Fourier transform infrared spectroscopic analysis (FTIR) FTIR analysis was conducted to investigate the compatibility of DTX with Soluplus ® and PF108. FTIR spectra were recorded for plain DTX, Soluplus ® , PF108, and a physical mixture of DTX, Soluplus ® , and PF108. Samples for FTIR were prepared following a methodology based on the principles outlined by Patravale et al. This involved maintaining a specific 1:0.5 ratio of active pharmaceutical ingredient (API) to solubilizers, mainly Soluplus ® and PF108. Each unit of the API was combined with 0.5 units of Soluplus ® and PF108. The FTIR measurements were performed using an Agilent Alpha 100508 instrument over a wave number range of 4000 to 400 cm -1 [27] .