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Nano systems self-assembled only by lidocaine salts exhibit unexpected unique behaviors in different local tissues based on their intermolecular interaction, and can achieve up to 7.8 h sensory block without excipient residue.

Background and objectiveLong-acting nociceptive-selective regional anesthesia has remained an elusive clinical goal. We aspired to identify a novel compound that would produce nociceptive-selective regional anesthesia through the transient receptor potential vanilloid 1 (TRPV1) channels.MethodsWe designed and synthesized a novel compound (LL-a) that penetrates the cell membrane through TRPV1 channels and binds to voltage-gated sodium channels. The regional anesthetic effect of LL-a was evaluated in a rodent sciatic nerve block model. Electrophysiological recording was applied to test the inhibition of LL-a on voltage-gated sodium channel currents.ResultsLL-a inhibited sodium channel currents on the dorsal root ganglion neurons of mice and this action was diminished by TRPV1 channel knockout. In a sciatic nerve block model of a rat, 0.2% and 0.4% (w/v) LL-a produced selective sensory block with median (IQR) durations of 42.0 (24.0, 48.0) and 72.0 (69.0, 78.0) hours, respectively. No motor block was found for 0.2% LL-a. 0.4% LL-a produced a motor block with a median (IQR) duration of 3.0 (0.0, 6.0) hours. This selective sensory block was not observed on TRPV1 knockout mice. As a positive control, 0.5% and 0.75% levobupivacaine produced a non-selective sciatic nerve block with median (IQR) durations of 2.8 (2.6, 2.8) and 3.8 (3.8, 4.8) hours, respectively. No systemic or local irritation was observed during injection of LL-a and sensory and motor function completely recovered for all the animals.ConclusionsLL-a is a potential novel local anesthetic for long-lasting nociceptive-selective analgesia.

Fei Peng,1 Jing Liu,1,2 Yujun Zhang,1,2 Guoyan Zhao,1,2 Deying Gong,1,2 Liu He,1,2 Wensheng Zhang,1,2 Feng Qiu1,2 1Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China; 2National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of ChinaCorrespondence: Feng Qiu; Wensheng Zhang, Email fengqiu@scu.edu.cn; zhang_ws@scu.edu.cnIntroduction: Ropivacaine as a conventional local anesthetic has been used more and more frequently in the treatment of postoperative pain, but its analgesic effect can only last for several hours. In order to fulfill the clinic requirement for long-term analgesia, a long-acting ropivacaine nanocrystal formulation was fabricated through the interaction between ropivacaine and a self-assembling peptide.Methods: Transmission electron microscopy, dynamic light scattering, circular dichroism and fluorescence spectrometry were used to examine the structural changes caused by the interaction between ropivacaine and the peptide. Scanning electron microscopy, dynamic light scattering, Fourier transform infrared spectrometry, X-ray diffraction and optical microscopy were used to characterize the ropivacaine-peptide nanocrystal. In vitro drug release and pharmacokinetics study were conducted to evaluate the slow-release profile of the nanocrystal formulation. A rodent cutaneous trunci muscle reflex model was used to evaluate the nociceptive blockade effects, and histological analysis was used to evaluate the local toxicity. A rodent plantar incisional pain model was used to evaluate the analgesic effect.Results: Soluble ropivacaine monomers interacted with the Q11 peptide through π-π stacking and remolded its self-assembling structure, leading to the formation of drug/peptide nanoparticles which could be mineralized to form drug/peptide nanocrystals by adjusting the pH. Under physiological condition, the nanocrystals could release free ropivacaine slowly. As evaluated in rodent models, the anesthetic and analgesic effects of this formulation were significantly extended without causing toxicity.Conclusion: Based on the interaction between ropivacaine and Q11, a controllable biomineralization process could be induced to obtain homogeneous nanocrystals, which could be used as an injectable long-acting analgesic formulation. This crystallization strategy utilizing the peptide-drug interaction also provided a promising pathway to fabricate long-acting formulations for many other small molecular drugs.Keywords: self-assembling peptide, nanocrystal, local anesthetics, π-π stacking, slow release, long-acting analgesia

The burst release of small molecular water-soluble drugs is a major problem when pursuing their long-acting formulations. Although various types of carrier materials have been developed for tackling this problem, it is still a big challenge to prevent water-soluble small molecules from fast release and diffusion. In this study, a biomineralization strategy based upon a self-assembling peptide is proposed for the slow release of lidocaine, a classic anesthetic with high solubility and a very small molecular weight. A bolaamphiphilic peptide was designed to self-assemble and produce negatively charged nanofibers, which were used as the template to absorb positively charged lidocaine molecules through an electrostatic interaction. The biomineralization of lidocaine was then induced by adjusting the pH, which lead to the formation of lidocaine microcrystals with a homogenous size. The microcrystals were incorporated into a hyaluronic acid hydrogel to form an injectable formulation. This formulation slowly released lidocaine and generate a prolonged anesthetic and analgesic effect in rodent models. Due to the constrained local and plasma lidocaine concentration, as well as the biocompatibility and biodegradability of the peptide materials, this formulation also showed considerable safety. These results suggest that nanofiber assisted biomineralization can provide a potential strategy for the fabrication of long-acting formulations for small molecular water-soluble drugs. STATEMENT OF SIGNIFICANCE: Long-acting formulations are highly pursued to achieve stronger therapeutic effect, or to avoid repeated administration of drugs, especially through painful injection. Using carrier materials to slow down the release of bioactive molecules is a common strategy to reach this goal. However, for many water-soluble small molecular drugs currently used in clinic, it is notoriously difficult to slow down their release and diffusion. This study proposes a novel strategy based on a controllable mineralization process using self-assembling peptide nanofibers as the template. Taking lidocaine as an example, we showed how peptide-drug microcrystals with well-controlled size and shape could be obtained, which exhibit significantly prolonged anesthetic and analgesic effect. As a proof-of-concept study, this work proposes a promising strategy to control the release of water-soluble small molecular drugs.

Jing Liu,1,2 Fei Peng,1,2 Yi Kang,1,2 Deying Gong,1,2 Jing Fan,1,2 Wensheng Zhang,1,2 Feng Qiu1,2 1Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China; 2National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of ChinaCorrespondence: Feng Qiu; Wensheng Zhang Email fengqiu@scu.edu.cn; zhang_ws@scu.edu.cnPurpose: Typical hydrophobic amino acids (HAAs) are important motifs for self-assembling peptides (SAPs), but they lead to low water-solubility or compact packing of peptides, limiting their capacity for encapsulating hydrophobic drugs. As an alternative, we designed a peptide GQY based on atypical HAAs, which could encapsulate hydrophobic drugs more efficiently. Although hydrophobic general anesthetics (GAs) have been formulated as lipid emulsions, their lipid-free formulations have been pursued because of some side effects inherent to lipids. Using GAs as targets, potential application of GQY as a carrier for hydrophobic drugs was evaluated.Methods: Thioflavin-T (ThT) binding test, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to examine the self-assembling ability of GQY. Pyrene and 8-Anilino-1-naphthalenesulfonic acid (ANS) were used to confirm formation of hydrophobic domain in GQY nanoparticles. Using pyrene as a model, GQY’s capacity to encapsulate hydrophobic drugs was evaluated. GAs including propofol, etomidate and ET26 were encapsulated by GQY. Loss of righting reflex (LORR) test was conducted to assess the anesthetic efficacy of these lipid-free formulations. Paw-licking test was used to evaluate pain-on-injection of propofol-GQY (PROP-GQY) formulation. Hemolytic and cytotoxicity assay were used to evaluate biocompatibility of GQY.Results: Stable nanoparticles containing plenty of hydrophobic cavities could be formed by GQY, which could encapsulate hydrophobic drugs at very high concentration and form stable suspensions. Propofol, etomidate and ET26 formulated by GQY showed anesthetic efficacy comparable to their currently available formulations. Unlike clinic lipid emulsion, PROP-GQY formulation did not cause pain-on-injection in rats. Neither obvious cytotoxicity nor hemolytic activity of GQY was observed.Conclusion: GQY could encapsulate GAs to obtain stable and effective formulations. As a lipid-free carrier, GQY exhibited considerable biocompatibility and other side benefits such as reducing pain-on-injection. More SAPs based on atypical HAAs could be designed as promising carriers for hydrophobic drugs.Keywords: self-assembling peptides, nanoparticles, hydrophobic drugs, lipid-free formulations, general anesthetics

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) and even induces remote organ damage. Accumulating proofs demonstrates that the endocannabinoid system may provide a promising access for treatment strategy of renal IRI associated AKI. In the current study, using the established renal IRI model of rat, we tested the hypothesis that pretreatment of URB602, 30 min before renal IRI, alleviates kidney injury and relevant distant organ damage via limiting oxidative stress and inflammation. Using Western blot analysis and LC-MS/MS, renal IRI showed to increase the levels of 2-arachidonoylglycerol (2-AG) in kidneys as well as COX-2, PGE2, TXA2, and decrease N-arachidonoylethanolamine (anandamide, AEA); the expressions of renal cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) were unchanged. The URB602 pretreatment in renal IRI, further enhanced renal 2-AG which is high affinity to both CB1 and CB2, and reduced renal COX-2 which is involved in the regulation of renal perfusion and inflammation. AM630 (CB2 antagonist) almost blocked all the antioxidant, anti-inflammatory and nephroprotective effects of URB602, whereas AM251 (CB1 antagonist) showed limited influence, and parecoxib (COX-2 inhibitor) slightly ameliorated renal function at the dose of 10 mg/kg. Taken together, our data indicate that URB602 acts as a reactive oxygen species scavenger and anti-inflammatory media in renal IRI mainly depending on the activation of CB2.

Objectives Monoacylglycerol lipase participates in organ protection by regulating the hydrolysis of the endocannabinoid 2-arachidonoylglycerol. This study investigated whether blocking monoacylglycerol lipase protects against postresuscitation myocardial injury and improves survival in a rat model of cardiac arrest and cardiopulmonary resuscitation. Design Prospective randomized laboratory study. Setting University research laboratory. Subjects Male Sprague-Dawley rat (n = 96). Interventions Rats underwent 8-minute asphyxia-based cardiac arrest and resuscitation. Surviving rats were randomly divided into cardiopulmonary resuscitation + URB602 group, cardiopulmonary resuscitation group, and sham group. One minute after successful resuscitation, rats in the cardiopulmonary resuscitation + URB602 group received a single dose of URB602 (5 mg/kg), a small-molecule monoacylglycerol lipase inhibitor, whereas rats in the cardiopulmonary resuscitation group received an equivalent volume of vehicle solution. The sham rats underwent all of the procedures performed on rats in the cardiopulmonary resuscitation and cardiopulmonary resuscitation + URB602 groups minus cardiac arrest and asphyxia. Measurements and main results Survival was recorded 168 hours after the return of spontaneous circulation (n = 22 in each group). Compared with vehicle treatment (31.8%), URB602 treatment markedly improved survival (63.6%) 168 hours after cardiopulmonary resuscitation. Next, we used additional surviving rats to evaluate myocardial and mitochondrial injury 6 hours after return of spontaneous circulation, and we found that URB602 significantly reduced myocardial injury and prevented myocardial mitochondrial damage. In addition, URB602 attenuated the dysregulation of endocannabinoid and eicosanoid metabolism 6 hours after return of spontaneous circulation and prevented the acceleration of mitochondrial permeability transition 15 minutes after return of spontaneous circulation. Conclusions Monoacylglycerol lipase blockade may reduce myocardial and mitochondrial injury and significantly improve the resuscitation effect after cardiac arrest and cardiopulmonary resuscitation.

Although existing mycological tests (bronchoalveolar lavage [BAL] galactomannan [GM], serum GM, serum (1,3)-β-D-glucan [BDG], and fungal culture) are widely used for diagnosing invasive pulmonary aspergillosis (IPA) in non-hematological patients with respiratory diseases, their clinical utility in this large population is actually unclear. We aimed to resolve this clinical uncertainty by evaluating the diagnostic accuracy and utility of existing tests and explore the efficacy of novel sputum-based Aspergillus assays.Existing tests were assessed in a prospective and consecutive cohort of patients with respiratory diseases in West China Hospital between 2016 and 2019 while novel sputum assays (especially sputum GM and Aspergillus-specific lateral-flow device [LFD]) in a case-controlled subcohort. IPA was defined according to the modified European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. Sensitivity and specificity were computed for each test and receiver operating characteristic (ROC) curve analysis was performed.The entire cohort included 3530 admissions (proven/probable IPA = 66, no IPA = 3464) and the subcohort included 127 admissions (proven/probable IPA = 38, no IPA = 89). Sensitivity of BAL GM (≥1.0 optical density index [ODI]: 86% [24/28]) was substantially higher than that of serum GM (≥0.5 ODI: 38% [39/102]) ( χ2 = 19.83, P 0.001), serum BDG (≥70 pg/mL: 33% [31/95]) ( χ2 = 24.65, P 0.001), and fungal culture (33% [84/253]) ( χ2 = 29.38, P 0.001). Specificity varied between BAL GM (≥1.0 ODI: 94% [377/402]), serum GM (≥0.5 ODI: 95% [2130/2248]), BDG (89% [1878/2106]), and culture (98% [4936/5055]). Sputum GM (≥2.0 ODI) had similar sensitivity (84% [32/38]) (Fisher's exact P = 1.000) to and slightly lower specificity (87% [77/89]) ( χ2 = 5.52, P = 0.019) than BAL GM (≥1.0 ODI). Area under the ROC curve values were comparable between sputum GM (0.883 [0.812-0.953]) and BAL GM (0.901 [0.824-0.977]) ( P = 0.734). Sputum LFD had similar specificity (91% [81/89]) ( χ2 = 0.89, P = 0.345) to and lower sensitivity (63% [24/38]) ( χ2 = 4.14, P = 0.042) than BAL GM (≥1.0 ODI), but significantly higher sensitivity than serum GM (≥0.5 ODI) ( χ2 = 6.95, P = 0.008), BDG ( χ2 = 10.43, P = 0.001), and fungal culture ( χ2 = 12.70, P 0.001).Serum GM, serum BDG, and fungal culture lack sufficient sensitivity for diagnosing IPA in respiratory patients. Sputum GM and LFD assays hold promise as rapid, sensitive, and non-invasive alternatives to the BAL GM test.

QXOH-LB, a fixed-dose combination (35 mM QXOH and 10 mM levobupivacaine) has been shown to induce a long duration of local anesthesia in animal efficacy testing, which indicates potential for postoperative pain management. In this study, we evaluated the potential toxicity of QXOH-LB in NIH mice under the Guidance on the repeated-dose toxicity published by the China Food and Drug Administration. Mice (n = 30 per sex per group) were subcutaneously injected 5, 10, 20 mg/kg QXOH-LB, 5, 10, 20 mg/kg QXOH, and 5 mg/kg levobupivacaine (LB) once a day for 14 days with sacrifice of main study animals; remaining mice (n = 10 per sex per group) were monitored for an additional 4-week recovery period. Mice in the 10 and 20 mg/kg QXOH, and 20 mg/kg QXOH-LB died, which was considered due to excessive respiratory inhibition. The doses of 10 mg/kg QXOH-LB and 5 mg/kg QXOH were well tolerated without any clinical signs of toxicity. Therefore, the no-observed-adverse-effect level (NOAEL) of QXOH-LB and QXOH was considered to be 10 and 5 mg/kg/day, respectively. In the dose range from 5 to 20 mg/kg, the exposure of QXOH and LB in QXOH-LB was equal to each agent used alone at the same dose in NIH mice. There was no gender difference on exposure and no evidence of accumulation.

QXOH-Levobupivacaine (LB) is a fixed-dose combination of 35-mM QXOH and 10-mM LB. It was developed for perioperative analgesia because of its long-acting analgesic effect. The purpose of this study was to evaluate the potential toxicity of QXOH-LB in beagle dogs in accordance with the Guidance on the repeated-dose toxicity published by the China Food and Drug Administration. Groups of five male and five female beagle dogs received normal saline, QXOH-LB (2, 4, and 8 mg/kg, calculated as QXOH), QXOH (2, 4, and 8 mg/kg), or LB (2 mg/kg, equals the concentration of LB in 8-mg/kg QXOH-LB group) at the volume of 1 mL/kg once per day for 14 days through subcutaneous injection. No mortality was observed. Dogs in the control group as well as animals treated with 2-mg/kg QXOH or QXOH-LB exhibited normal behaviors. Clinical signs of toxicity in dogs treated with 4 and 8 mg/kg of QXOH or QXOH-LB included decreased activity, unsteady gait, jerks, tremors, vocalization, emesis, ataxia, lateral/sternal recumbency, deep/rapid respiration, and gasping. Additionally, neurological function was found to be affected by QXOH and QXOH-LB at the doses of 4 and 8 mg/kg. All clinical signs were recovered within 24 h. The no-observed-adverse-effect level of QXOH and QXOH-LB was considered to be 2 mg/kg. Toxicokinetic data showed that exposure to QXOH and LB increased as QXOH-LB doses were increased from 4 to 8 mg/kg. There was no evidence of drug accumulation or any effect of gender.

Dexmedetomidine, as a safe sedative, mainly exerts on the central nervous system particularly in the locus coeruleus producing arousable sedation with potential analgesic and anxiolytic effects. The quantification and pharmacokinetic investigation of dexmedetomidine in the central nervous system have been described rarely. In order to estimate the unbound dexmedetomidine concentrations in brain extracellular fluid and blood simultaneously, we employed microdialysis technique as a sampling method and primarily established a rapid, sensitive and selective high-performance liquid chromatography coupled with tandem mass spectrometry method (HPLC-MS/MS). Dexmedetomidine and the internal standard (dexmedetomidine-d4) were extracted in liquid–liquid extraction procedure with ethyl acetate from 10 μL of alkalinized microdialysate sample. After evaporation under nitrogen at room temperature, the analytes were reconstituted in acetonitrile and transferred to be detected. HPLC was performed on an Agilent Poroshell 120 Hilic column (4.6 × 100 mm, 2.7 μm) with isocratic elution at a flow rate of 0.3 mL/min by 0.1% formic acid/acetonitrile (60:40, v/v). The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction monitoring (MRM) mode using the respective [M+H]+ ions m/z 201.2 to m/z 95.1 for DEX and m/z 205.2 to m/z 99.1 for IS (DEX-d4). The concentration–response relationship was of good linearity over a concentration range of 1.00–1000.00 ng/mL with the correlation coefficient above 0.999. The lower limit of quantification was 1.00 ng/mL with a relative standard deviation of less than 20%. The intra- and inter-day accuracy were within ±5.00% and precision was

As a trace element nutrient, cobalt is critical for both prokaryotes and eukaryotes. In the current study, a turn-on Cobalt Bioluminescent Probe 1 (CBP-1) for the detection of cobalt has been successfully developed based on oxidative C–O bond cleavage. This probe exhibited high selectivity and sensitivity toward cobalt over other analytes. By using CBP-1, the successful in vivo imaging of cobalt accumulation was carried out in a mouse model. Such an ability to determine cobalt in living animals provides a powerful technology for studying the system distribution, toxic potency, and biological effect of Co2+.

QX-OH, a new synthetic local anesthetic, produced concentration-dependent, reversible, and long-acting local anesthesia in animal models, with moderate local toxicity. As part of preclinical research for drug development, we developed and validated a method for the determination of QX-OH in the plasma, muscle, and sciatic nerve using liquid chromatography-mass spectrometry. After a simple protein precipitation procedure, analysis was performed on an Extend C18 column (100mm×3mm, 3.5μm) by isocratic elution with 0.05% formic acid/acetonitrile (78:22, v/v) at a flow rate of 0.3mL/min. A multiple-reaction monitoring mode at the transitions of m/z 279.1→102.1 for QX-OH and m/z 275.2→126.1 for an internal standard (ropivacaine hydrochloride) was used for the quantification, with a positive electrospray ionization interface. The approach was validated as per the U.S. Food and Drug Administration guidelines and successfully used in a pharmacokinetic study of QX-OH after a sciatic nerve block with 0.2mL of 35mM QX-OH. The results demonstrated that the new local anesthetic, QX-OH, had a high concentration in tissue, low systemic exposure, and long duration in the sciatic nerve.

ET-26 hydrochloride (ET-26HCl), a novel analog of etomidate, induces as effective sedation, with good cardiac and respiratory stability, as etomidate but with mild adrenocortical suppression. The objective of this study was to evaluate the potential adverse effects of ET-26HCl in rats. In a single-dose toxicity study, abnormal urine color (red) was observed in all groups: control (100%), 8 mg/kg (10%), 16 mg/kg (50%), and 20 mg/kg (70%) ET-26HCl, which returned to normal on the day of dosing. There were no mortalities or serious toxicological signs; the maximum tolerable dose of ET-26HCl was 20 mg/kg. In the repeated-dose toxicity study, deaths occurred in the 12- (13.33% of males) and 16-mg/kg/day (20% of males and 3.33% of females) groups. Abnormal urine color (red or brown) was detected in the control group (10%) and all treatment groups (30%, 46.67%, and 40% at 8, 12 and 16 mg/kg/day, respectively), at a frequency of 1.43% in the control group, 4.76% in 8 mg/kg/day, 7.62% in 12 mg/kg/day, and 4.29% in 16 mg/kg/day. Increases in neutrophils and plasma fibrinogen were temporary and recoverable effects. Macroscopic and histopathologic changes were found only at the injection sites: abnormal skin color, scabbing, thrombus, ulceration, and inflammation. During the recovery period, there was evidence of reversibility, including fibroblast proliferation and vessel recanalization. The no-observed-adverse-effect level of ET-26HCl was 8 mg/kg/day. Toxicokinetic variables of ET-26HCl, except the calculated initial concentration in females on Day 1, showed a dose-dependent increase to exposure, with no gender difference and no evidence of accumulation.

Etomidate is a sedative-hypnotic with excellent pharmacological effects, including rapid onset and hemodynamic stability. However, etomidate causes adrenocortical toxicity via binding to 11β-hydroxylase. Therefore, developing an approach to screen new etomidate analogues without endocrine-disrupting effects is urgently warranted. In this study, we employed the adrenocortical tumour cell line, NCI-H295R, as an in vitro system for etomidate analogues screening and detected the hormone levels in these cells using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. After obtaining the concentration-response curves of hormone release, the "Adrenocortical Inhibitory Index" was used to evaluate the adrenocortical inhibitory potency of each compound. In summary, we demonstrate the benefits of our methods for screening of etomidate analogues that lack adrenocortical suppression, especially when this in vitro system is combined with in vivo testing.

Background: ET-26 hydrochloride is a novel intravenous anesthetic, approved for clinical trials, that produces a desirable sedative-hypnotic effect with stable myocardial performance and mild adrenocortical suppression in rats and beagle dogs. The objective of this study was to assess the absorption, distribution, metabolism, and excretion of ET-26 hydrochloride. Methods: Hepatocytes from human, monkey, dog, rat, and mouse were used to determine the metabolites of ET-26 hydrochloride. Distribution and excretion were assessed in rats and pharmacokinetic studies were performed in beagle dogs. Results: The metabolic pathway and proposed structure of metabolites were fully assessed resulting from the biotransformation reactions of hydrolysis, dehydrogenation, demethylation and glucuronic acid conjugation. The main distribution of the drug was in fat (15067 ± 801 ng/ml) and liver (13647 ± 1126 ng/ml), and the kidney was the primary excretion route (4.47%-11.94%). The Cmax after injection with 1.045 mg/kg, 2.09 mg/kg, and 4.18 mg/kg was 1476.5 ± 138.9 ng/ml, 2846.1 ± 223.3 ng/ml, and 6233.3 ± 238.9 ng/ml, respectively. The t1/2 of the drug was similar across dose groups at 74.8 ± 10.8 min to 81.4 ± 4.2 min. The AUC0-t values were 30208.1 ± 2026.5 min*ng/ml, 62712.8 ± 1808.3 min*ng/ml, and 130465.2 ± 7457.4 min*ng/ml, respectively. Conclusion: The metabolic pathway and the proposed structure of metabolites for ET-26 hydrochloride were fully assessed. The majority of distribution for ET-26 hydrochloride occurs in the fat and liver, while the primary route of excretion for ET-26 hydrochloride is through the kidney. In dogs, pharmacokinetic features of ET-26 hydrochloride had a linear relationship with dosage.

QXOH, a QX314 derivative with longer duration and lesser local toxicity, is a novel local anesthetic in preclinical drug development. Previous studies demonstrated that bupivacaine can prolong the effects of QX314. So, we attempted to combine QXOH with levobupivacaine to shorten the onset time and lengthen the duration. In this study, we investigated the efficacy, local and systemic toxicity in rats. In subcutaneous infiltration anesthesia, the inhibition of cutaneous trunci muscle reflex for QXOH-LB was greater than QXOH and levobupivacaine in the first 8 h (QXOH-LB vs. QXOH, P = 0.004; QXOH-LB vs. LB, P = 0.004). The completely recovery time for QXOH-LB (17.5 ± 2.5 h) was significantly longer than levobupivacaine (9.0 ± 1.3 h, P = 0.034) and QXOH (9.8 ± 0.9 h, P = 0.049). In sciatic nerve block, QXOH-LB produced a rapid onset time, which was obviously shorter than QXOH. For sensory, the time to recovery for QXOH-LB was 17.3 ± 2.6 h, which was statistically longer than 6.0 ± 1.8 h for QXOH (P = 0.027), and 4 h for levobupivacaine (P = 0.001). Meanwhile, the time to motor recovery for QXOH-LB was 7.9 ± 2.8 h, significantly longer than 4 h for levobupivacaine (P = 0.003) but similar to 6.0 ± 1.7 h for QXOH (P = 0.061). In local toxicity, there was no significant difference of histological score regarding muscle and sciatic nerve in QXOH-LB, QXOH, levobupivacaine and saline (P < 0.01). In the combination, the interaction index of LD50 was 1.39, indicating antagonistic interaction between QXOH and levobupivacaine in terms of systemic toxicity. In this study, we demonstrated that QXOH-LB produced cutaneous anesthesia which was 2-fold greater than that produced by QXOH or LB alone, and elicited sciatic nerve block with a potency that was 5- and 3-fold that of LB and QXOH, respectively. Local tissue inflammation by QXOH-LB was mild, similar to that induced by LB. This fixed-dose combination led to an antagonistic interaction between QXOH and LB in terms of systemic toxicity. These results suggested that QXOH-LB induced a long-lasting local anesthesia, likely, avoiding clinically important local and systemic toxicities.

Lung ischemia-reperfusion injury (LIRI) is a common and severe postoperative pathologic complication that often occurs when the oxygen supply disrupted to the lung tissue fallowed by reperfusion period, in most cases after lung transplantation and cardiopulmonary bypass. Endocannabinoids such as 2-arachidonoylglycerol (2-AG) have very important role as regulators of inflammation. Monoacylglycerol lipase (MAGL) is the main 2-AG-degrading enzyme, and the downstream metabolites of 2-AG play a role in the inflammation. Ischemia reperfusion (IR) was induced by clamping the left pulmonary hilum for 60 min, followed by 120 min of reperfusion in male C57BL/6 mice. Effects of URB602, a MAGL inhibitor, were evaluated in a preventive or therapeutic regimen (5 min before ischemia or reperfusion, respectively). Oxygenation index, wet-to-dry weight ratio and lung injury score were analyzed. Endocannabinoids including 2-AG, anandamide (AEA) and arachidonic acid (AA) levels, metabolites such as Prostaglandin I2 (PGI2), Thromboxane B2 (TXB2) and Leukotrienes B4 (LTB4) and inflammatory markers (Interleukin 6 (IL-6) andTumor necrosis factor-α (TNF-α)) in lung tissues were measured by using mass spectrometry or ELISA analyses. We found that IR increased the wet-to-dry weight ratio of lung and lung injury score and decreased oxygenation index as compared to the sham group. Moreover, treatment with URB602 in preventive or therapeutic regimen reduced the wet-to-dry weight ratio and lung injury score while increased oxygenation index when compared with the IR group, with a more improvement in the preventive regimen group. In addition, treatment with URB602 before ischemia increased 2-AG level but decreased metabolites (AA, PGI2, TXB2, LTB4) and inflammatory markers (IL-6, TNF-α). Thus, our study demonstrated that a pretreatment with URB602 significantly reduced IR-induced lung injury and inflammation. URB602 inhibited LIRI and inflammation by increasing 2-AG level and reducing downstream metabolites from AA to PGI2, TXB2 and LTB4 in lung tissues.

BACKGROUND Neuropathic pain is often associated with depression. Enhancing endocannabinoids by fatty acid amide hydrolase (FAAH) inhibitors relieves neuropathic pain and stress-induced depressive-like behaviors in animal models. However, it is unclear whether FAAH inhibitor can relieve neuropathic pain-induced depression by or not by its antinociceptive effects. METHODS Adult male Wistar rats with chronic constriction injury (CCI) to the sciatic nerve were treated with the systemic FAAH inhibitor URB597 (5.8 mg·kg·day, intraperitoneally) or peripherally acting FAAH inhibitor URB937 (1.6 mg·kg·d, intraperitoneally; n = 11-12). The treatment was applied from the 15th day after surgery and continued for 15 days. Mechanical withdrawal threshold was examined by Von Frey test before surgery and on the 28th day after CCI. Depressive-like behaviors were evaluated by forced swimming test (FST) and novelty-suppressed feeding (NSF) after 15-day treatment. The levels of anandamide and 2-arachidonoylglycerol in hippocampus were examined by liquid chromatography and mass spectrometry. Hippocampal neurogenesis including proliferation, differentiation, and survival of newborn cells was assessed by immunohistochemistry. RESULTS After CCI injury, the rats developed significantly nociceptive and depressive-like behaviors, indicated by persistent mechanical hypersensitivity in Von Frey test, significantly prolonged immobility time in FST (sham: 84.2 ± 13.4 seconds versus CCI: 137.9 ± 18.8 seconds; P < .001), and protracted latency to feed in NSF (sham: 133.4 ± 19.4 seconds versus CCI: 234.9 ± 33.5 seconds; P < .001). For the CCI rats receiving treatment, compared to vehicle placebo group, pain threshold was increased by both URB597 (3.1 ± 1.0 vs 11.2 ± 1.2 g; P < .001) and URB937 (3.1 ± 1.0 vs 12.1 ± 1.3 g; P < .001). Immobility time of FST was reduced by URB597 (135.8 ± 16.6 vs 85.3 ± 17.2 seconds; P < .001) but not by URB937 (135.8 ± 16.6 vs 129.6 ± 17.8 seconds; P = .78). Latency to feed in NSF was also reduced by URB597 (235.9 ± 30.5 vs 131.8 ± 19.8 seconds; P < .001) but not by URB937 (235.9 ± 30.5 vs 232.2 ± 33.2 seconds; P = .72). Meanwhile, CCI decreased the number of proliferating cells and reduced survival of new mature neurons in hippocampus. URB597 but not URB937 treatment improved these cellular deficits. CONCLUSIONS Inhibition of FAAH can improve depressive-like behaviors induced by neuropathic pain independent of its peripheral antinociceptive action. Enhanced neurogenesis in hippocampus might contribute to the antidepressive effects of URB597.

Mercury is a highly toxic environmental pollutant that negatively affects human health. Thus, an in vivo method for noninvasive imaging of mercury(II) and visualization of its accumulation within living systems would be advantageous. Herein, we describe a reaction-based bioluminescent probe for detection of mercury(II) in vitro and accumulation in vivo. The application of this probe would help to shed light on the intricate contributions of mercury(II) to various physiological and pathological processes.

Considering that hydrogen sulfide (H2S) is an endogenous signaling molecule involved in numerous biological processes, a method for monitoring H2S as a powerful tool for investigating its complicated functions and mechanisms is urgently demanded. Herein, a bioluminescent turn-on probe was reported based on caged strategy for the detection of H2S in vitro and in vivo. This probe will help us understand the intricate contribution of H2S to a variety of physiological and pathological processes.

A series of atypical asymmetric gemini surfactants with an amphiphilic carbonate group (–O–CO–O–) have been prepared. Some of these compounds could self-assemble in water into gourd-shaped Janus particles (JPs). Initial results suggested that the formation of JPs was highly likely to be related to their atypical gemini surfactant structure. To our knowledge, this is the first report on JPs that are self-assembled from a single kind of small organic molecule. We believe that our results will be utilized in many fields.

A rhodium complex with an amphiphilic, chiral surfactant-type ligand is applied to the asymmetric transfer hydrogenation of long-chained aliphatic ketoesters.

A series of amphiphilic ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neat water. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and e-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst 2. The CH/π interaction and the strong hydrophobic interaction of long aliphatic chains between the catalyst and the substrate in the metallomicelle core played a key role in the catalytic transition state. Synergistic effects between the metal-catalyzed site and the hydrophobic microenvironment of the core in the micelle contributed to high stereoselectivity.