The present invention relates generally to pharmaceutical formulations of conjugated oligonucleotides, such as pegylated aptamers, as well as to a method of preparing and using the same. The pharmaceutical formulations have desirable shelf life characteristics under varied storage conditions. Formulations of oligonucleotides or oligonucleotides conjugates and methods for their preparation and use are provided having a shelf life of at least about 24 months or, more preferably, at least about 36 months at about 2 to about 30°C. In particular embodiments, the formulations have a pH of about 7 or less and contain methionine. Optionally, dissolved oxygen content is reduced during the manufacturing process is used to improve desired shelf life characteristics.
