Development and validation of a robust QbD-guided (RP-HPLC) analytical technique for quantifying coenzyme Q10 in pharmaceutical dosage form

Background: Coenzyme Q10 (CoQ10) is a lipophilic antioxidant that contributes to mitochondrial energy production but poses analytical challenges due to low solubility and oxidative sensitivity. An accurate and validated method is essential to ensure quality control of its pharmaceutical dosage forms. Methodology: A reverse-phase high-performance liquid chromatography (RP-HPLC) method was designed using Quality by Design (QbD) principles. A Central Composite Design was employed to study the influence of critical parameters, including flow rate, gradient time, and mobile phase ratio. Separation was carried out on a Gemini C18 column (250 × 4.6 mm, 5 µm) with gradient elution using ethyl acetate: acetonitrile (50:50) and methanol: acetonitrile (80:20) containing 0.1% ammonia. The method was validated in accordance with ICH-Q2 (R1) guidelines. Results: The optimized conditions yielded a sharp CoQ10 peak at approximately 12.9 minutes with high resolution (Rs > 36), theoretical plates (~33,800), and acceptable tailing (≤1.3). Linearity was established over 2.5–200 µg/mL (r² = 0.9997). Accuracy ranged from 99.2–101.4%, precision was within %RSD ≤1.5%, and robustness was demonstrated under deliberate variations. Discussion: The method proved capable of consistently quantifying CoQ10 with superior specificity and sensitivity. Application to commercial soft gel formulations confirmed assay values at 99.5% of the label claim, meeting pharmacopeial standards. Conclusion: This QbD-based RP-HPLC method offers a validated, reproducible, and regulation-compliant strategy for the quality control and stability assessment of CoQ10 dosage forms, with potential extension to similar pharmaceutical compounds.