Eclipse plus c8

Olanzapine concentrations were measured by HPLC with minor modifications to the methods described by Raggi et al. [19 (link)]. The analytical column was ZORBAX Eclipse Plus C8, 5 μm, 150 × 4.6 mm, the UV wavelength for olanzapine was 260 nm, and the mobile phase consisted of 17 mM tetramethylammonium perchlorate (pH 3.1):acetonitrile = 77:23. The flow rate was 0.4 mL/min.

The IMDQ release profile was evaluated using high-performance liquid chromatography (HPLC). PGN_4.9 nanoadjuvant was dispersed into different pH media (0.1 M Na₂HPO₄/citric acid buffer) with or without papain (30 mM) and incubated at 37 °C. At predesignated time points, the solution was taken out and quenched by adding acetonitrile. The amount of the released IMDQ was detected by HPLC at a UV wavelength of 322 nm. Chromatographic column: ZORBAX Eclipse Plus C8. Mobile phase: acetonitrile: 0.3% acetic acid = 10: 90–90: 10.

The major obstacle in vitamin separation is the segregation of isomers. With this in mind, as a starter setup, we used a mobile phase based on MeOH and water using an eight carbon-based alkyl stationary phase (0.75 mL min⁻¹, Eclipse Plus C₈, 4.6 mm ID × 150 mm, 3 μm, Agilent Technologies). As the resolution was insufficient, a C₁₈ column was selected, and only flow was modified (1 mL min⁻¹, Eclipse Plus C₁₈, 4.6 mm ID × 150 mm, 3 μm, Agilent Technologies). Then we substituted the column for a C₃₀, removed water, and used a less polar solvent in acetonitrile and 2-propanol, reducing yet again the solvent flow (0.5 mL min⁻¹) (Table 1). Finally, retaining a similar proportion of MeOH, we substituted acetonitrile and isopropanol for MTBE. The C₃₀ column was kept as it already had excellent capabilities reported for highly lipophilic compounds (e.g., carotenoids) [39 ].