x + 63037; R² = 0.99733). The method was validated according to the International Conference on Harmonization (ICH) guidelines. Limit of quantitation (LOQ) and limit of detection (LOD) values were found to be 5.33 and 1.76 μg mL⁻¹, respectively.