Drug crystallization under microgravity conditions

A method for crystallizing molecules, said method performed in outer space and comprising:

• placing a molecular substance having a molecular weight equal to or lower than 500 Dalton in a microgravity environment, wherein the microgravity environment has a gravitational acceleration in a range of below 0.01 g to 0.000001 g;
• crystalizing molecules of the molecular substance in said microgravity environment, thereby obtaining at least one crystalline polymorph in said microgravity environment, wherein the molecules are crystallized by adding an anti-solvent to a solution of the molecules, by cooling a saturated solution of the molecules, by reacting the solution of the molecules with a solution containing ions, thereby forming an insoluble salt of the molecules, or by changing the pH of a solution comprising the molecules, thereby causing the molecules to precipitate in crystalline form;
• and
• removing the at least one crystalline polymorph from the microgravity environment by transferring it into an environment having a gravitational acceleration of 1 g;
• and
• wherein the molecules are active pharmaceutical ingredients (APIs).