Solid pharmaceutical compositions comprising biopterin derivatives and uses of such compositions

A method of treating a disease in a subject, comprising the step of administering to a subject in need thereof a solid pharmaceutical composition comprising

• a) a compound having the formula (I):
• and/or a compound having the formula (II):
• and
• b) two different sodium phosphate salts, wherein the two different sodium phosphate salts are NaH2PO4.2 H2O and Na2HPO4.2 H2O, and wherein the quantity of the NaH2PO4.2 H2O and Na2HPO4.2 H2O present in the composition is chosen such that the molar ratio of both NaH2PO4.2 H2O and Na2HPO4.2 H2O to compound (I) or compound (II) ranges from 0.02 to 0.5, with the proviso that the composition does not include an antioxidant,
• wherein the disease is selected from the group consisting of traumatic brain injury, non-traumatic brain injury, elevated cranial pressure, and secondary brain injury.