Method development and validation of an analytical quality by design ultrafast liquid chromatographic method for the determination of bedaquiline from pharmaceutical bulk and nanoemulsions

Bedaquiline (BDQ) is a drug used to treat multidrug-resistant tuberculosis (MDR-TB). It exhibits exposure-dependent efficacy in eliminating Mycobacterium tuberculosis (Mtb). An easy, efficient and precise reverse-phase ultrafast liquid chromatography (RP-UFLC) method was developed to validate the free base of the antitubercular medication BDQ. BDQ was separated using a 10:90 v/v mobile phase of ammonium acetate buffer solution (pH = 5.4) and high-performance liquid chromatography-grade methanol, with a flow rate of 1.5 mL/min and a UV detection wavelength of 226 nm. By using the Box-Behnken design (BBD) and response surface methodology (RSM), the method was optimised by varying critical analytical attributes (CAA) and critical performance attributes (CPAs) namely ammonium acetate fraction (%), flow rate (ml/min), buffer system molarity (M) and pH. BDQ was eluted at 7.5 min utilising isocratic elution. The method was linear in the concentration range of 0.5-300 μg/mL with limit of detection values of 0.039 μg/mL and limit of quantification of 0.12 μg/mL. The results indicate that this validated method can be used as an alternative method for assay of BDQ.