Trimethoprim EP Impurity H

Trimethoprim EP Impurity H is a process-derived byproduct formed via hydroxylation and demethylation during the synthesis of Trimethoprim. It retains the pyrimidine-pteridine core but features a 3-hydroxy-4-methoxybenzyl side chain with an additional hydroxyl group at the 5-position of the pyrimidine ring. This impurity exhibits enhanced polarity compared to the parent drug due to its trihydroxylated aromatic substituent and oxygenated heterocyclic linkage. It serves as an HPLC reference standard for monitoring oxidative degradation pathways in Trimethoprim quality control.