Loperamide is extensively metabolized. The primary metabolic pathway is oxidative N-demethylation mediated by CYP2C8 and CYP3A4, to form N-demethyl loperamide. CYP2B6 and CYP2D6 play a minor role in loperamide N-demethylation. Metabolites of loperamide are pharmacologically inactive.
Loperamide is almost completely extracted by the liver, where it is predominantly metabolized, conjugated and excreted via the bile. Oxidative N-demethylation is the main metabolic pathway for loperamide, and is mediated mainly through CYP3A4 and CYP2C8. Due to this very high first pass effect, plasma concentrations of unchanged drug remain extremely low.
In contrast with the Parkinson's-like effects associated with the mitochondrial neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and the neuroleptic agent haloperidol, there exist no reports on adverse central nervous system (CNS) effects with the structurally related N-substituted-4-arylpiperidin-4-ol derivative and antidiarrheal agent loperamide. Although this difference can be attributed to loperamide's P-glycoprotein substrate properties that prevent it from accessing the brain, an alternative possibility is that loperamide metabolism in humans is different from that of MPTP and haloperidol and does not involve bioactivation to a neurotoxic pyridinium species. In the current study, loperamide bioactivation was examined with particular focus on identification of pyridinium metabolites. A NADPH-dependent disappearance of loperamide was observed in both rat and human liver microsomes (human t(1/2) = 13 min; rat t(1/2) = 22 min). Loperamide metabolism was similar in human and rat and involved N-dealkylation to N-desmethylloperamide (M3) as the principal metabolic fate. Other routes of loperamide biotransformation included N- and C-hydroxylation to the loperamide-N-oxide (M4) and carbinolamide (M2) metabolites, respectively. Furthermore, the formation of an additional metabolite (M5) was also discernible in human and rat liver microsomes. The structure of M5 was assigned to the pyridinium species (LPP(+)) based on comparison of the liquid chromatography/tandem mass spectrometry characteristics to the pyridinium obtained from loperamide via a chemical reaction. Loperamide metabolism in human microsomes was sensitive to ketoconazole and bupropion treatment, suggesting P4503A4 and -2B6 involvement. Recombinant P4503A4 catalyzed all of the loperamide biotransformation pathways in human liver microsomes, whereas P4502B6 was only responsible for N-dealkylation and N-oxidation routes. The wide safety margin of loperamide (compared with MPTP and haloperidol) despite metabolism to a potentially neurotoxic pyridinium species likely stems from a combination of factors that include a therapeutic regimen normally restricted to a few days and the fact that loperamide and perhaps LPP(+) are P-glycoprotein substrates and are denied entry into the CNS. The differences in safety profile of haloperidol and loperamide despite a common bioactivation event supports the notion that not all compounds undergoing bioactivation in vitro will necessarily elicit a toxicological response in vivo.
来源:Hazardous Substances Data Bank (HSDB)
代谢
洛哌丁胺已知的人类代谢物包括N-去甲基洛哌丁胺。
Loperamide has known human metabolites that include N-Desmethyloperamide.
IDENTIFICATION AND USE: Loperamide is a solid. Loperamide is used in the control and symptomatic relief of acute nonspecific diarrhea and of chronic diarrhea associated with inflammatory bowel disease. HUMAN EXPOSURE AND TOXICITY: Loperamide is an over-the-counter antidiarrheal with mu-opioid agonist activity. Central nervous system opioid effects are not observed after therapeutic oral dosing because of poor bioavailability and minimal central nervous system penetration. However, central nervous system opioid effects do occur after supratherapeutic oral doses. Oral loperamide abuse as an opioid substitute has been seen among patients attempting to self-treat their opioid addiction. Ventricular dysrhythmias and prolongation of the QRS duration and QTc interval have been reported after oral loperamide abuse. In postmarketing experiences, paralytic ileus associated with abdominal distention has been reported rarely. Most of these cases occurred in patients with acute dysentery, following overdosage of the drug, or in children younger than 2 years of age. ANIMAL STUDIES: Loperamide administration significantly suppressed foraging behavior in rats and reduced their body weight. The intravenous injection of loperamide induced an immediate fall in blood pressure and heart rate in anesthetized rats. In a study in rats using loperamide dosages up to 133 times the maximum human dosage (on a mg/kg basis) for 18 months, there was no evidence of carcinogenicity. Beagle dogs were given loperamide in gelatin capsules at 5.0, 1.25 and 0.31 mg/kg six days a week for 12 months. Some depression was seen during the first week of drug administration at 1.25 and 5 mg/kg. Behavior and appearance were normal during the rest of the experiment, except that hemorrhagic stools were seen from time to time at 5 mg/kg and soft stools at 0.31 and 1.25 mg/kg, especially during the first 6 weeks of drug administration. Pregnant primiparous female rats were given loperamide in their diet at 40, 10 and 2.5 mg/100 g of food from day 6 through day 15 of pregnancy. On day 22, fetuses were delivered by caesarean section. At 40 mg/100 g food, only 1 female out of 20 became pregnant. There was no significant difference between the control group and the 2.5 and 10 mg/100 g food-dosed groups in pregnancy rate; number of implantations per dam; litter size, percentage of live, dead and resorbed fetuses; distribution of live, dead and resorbed fetuses in the left and right uterine horns; and body weight of live young. No macroscopic, visceral, or skeletal malformations were seen. Results of in vivo and in vitro studies carried out indicated that loperamide is not genotoxic.
As with most opiates in current use, therapy with loperamide has not been linked to serum enzyme elevations. There have been no convincing cases of idiosyncratic acute, clinically apparent liver injury attributed to either agent. The reason for its lack of hepatotoxicity may relate to the low doses used and lack of significant systemic absorption. What loperamide is absorbed is metabolized in the liver.
References on the safety and potential hepatotoxicity of loperamide are given in the overview section of the Opioids. Last updated: 20 May 2019
Drug Class: Gastrointestinal Agents; Opioids
Loperamide is well absorbed from the gastrointestinal tract; however, it undergoes extensive first-pass metabolism to form metabolites that are excreted in the bile. Therefore, little loperamide actually reaches the systemic circulation. The drug bioavailability is less than 1%. Following oral administration of a 2 mg capsule of loperamide, plasma concentrations of unchanged drug were below 2 ng/mL. Plasma loperamide concentrations are highest approximately five hours after administration of an oral capsule of loperamide and 2.5 hours after the liquid formulation of the drug.
Loperamide and its metabolites in the systemic circulation undergo biliary excretion. Excretion of the unchanged loperamide and its metabolites mainly occurs through the feces. Only 1% of an absorbed dose excreted unchanged in the urine.
来源:DrugBank
吸收、分配和排泄
分布容积
洛哌丁胺具有较大的分布体积。尽管具有很强的亲脂性，洛哌丁胺不能穿过血脑屏障，通常在周围发挥作用。
Loperamide has a large volume of distribution. Although highly lipophilic, loperamide does not cross the blood-brain barrier and generally acts peripherally.
Tritium-labelled loperamide was administered orally to eight groups of five fasted male Wistar rats (250 +/- 10 g) at a dosage of 1.25 mg/kg. Urine and feces were collected for up to 4 days. The rats were killed at different times from 1 to 96 hours after drug administration in order to examine blood, organs and tissues. In one rat, the bile was cannulated for 48 hours. The radioactive content of each sample was measured and the fractions due to loperamide, metabolites, and volatile radioactivity were determined by the inverse isotope dilution technique and lyophilization. Only 5% of the drug and its metabolites was recovered from the urine, the bulk being excreted with the feces. Drug plasma levels were low at all times. Maximum plasma levels of unchanged loperamide did not exceed 0.22% of the administered dose corresponding to about 75 mg/mL of plasma. The gastrointestinal tract contained about 85% of loperamide 1 hour after dosing. Brain levels were extremely low, never exceeding 22 ng/g brain tissue, or 0.005% of the administered dose. The existence of an enterohepatic shunt was shown, but the uptake of the drug into the general circulation was low. Differentiation between total radioactivity and nonvolatile radioactivity demonstrated that most of the residual organ radioactivity was due to tritiated water.
Three male volunteers received orally 2.0 mg of 3H-loperamide (specific activity 64 mCi/mM) in gelatine capsules. Control samples of blood, urine and feces were obtained before administration. Blood was collected on heparin 1, 2, 4, 8, 24, 72 and 168 hours thereafter. Urine was collected for seven days and feces for eight days. The radioactive content of each sample was measured and the fractions due to loperamide, metabolites and volatile radioactivity were determined by the inverse isotope dilution technique and lyophilization. The fate of orally administered 3H-loperamide in man appeared to be similar to that in rats. The peak plasma level of loperamide occurred 4 hours after treatment and was less than 2 ng/mL or about 0.3% of the administered dose. About 1% of the administered dose was excreted unaltered with the urine and 6% as nonvolatile metabolites. About 40% of the administered dose was excreted with the feces, mainly within the first four days; 30% of this amount was due to unchanged drug.
A chemoselective deoxygenation of N-oxides by sodium borohydride–Raney nickel in water
摘要：
A simple and convenient protocol for deoxygenation of aliphatic and aromatic N-oxides to the corresponding amines in good to excellent yield using sodium borohydride-Raney nickel in water is reported. Other functional moieties such as alkenes, halides, ethers, and amides are unaffected under the present reaction condition. (C) 2010 Elsevier Ltd. All rights reserved.
A chemoselective deoxygenation of N-oxides by sodium borohydride–Raney nickel in water
摘要：
A simple and convenient protocol for deoxygenation of aliphatic and aromatic N-oxides to the corresponding amines in good to excellent yield using sodium borohydride-Raney nickel in water is reported. Other functional moieties such as alkenes, halides, ethers, and amides are unaffected under the present reaction condition. (C) 2010 Elsevier Ltd. All rights reserved.
[EN] PYRIMIDINE JAK INHIBITORS FOR THE TREATMENT OF SKIN DISEASES<br/>[FR] INHIBITEURS DE JAK À BASE DE PYRIMIDINE POUR LE TRAITEMENT DE MALADIES DE LA PEAU
申请人：THERAVANCE BIOPHARMA R&D IP LLC
公开号：WO2020219640A1
公开（公告）日：2020-10-29
The invention provides compounds of formula (I): or pharmaceutically-acceptable salts thereof, that are inhibitors of Janus kinases. The invention also provides pharmaceutical compositions comprising such compounds, and methods of using such compounds to treat inflammatory and autoimmune skin diseases.
The present invention provides compounds, compositions thereof, and methods of using the same.
本发明提供了化合物、其组合物以及使用这些化合物的方法。
[EN] ISOTOPE ENHANCED AMBROXOL FOR LONG LASTING AUTOPHAGY INDUCTION<br/>[FR] AMBROXOL À ISOTOPE AMÉLIORÉ POUR INDUCTION D'AUTOPHAGIE DURABLE
申请人：STC UNM
公开号：WO2018148113A1
公开（公告）日：2018-08-16
The present invention is directed to 13C and/or 2H isotope enhanced ambroxol ("isotope enhanced ambroxol") and its use in the treatment of autophagy infections, especially mycobacterial and other infections, disease states and/or conditions of the lung, such as tuberculosis, especially including drug resistant and multiple drag resistant tuberculosis. Pharmaceutical compositions comprising isotope enhanced amhroxol, alone or in combination with an additional bioactive agent, especially rifamycin antibiotics, including an additional autophagy modulator (an agent which is active to promote or inhibit autophagy), thus being useful against, an autophagy mediated disease state and/or condition), especially an antophagy mediated disease state and/or condition which occurs in the lungs, for example, a Mycobacterium infection. Chronic Obstructive Pulmonary Disease (COPD), asthma, pulmonary fibrosis, cystic fibrosis, Sjogren's disease and lung cancer (small cell and non-small cell lung cancer, among other disease states and/or conditions, especially of the lung. Methods of treating autophagy disease states and/or conditions, especially including autophagy disease states or conditions which occur principally in the lungs of a patient represent a further embodiment of the present invention. An additional embodiment includes methods of synthesizing compounds according to the present invention as otherwise disclosed herein.
[EN] LYMPHATIC SYSTEM-DIRECTING LIPID PRODRUGS<br/>[FR] PROMÉDICAMENTS LIPIDIQUES ORIENTANT VERS LE SYSTÈME LYMPHATIQUE
申请人：ARIYA THERAPEUTICS INC
公开号：WO2019046491A1
公开（公告）日：2019-03-07
The present invention provides lymphatic system-directing lipid prodrugs, pharmaceutical compositions thereof, methods of producing such prodrugs and compositions, as well as methods of improving the bioavailability or other properties of a therapeutic agent that comprises part of the lipid prodrug. The present invention also provides methods of treating a disease, disorder, or condition such as those disclosed herein, comprising administering to a patient in need thereof a provided lipid prodrug or a pharmaceutical composition thereof.
[EN] IRAK DEGRADERS AND USES THEREOF<br/>[FR] AGENTS DE DÉGRADATION D'IRAK ET LEURS UTILISATIONS
申请人：KYMERA THERAPEUTICS INC
公开号：WO2020264499A1
公开（公告）日：2020-12-30
The present invention provides compounds, compositions thereof, and methods of using the same. The compounds include an IRAK binding moiety capable of binding to IRAK4 and a degradation inducing moiety (DIM). The DIM could be DTM a ligase binding moiety (LBM) or lysine mimetic. The compounds could be useful as IRAK protein kinase inhibitors and applied to IRAK mediated disorders.
