HPLC-UV and spectrofluorimetric methods for simultaneous estimation of fluticasone furoate and vilanterol in rabbit plasma: A pharmacokinetic study.

Fluticasone furoate (FF) and vilanterol trifenatate (VT) is a widely prescribed combination in the management of asthma and chronic obstructive pulmonary disease. In the present study, two quantitative methods based on HPLC-UV and spectrofluorimetric analysis had been developed and validated for simultaneous estimation of FF and VT in rabbit plasma using baclomethasone as internal standard (ISTD). Analytes and ISTD were separated from plasma using simple step of protein precipitation with acetonitrile. Chromatographic separation was achieved on Spherisorb S5 ODS2 (250 mm × 4.6 mm, 5.0 µm) column using mobile phase that constitute acetonitrile-0.01% glacial acetic acid in water (70:30, v/v) and then detected on a UV detector at 235 nm wavelength. Spectrofluorimetric detection was performed using absorption/emission wavelength (λ) of 286/352 nm and 362/407 nm for FF and VT, respectively. For both analytes, linearity ranged from 4-200 ng/mL to 10-200 ng/mL using HPLC-UV and spectrofluorimetric method, respectively. Methods were validated as per FDA recommendations. Statistical analysis revealed that these detection methods are statistically insignificant difference and can be used interchangeably without any bias. Further, these methods were applied in pharmacokinetic study for simultaneous estimation of FF and VT in rabbit plasma.