Simultaneous determination of mometasone furoate and calcipotriol in a binary mixture by validated HPLC and chemometric-assisted UV spectrophotometric methods and identification of degradation products by LC-MS.

Objectives: A new binary mixture containing mometasone furoate (MF) and calcipotriol (CP) is suggested to manage psoriasis; since the combined stability profile of these drugs is poorly understood. Materials and Methods: Herein MF, CP, and their mixtures were subjected to various stress conditions. Also, stability-indicating HPLC was developed and validated according to ICH guidelines with Box-Behnken design. The degradation products (DPs) were predicted in silico and identified using LC-MS. The bioactivity and toxicity of DPs were studied using molecular docking and alamarBlue assay, respectively. Spectroscopic techniques of the first derivative, first-derivative ratio, and the mean-centering of ratio spectra were also used to determine MF and CP in the mixture because of spectra overlapping. Results: The major degradants for MF in alkaline conditions were DP1, DP2, and DP3, while in thermal and UV conditions, only DP1 was generated. CP gave one degradant in all conditions. No new impurity was observed in the MF and CP mixtures. The results of spectrophotometry showed good linearity in the range of 4-50 and 2-20 µg/ml, while linearity for HPLC was in the range of 4-50 and 0.5-2.5 µg/ml for MF and CP, respectively. Recovery was 99.61-100.38% for UV and 100.4% for HPLC methods of MF and 100.6-101.4% for UV and 99.5% for HPLC methods of CP. Conclusion: The developed methods can be used as simple, accurate, precise, and rapid techniques for routine quality control of MF and CP mixtures.