A novel Isoxazole (ISO) analog of curcumin is synthesized from curcumin and described as having a better pharmacological activity than curcumin, such as anti-cancer, anti-malarial, anti-mycobacterial, and many more. The present research aims to develop a bio-analytical method with a simple, rapid, selective, sensitive, accurate, and precise quantification of ISO by liquid chromatography coupled with tandem mass spectroscopy (LC-MS/MS) in rat plasma matrix. The simple plasma protein precipitation method was used for ISO extraction. The ISO was eluted in isocratic mode on a Water symmetry C18 column (75 × 4.6 mm2, 3.5 μm) at a 600 µL/min flow rate with a 0.1 % formic acid in water and methanol (20:80) as mobile phase. The MS/MS was used as a monitoring tool for the fragmentation of ISO as m/z = 366.1 → 145.1 and m/z = 237.1 → 194.07 for carbamazepine (CBZ; internal standard). The ISO showed good co-relation as (r2 = 0.999) linear and covered a wide range with a lower limit of quantification of 1.0 ng/mL. Finally, the developed method was successfully utilized for oral and intravenous pharmacokinetics of ISO in rats plasma. The absolute bioavailability of ISO was found at about 17.6 % after oral administration.