Development and Characterization of Enhanced Solubility High-Concentration Intrathecal Nicardipine HCl Formulation Utilizing Dextrose-Based Vehicles and Long-Term Stability

The uploaded dataset includes validated analytical and experimental data supporting the quantification, solubility, and stability of nicardipine HCl formulations. The validation of an HPLC method for nicardipine HCl analysis demonstrates a robust linear relationship between peak area and concentration over the range of 0.1–25 µg/mL. Representative chromatograms corresponding to the standard calibration curve confirm method specificity and reproducibility. A comparison between nominal (actual) concentrations and experimentally measured concentrations from stock solutions demonstrates the validated method's high accuracy and agreement across the tested range. Solubility of nicardipine HCl in 0.9% w/v NaCl solution was evaluated under varying pH conditions. Overlaid chromatograms (n=3) at concentrations of 0.25, 2.5, and 12.5 µg/mL confirm consistency and reproducibility of detection. The results further indicate pH-dependent variation in nicardipine HCl solubility. The effect of dextrose concentration (5–8% w/v) on nicardipine HCl solubility shows a positive correlation: higher dextrose concentration enhances solubility. Long-term stability data are included for nicardipine HCl (5 mg/mL) formulations prepared in 5% w/v dextrose solution. Samples stored under various conditions were analyzed over a one-year period. At each time point, duplicate samples were filtered (0.22 µm) and quantified using the validated HPLC method. The results confirm the stability of the formulation under the tested storage conditions.