Reversing neuromuscular blocking agent decamethonium by carboxylatopillar[6]arene based on host-guest encapsulation

Efficient Reversal of Neuromuscular Blocking Agent-Induced Biological Functions and Side Effects by an Extended Biphen[3]arene Carboxylate

Neuromuscular blocking agents (NMBAs) are widely administered during anethesia to prevent the patient from moving and optimize surgical conditions. Timely reversal of the muscle relaxation state induced by NMBAs at the end of surgery is necessary to recover autonomous respiration and muscle function. Herein, an extended biphen[3]arene carboxylate (ExBP3C) was designed and synthesized by a supramolecular sequestration approach as a reversal agent with high efficiency and generality against several representative NMBAs. ExBP3C exhibited robust host-guest complexation toward atracurium, rocuronium, vecuronium, pancuronium, and gallamine with an association constant of up to 108 M-1. A series of in vitro and in vivo safety tests preliminarily demonstrated that this synthetic macrocycle had good biocompatibility. Compared to sugammadex, post-treatment by an equivalent dose of ExBP3C could produce a more efficient reversal function. Additionally, a single dose of such a reversal agent was also able to completely recover overdose atracurium-induced heart rate abnormalities within 2 min.

A mini review of supramolecular antagonists based on macrocyclic host compounds

In the interdisciplinary domains of medicine and chemistry, addressing the issue of residual drugs (toxicants) that fail to fully exert therapeutic effects while potentially inducing toxic side effects has become increasingly critical. Researchers are actively seeking innovative solutions to this multifaceted challenge. Conventional small-molecule antagonists, commonly used in clinical settings, typically depend on "drug-receptor interactions" yet pose substantial developmental challenges. Recent advancements in the investigation of macrocyclic host compounds present a promising alternative. By leveraging the principles of host-guest chemistry, these macrocyclic hosts form stable inclusion complexes with residual drugs (toxicants), thereby decreasing their free concentration in the bloodstream and effectively mitigating associated toxic side effects. Consequently, macrocyclic host compounds represent a novel class of supramolecular antagonists (SAs). This article reviews recent progress in the application of macrocyclic host molecules-such as cyclodextrin, calix[n]arene, pillar[n]arene, and cucurbit[n]uril-as SA and examines current issues and future development prospects within the field.

Structure-Activity Relationship Studies Leading to the Discovery of Highly Water-Soluble and Biocompatible Acyclic Cucurbit[n]uril FY-3451 as a Universal Antagonist That Rapidly Reverses Neuromuscular Blocking Agents In Vivo

The development of a reversal agent that can rapidly reverse clinically used nondepolarizing neuromuscular blocking agents (NMBAs) has long been a challenge. Here, we report the synthesis of a series of highly water-soluble acyclic cucurbit[n]urils (acCBs). Systematic structure-activity relationship studies reveal that introducing two propylidene units on the peripheral benzene rings not only remarkably improves the activity of the corresponding derivative acCB6 (FY 3451) in reversing the neuromuscular block of rocuronium, cisatracurium, vecuronium, and pancuronium, the four clinically used NMBAs, through stable inclusion, but also allows for high water-solubility as well as a maximum tolerated dose (2000 mg/kg on rats). In vivo experiments with rats show that, at the identical dose of 25 mg/kg, for rocuronium, vecuronium, and pancuronium, acCB6 can achieve a recovery time shorter than that of sugammadex for rocuronium and, at the dose of 100 mg/kg, realize comparably rapid reversal for cisatracurium.

Macrocyclic Neutralizer to Polybrene via Direct Host-Guest Complexation

Hexadimethrine bromide (HB), a synthetic polycationic species, was introduced to clinical practice as a heparin antidote and recently used in gene therapy. However, HB causes various complications such as severe red blood cells (RBCs) aggregation and tissue damage. Herein, we have synthesized a water-soluble quaterphen[3]arene containing multiple sulfonate moieties (SQP3) as a novel macrocyclic neutralizer to reverse HB via direct host-guest complexation. SQP3 exhibited a robust binding affinity toward HB with a considerably high association constant of (4.73 ± 0.61) × 107 M-1. Co-dosed with 1 equiv of SQP3, HB-induced RBCs aggregation and blood coagulation could be effectively reversed. In vitro cellular assay verified that complexation of HB with SQP3 significantly decreased reactive oxygen species production, thereby suppressing cell apoptosis. In vivo neutralization efficacy studies demonstrated that HB/SQP3 was capable of alleviating related organic damage caused by HB and improving the survival rate of HB-treated mice from 20 to 100%.

Trapping and reversing neuromuscular blocking agent by anionic pillar[5]arenes: Understanding the structure-affinity-reversal effects

Selective relaxant binding agents (SRBA) have great potential in clinical surgeries for the precise reversal of neuromuscular blockades. Understanding the relationship between the structure-affinity-reversal effects of SRBA and neuromuscular blockade is crucial for the design of new SRBAs, which has rarely been explored. Seven anionic pillar[5]arenes (AP5As) with different aliphatic chains and anionic groups at both edges were designed. Their binding affinities to the neuromuscular blocking agent decamonium bromide (DMBr) were investigated using 1H NMR, isothermal titration calorimetry (ITC), and theoretical calculations. The results indicate that the capture of DMBr by AP5As is primarily driven by electrostatic interactions, ion-dipole interactions and C-H‧‧‧π interactions. The optimal size matching between the carboxylate AP5As and DMBr was ∼0.80. The binding affinity increased with an increase in the charge quantity of AP5As. Further animal experiments indicated that the reversal efficiency increased with increasing binding affinity for carboxylate or phosphonate AP5As. However, phosphonate AP5As exhibited lower reversal efficiencies than carboxylate AP5As, despite having stronger affinities with DMBr. By understanding the structure-affinity-reversal relationships, this study provides valuable insights into the design of innovative SRBAs for reversing neuromuscular blockade.

Pillar[6]MaxQ functions as an in vivo sequestrant for rocuronium and vecuronium

The binding affinity of pillar[6]MaxQ toward a panel of neuromuscular blockers and neurotransmitters was measured in phosphate buffered saline by isothermal titration calorimetry and 1H NMR spectroscopy. In vivo efficacy studies showed that P6MQ sequesters rocuronium and vecuronium and reverses their influence on the recovery of the train-of-four (TOF) ratio.

Adaptive and Ultrahigh-Affinity Recognition in Water by Sulfated Conjugated Corral[5]arene

The pursuit of synthetic receptors with high binding affinities has long been a central focus in supramolecular chemistry, driven by their significant practical relevance in various fields. Despite the numerous synthetic receptors that have been developed, most exhibit binding affinities in the micromolar range or lower. Only a few exceptional receptors achieve binding affinities exceeding 109  M-1 , and their substrate scopes remain rather limited. In this context, we introduce SC[5]A, a conjugated corral-shaped macrocycle functionalized with ten sulfate groups. Owing to its deep one-dimensional confined hydrophobic cavity and multiple sulfate groups, SC[5]A displays an extraordinarily high binding strength of up to 1011  M-1 towards several size-matched, rod-shaped organic dications in water. Besides, its conformation exhibits good adaptability, allowing it to encapsulate a wide range of other guests with diverse molecular sizes, shapes, and functionalities, exhibiting relatively strong affinities (Ka =106 -108  M-1 ). Additionally, we've explored the preliminary application of SC[5]A in alleviating blood coagulation induced by hexadimethrine bromide in vitro and in vivo. Therefore, the combination of ultrahigh binding affinities (towards complementary guests) and adaptive recognition capability (towards a wide range of functional guests) of SC[5]A positions it as exceptionally valuable for numerous practical applications.

Water-soluble terphen[3]arene macrocycle: a versatile reversal agent of neuromuscular blockers

Herein we report the design and synthesis of a terphen[n]arene derivative functionalised with sulfate acid ester groups. This water-soluble terphen[3]arene host effectively encapsulates a multitude of neuromuscular blocking agents (NMBAs) with high affinity, showing great potential as a NMBAs reversal agent in pharmaceutical research.

Pillar[6]MaxQ: A Potent Supramolecular Host for In Vivo Sequestration of Methamphetamine and Fentanyl

Pillar[6]MaxQ (P6AS) functions as an in vivo sequestration agent for methamphetamine and fentanyl. We use 1H NMR, isothermal titration calorimetry, and molecular modelling to deduce the geometry and strength of the P6AS•drug complexes. P6AS forms tight complexes with fentanyl (Kd=9.8 nM), PCP (17.1 nM), MDMA (25.5 nM), mephedrone (52.4 nM), and methamphetamine (101 nM). P6AS has good in vitro biocompatibility according to MTS metabolic, Adenylate Kinase cell death, and hERG ion channel inhibition assays, and the Ames fluctuation test. The no observed adverse effect level for P6AS is 45 mg/kg. The hyperlocomotion of mice treated with methamphetamine (0.5 mg/kg) can be ameliorated by treatment with P6AS (35.7 mg/kg) 5-minutes later, whereas the hyperlocomotion of mice treated with fentanyl (0.1 mg/kg) can be controlled by treatment with P6AS (5 mg/kg) up to 15-minutes later. P6AS has significant potential for development as a broad spectrum in vivo sequestration agent.

Host-guest binding of tetracationic cyclophanes to photodynamic agents inhibits posttreatment phototoxicity and maintains antitumour efficacy

In the past two decades, photodynamic therapy (PDT) has become an effective method for the treatment of cancer. However, the posttreatment residue of photodynamic agents (PDAs) causes long-term skin phototoxicity. Here, we apply naphthalene-derived, box-like tetracationic cyclophanes, named NpBoxes, to bind to clinically used porphyrin-based PDAs to alleviate their posttreatment phototoxicity by reducing their free content in skin tissues and 1O2 quantum yield. We show that one of the cyclophanes, 2,6-NpBox, could include the PDAs to efficiently suppress their photosensitivity for the generation of reactive oxygen species. A tumour-bearing mouse model study revealed that, when Photofrin, the most widely used PDA in clinic, was administrated at a dose corresponding to the clinical one, 2,6-NpBox of the same dose could significantly suppress its posttreatment phototoxicity on the skin induced by simulated sunlight irradiation, without imposing a negative influence on its PDT efficacy.

Separation of Low-Molecular-Weight Organics by Water-Soluble Macrocyclic Arenes

In this study, we fabricate a series of water-soluble anionic macrocyclic arenes, including pillar[5]arene (WP5), pillar[6]arene (WP6), leaning pillar[6]arene (WLT6), and biphenyl-extended pillar[6]arene (WBpP6), which show different separation capabilities toward low-molecular-weight organics, such as short chain haloalkanes, cyclic aliphatics, and aromatics, in water. The liquid-liquid distribution experiments are carried out at room temperature. The separation factor for low-molecular-weight organics is evaluated in the extraction of equimolar mixtures. WP6 demonstrates a high extraction efficiency of up to 89% in separating toluene/methylcyclohexane mixtures. These adsorbents also have the advantages of rapid adsorption, high separation efficiency, remarkable selectivity, and good recyclability. This work not only expands the application scope of macrocyclic chemistry, but also has practical research value for organics separation and water purification.