Tag: MONOGRAPH

  • Tretinoin

    Endogenous retinoid and pan-retinoic acid receptor agonist with genomic transcriptional regulation

    The principal biologically active metabolite of vitamin A, functioning as a pan-RAR agonist that regulates epithelial differentiation, collagen biosynthesis, and myeloid cell maturation, with established clinical applications spanning topical dermatology, photoaging reversal, and systemic differentiation therapy of acute promyelocytic leukemia.

    Abstract

    Tretinoin (all-trans-retinoic acid, ATRA) is the carboxylic acid form of vitamin A and the principal endogenous ligand of the nuclear retinoic acid receptors (RAR-alpha, RAR-beta, RAR-gamma), through which it regulates the transcription of over 500 target genes involved in cellular differentiation, proliferation, apoptosis, and immune modulation. First isolated and characterized in the mid-twentieth century as a metabolite of retinol, tretinoin was developed as a topical dermatological agent by Albert Kligman and James Fulton at the University of Pennsylvania in the 1960s and received United States Food and Drug Administration approval for acne vulgaris in 1971, making it the first retinoid approved for clinical use. The compound was subsequently approved for the treatment of fine facial wrinkles and mottled hyperpigmentation associated with photoaging in 1995. In the systemic setting, the landmark 1988 report by Huang and colleagues at Shanghai Second Medical University demonstrated that oral tretinoin at 45 mg/m2/day induced complete hematological remission in patients with acute promyelocytic leukemia (APL) harboring the t(15;17) translocation and the resulting PML-RAR-alpha fusion oncoprotein, establishing tretinoin as the first successful differentiation therapy in oncology and transforming APL from a rapidly fatal malignancy to one of the most curable forms of acute leukemia. The molecular pharmacology of tretinoin is mediated through ligand-dependent activation of RAR/RXR heterodimers bound to retinoic acid response elements in target gene promoters; in the unliganded state, these heterodimers recruit corepressor complexes (NCoR, SMRT) and histone deacetylases that maintain transcriptional silencing, while tretinoin binding induces conformational change, corepressor release, and coactivator recruitment with histone acetyltransferase activity, resulting in chromatin remodeling and transcriptional activation. In the dermatological context, this transcriptional program promotes keratinocyte differentiation, accelerates corneocyte shedding, inhibits comedone formation, stimulates type I procollagen synthesis, and blocks ultraviolet-induced matrix metalloproteinase activation through inhibition of activator protein 1. In APL, pharmacological concentrations of tretinoin overcome the dominant-negative transcriptional repression imposed by the PML-RAR-alpha fusion protein, driving terminal granulocytic differentiation of the leukemic clone.

    Pharmacokinetics differ substantially between the topical and systemic routes. Topical application produces minimal systemic absorption, with percutaneous bioavailability estimated at less than 2 percent and negligible alteration of endogenous plasma retinoid concentrations. Oral tretinoin at the 45 mg/m2 APL dose is rapidly absorbed, reaching peak plasma concentrations of approximately 350 ng/mL (1.2 micromolar) within 1 to 2 hours, with greater than 95 percent plasma protein binding predominantly to albumin. The terminal elimination half-life is short (0.5 to 2 hours) and is dominated by oxidative metabolism through CYP26A1, CYP2C8, and CYP3A4, with a clinically significant autoinduction phenomenon: tretinoin potently upregulates CYP26A1 transcription through retinoic acid response elements in the CYP26A1 promoter, resulting in progressive acceleration of its own clearance such that plasma concentrations decline to approximately one-third of initial values within one week of continuous dosing at constant dose. This autoinduction has clinical implications for APL treatment duration and has motivated intermittent dosing schedules and combination regimens with arsenic trioxide. The compound is teratogenic through disruption of retinoic acid gradient signaling during embryogenesis, classified as FDA pregnancy category X for systemic use; topical tretinoin, by contrast, does not produce measurable increases in systemic retinoid exposure and is not associated with increased teratogenic risk in epidemiological studies, though precautionary avoidance during pregnancy is recommended. The principal systemic toxicity in APL therapy is the differentiation syndrome (formerly retinoic acid syndrome), a potentially fatal inflammatory response occurring in approximately 25 percent of treated patients and characterized by fever, dyspnea, weight gain, pulmonary infiltrates, and pleural or pericardial effusions, managed with early recognition and high-dose corticosteroids.

    This monograph reviews the chemistry, structural identity, and synthesis of tretinoin; the RAR/RXR nuclear receptor pharmacology and downstream transcriptional programs; the divergent pharmacokinetics of topical and systemic administration including autoinduction; the preclinical pharmacology across dermatological, oncological, and wound-healing models; the clinical evidence base in acne, photoaging, and acute promyelocytic leukemia; sourcing and quality verification considerations; reconstitution and handling; stack-interaction implications; adverse-event and safety signal; and a comparative assessment of five retinoid alternatives (adapalene, tazarotene, isotretinoin, bexarotene, tamibarotene) against tretinoin on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1566Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Bacoside A

    Dammarane-type triterpenoid saponin mixture with multi-target nootropic, antioxidant, and neuroprotective activity

    A mixture of dammarane-type triterpenoid saponin glycosides isolated from Bacopa monnieri (Linn.) Wettst., constituting the principal bioactive fraction responsible for the cognitive-enhancing, neuroprotective, and antioxidant pharmacology of the Ayurvedic nootropic brahmi, with demonstrated activity across cholinergic modulation, serotonergic and dopaminergic neurotransmission, amyloid-beta aggregation inhibition, and synaptic plasticity.

    Abstract

    Bacoside A is a mixture of four dammarane-type triterpenoid saponin glycosides (bacoside A3, bacopaside II, bacopasaponin C, and bacopaside X) isolated from the aerial parts and roots of Bacopa monnieri (Linn.) Wettst. (family Plantaginaceae, formerly Scrophulariaceae), a creeping perennial herb used in the Ayurvedic medical tradition for over three millennia under the name brahmi as a medhya rasayana (intellect-rejuvenating) agent. The bacoside A fraction, typically comprising 40 to 55 percent of standardized Bacopa monnieri extracts by weight, is the principal pharmacologically active constituent and the basis of standardization for all clinically studied Bacopa preparations including CDRI-08 (KeenMind, Synapsa), BacoMind, and BaCognize. The aglycone cores of the constituent saponins are jujubogenin and pseudojujubogenin, linked to arabinose-glucose trisaccharide chains that modulate solubility, bioavailability, and receptor interaction profiles.

    The pharmacology of bacoside A is multi-target and operates through at least five characterized mechanisms: (1) enhancement of cholinergic neurotransmission through upregulation of choline acetyltransferase activity and inhibition of acetylcholinesterase; (2) modulation of serotonergic neurotransmission through interaction with 5-HT1A and 5-HT2C receptor subtypes, with downstream effects on anxiety, mood, and cognitive flexibility; (3) dopaminergic modulation in prefrontal and hippocampal circuits; (4) potent antioxidant neuroprotection through scavenging of reactive oxygen species, suppression of lipid peroxidation, and upregulation of endogenous antioxidant enzymes including superoxide dismutase, catalase, and glutathione peroxidase; and (5) inhibition of amyloid-beta peptide fibrillation and cytotoxicity through direct interaction with amyloid-beta (1-42), reducing aggregation and membrane disruption in neuronal cell models. Additional mechanisms include enhancement of brain-derived neurotrophic factor (BDNF) expression, promotion of hippocampal dendritic branching and synaptic density in the CA1 and CA3 regions, and modulation of GABAergic neurotransmission.

    The clinical evidence base for Bacopa monnieri standardized to bacoside A content comprises at least nine randomized, double-blind, placebo-controlled trials in healthy adults, elderly populations, and children, conducted principally at Swinburne University of Technology (Stough laboratory), the University of Wollongong (Roodenrys laboratory), and multiple Indian academic medical centers. The consistent finding across these trials is statistically significant improvement in speed of visual information processing, learning rate, memory consolidation, and delayed recall after 8 to 12 weeks of oral administration at 300 to 450 mg per day of extract standardized to 50 to 55 percent bacosides, with secondary anxiolytic effects and reduction in state anxiety scores. Effect onset requires sustained administration; acute single-dose cognitive enhancement has not been reliably demonstrated. A 2012 systematic review by Pase et al. confirmed the cognitive-enhancing effects across six qualifying trials and identified memory consolidation as the most reproducible endpoint.

    Pharmacokinetic characterization of isolated bacoside A in humans remains incomplete. In silico ADMET analyses of the constituent saponins and their aglycone derivatives indicate favorable predicted oral absorption for the aglycones (jujubogenin, pseudojujubogenin), with central nervous system drug-like properties including adequate predicted blood-brain barrier penetration. The intact glycosides are poorly water-soluble and are believed to undergo gastrointestinal hydrolysis to active aglycone metabolites, a transformation consistent with the delayed onset of clinical effect observed in human trials. Hepatic metabolism involves cytochrome P450 enzymes; Bacopa monnieri standardized extract has been demonstrated to inhibit CYP3A4, CYP2C9, CYP2C19, and CYP1A2 in vitro at estimated gut concentrations, with potential for clinically significant herb-drug interactions.

    The compound is well tolerated at standard doses (300 to 600 mg per day of standardized extract). The principal adverse events are mild gastrointestinal disturbances (nausea, abdominal cramps, increased stool frequency) that typically attenuate with continued use. No hepatotoxicity has been reported despite widespread use. A thyroid-stimulating effect (elevation of serum T4) has been characterized in animal studies and warrants caution in individuals with thyroid disorders. This monograph reviews the chemistry, biosynthesis, and structural characterization of bacoside A; the multi-target molecular pharmacology; the pharmacokinetic profile; the preclinical neuroprotective and cognitive evidence; the clinical trial evidence base; sourcing and quality verification for standardized extracts; reconstitution and handling; stack interactions; adverse events and safety; and a comparative assessment of five alternative nootropic candidates (Hericium erinaceus, Ginkgo biloba EGb 761, phosphatidylserine, alpha-GPC, and citicoline) against bacoside A on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1614Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Cycloastragenol

    Lanostane-type tetracyclic triterpenoid sapogenin with telomerase-activating, anti-inflammatory, and antioxidant activity

    A naturally occurring triterpenoid aglycone derived from Astragalus membranaceus, identified as the bioactive sapogenin of astragaloside IV and the principal small-molecule telomerase activator in the TA-65 formulation, with expanding preclinical evidence in anti-inflammatory, neuroprotective, cardioprotective, and anti-senescence applications.

    Abstract

    Cycloastragenol (CAG) is a lanostane-type tetracyclic triterpenoid sapogenin obtained by acid or enzymatic hydrolysis of astragaloside IV, the principal bioactive saponin of Astragalus membranaceus (Huangqi), a plant with extensive use in traditional Chinese medicine. The compound gained prominence following a systematic screen of natural product libraries at Geron Corporation in the early 2000s that identified it as a small-molecule activator of human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase. This discovery led to the development and commercialization of TA-65, a proprietary cycloastragenol-containing nutraceutical formulation marketed by T.A. Sciences for telomere health and anti-aging applications. The telomerase-activating mechanism involves upregulation of hTERT gene expression, enhanced nuclear localization of the hTERT protein via upregulation of the Hsp90 chaperone complex, and activation of the cAMP response element binding protein (CREB) signaling axis. At the cellular level, cycloastragenol activates telomerase in multiple cell types including peripheral blood mononuclear cells, CD4-positive and CD8-positive T lymphocytes, fibroblasts, and neuronal cells, with functional consequences including telomere elongation, reduced replicative senescence, and enhanced proliferative capacity. A 2016 randomized, double-blind, placebo-controlled clinical trial of TA-65 in 117 cytomegalovirus-positive subjects aged 53 to 87 years demonstrated dose-dependent telomere lengthening in the low-dose group (530 plus or minus 180 base pairs; p equals 0.005) over 12 months, with the placebo group losing telomere length (290 plus or minus 100 base pairs; p equals 0.01). The compound additionally exhibits pharmacological activities independent of the telomerase mechanism. Preclinical studies have characterized anti-inflammatory effects through inhibition of NF-kappaB signaling and pyroptosis pathways; neuroprotective activity through upregulation of SIRT1 expression, activation of the Nrf2/HO-1 pathway, and promotion of BDNF/p-TrkB/CREB signaling; cardioprotective effects through promotion of myocardial autophagy via inhibition of AKT1-RPS6KB1 signaling; anti-fibrotic activity in hepatic and pulmonary models; and antioxidant effects through activation of the Nrf2/ARE transcriptional pathway. Pharmacokinetics in the rat model show oral bioavailability of approximately 25.7 percent following acid hydrolysis-mediated absorption, substantially higher than the parent compound astragaloside IV (2.2 percent), with extensive first-pass hepatic metabolism limiting systemic exposure. In human liver microsomes, only 8.2 percent of cycloastragenol remained after 30 minutes of incubation, indicating rapid phase I metabolism. A 91-day subchronic toxicity study in rats at doses up to 150 mg/kg/day by oral gavage produced no treatment-related mortalities, no cardiac effects, and no evidence of genotoxicity or carcinogenicity. Clinical safety data from TA-65 studies over 12 months of supplementation report no serious adverse events, with mild gastrointestinal discomfort as the principal dose-dependent adverse effect. The theoretical concern of telomerase activation promoting oncogenesis has not been substantiated in preclinical cancer bioassays or in clinical observation, though the mechanism warrants continued surveillance. This monograph reviews the chemistry and structural classification of cycloastragenol; its discovery as a telomerase activator and subsequent commercial development; the molecular pharmacology across telomerase, anti-inflammatory, neuroprotective, and cardioprotective pathways; the pharmacokinetic profile including metabolism and bioavailability; the preclinical evidence base; the clinical evidence from TA-65 trials and related human studies; sourcing, quality verification, and reconstitution considerations; stack interactions; adverse events and safety signals; and a comparative assessment of five telomerase-modulating or astragalus-derived compounds against cycloastragenol on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1611Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Eplerenone

    Selective steroidal mineralocorticoid receptor antagonist with 9-alpha,11-alpha-epoxy modification conferring high receptor selectivity over androgen and progesterone receptors

    A selective aldosterone antagonist derived from the spironolactone scaffold through introduction of a 9-alpha,11-alpha-epoxy group, developed across four pharmaceutical sponsors over two decades and validated in landmark heart failure and post-myocardial infarction trials as the first mineralocorticoid receptor antagonist with clinically meaningful selectivity over sex steroid hormone receptors.

    Abstract

    Eplerenone is a steroidal mineralocorticoid receptor (MR) antagonist and the second agent approved in this pharmacological class, reaching United States Food and Drug Administration registration in 2002 (marketed as Inspra) approximately four decades after the introduction of spironolactone, the first-generation nonselective aldosterone blocker. The compound is distinguished from spironolactone by the presence of a 9-alpha,11-alpha-epoxy bridge and a 17-alpha-carbomethoxy substituent, structural modifications that confer approximately 20- to 40-fold lower binding affinity at the mineralocorticoid receptor but approximately 500- to 800-fold greater selectivity over the androgen, progesterone, and glucocorticoid receptors. This selectivity profile eliminates the gynecomastia, breast pain, menstrual irregularity, and sexual dysfunction that limit spironolactone tolerability in chronic cardiovascular and renal indications.

    The clinical evidence base for eplerenone rests on two landmark randomized controlled trials. The Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS), published in 2003 in the New England Journal of Medicine, enrolled 6,632 patients with left ventricular dysfunction (ejection fraction 40 percent or less) 3 to 14 days after acute myocardial infarction and demonstrated that eplerenone 25 to 50 mg daily reduced all-cause mortality by 15 percent (relative risk 0.85; 95 percent confidence interval 0.75 to 0.96) and heart failure hospitalization by 15 percent compared to placebo on top of optimal medical therapy. The Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF), published in 2011 in the New England Journal of Medicine, enrolled 2,737 patients with chronic systolic heart failure (ejection fraction 35 percent or less) and New York Heart Association class II symptoms and demonstrated that eplerenone reduced the composite of cardiovascular death and heart failure hospitalization by 37 percent (hazard ratio 0.63; 95 percent confidence interval 0.54 to 0.74). These trials established eplerenone as a guideline-recommended therapy in heart failure with reduced ejection fraction and in post-myocardial infarction left ventricular dysfunction across all major international cardiovascular society guidelines.

    Eplerenone is approved in the United States for hypertension and for heart failure following myocardial infarction with left ventricular dysfunction. The compound is also approved in the European Union, Japan, and multiple additional jurisdictions for heart failure with reduced ejection fraction. The pharmacokinetic profile is characterized by rapid oral absorption (time to maximum plasma concentration approximately 1.5 hours), absolute bioavailability of approximately 69 percent, elimination half-life of 4 to 6 hours, and predominant hepatic metabolism by cytochrome P450 3A4 (CYP3A4) with contributions from CYP3A5. The principal adverse event is dose-dependent hyperkalemia, occurring in approximately 5 to 10 percent of treated patients depending on baseline renal function and concurrent renin-angiotensin-aldosterone system blockade; the risk is substantially increased in patients with estimated glomerular filtration rate below 30 mL/min/1.73 m2 and in those with serum potassium above 5.0 mEq/L at baseline. The absence of clinically meaningful gynecomastia (0.7 percent versus 9 to 10 percent for spironolactone in controlled trials) is the principal tolerability advantage.

    This monograph reviews the chemistry, synthesis, and structural pharmacology of eplerenone; the molecular pharmacology at the mineralocorticoid receptor in detail; the comprehensive human pharmacokinetic record; the preclinical pharmacology in cardiac fibrosis, remodeling, and inflammatory models; the clinical evidence base across heart failure, post-myocardial infarction, hypertension, and emerging renal indications; sourcing and quality verification considerations; reconstitution and handling; stack-interaction implications with emphasis on CYP3A4-mediated drug-drug interactions and potassium homeostasis; adverse-event signal with focus on hyperkalemia risk stratification; and a structured comparative assessment of five mineralocorticoid receptor antagonists (spironolactone, finerenone, esaxerenone, canrenone, ocedurenone) against eplerenone on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1564Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Tributyrin

    Triglyceride prodrug of butyric acid with histone deacetylase inhibitory activity

    A glycerol tributyrate ester functioning as a stable, orally bioavailable prodrug of butyric acid, distinguished from other butyrate delivery forms by its resistance to gastric degradation, intracellular lipase-mediated release of three butyrate equivalents, and HDAC-inhibitory activity supporting applications in oncology chemoprevention, intestinal barrier maintenance, hepatoprotection, metabolic inflammation, and skeletal muscle differentiation.

    Abstract

    Tributyrin (glycerol tributyrate, CAS 60-01-5) is the 1,2,3-tributanoyl ester of glycerol and the principal triglyceride prodrug of butyric acid studied in human clinical pharmacology and preclinical oncology. Classified by the United States Food and Drug Administration as Generally Recognized as Safe (GRAS) for food use, tributyrin is a naturally occurring lipid constituent of bovine milk fat and honey that has attracted sustained research interest as a vehicle for delivering pharmacologically active butyrate concentrations to systemic circulation and to the colonic epithelium, overcoming the rapid first-pass hepatic clearance, objectionable odor, and poor oral bioavailability that limit the therapeutic application of free butyric acid and its sodium salt.

    The molecular pharmacology of tributyrin is mediated through its hydrolytic product, butyrate, a four-carbon short-chain fatty acid that operates through at least three characterized molecular mechanisms: inhibition of class I and class II histone deacetylases (HDACs), particularly HDAC1, HDAC2, and HDAC3; agonism at the G-protein-coupled receptor GPR109A (also designated HCAR2 or HM74a), the niacin receptor expressed on colonocytes, adipocytes, and immune cells; and agonism at the free fatty acid receptors GPR41 (FFAR3) and GPR43 (FFAR2) on enteroendocrine cells and immune cells. The HDAC-inhibitory activity produces histone hyperacetylation, chromatin remodeling, and consequent transcriptional activation of tumor suppressor genes (p21WAF1/CIP1, BAX, p53), cell cycle arrest proteins, and differentiation-associated gene programs in neoplastic cells. The GPR109A agonism mediates anti-inflammatory signaling through suppression of NF-kappaB-dependent proinflammatory cytokine production and through promotion of regulatory T-cell and M2-macrophage phenotypes in adipose tissue and intestinal lamina propria.

    Two Phase I clinical trials in patients with advanced solid tumors have characterized the human pharmacology of tributyrin. The Conley et al. (1998) study administered tributyrin at 50 to 400 mg/kg/day orally to 13 patients and demonstrated dose-proportional plasma butyrate concentrations reaching 0 to 0.45 mM, with no dose-limiting toxicity. The Edelman et al. (2003) study administered tributyrin at 150 to 200 mg/kg three times daily to 20 patients with advanced solid tumors and achieved median plasma butyrate concentrations of 52 micromolar with considerable interpatient variability; escalation was halted at 200 mg/kg three times daily owing to the large number of capsules required rather than to toxicity. Both trials confirmed that tributyrin is well tolerated, with mild gastrointestinal complaints (nausea, eructation, diarrhea) as the principal adverse events.

    Preclinical pharmacology spans oncology, gastroenterology, hepatology, metabolic disease, and muscle biology. In oncology, tributyrin induces differentiation, growth arrest, and apoptosis in human prostate cancer (PC3, LNCaP, TSU-Pr1), colon cancer (HT-29, Caco-2), breast cancer (MCF-7), and leukemia cell lines at concentrations of 0.1 to 4 mM, and suppresses hepatocarcinogenesis in the resistant hepatocyte rat model through p53 acetylation and activation of the p53 apoptotic signaling pathway. In gastroenterology, tributyrin maintains intestinal tight junction integrity, reduces antibiotic-induced intestinal injury in combination with Lactobacillus GG, and mitigates chronic-binge ethanol-induced intestinal barrier disruption and liver injury. In metabolic disease, tributyrin attenuates obesity-associated inflammation, improves insulin responsiveness, and reduces hepatic triglyceride accumulation through a GPR109A-dependent mechanism. In muscle biology, dietary tributyrin promotes satellite cell terminal differentiation through HDAC inhibition and epigenetic priming, producing measurable increases in muscle fiber cross-sectional area in neonatal piglet models.

    This monograph reviews the chemistry, synthesis, and physicochemical properties of tributyrin; the three-arm molecular pharmacology (HDAC inhibition, GPR109A agonism, FFAR agonism); the human pharmacokinetic record from Phase I oncology trials; the preclinical evidence base across oncology, gastrointestinal, hepatoprotective, metabolic, and muscle biology applications; sourcing and quality verification for research use; reconstitution and handling; stack-interaction considerations; adverse-event signal; and a comparative assessment of five alternative butyrate delivery forms against tributyrin on five competency standards (bioavailability, effect size, delivery specificity, tolerability profile, and overall validation). The compound is not approved as a drug by any regulatory authority. It is sold as a dietary supplement and as a research-grade preparation; investigators should obtain analytical confirmation of identity and purity on every lot.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1609Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Zelquistinel

    Novel positive allosteric modulator of the N-methyl-D-aspartate receptor acting at a unique extracellular binding site independent of the glycine co-agonist site

    A third-generation, orally bioavailable spirocyclic beta-lactam NMDA receptor modulator developed from the rapastinel peptidomimetic platform, distinguished by nanomolar positive allosteric modulation of NR2A-, NR2B-, and NR2C-containing NMDA receptors through reduction of calcium-dependent inactivation, producing rapid and sustained antidepressant-like effects without psychotomimetic liability.

    Abstract

    Zelquistinel (GATE-251, formerly AGN-241751) is a novel, orally bioavailable, small-molecule positive allosteric modulator of the N-methyl-D-aspartate (NMDA) glutamate receptor, currently in Phase 2b clinical development for major depressive disorder (MDD) under the sponsorship of Syndeio Biosciences (operating as Gate Neurosciences). The compound is the third-generation successor to the tetrapeptide rapastinel (GLYX-13) and the dipeptide apimostinel (NRX-1074), sharing a common mechanism of NMDA receptor positive modulation but replacing the peptide scaffold with a spirocyclic 2,5-diazaspiro[3.4]octane (beta-lactam) core that confers oral bioavailability approaching 100 percent in preclinical species, a plasma half-life of approximately 1.2 to 2.1 hours, and approximately 1000-fold greater potency than rapastinel on a weight basis.

    Zelquistinel binds to a unique extracellular site on the NMDA receptor that is distinct from the glutamate agonist site, the glycine co-agonist site, the phencyclidine channel-blocking site, and the polyamine modulatory site. The compound does not displace radioligands at any of these four canonical sites and shows no significant activity across a panel of 80 receptors, ion channels, and monoamine transporters. Mechanistically, zelquistinel acts through a long-distance allosteric pathway: extracellular binding reduces intracellular calcium-dependent inactivation (CDI) of the NMDA receptor channel, thereby enhancing NMDA receptor current in an activity-dependent manner. This mechanism has been demonstrated through experiments showing that replacement of the intracellular calcium chelator EGTA with the fast chelator BAPTA abolishes zelquistinel potentiation, and that removal of the NR1 C-terminal intracellular domain or infusion of calmodulin-blocking peptide similarly eliminates the modulatory effect. Subtype selectivity studies reveal potent enhancement at NR2A-containing (EC50 approximately 9.9 nM) and NR2C-containing (EC50 approximately 9.7 nM) receptors, with a larger ceiling enhancement at NR2B-containing receptors (EC50 approximately 35.0 nM) and no effect at NR2D-containing receptors.

    The pharmacological profile produces a characteristic biphasic, inverted-U dose-response relationship: potentiation of NMDA receptor-mediated calcium influx at concentrations of 0.3 to 60 nM and mild inhibition at concentrations exceeding 100 nM. In preclinical behavioral models, single oral doses of zelquistinel at 30 micrograms per kilogram produce rapid antidepressant-like effects in the forced swim test (onset within one hour) that are sustained for more than seven days, and rescue social approach behavior in the chronic social defeat model at efficacy comparable to ketamine at 10 mg/kg subcutaneous. The compound enhances long-term potentiation (LTP) in both medial prefrontal cortex and hippocampal Schaffer collateral-CA1 pathways, with metaplastic enhancement persisting for at least two weeks after a single dose. Critically, zelquistinel produces no motor impairment on the rotarod test at doses 100-fold above the antidepressant-effective dose and no psychotomimetic symptoms as measured by validated clinical scales in human subjects.

    In Phase 1 clinical evaluation, single ascending oral doses from 100 micrograms to 50 mg were well tolerated in 60 healthy volunteers, with dose-proportional pharmacokinetics, rapid absorption, significant cerebrospinal fluid penetration, and no clinically significant adverse events, vital sign changes, electrocardiographic abnormalities, or psychotomimetic symptoms. A Phase 2a exploratory trial in 251 patients with major depressive disorder demonstrated statistically significant reductions in Montgomery-Asberg Depression Rating Scale (MADRS) scores at the two highest once-weekly oral doses (reductions of 9.5 and 10.6 points versus 7.7 points with placebo at week three). The U.S. Food and Drug Administration granted Fast Track designation for zelquistinel in MDD in July 2018. As of the date of this monograph, a Phase 2b confirmatory trial is actively recruiting under Syndeio Biosciences sponsorship. Additional preclinical research has demonstrated durable relief of core behavioral deficits in three mouse models of autism spectrum disorder, and dose-dependent reversal of phencyclidine-induced hyperlocomotion, expanding the potential therapeutic scope beyond depression.

    This monograph reviews the chemistry, structural class, and synthesis of zelquistinel; the dual extracellular-intracellular allosteric mechanism in molecular and electrophysiological detail; the comprehensive preclinical and human pharmacokinetic record; the clinical evidence base in major depressive disorder; sourcing and quality verification considerations for research applications; reconstitution and handling; stack-interaction implications; adverse-event signal; and a comparative assessment of five NMDA receptor-targeting antidepressant candidates (rapastinel, apimostinel, esketamine, REL-1017, and AV-101) against zelquistinel on five competency standards (novelty, effect size, promising potential, side-effect profile, and overall validation). The compound is not approved by any regulatory authority for any indication. It is available as a research-grade preparation from chemical suppliers; investigators should obtain analytical confirmation of identity and purity on every lot.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1569Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Cytoflavin

    Fixed-dose combination metabolic cytoprotectant comprising succinic acid, inosine, nicotinamide, and riboflavin for mitochondrial energy rescue and antihypoxant neuroprotection

    A four-component metabolic combination drug developed by POLYSAN Ltd. that supplies Krebs cycle substrate, purine nucleoside, NAD+ precursor, and FAD cofactor to restore aerobic energy production in ischemic, hypoxic, and neurodegenerative tissue.

    Abstract

    Cytoflavin is a fixed-dose combination metabolic agent comprising succinic acid (the principal mass component and Krebs cycle substrate), inosine (a purine nucleoside and precursor to adenine nucleotides), nicotinamide (the amide form of vitamin B3 and precursor to nicotinamide adenine dinucleotide), and riboflavin (vitamin B2, the precursor to flavin adenine dinucleotide and flavin mononucleotide). Developed and manufactured by POLYSAN Scientific and Technological Pharmaceutical Company (Saint Petersburg, Russia), the product is formulated as enteric-coated tablets (300 mg succinic acid, 50 mg inosine, 25 mg nicotinamide, 5 mg riboflavin per tablet) and as a concentrate for intravenous infusion (1000 mg succinic acid, 200 mg inosine, 100 mg nicotinamide, 20 mg riboflavin sodium phosphate per 10 mL ampoule, with meglumine and sodium hydroxide as excipients). The pharmacological rationale is the simultaneous provision of four complementary metabolic substrates and cofactors whose intracellular availability becomes rate-limiting during ischemia, hypoxia, and oxidative stress: succinic acid feeds directly into mitochondrial Complex II (succinate dehydrogenase), bypassing the NAD-dependent steps of the Krebs cycle that fail under hypoxic conditions; inosine supports purine salvage and ATP resynthesis; nicotinamide replenishes the NAD+ pool consumed by poly(ADP-ribose) polymerase activation during ischemic injury; and riboflavin provides the FAD prosthetic group required for succinate dehydrogenase function and for multiple flavoprotein-dependent antioxidant enzymes including glutathione reductase.

    The clinical evidence base for Cytoflavin spans ischemic stroke (acute and chronic cerebral ischemia), traumatic brain injury, diabetic polyneuropathy, postoperative cognitive decline in elderly surgical patients, post-COVID-19 asthenic syndrome, and organic asthenic disorder. The largest and most rigorous published trial is the CYLINDER study, a multicenter, double-blind, placebo-controlled, randomized trial in 216 patients with type 2 diabetes mellitus and symptomatic distal sensorimotor diabetic polyneuropathy conducted across 10 Russian clinical centers, which reported a statistically significant reduction in Total Symptom Score (TSS change of negative 2.65 points in the experimental group versus negative 1.73 points in the placebo group, p less than 0.001) after a sequential intravenous-then-oral treatment regimen. In acute ischemic stroke, multicenter studies have demonstrated marked reduction in neurological deficit severity by day 10 and higher probability of favorable functional outcome compared to standard-of-care controls. The CITADEL prospective randomized study demonstrated a pronounced anti-asthenic effect and correction of cognitive impairments in post-COVID-19 rehabilitation. An international, multicenter, randomized, single-blind, placebo-controlled trial (NCT04631484) evaluating Cytoflavin in moderate traumatic brain injury in adults was completed in 2024, with results published in Frontiers in Neurology in 2025, representing the first large-scale international trial of the compound outside the Russian Federation and Commonwealth of Independent States.

    Cytoflavin is registered as a medicinal product in the Russian Federation and in Vietnam. The manufacturing facility holds GMP EU certification. The compound is not approved by the United States Food and Drug Administration, by the European Medicines Agency, or by other major Western regulatory authorities. The clinical literature is predominantly in Russian-language journals, with an expanding body of English-language publications in international peer-reviewed venues. The safety profile across published clinical studies is favorable; the principal adverse events are transient epigastric discomfort, headache, hyperuricemia (attributable to inosine-derived purine catabolism), and rare hypersensitivity reactions. No serious adverse events attributable to the drug have been reported in published controlled trials.

    This monograph reviews the composition, identification, and formulation chemistry of Cytoflavin; the individual and composite pharmacology of its four active components; the pharmacokinetic considerations for each component; the preclinical pharmacology; the clinical evidence base across all studied indications; sourcing and quality verification; reconstitution and handling; stack interactions and combinations; adverse events and safety signals; and a comparative assessment of five alternative neuroprotective metabolic agents (Mexidol, Actovegin, Cerebrolysin, citicoline, and Reamberin) against Cytoflavin on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1583Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Hopantenic acid

    Pantoyl-GABA conjugate nootropic with GABAergic, cholinergic, and pantothenic acid-related central nervous system activity

    A synthetic homolog of pantothenic acid in which beta-alanine is replaced by gamma-aminobutyric acid, developed in the Soviet Union and Japan as a nootropic and neuroprotective agent with registered indications across pediatric and adult neurology in the Russian Federation.

    Abstract

    Hopantenic acid (homopantothenic acid, D-homopantothenic acid, N-pantoyl-GABA) is a synthetic structural analog of pantothenic acid (vitamin B5) in which the beta-alanine moiety is replaced by gamma-aminobutyric acid (GABA), producing a hybrid molecule that combines GABAergic pharmacology with pantothenate-related metabolic activity and the capacity to cross the blood-brain barrier, a property that free GABA lacks. The compound was first synthesized in the 1950s in Japan, entered clinical use as the calcium salt (calcium hopantenate) in Japan in 1978 and in the Soviet Union in 1977, and is registered in the Russian Federation under the brand names Pantogam and Pantocalcin for a broad range of neurological, psychiatric, and developmental indications in children and adults, including cognitive impairment of cerebrovascular origin, attention deficit hyperactivity disorder, perinatal encephalopathy, cerebral palsy with hyperkinetic features, epilepsy adjunctive therapy, neurogenic bladder disorders, stuttering, and tic disorders. A racemic formulation (D,L-hopantenic acid, marketed as Pantogam Active) was introduced in Russia in 2008 and exhibits enhanced anxiolytic and anticonvulsant properties attributed to the L-isomer’s interaction with GABA-A receptors and dopamine D2 receptors. The compound is not approved by the United States Food and Drug Administration, by the European Medicines Agency, or by any Western regulatory authority. The molecular pharmacology of hopantenic acid is multifaceted. At the neurotransmitter level, the compound acts as a weak agonist at the GABA-B receptor complex, with a cross-reactive potency of approximately 0.2 percent relative to GABA in radioreceptor assays, and interacts with GABA-A receptors and dopamine D2 receptors at higher concentrations. In parallel, hopantenic acid enhances high-affinity choline transport into cortical and hippocampal synaptosomes and stimulates choline acetyltransferase activity, producing a secondary cholinergic facilitation that is the principal basis for the nootropic and antidementia pharmacology characterized in preclinical studies by Nakahiro et al. (1988) and others [1, 2]. At the metabolic level, the compound is a competitive antagonist of pantothenic acid at the pantothenate kinase step of coenzyme A (CoA) biosynthesis; phosphorylation by pantothenate kinase produces phospho-hopantenic acid, which potently inhibits phosphopantothenoylcysteine synthetase and reduces cellular CoA levels [3]. This pantothenic acid antagonism is the molecular basis for the most serious reported adverse effect of the compound: a Reye-like syndrome of acute encephalopathy with hepatic steatosis, hyperammonemia, and hypoglycemia reported in multiple case series in Japan during the 1980s, principally in elderly and pediatric patients on chronic high-dose therapy, and reproduced in dogs by Noda et al. (1991) [4, 5, 6]. The encephalopathy was preventable by concurrent pantothenic acid supplementation, confirming the antagonistic mechanism. Pharmacokinetics following oral administration of the calcium salt are characterized by rapid absorption (time to peak plasma concentration approximately 1.5 hours), moderate oral bioavailability (approximately 64 percent in preclinical models), an elimination half-life of approximately 6.7 hours, and predominantly renal excretion without significant hepatic metabolism [7]. The clinical evidence base for hopantenic acid is dominated by Russian-language publications of variable methodological rigor, with the most robust trial being a multicenter, double-blind, placebo-controlled study of Pantogam in 100 children with attention deficit hyperactivity disorder, which reported statistically significant improvement on the ADHD-DSM-IV rating scale and sustained attention measures over four months at 30 mg/kg/day [8]. Additional clinical evidence supports the use of the racemic formulation (Pantogam Active) for cognitive and anxiety disorders in patients with arterial hypertension and chronic cerebral ischemia [9, 10]. This monograph reviews the chemistry, synthesis, and stereochemistry of hopantenic acid; the multifaceted mechanism of action spanning GABAergic, cholinergic, and CoA-related pathways; the pharmacokinetic profile; the clinical evidence across registered and investigational indications; the Reye-like encephalopathy safety signal and its mechanistic basis; sourcing and quality verification; reconstitution and handling; stack interactions; and a structured comparative assessment of five alternative nootropic and GABAergic compounds against hopantenic acid on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1581Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • NA-1

    Synthetic eicosapeptide inhibitor of postsynaptic density protein 95 (PSD-95) with neuroprotective activity mediated by disruption of NMDA receptor excitotoxic signaling

    A cell-permeant Tat-conjugated peptide designed to uncouple NMDA receptor activation from downstream neurotoxic signaling by inhibiting the scaffolding protein PSD-95, advanced through Phase 3 clinical trials for acute ischemic stroke neuroprotection.

    Abstract

    NA-1, designated nerinetide in clinical development and also known by its research name Tat-NR2B9c, is a synthetic, cell-permeant eicosapeptide composed of the 11-residue cell-membrane transduction domain of the human immunodeficiency virus type 1 (HIV-1) Tat protein fused to the nine C-terminal residues of the GluN2B (NR2B) subunit of the N-methyl-D-aspartate (NMDA) glutamate receptor. The compound was designed to inhibit the protein-protein interaction between postsynaptic density protein 95 (PSD-95) and the GluN2B subunit, thereby uncoupling NMDA receptor activation from the downstream excitotoxic signaling cascade that drives neuronal injury in ischemic stroke and related conditions, without blocking normal NMDA receptor ion channel function or calcium influx. The foundational discovery was reported by Aarts et al. in Science in 2002, demonstrating that perturbation of the NMDA receptor-PSD-95 interaction reduced excitotoxic neuronal death in vitro and focal ischemic brain damage in rats. Subsequent preclinical work extended the neuroprotective efficacy to nonhuman primates, where Cook et al. (2012) demonstrated greater than 50 percent reduction in stroke volume in cynomolgus macaques subjected to transient middle cerebral artery occlusion and treated with Tat-NR2B9c at 2.6 mg/kg intravenous. The compound was advanced into clinical development by NoNO Inc., a Toronto-based biotechnology company founded by the originating investigator Michael Tymianski. The Phase 2 ENACT trial (Hill et al. 2012, Lancet Neurology) in 185 patients undergoing endovascular aneurysm repair demonstrated safety and a significant reduction in the number of procedure-related ischemic infarcts on diffusion-weighted magnetic resonance imaging. The Phase 3 ESCAPE-NA1 trial (Hill et al. 2020, Lancet) in 1105 patients with acute ischemic stroke undergoing endovascular thrombectomy did not meet its primary endpoint of improved 90-day modified Rankin Scale outcomes in the overall population, but a pre-specified subgroup analysis revealed a clinically meaningful 9.5 percent absolute benefit in patients who did not receive concurrent alteplase, with subsequent mechanistic work demonstrating that plasmin generated by alteplase degrades the nerinetide peptide in vivo. The Phase 3 ESCAPE-NEXT trial (2025, Lancet) in 850 patients undergoing thrombectomy without prior thrombolysis did not confirm the subgroup benefit. The Phase 2 FRONTIER trial (2025, Lancet) in 532 patients with suspected acute cerebral ischemia treated by paramedics in the prehospital setting demonstrated safety and feasibility but did not meet primary efficacy endpoints. Pharmacokinetically, nerinetide exhibits a plasma half-life of approximately 5 to 10 minutes following intravenous bolus administration, consistent with rapid peptide clearance by endogenous proteases and tissue distribution. The clinical dose is 2.6 mg/kg intravenous (maximum 270 mg) administered as a single infusion. The safety profile across all clinical trials has been favorable, with adverse event rates comparable to placebo; the only notable signal is a small excess of serious hypotension events immediately following infusion. This monograph reviews the chemistry, structure, and synthesis of nerinetide; the PSD-95 inhibitory mechanism in molecular detail; the pharmacokinetic profile; the preclinical neuroprotection evidence across species; the complete clinical trial record; sourcing and quality considerations; reconstitution and handling; stack-interaction considerations; the adverse event and safety record; and a comparative assessment of five PSD-95 pathway neuroprotective candidates against nerinetide on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1596Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

  • Esmethadone

    Uncompetitive N-methyl-D-aspartate receptor antagonist with residual low-affinity opioid receptor activity

    The (S)-enantiomer of racemic methadone, developed by Relmada Therapeutics as REL-1017 for major depressive disorder on the basis of low-potency, voltage-dependent uncompetitive NMDA receptor channel blockade with preferential tonic inhibition of GluN2D-containing receptors, negligible clinically relevant opioid agonist activity, and rapid mTORC1- and BDNF-dependent antidepressant-like effects in preclinical models.

    Abstract

    Esmethadone (REL-1017, d-methadone, dextromethadone) is the (S)-enantiomer of the synthetic opioid methadone and a low-potency, voltage-dependent, uncompetitive antagonist of the N-methyl-D-aspartate (NMDA) glutamate receptor that was advanced through Phase 3 clinical development by Relmada Therapeutics for the adjunctive and monotherapy treatment of major depressive disorder (MDD). Unlike the (R)-enantiomer levomethadone, which carries the analgesic opioid activity of the racemate, esmethadone exhibits approximately 10-fold lower affinity at mu-opioid receptors and lacks clinically meaningful opioid agonist effects, respiratory depression, reinforcing properties, or physical dependence liability at the doses studied for antidepressant activity. The compound blocks NMDA receptor ion channels with IC50 values in the low micromolar range (approximately 13 to 68 micromolar across GluN2A through GluN2D subunit combinations), with functional selectivity for tonically active GluN2D-containing receptors under physiological magnesium concentrations. This tonic blockade is proposed to disinhibit downstream alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-mediated glutamatergic transmission, activate mammalian target of rapamycin complex 1 (mTORC1) signaling, and increase brain-derived neurotrophic factor (BDNF) expression, producing rapid-onset antidepressant effects comparable in mechanism (though not in potency or dissociative liability) to ketamine and esketamine. Preclinical studies in rodent models of depressive-like behavior (forced swimming test, novelty-suppressed feeding test, female urine sniffing test, chronic unpredictable stress) demonstrated that oral esmethadone produced antidepressant effects comparable to injectable ketamine in magnitude and duration, mediated by mTORC1 signaling in the medial prefrontal cortex and blocked by the selective mTORC1 inhibitor rapamycin. A Phase 1 study in healthy volunteers demonstrated that esmethadone increased circulating BDNF levels, providing translational biomarker support for the preclinical mechanism. Pharmacokinetics are characterized by approximately 70 to 80 percent oral bioavailability, a long elimination half-life exceeding 30 hours that supports once-daily dosing, and hepatic metabolism principally through CYP3A4/5 and CYP2B6 to the inactive metabolite EDDP, with approximately half the dose recovered in urine and 40 percent in feces. The compound is a CYP2D6 inhibitor in vitro, producing clinically relevant increases in exposure of CYP2D6 substrates such as dextromethorphan. The Phase 2a randomized, double-blind, placebo-controlled adjunctive trial in MDD patients with inadequate response to standard antidepressants (Fava et al., American Journal of Psychiatry, 2022) demonstrated rapid and sustained improvement on the Montgomery-Asberg Depression Rating Scale (MADRS) at 25 mg and 50 mg daily doses, with effect sizes of 0.7 to 1.0 and day-14 remission rates of 31 percent and 39 percent versus 5 percent on placebo. No dissociative or psychotomimetic effects were observed. The Phase 3 Reliance I trial (published 2024) did not meet its primary efficacy endpoint, attributed in part to an elevated placebo response during the COVID-19 pandemic enrollment period. A second Phase 3 trial (Reliance II) was initiated, but interim analysis in late 2024 indicated that the study was unlikely to meet its primary efficacy endpoint, and Relmada Therapeutics paused further development of REL-1017. A 12-month open-label extension study in 624 MDD patients confirmed long-term safety and tolerability, with the most common treatment-related adverse events being headache (4.6 percent), nausea (4.2 percent), and dizziness (2.6 percent), no signal for cardiovascular, metabolic, neurological, or sexual adverse events, no suicides or suicide attempts, and no withdrawal syndrome on discontinuation. A dedicated abuse-potential study in recreational drug users demonstrated no meaningful abuse potential. The compound is not approved by any regulatory authority. This monograph reviews the chemistry, stereochemistry, and synthesis of esmethadone; the NMDA receptor pharmacology including subunit selectivity and downstream signaling; the opioid receptor binding profile; comprehensive pharmacokinetics including drug-drug interactions; the preclinical and clinical evidence base across Phase 1, Phase 2, and Phase 3 programs; sourcing and quality considerations; reconstitution and handling; stack interactions; the adverse-event and safety profile; and a comparative assessment of five alternative NMDA receptor-targeting antidepressant candidates against esmethadone on five competency standards.

    Read the full monograph

    The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

    KDC-MN-1586Open in new tab →

    Download PDF →

    FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.