- Family of Structurally Related Bioconjugates Yields Antibodies with Differential Selectivity against Ketamine and 6-Hydroxynorketamine
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The dissociative-hypnotic compound ketamine is being used in an increasingly wide range of therapeutic contexts, including anesthesia, adjunctive analgesia, treatment-resistant depression, but it also continues to be a notable substance of abuse. No specific antidotes exist for ketamine intoxication or overdose. Immunopharmacotherapy has demonstrated the ability to offer overdose protection through production of highly specific antibodies that prevent psychoactive drug penetration across the blood-brain barrier, although antiketamine antibodies have not yet been assessed or optimized for use in this approach. Moreover, generation of specific antibodies also provides an opportunity to address the role of 6-hydroxynorketamine metabolites in ketamine's rapid-acting antidepressant effect through selective restriction of metabolite access to the central nervous system. Hapten design is a critical element for tuning immune recognition of small molecules, as it affects the presentation of the target antigen and thus the quality and selectivity of the response. Here, we report the synthesis and optimization of carrier protein and conjugation conditions for an initial hapten, norketamine-N-COOH (NK-N-COOH), to optimize vaccination conditions and assess the functional consequences of such vaccination on ketamine-induced behavioral alterations occurring at dissociative-like (50 mg/kg) doses. Iterating from this initial approach, two additional haptens, ketamine-N-COOH (KET-N-COOH) and 6-hydroxynorketamine-N-COOH (HNK-N-COOH), were synthesized to target either ketamine or 6-hydroxynorketamine with greater selectivity. The ability of these haptens to generate antiketamine, antinorketamine, and anti-6-hydroxynorketamine immune responses in mice was then assessed using enzyme-linked immunosorbent assay (ELISA) and competitive surface plasmon resonance (SPR) methods. All three haptens provoked immune responses in vivo, although the KET-N-COOH and 6-HNK-N-COOH haptens yielded antibodies with 5- to 10-fold improvements in affinity for ketamine and/or 6-hydroxynorketamine, as compared to NK-N-COOH. Regarding selectivity, vaccines bearing a KET-N-COOH hapten yielded an antibody response with approximately equivalent Kd values against ketamine (86.4 ± 3.2 nM) and 6-hydroxynorketamine (74.1 ± 7.8 nM) and a 90-fold weaker Kd against norketamine. Contrastingly, 6-HNK-N-COOH generated the highest affinity and most selective antibody profile, with a 38.3 ± 4.7 nM IC50 against 6-hydroxynorketamine; Kd values for ketamine and norketamine were 33- to 105-fold weaker, at 1290 ± 281.5 and 3971 ± 2175 nM, respectively. Overall, these findings support the use of rational hapten design to generate antibodies capable of distinguishing between structurally related, yet mechanistically distinct, compounds arising from the same precursor molecule. As applied to the production of the first-reported anti-6-hydroxynorketamine antibodies to date, this approach demonstrates a promising path forward for identifying the individual and combinatorial roles of ketamine and its metabolites in supporting rewarding effects and/or rapid-acting antidepressant activity.
- Kyzer, Jillian L.,Wenthur, Cody J.,Worob, Adam,Zheng, Zhen
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p. 4113 - 4122
(2021/11/01)
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- Process Research and Impurity Control Strategy of Esketamine
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An improved synthesis of (S)-ketamine (esketamine) has been developed, which was cost-effective, and the undesired isomer could be recovered by racemization. Critical process parameters of each step were identified as well as the process-related impurities. The formation mechanisms and control strategies of most impurities were first discussed. Moreover, the (S)-ketamine tartrate is a dihydrate, which was disclosed for the first time. The practicable racemization catalyzed by aluminum chloride was carried out in quantitative yield with 99% purity. The ICH-grade quality (S)-ketamine hydrochloride was obtained in 51.1% overall yield (14.0% without racemization) by chiral resolution with three times recycling of the mother liquors. The robust process of esketamine could be industrially scalable.
- Gao, Shenghua,Gao, Xuezhi,Yang, Zhezhou,Zhang, Fuli
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p. 555 - 566
(2020/05/19)
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- Catalytic Asymmetric Acyloin Rearrangements of α-Ketols, α-Hydroxy Aldehydes, and α-Iminols by N, N′-Dioxide-Metal Complexes
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A highly enantioselective acyloin rearrangement of cyclic α-ketols has been developed with a chiral Al(III)-N,N′-dioxide complex as catalyst. This strategy provided an array of optically active 2-acyl-2-hydroxy cyclohexanones in moderate to good yields with high enantioselectivities. The asymmetric isomerizations of acyclic α-hydroxy aldehydes and α-iminols were achieved as well under modified conditions, affording the corresponding chiral α-hydroxy ketones and α-amino ketones in moderate results. Moreover, further transformations of product to enantioenriched diols were carried out.
- Dai, Li,Li, Xiangqiang,Zeng, Zi,Dong, Shunxi,Zhou, Yuqiao,Liu, Xiaohua,Feng, Xiaoming
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supporting information
p. 5041 - 5045
(2020/07/03)
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- COMPOSITIONS AND METHODS FOR THE TREATMENT OF NEUROLOGICAL DISEASES
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The invention relates to the compounds or its pharmaceutical acceptable polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I, formula II and formula III and the methods for the treatment of neurological diseases may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, lozenge, spray, intravenous, oral solution, nasal spray, oral solution, suspension, oral spray, buccal mucosal layer tablet, parenteral administration, syrup, or injection. Such compositions may be used to treatment of neurological diseases.
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- PROCESS FOR SYNTHESIS AND PURIFICATION OF (2R,6R)-HYDROXYNORKETAMINE
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A process for the preparation of (2R,6R)-hydroxynorketamine is provided. The process requires no chromatography purification and affords the (2R,6R)-hydroxynorketamine in eight steps with a 26% overall yield and greater than 97% purity.
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Paragraph 0065-0066
(2019/12/28)
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- Synthesis and N-Methyl- d -aspartate (NMDA) Receptor Activity of Ketamine Metabolites
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Ketamine is rapidly metabolized in the human body to a variety of metabolites, including the hydroxynorketamines. At least two hydroxynorketamines have significant antidepressant action in rodent models, with limited action against the N-methyl-d-aspartate (NMDA) receptor. The synthesis of 12 hydroxynorketamines and their binding affinity to the NMDA receptor is presented here.
- Morris, Patrick J.,Moaddel, Ruin,Zanos, Panos,Moore, Curtis E.,Gould, Todd,Zarate, Carlos A.,Thomas, Craig J.
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p. 4572 - 4575
(2017/09/11)
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- KETAMINE DERIVATIVES
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The present invention relates to ketamine derivatives of the formula (I), pharmaceutical compositions comprising them, and methods for treating pain comprising administering them, and their use in the manufacture of medicaments for treating pain. The present invention also relates to methods for anaesthetizing and methods for sedating a subject comprising administering ketamine derivatives of the formula (II).
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Page/Page column 24; 33; 34
(2014/05/07)
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- The CYP2B6*6 allele significantly alters the N-demethylation of ketamine enantiomers in vitro
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Ketamine is primarily metabolized to norketamine by hepatic CYP2B6 and CYP3A4-mediated N-demethylation. However, the relative contribution from each enzyme remains controversial. The CYP2B6*6 allele is associated with reduced enzyme expression and activity that may lead to interindividual variability in ketamine metabolism. We examined the N-demethylation of individual ketamine enantiomers using human liver microsomes (HLMs) genotyped for the CYP2B6*6 allele, insect cell-expressed recombinant CYP2B6 and CYP3A4 enzymes, and COS-1 cell-expressed recombinant CYP2B6.1 and CYP2B6.6 protein variant. Effects of CYP-selective inhibitors on norketamine formation were also determined in HLMs. The two-enzyme Michaelis-Menten model best fitted the HLM kinetic data. The Michaelis-Menten constants (Km) for the highaffinity enzyme and the low-affinity enzyme were similar to those for the expressed CYP2B6 and CYP3A4, respectively. The intrinsic clearance for both ketamine enantiomers by the high-affinity enzyme in HLMs with CYP2B6 *1/*1 genotype were at least 2-fold and 6-fold higher, respectively, than those for CYP2B6*1/ *6 genotype and CYP2B6*6/*6 genotype. The Vmax and Km values for CYP2B6.1 were approximately 160 and 70% of those for CYP2B6.6, respectively. N,N9N9-triethylenethiophosphoramide (thioTEPA) (CYP2B6 inhibitor, 25 μM) and the monoclonal antibody against CYP2B6 but not troleandomycin (CYP3A4 inhibitor, 25 μM) or the monoclonal antibody against CYP3A4 inhibited ketamine N-demethylation at clinically relevant concentrations. The degree of inhibition was significantly reduced in HLMs with the CYP2B6*6 allele (genedose P *6 allele on enzyme-ketamine binding and catalytic activity. Copyright
- Li, Yibai,Coller, Janet K.,Hutchinson, Mark R.,Klein, Kathrin,Zanger, Ulrich M.,Stanley, Nathan J.,Abell, Andrew D.,Somogyi, Andrew A.
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p. 1264 - 1272
(2013/07/28)
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- Structure-activity relationships for ketamine esters as short-acting anaesthetics
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A series of aliphatic esters of the non-opioid anaesthetic/analgesic ketamine were prepared and their properties as shorter-acting analogues of ketamine itself were explored in an infused rat model, measuring the time after infusion to recover from both the anaesthetic (righting reflex) and analgesic (response to stimulus) effects. The potency of the esters as sedatives was not significantly related to chain length, but Me, Et and i-Pr esters were the more dose potent (up to twofold less than ketamine), whereas n-Pr esters were less potent (from 2- to 6-fold less than ketamine). For the Me, Et and i-Pr esters recovery from anaesthesia was 10-15-fold faster than from ketamine itself, and for the n-Pr esters it was 20-25-fold faster than from ketamine. A new dimethylamino ketamine derivative (homoketamine) had ketamine-like sedative effects but was slightly less potent than, but ester analogues of homoketamine had very weak sedative effects.
- Jose, Jiney,Gamage, Swarna A.,Harvey, Martyn G.,Voss, Logan J.,Sleigh, James W.,Denny, William A.
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p. 5098 - 5106
(2013/09/02)
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- SUBSTITUTED CYCLOHEXANONES
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Disclosed herein are substituted cyclohexanone-based NMDA receptor modulators of Formula I, process of preparation thereof, pharmaceutical compositions thereof, and methods of use thereof.
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Page/Page column 26
(2008/12/04)
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- Haptens, immunogens, antibodies and conjugates to ketamine and its metabolites
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The invention provides haptens, immunogens comprising such haptens coupled to an antigenicity-conferring carrier material, conjugates comprising such haptens bonded to a labelling agent as well as, antibodies raised against such immunogens and capable of binding with ketamine and its primary metabolite, norketamine.
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