HPLC-Based Analysis of Impurities in Sapropterin Branded and Generic Tablets.

This work was aimed at the definition of a chromatographic method able to separate and quantify impurities present in sapropterin-containing drugs during an accelerated stability study. The chromatographic method was applied to the orphan drug Kuvan((R)) and to its corresponding generic sapropterin Dipharma (Diterin((R))), both of which are approved for the treatment of hyperphenylalaninemia-induced symptoms. The two products tested had a similar manufacture date and both had an approved stability shelf-life of three years. Samples were analyzed by HPLC at T = 0 and after six months of storage at 40 degrees C and 75% relative humidity. Identification of the impurities was supported by a detailed mass spectrometry and MS/MS profile. The analysis demonstrated an overall higher stability for the Diterin((R)) formulation, which was related to a lower increase of some impurities compared to Kuvan((R)).