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The first method was based on measuring the absorbance of STA at 268 nm in the range of 25-500 µg mL-1. The second method was the isosbestic point method. The total mixture concentration was calculated by measuring the absorbance at 257 nm. The proposed methods used to determine each drug in binary mixture. The results were statistically compared using one-way analysis of variance (ANOVA). The developed methods were satisfactory applied to the analysis of the pharmaceutical formulation and proved to be selective and accurate for the quality control of the cited drugs in their pharmaceutical formulation.enUniversity of metformin; sitagliptin phosphate; spectrophotometry.Articlehttps://doi.org/