Development and Validation of a Novel Stability-Indicating RP-HPLC Method for Simultaneous Determination of Tezacaftor and Ivacaftor in Fixed Dose Combination.

A simple and precise novel stability-indicating method for the simultaneous estimation of tezacaftor and ivacaftor in combined tablet dosage form was developed and validated using reversed-phase high-performance liquid chromatography (RP-HPLC). The method is being reported for the first time and includes an estimation of degradation products produced post-stress conditions without any extraction or derivatization. The chromatographic separation of the drugs was achieved with a Symmetry Shield RP18 Column (100 Å, 5 μm, 4.