A brief history behind the most used local anesthetics

Discovery and identification of natural alkaloids with potential to impact insulin resistance syndrome in Cyclocarya paliurus. (Batal) leaves by UPLC-QTOF-MS combined with HepG2 cells

Cyclocarya paliurus (Batal.) leaves, which contain a range of bioactive compounds, have been used as a traditional Chinese medicine homologous food since ancient times. However, there is a paucity of literature on comprehensive studies of alkaloids in the leaves of Cyclocarya paliurus (Batal.). For the first time, this study aimed to discover and identify alkaloids extracted from Cyclocarya paliurus (Batal.) leaves by ultra-high performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UPLC-QTOF-MS). A total of ten alkaloids have been identified from Cyclocarya paliurus (Batal.) leaves based on accurate mass spectra (mass accuracy, isotopic spacing and distribution) and comparison to fragmentation spectra reported in the literature. In vitro, alkaloids alleviated insulin resistance by increasing glucose consumption and glycogen content in insulin resistance HepG2 cells. The RNA-seq and western blotting results showed that alkaloids could upregulate the expression of phosphatidylinositol 3-kinase (PI3K), and increase the phosphorylation of insulin receptor protein kinase B (AKT). This study not only clarified the chemical constituents and revealed that diverse alkaloids also presented from Cyclocarya paliurus (Batal.) leaves, also, it will provide chemical information on potential compounds for developing new drugs.

Isolation and characterization of reference standard candidates for cocaine and benzoylecgonine obtained from illicit substances seized

The area of forensic chemistry has been growing and developing as a line of research due to the high demands of public safety that require increasingly reliable results due to their importance in criminalistics. In this way, the development of new technologies that help this area, whether in the identification and quantification of drugs or the fight against fraud, becomes promising. In this context, the present work explored the production of reference standards from the purification of cocaine/crack samples seized by the Civil Police of the State of Espírito Santo. Cocaine was purified using chromatographic techniques, and benzoylecgonine was synthesized from purified cocaine. All substances were characterized by ultra-high-resolution mass spectrometry and nuclear magnetic resonance. Homogeneity and stability studies were also performed with benzoylecgonine, and the results were evaluated using analysis of variance (ANOVA). Cocaine and benzoylecgonine showed purities of 98.37% and 96.34%, respectively. The homogeneity of the batch, short-term stability, and other parameters were also evaluated, which together indicate this proposal as promising in the development of reference standards for drugs of abuse from samples seized by the Brazilian forensic police.

Local anesthetics via multicomponent reactions

Local anesthetics occupy a prime position in clinical medicine as they temporarily relieve the pain by blocking the voltage-gated sodium channels. However, limited structural diversity, problems with the efficiency of syntheses and increasing toxicity, mean that alternative scaffolds with improved chemical syntheses are urgently needed. Here, we demonstrate an MCR-based approach both towards the synthesis of commercial local anesthetics and towards novel derivatives as potential anesthesia candidates via scaffold hopping. The reactions are efficient and scalable and several single-crystal structures have been obtained. In addition, our methodology has been applied to the synthesis of the antianginal drug ranolazine, via an Ugi three-component reaction. Representative derivatives from our libraries were evaluated as neuronal activity inhibitors using local field potential recordings (LFPs) in mouse hippocampal brain slices and showed very promising results. This study highlights new opportunities in drug discovery targeting local anesthetics.

A Novel Photoswitchable Azobenzene-Containing Local Anesthetic Ethercaine with Light-Controlled Biological Activity In Vivo

Pain is a common symptom that impairs the quality of life for people around the world. Local anesthetics widely used for pain relief have a number of side effects, which makes the development of both new drugs and new ways to control their activity particularly important. Photopharmacology makes it possible to reduce the side effects of an anesthetic and control its biological activity in the body. The purpose of this work was to create a new light-controlled local anesthetic and study its biological activity in animals. A compound with a simple scheme of synthesis was chosen to shift the UV-Vis absorption band towards the visible range of the spectrum and was synthesized for the first time. Some computer calculations were performed to make sure that the aforementioned changes would not lead to loss of biological activity. The micellar form of the new compound was prepared, and in vivo biological studies were carried out in rabbits. The existence of a local anesthetic effect, which disappeared almost completely on irradiation with light (λ = 395 nm), was shown using the surface anesthesia model. Moreover, the possibility of multiple reversible changes in the biological activity of ethercaine under the action of light was demonstrated. The latter compound manifests no local irritating effect, either. The data obtained indicate the prospects for the development of new compounds based on azobenzene for light-controlled local anesthesia.

Tropane Skeleta from the Intramolecular Photocycloaddition of (4+3) Cycloadducts of Oxidopyridinium Ions and Dienes

Easily prepared cycloadducts derived from the (4+3) cycloaddition of oxidopyridinium ions with dienes reacted intramolecularly in a [2+2] cycloaddition process to afford complex polycyclic species in which the tropane skeleton was embedded.

Born on the Battlefield: Celebrating the Centennial of the Discovery of Epidural Anesthesia

The year 2021 marks the 100th anniversary of the discovery of epidural anesthesia by Spanish military surgeon Major Fidel Pagés. The idea for the technique was born from Pagés' experiences in forward military hospitals in North Africa and Austria and would go on to revolutionize the fields of surgery and obstetrics.

Subcutaneous Bupivacaine Infiltration Is Not Effective to Support Control of Postoperative Pain in Paediatric Patients Undergoing Spinal Surgery

Spinal deformity corrections in paediatric patients are long-lasting procedures involving damage to many tissues and long pain exposure; therefore, effective pain management after surgical treatment is an important issue. In this study, the effect of inclusion of local infiltration analgesia, as an integral part of the scheme in postoperative pain control, in children and adolescents, subjected to the spinal deformity correction procedure, was assessed. Thirty patients, aged 8 to 17 years, undergoing spinal deformity correction were divided into a study group, receiving a 0.25% bupivacaine solution before wound closure, and a control group (no local analgesic agent). Morphine, at the doses of 0.10 mg/kg of body weight, was administered to the patients when pain occurred. Pain scores, morphine administration, and bleeding were observed during 48 postoperative hours. The pain scores were slightly lower in a 0–4 h period in patients who received bupivacaine compared with those in the control group. However, no differences were observed in a longer period of time and in the total opioid consumption. Moreover, increasing bleeding was observed in the bupivacaine-treated patients (study group) vs. the control. Bupivacaine only modestly affects analgesia and, due to the increased bleeding observed, it should not to be part of pain control management in young patients after spinal deformity correction.