Quality by Design‐Assisted RP‐HPLC Method for Determination of Ritonavir and Darunavir in Pharmaceutical Formulation Using Central Composite Design.

The quality by design enabled the development of cost‐effective, simple, precise, and rapid Reversed phase‐ high‐performance liquid chromatography techniques for determining ritonavir (RIT) and darunavir (DAR) in the tablet dosage form. Systematic method optimization was performed through central composite design by altering the flow rate and composition of the organic phase in the mobile phase as the critical method parameters for evaluating the necessary analytical attributes, namely, the tailing factor, theoretical plate count, and resolution. The optimal separation was achieved on a column with C18 in nature and dimensions of (250 mm length × 4.6 mm id × 5 µm particle size) using a mobile phase consisting of acetonitrile and water (75:25 v/v) at a flow rate of 0.9 mL/min. Detection was carried out at 247 nm. The retention time of DAR and RIT was 2.939 and 3.537 min, respectively, as per International Council for Harmonization (ICH) guidelines. The developed method was useful for the determination of bulk drug and formulations. [ABSTRACT FROM AUTHOR]