Pharmaceutical compositions comprising sepiapterin and uses thereof

1. A pharmaceutical composition comprising an effective amount of sepiapterin and a pharmaceutically acceptable carrier, wherein the relative amount of antioxidant to sepiapterin is between 0 and 20% wt/wt;

wherein the antioxidant is ascorbic acid, an ester of ascorbic acid, or a salt of ascorbic acid.

2. The pharmaceutical composition of claim 1 , wherein the pharmaceutical composition comprises less than 1.3% of lactoylpterin by weight of the combined amount of sepiapterin and lactoylpterin in the composition.

3. The pharmaceutical composition of claim 1 , wherein the pharmaceutical composition is stable at room temperature for at least 6 months.

4. A method of treating phenylketonuria in a subject in need thereof, the method comprising administering to the subject an effective amount of a pharmaceutical composition of claim 1 .

5. A method of decreasing phenylalanine levels in a subject in need thereof, the method comprising administering to the subject an effective amount of a pharmaceutical composition of claim 1 .

6. A method of treating a tetrahydrobiopterin deficiency in a subject in need thereof, the method comprising administering to the subject an effective amount of a pharmaceutical composition of claim 1 .

7. The method of claim 6 , wherein the tetrahydrobiopterin deficiency is primary tetrahydrobiopterin deficiency.

8. The pharmaceutical composition of claim 1 , formulated as a powder.

9. The pharmaceutical composition of claim 2 , formulated as a powder.

10. The pharmaceutical composition of claim 3 , formulated as a powder.

11. The pharmaceutical composition of claim 1 , wherein the composition further comprises a dispersant selected from crosslinked polyvinylpyrrolidone, carboxymethylcellulose, croscarmellose sodium, starch, or alginic acid, wherein the pharmaceutical composition comprises 0.5-1.5% dispersant by total weight.

12. The pharmaceutical composition of claim 11 , wherein the dispersant is croscarmellose sodium, wherein the composition comprises 1% croscarmellose sodium by weight.

13. The pharmaceutical composition of claim 1 , wherein the composition further comprises an anti-caking agent or bulking agent selected from colloidal silicon dioxide, microcrystalline cellulose, tricalcium phosphate, microcrystalline cellulose, magnesium stearate, sodium bicarbonate, sodium ferrocyanide, potassium ferrocyanide, calcium ferrocyanide, calcium phosphate, sodium silicate, colloidal silicon dioxide, calcium silicate, magnesium trisilicate, talcum powder, sodium aluminosilicate, potassium aluminum silicate, calcium aluminosilicate, bentonite, aluminum silicate, stearic acid, and polydimethylsiloxane, wherein the composition comprises about 60-80% anti-caking or bulking agent by total weight.

14. The pharmaceutical composition of claim 13 , wherein the anti-caking or bulking agents are microcrystalline cellulose and silicon dioxide, wherein the composition comprises about 63% microcrystalline cellulose by weight and about 6% colloidal silicon dioxide by weight.

15. The pharmaceutical composition of claim 1 , wherein the antioxidant is selected from ascorbic acid, ascorbyl palmitate, ascorbyl myristate, ascorbyl stearate, or sodium ascorbate.

16. The pharmaceutical composition of claim 15 , wherein the antioxidant is ascorbic acid.

17. The pharmaceutical composition of claim 1 , wherein the ratio of sepiapterin to antioxidant is greater than 20:1.

18. The pharmaceutical composition of claim 1 , wherein the composition is substantially free of antioxidant.

19. The pharmaceutical composition of claim 1 , wherein the pharmaceutical composition comprises about 25% sepiapterin by total weight.

20. The pharmaceutical composition of claim 1 , wherein the composition comprises about 25% sepiapterin, about 63% microcrystalline cellulose, about 6% colloidal silicon dioxide, about 1% croscarmellose sodium, and about 5% ascorbic acid.