Objective We aimed to monitor the physicochemical stability of prostaglandin E₁ (PGE₁) 1.5 and 15 µg/mL in 10% dextrose stored in polypropylene syringes.

Methods We developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method to detect and quantify levels of PGE₁. Method selectivity was performed with a mixture of PGE₁ and its degradation products. Forced degradation tests were performed to determine which degradation products were most likely to form. PGE₁ injection solutions in 10% dextrose were stored in unprotected and shielded-from-light polypropylene syringes in a climatic chamber. Samples were taken immediately after preparation (T₀) and after 24, 48, 72 and 168 hours for analysis. PGE₁ solutions were considered stable if ≥90.0% of the initial concentration was retained.

Results The LC-HRMS method was validated in the range of 0.086-0.200µg/mL PGE₁ with trueness values between 98.2% and 100.3%, and repeatability and intermediate precision values of <2.2%and <4.7%, respectively. The quantification and detection limits of the method were 0.086 and 0.026µg/mL, respectively. PGE₁ and its degradation products were resolved chromatographically. PGE₁ injection solutions were≥90.0%stable after 48hours in unprotected from light (UPL) syringes. The solutions remained clear without precipitation, colour or pH modification and subvisible particles within the permitted levels. Prostaglandin A₁ was the sole degradation product observed.

Conclusions A LC-HRMS method to evaluate PGE₁ stability in a 10% dextrose was developed and validated. PGE₁ 1.5 and 15µg/mL in 10% dextrose solution are stable for 48hours when stored at 30ºC in UPL polypropylene syringes.