High-purity large-scale preparation of stannsoporfin

1. A method for producing a tin (IV) mesoporphyrin compound or salt thereof comprising:

a. preparing a solution or suspension of mesoporphyrin IX dihydrochloride or a salt thereof by:

(1) exposing a metallic hydrogenation catalyst to a hydrogen atmosphere to form a pre-hydrogenated catalyst; and

(2) contacting hemin with the pre-hydrogenated catalyst and maintaining the hemin and catalyst under one or more combinations of temperature, hydrogen pressure, and time to remove iron from the hemin and to reduce the vinyl groups of the hemin to ethyl groups, thus forming mesoporphyrin IX,

(3) isolating the mesoporhyrin IX as mesoporphyrin IX formate;

(4) purifying the isolated mesoporphyrin IX formate;

(5) converting the purified mesoporphyrin IX formate into mesoporphyrin IX dihydrochloride:

b. adding an organic solvent to the mesoporphyrin IX dihydrochloride to form the solution or suspension of mesoporphyrin IX dihydrochloride or a salt thereof; preparing a solution or suspension of tin (II) oxide, wherein steps (a) and (b) can occur in any order or simultaneously;

c. contacting the solution or suspension of tin (II) oxide with the solution or suspension of mesoporphyrin IX dihydrochloride or salt thereof by dropwise addition of the solution or suspension of mesoporphyrin IX dihydrochloride or salt thereof to form the tin (IV) mesoporphyrin compound or salt thereof; and

d. purifying the tin (IV) mesoporphyrin IX compound via hot acid trituration, followed by, treatment at high pH at or above pH 9 followed by re-acidification, and subsequent hot acid trituration.

2. The method of claim 1 , wherein the solution or suspension of tin (II) oxide and the solution or suspension of mesoporphyrin IX dihydrochloride or salt thereof are independently prepared with formic acid or acetic acid.

3. The method of claim 1 , wherein the metallic hydrogenation catalyst is palladium on carbon.