Extension Effect of Poly(Lactic-Co-Glycolic Acid)-Polyethylene Glycol Encapsulated Bupivacaine on Postoperative Neuroblockade in Cardiothoracic Surgery

Abstract

This research was aimed to evaluate extension effect of poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA/PEG) thermosensitive hydrogel-encapsulated bupivacaine (BUP) on neuroblockade in cardiothoracic surgery and explore the potential adoption of this thermosensitive hydrogel as a drug carrier for postoperative neuroblockade. An animal experimental design was adopted. First, PLGA/PEG thermosensitive hydrogel was prepared and BUP was encapsulated as the drug carrier and evaluated. Then, 40 rats were selected for thoracic surgery and randomly rolled into experimental group (injection of hydrogel in the cardiothoracic region for neuroblockade after cardiothoracic surgery) and control group (conventional BUP injection). The neuroblockade effects (maximum possible effect (MPE), sensory and motor blockade duration) in the two groups of rats were compared and analyzed. The Results showed that gel-microsphere (Gel-MS) composite drug delivery system was successfully prepared, which exhibited a complete 3D porous structure and favorable encapsulation effect for BUP. Rheological testing showed favorable hardness (G′) and viscosity (G″) for Gel-MS/BUP (GMB). The experimental group exhibited a notably prolonged period of 100% MPE with a slower rate of decline versus controls. Sensory blockade and motor blockade durations in the experimental group rats were (22.4±3.8) h and (22.7±3.5) h, respectively, both markedly longer than those in the control group rats (P <0.05). In Conclusion, Gel/MS-BUP demonstrated a remarkable extension effect on neuroblockade in cardiothoracic surgery, indicating its potential adoption value in prolonging anesthesia duration.