Metronidazole is a white to pale-yellow crystalline powder with a slight odor. Bitter and saline taste. pH (saturated aqueous solution) about 6.5. (NTP, 1992)
颜色/状态：
Cream-colored crystals
气味：
ODORLESS
蒸汽压力：
3.1X10-7 mm Hg at 25 °C (est)
水溶性：
-1.5
稳定性/保质期：
Metronidazole conventional tablets should be stored in well-closed, light-resistant containers at less than 25 °C. Metronidazole capsules should be stored in tight containers at 15-25 °C. Metronidazole extended-release tablets should be stored in well-closed containers at approximately 25 °C; temporary exposure to temperatures of 15-30 °C is acceptable.
Metronidazole undergoes hepatic metabolism via hydroxylation, oxidation, and glucuronidation. The metabolism of metronidazole yields 5 metabolites. The hydroxy metabolite, 1-(2-hydroxy-ethyl)-2-hydroxy methyl-5-nitroimidazole, is considered the major active metabolite. Unchanged metronidazole is found in the plasma along with small amounts of its 2- hydroxymethyl metabolite. Several metabolites of metronidazole are found in the urine. They are primarily a product of side-chain oxidation in addition to glucuronide conjugation. Only 20% of the dose found in the urine is accounted for by unchanged metronidazole. The two main oxidative metabolites of metronidazole are hydroxy and acetic acid metabolites.
Approximately 30-60% of an oral or IV dose of metronidazole is metabolized in the liver by hydroxylation, side-chain oxidation, and glucuronide conjugation. The major metabolite, 2-hydroxy metronidazole, has some antibacterial and antiprotozoal activity.
... Four other nitro-group-containing metabolites have been identified, each derived from side-chain oxidation of ethyl and/or methyl group. They include 1-acetic acid-2-methyl-5-nitroimidazole and 1-(2-hydroxyethyl)-2-carboxylic acid-5-nitroimidazole salt.
The liver is the main site of metabolism, and this accounts for over 50% of the systemic clearance of metronidazole. The 2 principal metabolites result from oxidation of side chains, a hydroxy derivative and an acid. The hydroxy metabolite has a longer half-life (about 12 hr) and nearly 50% of the antitrichomonal activity of metronidazole. Formation of glucuronides also is observed. Small quantities of reduced metabolites, including ring-cleavage products, are formed by the gut flora. The urine of some patients may be reddish-brown owing to the presence of unidentified pigments derived from the drug.
Metronidazole is a prodrug. Unionized metronidazole is selective for anaerobic bacteria due to their ability to intracellularly reduce metronidazole to its active form. This reduced metronidazole then covalently binds to DNA, disrupt its helical structure, inhibiting bacterial nucleic acid synthesis and resulting in bacterial cell death.
Despite the wide use of metronidazole, only rare cases of hepatotoxicity have been reported, and metronidazole is not listed among causes of drug induced liver injury and acute liver failure in large case series. High doses of metronidazole given parenterally or in an overdose can cause elevations in serum aminotransferase levels, but these are usually self-limited and minimally symptomatic (Case 1). Acute, clinically apparent liver injury from metronidazole is rare. Ornidazole, another synthetic nitroimidazole that was available in Europe, was implicated in several cases of drug induced liver injury, with a latency of a few days or weeks and a hepatocellular pattern of injury. Metronidazole has been associated with a similar acute hepatitis-like syndrome with a short incubation period, but much more rarely. Fever, rash and eosinophilia are uncommon as are autoimmune features. A fatal recurrence of acute liver injury after reexposure to metronidazole has been published (Case 2). Strikingly, multiple instances of metronidazole hepatoxicity have been reported in the rare genetic disease, Cockayne syndrome in which there is an absence or deficiency in an important DNA repair enzyme responsible for nucleotide excision repair. The cases were marked by a short latency (1 to 7 days) to onset of jaundice, a hepatocellular pattern of enzyme elevations and severe course with a high mortality rate. Whether patients with Cockayne syndrome have a similar high risk for severe hepatitis with other nitroimidazoles (such as tinidazole) is not known.
After the intravenous infusion of a 1.5g dose, peak concentration was reached within 1 hour and was peak level of 30-40 mg/L. When a multiple-dose regimen of 500mg three times a day administered intravenously, steady-state concentrations were achieved within about 3 days and peak concentration was measured at 26 mg/L. When administered orally in the tablet form, metronidazole is absorbed entirely absorbed, showing a bioavailability of greater than 90%. One resource indicates that Cmax after a single oral dose of 500mg metronidazole ranges from 8 to 13 mg/L, with a Tmax of 25 minutes to 4 hours. The AUC following a single 500mg oral dose of metronidazole was 122 ± 10.3 mg/L • h. A note on the absorption of topical preparations Insignificant percutaneous absorption of metronidazole occurs after the application of 1% metronidazole cream topically. Healthy volunteers applied one 100 mg dose of 14C-labelled metronidazole 2% cream to unbroken skin. After 12 hours, metronidazole was not detected in the plasma. Approximately 0.1% to 1% of the administered metronidazole was measured in the urine and feces.
Metronidazole is widely distributed throughout the body and various body fluids. They include the bile, saliva, breastmilk, cerebrospinal fluid, and the placenta. Steady-state volume distribution of metronidazole in adults ranges from 0.51 to 1.1 L/kg. It attains 60 to 100% of plasma concentrations in various tissues, such as the central nervous system, however, is not measured in high concentrations in the placental tissue.
Dose adjustments may be required in patients with hepatic impairment, as clearance is impaired in these patients. The clearance of metronidazole in the kidneys is estimated at 10 mL/min/1.73 m2. The total clearance from serum is about 2.1 to 6.4 L/h/kg.
Catalytic Metal-free Allylic C–H Amination of Terpenoids
作者：Wei Pin Teh、Derek C. Obenschain、Blaise M. Black、Forrest E. Michael
DOI：10.1021/jacs.0c06997
日期：2020.9.30
selective replacement of C-H bonds in complex molecules, especially natural products like terpenoids, is a highly efficient way to introduce new functionality and/or couple fragments. Here, we report the development of a new metal-free allylic amination of alkenes that allows the introduction of a widerange of nitrogen functionality at the allylic position of alkenes with unique regioselectivity and no
[EN] DERIVATIVES OF AMANITA TOXINS AND THEIR CONJUGATION TO A CELL BINDING MOLECULE<br/>[FR] DÉRIVÉS DE TOXINES D'AMANITES ET LEUR CONJUGAISON À UNE MOLÉCULE DE LIAISON CELLULAIRE
申请人：HANGZHOU DAC BIOTECH CO LTD
公开号：WO2017046658A1
公开（公告）日：2017-03-23
Derivatives of Amernita toxins of Formula (I), wherein, formula (a) R 1, R 2, R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10, X, L, m, n and Q are defined herein. The preparation of the derivatives. The therapeutic use of the derivatives in the targeted treatment of cancers, autoimmune disorders, and infectious diseases.
[EN] A CONJUGATE OF A CYTOTOXIC AGENT TO A CELL BINDING MOLECULE WITH BRANCHED LINKERS<br/>[FR] CONJUGUÉ D'UN AGENT CYTOTOXIQUE À UNE MOLÉCULE DE LIAISON CELLULAIRE AVEC DES LIEURS RAMIFIÉS
申请人：HANGZHOU DAC BIOTECH CO LTD
公开号：WO2020257998A1
公开（公告）日：2020-12-30
Provided is a conjugation of cytotoxic drug to a cell-binding molecule with a side-chain linker. It provides side-chain linkage methods of making a conjugate of a cytotoxic molecule to a cell-binding ligand, as well as methods of using the conjugate in targeted treatment of cancer, infection and immunological disorders.
[EN] CROSS-LINKED PYRROLOBENZODIAZEPINE DIMER (PBD) DERIVATIVE AND ITS CONJUGATES<br/>[FR] DÉRIVÉ DE DIMÈRE DE PYRROLOBENZODIAZÉPINE RÉTICULÉ (PBD) ET SES CONJUGUÉS
申请人：HANGZHOU DAC BIOTECH CO LTD
公开号：WO2020006722A1
公开（公告）日：2020-01-09
A novel cross-linked cytotoxic agents, pyrrolobenzo-diazepine dimer (PBD) derivatives, and their conjugates to a cell-binding molecule, a method for preparation of the conjugates and the therapeutic use of the conjugates.
