Epidural administration of neostigmine-loaded nanofibers provides extended analgesia in rats

Epidural Administration of Curcumin-Loaded Polycaprolactone/Gelatin Electrospun Nanofibers for Extended Analgesia After Laminectomy in Rats

Several clinical studies have reported the analgesic effect of curcumin (Curc) in various situations such as rheumatoid arthritis, osteoarthritis, and postsurgical pain. Therefore, in this work, Curc-loaded electrospun nanofibers (NFs) are designed to evaluate their sustained release on analgesic effect duration in rats after epidural placement via repeated formalin and tail-flick tests. The Curc-loaded polycaprolactone/gelatin NFs (Curc-PCL/GEL NFs) are prepared through an electrospinning technique and introduced to the rat's epidural space after laminectomy. The physicochemical and morphology features of the prepared Curc-PCL/GEL NFs were characterized via FE-SEM, FTIR, and degradation assay. The in vitro and in vivo concentrations of Curc were measured to evaluate the analgesic efficacy of the drug-loaded NFs. Rat nociceptive responses are investigated through repeated formalin and tail-flick tests for 5 weeks after the placement of NFs. Curc had a sustained release from the NFs for 5 weeks, and its local pharmaceutical concentrations were much greater than plasma concentrations. Rat's pain scores in both early and late phases of the formalin test were remarkably decreased in the experimental period. Rat's tail-flick latency was remarkably enhanced and remained constant for up to 4 weeks. Our findings show that the Curc-PCL/GEL NFs can supply controlled release of Curc to induce extended analgesia after laminectomy.

Epidural Injection of Harpagoside for the Recovery of Rats with Lumbar Spinal Stenosis

Epidural administration is the leading therapeutic option for the management of pain associated with lumbar spinal stenosis (LSS), which is characterized by compression of the nerve root due to narrowing of the spinal canal. Corticosteroids are effective in alleviating LSS-related pain but can lead to complications with long-term use. Recent studies have focused on identifying promising medications administered epidurally to affected spinal regions. In this study, we aimed to investigate the effectiveness of harpagoside (HAS) as an epidural medication in rats with LSS. HAS at various concentrations was effective for neuroprotection against ferrous sulfate damage and consequent promotion of axonal outgrowth in primary spinal cord neurons. When two concentrations of HAS (100 and 200 μg/kg) were administered to the rat LSS model via the epidural space once a day for 4 weeks, the inflammatory responses around the silicone block used for LSS were substantially reduced. Consistently, pain-related factors were significantly suppressed by the epidural administration of HAS. The motor functions of rats with LSS significantly improved. These findings suggest that targeted delivery of HAS directly to the affected area via epidural injection holds promise as a potential treatment option for the recovery of patients with LSS.

Epidural Injection Method for Long-Term Pain Management in Rats with Spinal Stenosis

Epidural injection is one of the most common nonsurgical treatment options for long-term pain relief in lumbar spinal stenosis. Recently, various nerve block injections have been used for pain management. Among them, nerve block through epidural injection is a safe and effective method for the clinical treatment of low back or lower extremity pain. Although the epidural injection method has a long history, the effectiveness of long-term epidural injections in disc diseases has not been scientifically proven. In particular, to verify the safety and efficacy of drugs in preclinical studies, the route and method of drug administration in terms of the clinical application method and duration of use must be established. However, there is no standardized method for long-term epidural injections in a rat model of stenosis to identify the precise efficacy and safety of epidural injections. Therefore, standardizing the epidural injection method is very important for evaluating the efficacy and safety of drugs used for back or lower extremity pain. We describe the first standardized long-term epidural injection method for evaluating the efficacy and safety of drugs according to their route of administration in rats with lumbar spinal stenosis.

In pursuit of functional electrospun materials for clinical applications in humans

Electrospinning is a simple, low-cost and versatile approach to fabricate multifunctional materials useful in drug delivery and tissue engineering applications. Despite its emergence into other manufacturing sectors, electrospinning has not yet made a transformative impact in the clinic with a pharmaceutical product for use in humans. Why is this the current state of electrospun materials in biomedicine? Is it because electrospun materials are not yet capable of overcoming the biological safety and efficacy challenges needed in pharmaceutical products? Or, is it that technological advances in the electrospinning process are needed? This review investigates the current state of electrospun materials in medicine to identify both scientific and technological gaps that may limit clinical translation.