Injectable PLGA-Coated Ropivacaine Produces A Long-Lasting Analgesic Effect on Incisional Pain and Neuropathic Pain

Local anesthetic delivery systems for the management of postoperative pain

Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs), including amide-type LAs, ester-type LAs, and other potential ion-channel blockers, are emerging as drugs for POP management because of their effectiveness and affordability. However, LAs typically exhibit short durations of action and prolonging the duration by increasing their dosage or concentration may increase the risk of motor block or systemic local anesthetic toxicity. In addition, techniques using LAs, such as intrathecal infusion, require professional operation and are prone to catheter displacement, dislodgement, infection, and nerve damage. With the development of materials science and nanotechnology, various LAs delivery systems have been developed to compensate for these disadvantages. Numerous delivery systems have been designed to continuously release a safe dose in a single administration to ensure minimal systemic toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia according to changes in the external trigger conditions, achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this review, we summarize POP pathways, animal models and methods for POP testing, and highlight LAs delivery systems for POP management. STATEMENT OF SIGNIFICANCE: Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs) are emerging as drugs for POP management because of their effectiveness and affordability. However, they exhibit short durations and toxicity. Various LAs delivery systems have been developed to compensate for these disadvantages. They have been designed to continuously release a safe dose in a single administration to ensure minimal toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia to achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this paper, we summarize POP pathways, animal models, and methods for POP testing and highlight LAs delivery systems for POP management.

Sustained release local anesthetics for pain management: relevance and formulation approaches

This review attempted to ascertain the rationale for the formulation of sustained-release local anesthetics and summarize the various formulation approaches designed to date to achieve sustained and localized local analgesic effects. The incidence of pain, which is the concern of patients as well as health care professionals, is increasing due to accidents, surgical procedures, and other diseases. Local anesthetics can be used for the management of moderate to severe acute and chronic pain. They also allow regional analgesia, in situations where the cause and source of the pain are limited to a particular site or region, without the need for loss of consciousness or systemic administration of other analgesics thereby decreasing the risk of potential toxicities. Though they have an interesting antipain efficacy, the short duration of action of local anesthetics makes the need for their multiple injections or opioid adjuvants mandatory. To overcome this problem, different formulations are being designed that help achieve prolonged analgesia with a single dose of administration. Combination with adjuvants, liposomal formulations, lipid-based nanoparticles, thermo-responsive nanogels, microspheres, microcapsules, complexation with multivalent counterions and HP-β-CD, lipid-based nanoparticles, and bio-adhesive films, and polymeric matrices are among the approaches. Further safety studies are required to ensure the safe and effective utilization of sustained-release local anesthetics. Moreover, the release kinetics of the various formulations should be adequately established.

Ropivacaine microsphere-loaded electroconductive nerve dressings for long-acting analgesia and functional recovery following diabetic peripheral nerve injury

In recent years, electroconductive hydrogels (ECHs) have shown great potential in promoting nerve regeneration and motor function recovery following diabetic peripheral nerve injury (PNI), attributed to their similar electrical and mechanical characteristics to innate nervous tissue. It is well-established that PNI causes motor deficits and pain, especially in diabetics. Current evidence suggests that ropivacaine (ROP) encapsulated in poly lactic-co-glycolic acid (PLGA) microspheres (MSs) yield a sustained analgesic effect. In this study, an ECH electroconductive network loaded with MS/ROP (ECH-MS/ROP) was designed as a promising therapeutic approach for diabetic PNI to exert lasting analgesia and functional recovery. This dual delivery system allowed ROP's slow and sequential release, achieving sustained analgesia as demonstrated by our in vivo experiments. Meanwhile, this system was designed like a lamellar dressing, with desirable adhesive and self-curling properties, convenient for treating injured nerve tissues via automatically wrapping tube-like structures, facilitating the process of implantation. Our in vitro assays verified that ECH-MS/ROP was able to enhance the adhesion and motility of Schwann cells. Besides, both in vitro and in vivo studies substantiated that ECH-MS/ROP stimulated myelinated axon regeneration through the MEK/ERK signaling pathway, thereby improving muscular denervation atrophy and facilitating functional recovery. Therefore, this study suggests that the ECH-MS/ROP dressing provides a promising strategy for treating diabetic PNI to facilitate nerve regeneration, functional recovery and pain relief.

Preparation of Ropivacaine Encapsulated by Zeolite Imidazole Framework Microspheres as Sustained-Release System and Efficacy Evaluation

The management of persistent postoperative pain still remains a clinical challenge currently. Although ropivacaine (RVC) is widely used for postoperative analgesia as a local anesthetic, the short half-life makes it difficult to achieve the desired duration of analgesia. Herein, a RVC sustained-release microspheres encapsulated by zeolite imidazole framework-8 (RVC@ZIF-8) was synthesized for the first time, which prolonged the sustained-release of RVC and decreased the resulting drug toxicity. RVC can continuously release in vitro for at least 96 h with high drug loading of 30.6 % and RVC@ZIF-8 had excellent biocompatibility and low cytotoxicity. In sciatic nerve block model, the sensory block time of RVC@ZIF-8 was significantly prolonged compared with RVC, achieving more than 72 h post injection and no inflammation or lesion were found. Based on high drug loading, ideal sustained-release and superior biological safety, RVC@ZIF-8 will be a novel delivery material for local anesthetic with potential application.

Enzyme-Catalyzed One-Step Synthesis of Ionizable Cationic Lipids for Lipid Nanoparticle-Based mRNA COVID-19 Vaccines

Ionizable cationic lipid-containing lipid nanoparticles (LNPs) are the most clinically advanced non-viral gene delivery platforms, holding great potential for gene therapeutics. This is exemplified by the two COVID-19 vaccines employing mRNA-LNP technology from Pfizer/BioNTech and Moderna. Herein, we develop a chemical library of ionizable cationic lipids through a one-step chemical-biological enzyme-catalyzed esterification method, and the synthesized ionizable lipids were further prepared to be LNPs for mRNA delivery. Through orthogonal design of experiment methodology screening, the top-performing AA3-DLin LNPs show outstanding mRNA delivery efficacy and long-term storage capability. Furthermore, the AA3-DLin LNP COVID-19 vaccines encapsulating SARS-CoV-2 spike mRNAs successfully induced strong immunogenicity in a BALB/c mouse model demonstrated by the antibody titers, virus challenge, and T cell immune response studies. The developed AA3-DLin LNPs are an excellent mRNA delivery platform, and this study provides an overall perspective of the ionizable cationic lipids, from aspects of lipid design, synthesis, screening, optimization, fabrication, characterization, and application.

Lipid-Polymer Hybrid "Particle-in-Particle" Nanostructure Gene Delivery Platform Explored for Lyophilizable DNA and mRNA COVID-19 Vaccines

SARS-CoV-2 has led to a worldwide pandemic, catastrophically impacting public health and the global economy. Herein, a new class of lipid-modified polymer poly (β-amino esters) (L-PBAEs) is developed via enzyme-catalyzed esterification and further formulation of the L-PBAEs with poly(d,l-lactide-coglycolide)-b-poly(ethylene glycol) (PLGA-PEG) leads to self-assembly into a "particle-in-particle" (PNP) nanostructure for gene delivery. Out of 24 PNP candidates, the top-performing PNP/C12-PBAE nanoparticles efficiently deliver both DNA and mRNA in vitro and in vivo, presenting enhanced transfection efficacy, sustained gene release behavior, and excellent stability for at least 12 months of storage at -20 °C after lyophilization without loss of transfection efficacy. Encapsulated with spike encoded plasmid DNA and mRNA, the lipid-modified polymeric PNP COVID-19 vaccines successfully elicit spike-specific antibodies and Th1-biased T cell immune responses in immunized mice even after 12 months of lyophilized storage at -20 °C. This newly developed lipid-polymer hybrid PNP nanoparticle system demonstrates a new strategy for both plasmid DNA and mRNA delivery with the capability of long-term lyophilized storage.

Computational approach to decode the mechanism of curcuminoids against neuropathic pain

BACKGROUND

Curcumin (CUR), demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) are the main components of turmeric that commonly used to treat neuropathic pain (NP). However, the mechanism of the therapy is not sufficiently clarified. Herein, network pharmacology, molecular docking and molecular dynamics (MD) approaches were used to investigate the mechanism of curcuminoids for NP treatment.

METHODS

Active targets of curcuminoids were obtained from the Swiss Target database, and NP-related targets were retrieved from GeneCards, OMIM, Drugbank and TTD databases. A protein-protein interaction (PPI) network was built to screen the core targets. Furthermore, DAVID was used for GO and KEGG pathway enrichment analyses. Interactions between potential targets and curcuminoids were assessed by molecular docking and the MD simulations were run for 100ns to validate the docking results on the top six complexes.

RESULTS

CUR, DMC, and BDMC had 100, 99 and 100 targets respectively. After overlapping with NP there were 33, 33 and 31 targets respectively. PPI network analysis of TOP 10 core targets, TNF, GSK3β were common targets of curcuminoids. Molecular docking and MD results indicated that curcuminoids bind strongly with the core targets. The GO and KEGG showed that curcuminoids regulated nitrogen metabolism, the serotonergic synapse and ErbB signaling pathway to alleviate NP. Furthermore, specific targets in these three compounds were also analysed at the same time.

CONCLUSIONS

This study systematically explored and compared the anti-NP mechanism of curcuminoids, providing a novel perspective for their utilization.

Drug delivery to the central nervous system

Despite the rising global incidence of central nervous system (CNS) disorders, CNS drug development remains challenging, with high costs, long pathways to clinical use and high failure rates. The CNS is highly protected by physiological barriers, in particular, the blood-brain barrier and the blood-cerebrospinal fluid barrier, which limit access of most drugs. Biomaterials can be designed to bypass or traverse these barriers, enabling the controlled delivery of drugs into the CNS. In this Review, we first examine the effects of normal and diseased CNS physiology on drug delivery to the brain and spinal cord. We then discuss CNS drug delivery designs and materials that are administered systemically, directly to the CNS, intranasally or peripherally through intramuscular injections. Finally, we highlight important challenges and opportunities for materials design for drug delivery to the CNS and the anticipated clinical impact of CNS drug delivery.

Synthesis of nanocapsules blended polymeric hydrogel loaded with bupivacaine drug delivery system for local anesthetics and pain management

Local anesthetics are used clinically for the control of postoperative pain management. This study aimed to develop chitosan (CS) with genipin (GP) hydrogels as the hydrophilic lipid shell loaded poly(ε-caprolactone) (PC) nanocapsules as the hydrophobic polymeric core composites (CS-GP/PC) to deliver bupivacaine (BPV) for the prolongation of anesthesia and pain relief. The swelling ratio, in vitro degradation, and rheological properties enhancement of CS-GP/PC polymeric hydrogel. The incorporation of PC nanocapsules into CS-GP hydrogels was confirmed by SEM, FTIR, and XRD analysis. Scanning electron microscopy results demonstrated that the CS-GP hydrogels and CS-GP/PC polymeric hydrogels have a porous structure, the pore dimensions being non-uniform with diameters between 25 and 300 μm. The in vitro drug release profile of CS-GP/PC polymeric hydrogel has been achieved 99.2 ± 1.12% of BPV drug release in 36 h. Cellular viability was evaluated using the CCK-8 test on 3T3 fibroblast cells revealed that the obtained CS-GP/PC polymeric hydrogel with BPV exhibited no obvious cytotoxicity. The CS-GP/PC polymeric hydrogel loaded with BPV showed significant improvement in pain response compared to the control group animals for at least 7 days. When compared with BPV solution, CS-GP hydrogel and CS-GP/PC polymeric hydrogel improved the skin permeation of BPV 3-fold and 5-fold in 24 h, respectively. In vitro and in vivo results pointed out PC nanocapsules loaded CS-GP hydrogel can act as effective drug carriers, thus prolonging and enhancing the anesthetic effect of BPV. Histopathological results demonstrated the excellent biodegradability and biocompatibility of the BPV-loaded CS-GP/PC polymeric hydrogel system on 7, 14, and 21 days without neurotoxicity.

HIGHLIGHTS

Preparation and characterization of CS-GP/PC polymeric hydrogel system.

BPV-loaded CS-GP/PC exhibited prolonged in vitro release in PBS solution.

Cytotoxicity of BPV-loaded CS-GP/PC polymeric hydrogel against fibroblast (3T3) cells.

Development of CS-GP/PC a promising skin drug-delivery system for local anesthetic BPV.

Escherichia coli adhesin protein-conjugated thermal responsive hybrid nanoparticles for photothermal and immunotherapy against cancer and its metastasis

Background

Advanced cancer therapy is targeted at primary tumors and also recurrent or metastatic cancers. Combinational cancer treatment has recently shown high efficiency against recurrent and metastatic cancers. In this study, we synthesized a thermal responsive hybrid nanoparticle (TRH) containing FimH, an immune stimulatory recombinant protein, for the induction of a combination of photothermal therapy (PTT) and immunotherapy against cancer and its metastasis.

Methods

The hybrid nanoparticle was incorporated with a near-infrared (NIR) absorbent, indocyanine green, and decorated with FimH on its surface to form F-TRH. F-TRH was evaluated for its anticancer and antimetastatic effects against CT-26 carcinoma in mice by combining PTT and immunotherapy.

Results

NIR laser irradiation elicited an elevation of temperature in F-TRH, which induced apoptosis in CT-26 carcinoma cells in vitro. In addition, F-TRH and NIR laser irradiation promoted photothermal-mediated therapeutic effects against CT-26 and 4T1 tumors in mice. The release of FimH from F-TRH in response to elevated temperature and apoptotic bodies of cancer cells via PTT elicited dendritic cell-mediated cancer antigen-specific T-cell responses, which subsequently inhibited the second challenge of CT-26 and 4T1 cell growth in the lung.

Conclusions

These data demonstrate the potential use of F-TRH for immuno-photothermal therapy against cancer and its recurrence and metastasis.

A Recent Update on Drug Delivery Systems for Pain Management

Pain remains a global health challenge affecting approximately 1.5 billion people worldwide. Pain has been an implicit variable in the equation of human life for many centuries considering different types and the magnitude of pain. Therefore, developing an efficacious drug delivery system for pain management remains an open challenge for researchers in the field of medicine. Lack of therapeutic efficacy still persists, despite high throughput studies in the field of pain management. Research scientists have been exploiting different alternatives to curb the adverse side effects of pain medications or attempting a more substantial approach to minimize the prevalence of pain. Various drug delivery systems have been developed such as nanoparticles, microparticles to curb adverse side effects of pain medications or minimize the prevalence of pain. This literature review firstly provides a brief introduction of pain as a sensation and its pharmacological interventions. Second, it highlights the most recent studies in the pharmaceutical field for pain management and serves as a strong base for future developments. Herein, we have classified drug delivery systems based on their sizes such as nano, micro, and macro systems, and for each of the reviewed systems, design, formulation strategies, and drug release performance has been discussed.

FTO (Fat-Mass and Obesity-Associated Protein) Participates in Hemorrhage-Induced Thalamic Pain by Stabilizing Toll-Like Receptor 4 Expression in Thalamic Neurons

[Figure: see text].