A Selective and Sensitive Method Development and Validation for Impurity Quantification in Cysteamine Bitartrate Bulk and Formulation by RP‐HPLC

RP-HPLC was used to develop and validate a simple, selective, and sensitive impurity quantification method for cysteamine bitartrate formulation. Chromatographic separation was achieved using Shim-pack Sceptre HD-C₁₈-5 μm 4.6 × 250 mm column. The mobile phase-A was 43 mM 1-hexane sulfonic acid sodium salt monohydrate buffer adjusted to pH 2.2 with 0.1% orthophosphoric acid. Mobile phase-B was acetonitrile. The column oven temperature was 40°C, and gradient elution was done at 0.8 mL per minute, and the gradient program was T/A: 0/100, 12/100, 12.1/90, 30/80, 35/70, 45/70, 45.1/100, and 60/100. To measure component quantities, a 200 nm wavelength and 10 μL injection volumes were utilized. The drug product and drug substance were subjected to the stress conditions such as acid, base, oxidation, heat, and photolysis as per the recommendations of the International Conference on Harmonization (Q2) methodology. Stress research shows that the approach is stable and peak homogeneous. High accuracy (97%-103% recoveries), precision (≤ 1.0%), specificity (R2 > 0.999), and linearity (R2 > 0.999) were achieved with the approach. The detection limit (LOD) was 0.3 μg mL^-1, whereas the quantification limit (LOQ) was 1.0 μg mL^-1. The analytical method was validated according to ICH and USP < 1225 > guidelines. For quality control, the method was exact, particular, linear, accurate, and resilient.