R-Isomer Ketamine (Arketamine hydrochloride) crystalline

Product Description

R-Isomer Ketamine $((2R)\text{-2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one hydrochloride})$, commonly designated as arketamine, is the isolated $(R)\text{-(-)}$ stereoisomer of racemic ketamine. In analytical chemistry, stereoselective pharmacology, and experimental neuroscience, enantiopure arketamine crystalline reference materials serve as critical tools for investigating non-competitive glutamatergic modulation, active metabolite pathways, and differential behavioral toxicology between optical antipodes.

Chemical & Stereochemical Properties

• Molecular Formula & Mass: $\text{C}_{13}\text{H}_{16}\text{ClNO} \cdot \text{HCl}$ | 274.19 g/mol (hydrochloride salt)

• Physical Form: High-purity crystalline solid / crystalline aggregate matrix optimized for quantitative reference standards, solubility profiling, and recrystallization assays.

• Optical Rotation: Demonstrates levorotatory optical activity in polar solvents ($[\alpha]_D \approx -56^\circ$ depending on concentration and solvent temperature).

Pharmacodynamics & Neurobiological Mechanisms

• NMDA Receptor Interactions: Exhibits approximately 3- to 4-fold lower binding affinity ($K_i$) for the open channel pore of the $N$-methyl-D-aspartate (NMDA) receptor complex compared to $(S)\text{-ketamine}$. Consequently, it induces significantly less marked direct channel blockade and lower behavioral dissociation at equimolar concentrations.

• Synaptogenesis & AMPA Activation: Preclinical neuropharmacology demonstrates that arketamine promotes rapid and sustained synaptogenesis and dendritic spine proliferation within the prefrontal cortex and hippocampus. Its cellular signaling cascade involves early activation of $\alpha$-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, increased transcription of brain-derived neurotrophic factor (BDNF), and downstream activation of the vascular endothelial growth factor receptor 2 ($\text{VEGFR}_2$) pathway, largely independent of high-affinity NMDA pore inhibition.

• Metabolite Kinetics: Undergoes hepatic $N$-demethylation to $(R)\text{-norketamine}$, followed by downstream biotransformation to hydroxynorketamine metabolites—predominantly $(2R,6R)\text{-hydroxynorketamine}$ ($(2R,6R)\text{-HNK}$)—which are widely studied for their non-dissociative neurotrophic activity.

Analytical & Laboratory Applications

• Chiral Chromatography Calibration: Utilized as an enantiopure standard to develop, validate, and calibrate chiral high-performance liquid chromatography ($\text{HPLC}$) and supercritical fluid chromatography ($\text{SFC}$) methods aimed at resolving ketamine enantiomeric ratios in biological fluids or forensic casework.

• Forensic Profiling & Mass Spectrometry: Serves as a reference calibrant for Gas Chromatography-Mass Spectrometry ($\text{GC-MS}$) and Liquid Chromatography-Tandem Mass Spectrometry ($\text{LC-MS/MS}$) fragmentation libraries, confirming retention indices and base peak transitions ($m/z$ 180, 209).

• Presumptive Assay Profiling: Validates colorimetric response thresholds with standard screening reagents (e.g., Marquis, Mandelin, and Morris reagents) to distinguish arylcyclohexylamine salts from common cutting agents or adulterants.

Toxicological Profile & Regulatory Framework

• Laboratory Safety Profile: Inadvertent in vivo systemic exposure carries risks of acute sympathomimetic stimulation (elevated heart rate, transient blood pressure elevation), ataxia, sensory distortion, and central nervous system depression. Chronic, repetitive administration is associated with lower urinary tract pathology, including ketamine-induced ulcerative cystitis and renal impairment.

• Controlled Substance Classification: In the United States, ketamine and all of its optical isomers, enantiomers, and salts are classified as Schedule III controlled substances under the Controlled Substances Act (Class B in the United Kingdom; Schedule II/IV in various international jurisdictions). Handling, procurement, storage, and disposal require institutional DEA registration, secure physical vault containment, and perpetual chain-of-custody documentation.