Zorbax sb cn column

High-performance liquid chromatography (HPLC), widely used in quality control of raw materials and final dosage forms, was chosen as a reference method for a comparison between the concentrations predicted by the HSI models and the actual API content in the printed samples. In order to extract the API for further analysis, the printed samples were dissolved in 5 ml of deionized water (Milli-Q) and shaken at room temperature at 300 rpm for 2 h. The resulting API solution was analyzed using a Waters Alliance (Milford, USA) HPLC system.
Separation was carried out in a Zorbax SB-CN column (150 mm × 2.1 mm, 5 μm; Agilent Technologies, California, USA) using isocratic elution at a flow rate of 0.4 mL/min. The column temperature was set to 30°C and the auto sampler temperature was 20°C. The mobile phase consisted of a mixture of 90% 1 mM ammonium acetate in water (Milli-Q) and 10% acetonitrile. UV-detection of the analyte was performed at a wavelength of 233 nm using a Waters 2996 photodiode array detector (Waters, Milford, USA) and at a chromatographic retention time of 4.5 min. The method was found to be linear and precise within the range of 1–90 μg/ml. The results of HPLC measurements were used to assess the model’s prediction values.

Drug concentrations were determined using an liquid chromatography-mass spectrometry/mass spectrometry based assay, validated according to US Food and Drug Administration guidelines. In brief, plasma sample preparation was performed by protein precipitation using a Hybrid Solid Phase Extraction-Precipitation 96-wellplate plate (Supelco) and a Freedom EVO liquid handler system (Tecan). Internal standards were used to compensate for recovery and matrix effects. The extracted drugs were separated using a Dionex Ultimate 3000 ultra high performance liquid chromatography system (Thermo Fisher) equipped with a Zorbax SB-CN column (Agilent). An API500 0 triple-quadrupole mass spectrometer and Analyst 1.6.3 software (both ABSciex) were used for drug detection and quantification. The lower limit of quantification was 9.71 ng/mL for lumefantrine and 1.01 ng/mL for desbutyl-lumefantrine. Three replicates of quality control samples at low, middle, and high concentrations were included in the analysis to ensure precision and accuracy. The total coefficient of variation of all quality control samples were <8% during drug quantification of clinical samples.