HYR-PB21: A Comprehensive Analysis of a Novel Bupivacaine Pamoate Cocrystal Formulation for Extended-Duration Postoperative Analgesia

Executive Summary

HYR-PB21 is an investigational, sustained-release formulation of the well-established local anesthetic bupivacaine, engineered specifically for the management of postoperative pain.[1] Developed by Hefei Cosource Pharmaceuticals, Inc., this novel therapeutic is currently in Phase 3 clinical trials in China for anesthesia and postoperative pain, positioning it as a significant new entrant in the non-opioid analgesics market.[2]

It is critical to establish at the outset that the vast majority of peer-reviewed literature, patent filings, and clinical trial registrations unequivocally identify HYR-PB21 as a bupivacaine formulation.[1] A single source describing a similarly named compound as a small-molecule kinase inhibitor for oncology is considered erroneous or referring to a separate, unrelated agent and is disregarded for the purposes of this analysis.[5]

The core innovation of HYR-PB21 lies in its unique pharmaceutical formulation: a bupivacaine pamoate cocrystal that forms a microparticle suspension for injection.[6] This molecular architecture confers very low solubility in aqueous environments, creating a depot effect at the site of administration that facilitates a slow, continuous release of bupivacaine over an extended period.[6] This mechanism contrasts with more complex delivery platforms, such as the liposomal technology used in market competitors.