Factorial design assisted RP-HPLC method for simultaneous determination of fluconazole, itraconazole, and terbinafine

A 23 full factorial design model was utilized for development of a new
HPLC method with UV detection to estimate three antifungal drugs
simultaneously. Fluconazole (FLU), itraconazole (ITR) and terbinafine
(TRH), which are co-administered for severe fungal infections have been
determined using MOS-1 Hypersil C18 column and an isocratic eluent;
methanol 95% and phosphate buffer 5% with 0.001% triethylamine. The pH
adjusted 7, and flow rate of  0.7 mL/min. The three drugs were
separated within less than 7 minutes at 210 nm. The developed method gave
linear response over 5-80, 5-50 and 1-50 μg/mL for FLU, ITR and TRH,
respectively. It showed detection limits of 0.8761, 0.293 and 0.1965 μg/mL
and quantification limits of 2.655, 0.8788 and 0.5956 μg/mL for the three
drugs, respectively. The design of experiment facilitated the optimization
of different variables affecting the separation of the three drugs. The
designed method sensitivity permitted the simultaneous estimation of ITR
and TRH in spiked human plasma successfully.