Repeat Epidural Injections of SP-102 (Dexamethasone Sodium Phosphate Injectable Gel) in Subjects with Lumbosacral Radiculopathy

Paravertebrally-Injected Multifunctional Hydrogel for Sustained Anti-Inflammation and Pain Relief in Lumbar Disc Herniation

Pain caused by lumbar disc herniation (LDH) severely compromises patients' quality of life. The combination of steroid and local anesthetics is routinely employed in clinics to alleviate LDH-induced pain. However, the approach only mediates transient efficacy and requires repeated and invasive lumbar epidural injections. Here a paravertebrally-injected multifunctional hydrogel that can efficiently co-load and controlled release glucocorticoid betamethasone and anesthetics ropivacaine for sustained anti-inflammation, reactive oxygen species (ROS)-removal and pain relief in LDH is presented. Betamethasone is conjugated to hyaluronic acid (HA) via ROS-responsive crosslinker to form amphiphilic polymer that self-assemble into particles with ropivacaine loaded into the core. Solution of drug-loaded particles and thermo-sensitive polymer rapidly forms therapeutic hydrogel in situ upon injection next to the herniated disc, thus avoiding invasive epidural injection. In a rat model of LDH, multifunctional hydrogel maintains the local drug concentration 72 times longer than free drugs and more effectively inhibits the expression of pro-inflammatory cytokines and pain-related molecules including cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2). Therapeutic hydrogel suppresses the LDH-induced pain in rats for 12 days while the equivalent dose of free drugs is only effective for 3 days. This platform is also applicable to ameliorate pain caused by other spine-related diseases.

Dexamethasone-Loaded Injectable In-situ Thermal Crosslinking Magnetic Responsive Hydrogel for the Physiochemical Stimulation of Acupoint to Suppress Pain in Sciatica Rats

The physicochemical stimulation of acupoints is a widespread treatment strategy for different diseases, such as sciatica. Its efficacy is mainly based on the temporal and spatial modulation of the physicochemical properties of the acupoints. The existing therapies based on the stimulation of acupoints have certain disadvantages. Therefore, in this study, injectable dexamethasone (DXM)- and magnetic Fe₃O₄ nanoparticles-loaded chitosan/β-glycerophosphate (CS/GP) thermal crosslinking hydrogels were prepared, thereby improving the performance of embedding materials. The sciatica rat models were established to compare the therapeutic effects of hydrogels and catgut. The DXM or Fe₃O₄-loaded CS/GP hydrogels were compared in terms of their gelation kinetics, release kinetics, magnetic responsiveness in-vitro, and biocompatibility as well as their analgesic effects on the chronic constriction injury of the sciatic nerve (CCI) rats in-vivo. The CS/GP/Fe₃O₄/DXM hydrogel showed comparable gelation kinetics and good magnetic responsiveness in-vitro. This hydrogel could relieve sciatica by reducing the expression levels of inflammatory factors in serum, inhibiting the p38MAPK (p38, mitogen-activated protein kinase) phosphorylation, and decreasing the expression level of the P2X4 receptor (P2X4R) in the spinal dorsal horn. In conclusion, the DXM or Fe₃O₄-loaded CS/GP hydrogels can be considered as a treatment option for the physiochemical stimulation therapy of acupoints to improve sciatica.