Patent ID: 6969708

Claim:
A process for reducing the rate of formation of (7Î±, 17Î±)-17-hydroxy-7-methyl-19-nor-17-pregn-4-en-20-yn-3-one impurity in crystals of (7Î±, 17Î±)-17-hydroxy-7-methyl-19-nor-17-pregn-5(10)-en-20-yn-3-one, wherein the (7Î±, 17Î±)-17-hydroxy-7-methyl-19-nor-17-pregn-5(10)-en-20-yn-3-one contains less than 0.5% by weight of (7Î±, 17Î±)-17-hydroxy-7-methyl-19-nor-17-pregn-4-en-20-yn-3-one as the impurity relative to (7Î±, 17Î±)-17-hydroxy-7-methyl-19-nor-17-pregn-5(10)-en-20-yn-3-one after drying, said process comprising: aging crystals of (7Î±, 17Î±)-17-hydroxy-7-methyl-19-nor-17-pregn-5(10)-en-20-yn-3-one in the presence of water for a period of time of at least 24 hours.