Use of Microfluidics to Fabricate Bioerodable Lipid Hybrid Nanoparticles Containing Hydromorphone or Ketamine for the Relief of Intractable Pain.

The two-stage microfluidic method allowed efficient production of analgesic/adjuvant drug-loaded NPs. Our proof-of-principle in vivo study shows prolonged hydromorphone analgesic for 78 h after single i.t. injection. At the i.t. dose administered, ketamine released from NPs was insufficient to augment hydromorphone analgesia.