UHPLC‐MS/MS Single Run Quantification Method for Simultaneous Determination of Triazolopyrazine and N ‐Nitroso‐Triazolopyrazine in Sitagliptin; Risk Assessment, Scavenger‐Based Mitigation, and Stress Stability Study

N ‐nitroso‐triazolopyrazine(NTTP/7‐nitroso‐3‐(trifluoromethyl)‐5,6,7,8‐tetrahydro‐[1,2,4]triazolo[4,3‐a]pyrazine), an NDSRI associated with sitagliptin, poses a significant nitrosamine risk due to its very low acceptable intake (37 ng/day). A robust UHPLC–MS/MS method was developed and validated for the simultaneous quantification of N ‐nitroso‐triazolopyrazine and its precursor, triazolopyrazine(3‐(Trifluoromethyl)‐5,6,7,8‐tetrahydro[1,2,4]triazolo[4,3‐a]pyrazine), in both drug substance and drug product within a single run. The method uses an Agilent Poroshell C18 column with 10 mM ammonium formate as mobile phase A and 0.1% formic acid in methanol as mobile phase B, detected in ESI‐positive MRM mode. The method demonstrated excellent linearity ( R 2 ≈0.9992–0.9994), high sensitivity (LOD/LOQ: 0.037/0.11 ppm), good accuracy (recoveries: ∼90.9–115.3%), and precision (%RSD ≤ 4.2%). Mechanistic studies showed N ‐nitroso‐triazolopyrazine formation is strongly pH‐dependent, favoring acidic, nitrite‐rich conditions. Degradation studies confirmed the formation of both impurities under all stress conditions, predominantly acidic. Scavenger studies identified ascorbic acid and 2,5‐dihydroxybenzoic acid as effective in suppressing N ‐nitroso‐triazolopyrazine formation.