Disclosed herein are compositions comprising a compound represented by structural formula (I): 2 g of which is reconstitutable in 10 mL of a water in less than 10 minutes, and methods for preparing these compositions. Also disclosed are compositions comprising a compound represented by structural formula (I) and a pharmaceutically acceptable excipient, wherein the molar ratio of said compound to said excipient is from 1:20 to 1:1, and methods for preparing these compositions.