High-purity levetiracetam and pharmaceutical composition comprising high-purity levetiracetam

The invention provides high-purity levetiracetam and a pharmaceutical composition comprising high-purity levetiracetam. The high-purity levetiracetam is prepared with a one-pot method. According to the invention, (S)-2-aminobutyryl hydrochloride is adopted as an initial material, and is subjected to condensation and cyclization with 4-chlorobutyryl chloride, such that levetiracetam with a purity higher than 99.5% and with unknown individual impurity lower than 0.05% is obtained. Further, the levetiracetam obtained with the above method is dissolved in an organic solvent; the solution is filtered with a filter of 0.22-0.45mum while still hot, such that a chloride-qualified product with a chloride impurity amount lower than 0.02% can be obtained with high conversion rate. According to the invention, levetiracetam purity can be substantially improved, and a raw material and a pharmaceutical composition with excellent qualities can be further obtained.