Patent ID: 7276359

Claim:
A method for preparing a lyophilized polynucleotide composition comprising the steps of: (a) forming an aqueous plasmid DNA solution having a pH of from about 6.2 to about 7.8 and comprising from about 0.1 mg/mL to about 5 mg/mL of at least one plasmid DNA based on the total volume of said plasmid DNA solution, and from about 0.5 weight percent to about 10 weight percent of at least one carbohydrate cryoprotectant, based on the total weight of said plasmid DNA solution: (b) cooling said plasmid DNA solution to a temperature of from about −30° C. to about −70° C., until frozen; (c) applying vacuum to reduce the pressure to about 25 mTorr to about 250 mTorr; (d) gradually heating said plasmid DNA solution a first time to a temperature of from about −40° C. to about 20° C. over a period of from about 5 hours to about 40 hours; (e) holding said plasmid DNA solution after heating step (d), at a temperature of from about −35° C. to about 10° C. and at a pressure of from 25 mTorr to about 250 mTorr for a period of from about 1 hour to about 10 hours; (f) drying the plasmid DNA solution by gradually heating said solution after the holding step (e), to a temperature of from about 20° C. to about 30° C. over a period of from about 1 hour to about 20 hours and at a pressure of from about 25 mTorr to about 150 mTorr; and (g) recovering the lyophilized composition having water content of from about 0.5 weight percent to about 6 weight percent based on the total weight of said recovered composition.