The disclosure relates generally to nanoparticles to have about 0.The antibiotic therapy agent of 2 to about 35 % About 0.The hydrophobicity acid of 05 to about 30 weight % And about 35 to about 99.75 %s is this Biocompatible polymer diblock poly- (cream) poly- (second) glycol of acid or poly- poly- (second) glycol of (lactic acid) diblock -co- poly(ethylene glycol) acid. Other aspects include the method for preparing this nanoparticle.