Tag: MONOGRAPH

  • Boswellic-Acid

    Pentacyclic triterpenic acid from Boswellia serrata oleogum resin with selective 5-lipoxygenase inhibition and pleiotropic anti-inflammatory activity

    A family of ursane- and oleanane-type pentacyclic triterpenes isolated from Boswellia serrata frankincense resin, distinguished by noncompetitive allosteric inhibition of 5-lipoxygenase and convergent anti-inflammatory activity through NF-kappaB suppression, topoisomerase inhibition, and leukotriene biosynthesis blockade.

    Abstract

    Boswellic acids are a family of pentacyclic triterpenic acids isolated from the oleogum resin (frankincense) of Boswellia serrata and related species (B. carterii, B. sacra, B. papyrifera) that have been used in Ayurvedic medicine for centuries under the name Salai guggal and are now recognized as pharmacologically active anti-inflammatory agents with a distinct mechanism of action centered on selective, noncompetitive, allosteric inhibition of 5-lipoxygenase (5-LOX). The family comprises four principal bioactive congeners: beta-boswellic acid (beta-BA), 11-keto-beta-boswellic acid (KBA), 3-O-acetyl-beta-boswellic acid (ABA), and 3-O-acetyl-11-keto-beta-boswellic acid (AKBA), with AKBA representing the most potent 5-LOX inhibitor (IC50 approximately 1.5 micromolar in human neutrophils) and the primary pharmacologically characterized congener. The 5-LOX inhibition by AKBA proceeds through an allosteric, nonredox, noncompetitive mechanism that is unique among clinically studied leukotriene synthesis inhibitors and distinguishes the boswellic acid class from both the redox-type 5-LOX inhibitors (zileuton) and the competitive cysteinyl leukotriene receptor antagonists (montelukast, zafirlukast). Beyond 5-LOX inhibition, boswellic acids exert convergent anti-inflammatory activity through suppression of NF-kappaB signaling via direct inhibition of IkappaB kinases (IKKalpha and IKKbeta), inhibition of human leukocyte elastase, inhibition of topoisomerases I and IIalpha, modulation of complement system activation, and suppression of proinflammatory cytokine release including tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6. Pharmacokinetics in humans are characterized by poor oral bioavailability of the keto-boswellic acids (KBA and AKBA) attributable to extensive first-pass hepatic metabolism via CYP3A4-mediated hydroxylation and carboxylesterase 2-mediated deacetylation, with plasma elimination half-lives of approximately 6 hours. Concomitant administration with a lipid-rich meal substantially improves absorption. Clinical evidence from randomized controlled trials supports efficacy in osteoarthritis (pain reduction and functional improvement at 100 to 250 mg AKBA-enriched extract daily), bronchial asthma (improvement in 70 percent of patients at 300 mg three times daily), inflammatory bowel disease (Crohn’s disease and ulcerative colitis, with response rates comparable to mesalazine), and radiation-induced cerebral edema (greater than 75 percent edema reduction in 60 percent of patients at 4200 mg daily). The compound class is generally well tolerated, with the principal adverse events being mild gastrointestinal discomfort (nausea, acid reflux, diarrhea) and rare allergic dermatitis. This monograph reviews the chemistry, structural pharmacology, and biosynthesis of the boswellic acid family; the multi-target mechanism of action in molecular detail; the comprehensive human pharmacokinetic record including bioavailability enhancement strategies; the clinical evidence base across osteoarthritis, asthma, inflammatory bowel disease, cerebral edema, and oncology-supportive indications; sourcing and quality verification considerations; reconstitution and handling; stack-interaction implications; adverse-event signal; and a comparative assessment of five alternative anti-inflammatory natural compounds against boswellic acids on five competency standards.

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  • Pirenzepine

    Selective M1 muscarinic acetylcholine receptor antagonist of the pyridobenzodiazepinone structural class

    A peripherally selective, M1-preferring muscarinic antagonist developed at Dr. Karl Thomae GmbH (Boehringer Ingelheim) as a gastric antisecretory agent for peptic ulcer disease, subsequently investigated as a topical ophthalmic intervention for the retardation of progressive myopia in children.

    Abstract

    Pirenzepine (LS 519, Gastrozepin) is a tricyclic pyridobenzodiazepinone and the prototypical selective antagonist of the M1 subtype of the muscarinic acetylcholine receptor. Synthesized at Dr. Karl Thomae GmbH, a subsidiary of Boehringer Ingelheim, in the mid-1970s, the compound was the first muscarinic antagonist demonstrated to discriminate pharmacologically between what were subsequently classified as M1 and M2 receptor subtypes, a finding reported by Hammer et al. in 1980 in Nature and foundational to the modern subtype classification of muscarinic receptors [1]. Pirenzepine binds the M1 muscarinic receptor with a dissociation constant (Ki) of approximately 5 to 14 nanomolar and displays 5- to 20-fold selectivity over the M2, M3, and M5 subtypes, with intermediate affinity at M4 receptors [2, 3]. The compound is peripherally selective, exhibiting negligible penetration of the blood-brain barrier at therapeutic oral doses, a property that minimizes central anticholinergic adverse effects and distinguishes it from atropine and other non-selective muscarinic antagonists. The primary registered indication is peptic ulcer disease. Pirenzepine inhibits vagally mediated and pentagastrin-stimulated gastric acid secretion through antagonism of M1 receptors on intramural gastric plexus neurons, reducing basal acid output by approximately 50 percent at oral doses of 50 mg twice daily [4, 5]. Extensive controlled trials conducted through the late 1970s and 1980s demonstrated duodenal ulcer healing rates of 60 to 76 percent at 4 to 8 weeks on pirenzepine 100 to 150 mg per day, broadly comparable to cimetidine 1 g per day and superior to placebo and gefarnate [6, 7]. The compound was registered as Gastrozepin in numerous European, Asian, and Latin American jurisdictions but was never approved by the United States Food and Drug Administration. The clinical importance of pirenzepine as a gastric antisecretory agent has diminished substantially following the introduction of histamine H2 receptor antagonists and proton pump inhibitors, which offer superior acid suppression and ulcer healing rates. A second, more recent research application is the retardation of progressive myopia (axial elongation of the globe) in children aged 8 to 12 years. Two multicenter, randomized, double-masked, placebo-controlled trials of 2% pirenzepine ophthalmic gel, conducted by Siatkowski et al. (2004, 2008), demonstrated approximately 50 percent reduction in the rate of myopia progression over 1- and 2-year treatment periods, with a clinically acceptable safety profile dominated by mild pupil dilation and accommodation difficulty [8, 9]. The mechanism of the antimyopic effect is incompletely characterized but is attributed to M1 and possibly M4 muscarinic receptor antagonism in the retina and sclera, modulating signaling cascades that regulate scleral extracellular matrix remodeling and axial elongation [10]. The ophthalmic application has not received regulatory approval; the compound remains investigational for myopia control, with atropine (a non-selective muscarinic antagonist applied at low concentrations) having advanced further in clinical development for this indication. Pharmacokinetics are characterized by low oral bioavailability (20 to 30 percent in fasted subjects, further reduced by food), a plasma elimination half-life of approximately 10 to 12 hours, negligible hepatic first-pass metabolism, predominant renal elimination of unchanged drug, and low plasma protein binding (approximately 12 percent) [11, 12]. The compound does not undergo significant cytochrome P450-mediated metabolism and has a correspondingly limited drug-drug interaction profile. The principal adverse events at registered oral doses are mild anticholinergic effects: dry mouth (approximately 14 percent), blurred vision (1 to 5 percent, dose-dependent), and constipation (approximately 3 percent), with an overall discontinuation rate of approximately 2 percent in controlled trials [6]. Serious adverse events are rare. This monograph reviews the chemistry, synthesis, and structural pharmacology of pirenzepine; the molecular pharmacology at muscarinic receptor subtypes; comprehensive human pharmacokinetics; the clinical evidence base across peptic ulcer and myopia indications; sourcing and quality verification; reconstitution and handling; stack-interaction considerations; adverse-event signal; and a structured comparative assessment of five gastric antisecretory and muscarinic antagonist alternatives (telenzepine, atropine, cimetidine, ranitidine, omeprazole) against pirenzepine on five competency standards.

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    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.

  • Apigenin

    Trihydroxyflavone with multi-target activity spanning CD38 NADase inhibition, GABA-A receptor modulation, aromatase suppression, and broad anti-inflammatory and pro-apoptotic signaling

    A dietary flavone abundant in chamomile, parsley, and celery, distinguished from other common flavonoids by potent CD38 NADase inhibition with consequent elevation of intracellular NAD+, moderate GABA-A receptor activity at the benzodiazepine site, competitive aromatase inhibition, and a broad preclinical pharmacology spanning anti-inflammatory, neuroprotective, anti-cancer, and metabolic endpoints.

    Abstract

    Apigenin (4′,5,7-trihydroxyflavone) is a naturally occurring flavone present at high concentration in chamomile flowers, parsley, celery, and numerous other dietary plant sources. It is one of the most extensively studied plant flavonoids, with a preclinical research literature encompassing anti-inflammatory, antioxidant, neuroprotective, anxiolytic, anti-cancer, cardioprotective, and metabolic activities. The compound is distinguished from the structurally related flavonoids quercetin, luteolin, and kaempferol by several pharmacological features of particular current research interest: potent inhibition of CD38, the principal mammalian NAD+-degrading ectoenzyme, resulting in elevation of intracellular nicotinamide adenine dinucleotide (NAD+) and consequent activation of sirtuin-dependent deacetylation pathways relevant to metabolic syndrome and aging; moderate activity at the benzodiazepine binding site of the gamma-aminobutyric acid type A (GABA-A) receptor, producing anxiolytic and sedative effects in rodent models; competitive inhibition of aromatase (CYP19A1) with an IC50 of approximately 20 to 23 micromolar, reducing estrogen biosynthesis; and suppression of NF-kappaB-driven proinflammatory cytokine production through multiple converging mechanisms including direct IKK-beta inhibition and modulation of the PI3K/AKT and MAPK/ERK signaling cascades.

    The CD38 inhibitory activity, formally characterized by Escande et al. (2013) in a report from the Bhatt, Chini, and Sinclair laboratories, demonstrated that apigenin administration to obese mice increased tissue NAD+ levels, decreased global protein acetylation through sirtuin activation, and improved glucose and lipid homeostasis parameters [1]. This finding positioned apigenin within the NAD+ restoration research framework alongside nicotinamide mononucleotide and nicotinamide riboside, though through a mechanistically distinct pathway (reduced NAD+ degradation rather than precursor supplementation). The GABA-A receptor activity, first reported by Viola et al. (1995) using competitive radioligand displacement at the benzodiazepine site, produced anxiolytic effects in elevated plus maze and open field paradigms in mice without the sedation, amnesia, or muscle relaxation characteristic of classical benzodiazepines [2]. Subsequent electrophysiological and behavioral studies have produced conflicting characterizations of the precise nature of the GABA-A interaction, with reports variously describing apigenin as a weak partial agonist, an antagonist, or an inverse agonist at the benzodiazepine site depending on assay system and concentration.

    Pharmacokinetics in humans are incompletely characterized. Oral bioavailability is estimated at approximately 30 percent, limited by poor aqueous solubility and extensive first-pass phase II conjugation (glucuronidation and sulfation). Phase I oxidative metabolism is mediated principally by CYP1A1, CYP1A2, and CYP2E1, producing the hydroxylated metabolite luteolin as the major oxidative product. The plasma elimination half-life after oral administration is approximately 2 to 3 hours in the limited human pharmacokinetic data available. Apigenin inhibits CYP2C9, CYP3A4, and P-glycoprotein in vitro at concentrations that may be clinically relevant at supplemental doses, raising drug-drug interaction considerations.

    The compound is non-mutagenic and non-genotoxic in standard regulatory toxicology assays. No significant toxicity has been observed in animal studies at doses up to 50 mg/kg, though hepatotoxicity has been reported at intraperitoneal doses of 100 mg/kg and above in mice. Human safety data at supplemental doses (50 to 500 mg daily) are limited but have not produced serious adverse event signals. The principal reported adverse effects at supplemental doses are drowsiness (consistent with GABA-A activity) and mild gastrointestinal discomfort.

    This monograph reviews the chemistry, natural sources, and isolation history of apigenin; the multi-target molecular pharmacology spanning CD38, GABA-A, aromatase, and inflammatory signaling; the available pharmacokinetic data in animals and humans; the preclinical pharmacology across neuroprotective, anti-cancer, anti-inflammatory, and metabolic endpoints; the limited clinical evidence base; sourcing and quality verification for research applications; reconstitution and handling; stack interactions; adverse events and safety; and a comparative assessment of five structurally or functionally related flavonoid compounds against apigenin on five competency standards.

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    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.

  • Dihydro-NMN

    Reduced pyridine nucleotide and potent NAD+ precursor of the dihydronicotinamide mononucleotide class

    A reduced-form nicotinamide mononucleotide that bypasses canonical salvage pathway enzymes to elevate cellular NAD+ and NADH more rapidly and to a greater extent than its oxidized counterpart NMN, with emerging preclinical evidence in renal cytoprotection, metabolic reprogramming, and anti-proliferative activity.

    Abstract

    Dihydronicotinamide mononucleotide (NMNH), also designated reduced nicotinamide mononucleotide or dihydro-NMN, is the 1,4-dihydropyridine analog of beta-nicotinamide mononucleotide (NMN). The compound differs from NMN by a single additional hydrogen at the C-4 position of the nicotinamide ring, converting the aromatic pyridinium to a non-aromatic 1,4-dihydropyridine and conferring distinct biochemical, pharmacokinetic, and pharmacological properties. NMNH was first characterized as a potent nicotinamide adenine dinucleotide (NAD+) precursor in mammalian systems in two independent 2021 reports: Zapata-Perez et al. in The FASEB Journal demonstrated that NMNH increases NAD+ levels to a substantially greater extent and faster than NMN or nicotinamide riboside (NR) across multiple tissues in mice, while Liu et al. in the Journal of Proteome Research showed that NMNH potently enhances NAD+ and NADH, suppresses glycolysis and the tricarboxylic acid cycle, induces reductive stress, and inhibits cell growth in hepatocellular carcinoma cells. The metabolic pathway of NMNH is mechanistically distinct from that of NMN: NMNH is converted directly to NADH by nicotinamide mononucleotide adenylyltransferase (NMNAT) without requiring nicotinamide phosphoribosyltransferase (NAMPT) or nicotinamide riboside kinase (NRK), the two rate-limiting enzymes of the canonical salvage and Preiss-Handler pathways. The resulting NADH is then oxidized to NAD+ by cellular oxidoreductases, producing a net elevation of both reduced and oxidized pyridine dinucleotide pools. In vivo, intraperitoneal administration of NMNH to mice elevates hepatic NAD+ approximately five-fold and renal NAD+ approximately two-fold, with significant increases also observed in brain, skeletal muscle, brown adipose tissue, and heart, tissues in which equivalent doses of NMN produce no statistically significant NAD+ elevation. The Zapata-Perez et al. study additionally demonstrated that NMNH protects conditionally immortalized proximal tubular epithelial cells against hypoxia and reoxygenation injury, reducing expression of the kidney injury biomarker Kim-1 and the mitochondrial dysfunction marker Tfam, establishing a preclinical basis for renal cytoprotection. The Liu et al. metabolomic analysis revealed that NMNH-treated cells exhibit marked suppression of glycolytic intermediates (glucose-6-phosphate, fructose-1,6-bisphosphate, phosphoenolpyruvate, pyruvate) and tricarboxylic acid cycle intermediates (citrate, alpha-ketoglutarate, succinate, fumarate, malate), accompanied by cell cycle arrest and growth inhibition. The compound induces cellular reductive stress through elevation of the NADH/NAD+ ratio, which paradoxically increases reactive oxygen species (ROS) production, linking the reductive stress phenotype to the anti-proliferative activity. NMNH is prepared by chemical reduction of NMN with thiourea dioxide in alkaline aqueous solution or by enzymatic cleavage of NADH with NADH pyrophosphatase (NudC). The compound is supplied as the disodium salt (CAS 108347-85-9) and is commercially available from multiple research chemical suppliers. A first-in-human clinical trial reported in January 2026 indicated that oral NMNH at 500 mg daily for 90 days approximately tripled circulating NAD+ levels in healthy adults, though these results remain unpublished and unverified by independent peer review. No regulatory approval exists for NMNH in any jurisdiction; the compound is sold as a dietary supplement or research reagent. This monograph reviews the chemistry, synthesis, and structural distinction from NMN; the NMNAT-dependent metabolic pathway; the preclinical pharmacology across NAD+ elevation, renal cytoprotection, metabolic reprogramming, and anti-proliferative activity; the limited pharmacokinetic data in mice and humans; the emerging clinical evidence; sourcing and quality verification; reconstitution and handling; stack interactions with other NAD+ precursors and metabolic modulators; the adverse-event and safety signal including reductive stress and reactive oxygen species concerns; and a comparative assessment of five NAD+ precursor candidates against NMNH on five competency standards.

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    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.

  • Urolithin A

    Plain-language summaryIntrigue 78 / 100

    Urolithin A is a natural compound produced by gut bacteria from pomegranate, walnuts, and berries. It induces mitophagy, the process of cleaning out damaged mitochondria. Amazentis sells a clinical-grade form as Mitopure. Not stocked by Kodiac. This monograph is provided for research and educational reference.

    Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

    Dibenzo[b,d]pyranone mitophagy inducer derived from gut microbial metabolism of dietary ellagitannins

    A naturally occurring benzo[c]chromenone produced by human gut microbiota from ellagitannin precursors, identified as the first dietary metabolite to induce mitophagy through the PINK1/Parkin pathway in human skeletal muscle at oral doses, with clinical evidence in age-related mitochondrial decline, muscle function, immune senescence, and emerging neuroprotective applications.

    Abstract

    Urolithin A (3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one) is a dibenzopyranone metabolite produced by the human gut microbiota through sequential dehydroxylation of ellagic acid, itself the hydrolysis product of dietary ellagitannins found in pomegranates, walnuts, raspberries, and strawberries. The compound was first characterized as a bioactive ellagitannin metabolite in human plasma and urine by the Tomas-Barberan and Espin laboratories at CEBAS-CSIC (Murcia, Spain) in the early 2000s and was subsequently identified by the Auwerx laboratory at the Ecole Polytechnique Federale de Lausanne (EPFL) as a potent, first-in-class inducer of mitophagy in Caenorhabditis elegans and in mammalian systems through the PINK1/Parkin-dependent mitochondrial quality control pathway. The seminal Ryu et al. (2016) report in Nature Medicine demonstrated that urolithin A extends lifespan in C. elegans, improves exercise capacity in aged rodents, and induces a molecular signature of mitophagy in skeletal muscle, establishing the compound as the first dietary metabolite with demonstrated mitophagy-inducing activity at physiologically achievable concentrations [1]. Amazentis SA (Lausanne, Switzerland) subsequently developed a synthetic, pharmaceutical-grade form of urolithin A (marketed as Mitopure) and advanced the compound through a series of randomized, placebo-controlled clinical trials in human subjects. The first-in-human trial (Andreux et al. 2019, Nature Metabolism) demonstrated safety, oral bioavailability, and upregulation of mitochondrial gene expression in skeletal muscle of 60 healthy elderly subjects at doses of 250 to 2000 mg administered over 28 days [2]. A subsequent four-month randomized trial in 88 middle-aged adults (Singh et al. 2022, Cell Reports Medicine) demonstrated significant improvement in muscle strength (approximately 12 percent increase in hamstring muscle strength) and exercise performance at 500 mg and 1000 mg daily doses, with concurrent improvement in plasma biomarkers of mitochondrial health [3]. A parallel randomized trial (Liu et al. 2022, JAMA Network Open) in 66 older adults confirmed improvement in muscle endurance at 1000 mg daily over four months [4]. Most recently, a 2025 randomized trial (Singh et al. 2025, Nature Aging) in 50 healthy middle-aged adults demonstrated that 1000 mg daily urolithin A for four weeks expanded peripheral naive-like CD8+ T cell populations, reduced markers of T cell exhaustion, and increased CD8+ fatty acid oxidation capacity, establishing the first clinical evidence of urolithin A activity on immune senescence [5]. The molecular pharmacology of urolithin A extends beyond mitophagy induction to include activation of AMP-activated protein kinase (AMPK), inhibition of mechanistic target of rapamycin (mTOR), activation of sirtuin 1 (SIRT1) with consequent deacetylation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1alpha) to promote mitochondrial biogenesis, suppression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) signaling with reduction of proinflammatory cytokines, and inhibition of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) relevant to Alzheimer’s disease pathology. Pharmacokinetics in humans are characterized by intestinal absorption followed by extensive hepatic phase II conjugation (glucuronidation and sulfation), producing circulating glucuronide and sulfate conjugates with peak plasma concentrations at approximately 6 to 8 hours and elimination half-lives of 17 to 24 hours for the predominant glucuronide species. The compound received Generally Recognized as Safe (GRAS) status from the United States Food and Drug Administration in 2018 (GRN 000791) at dietary intake levels up to 1000 mg per serving. Preclinical safety assessment established a no-observed-adverse-effect level (NOAEL) of 3451 mg/kg/day in male rats and 3826 mg/kg/day in female rats in a 90-day oral toxicity study, with no evidence of genotoxicity or mutagenicity. This monograph reviews the chemistry, endogenous biosynthesis, and chemical synthesis of urolithin A; the multi-target molecular pharmacology encompassing mitophagy, mitochondrial biogenesis, anti-inflammatory, and neuroprotective mechanisms; the human pharmacokinetic profile including interindividual variability driven by gut microbiome metabotype; the clinical evidence base across muscle function, immune health, and emerging neurodegenerative and cardiometabolic indications; sourcing and quality verification for research applications; reconstitution and handling; stack interaction considerations; adverse-event profile; and a structured comparative assessment of five mitochondrial-targeted compounds against urolithin A on five competency standards.

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    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.

  • SRT2104

    Plain-language summaryIntrigue 50 / 100

    SRT2104 is a small-molecule sirtuin 1 (SIRT1) activator developed at Sirtris Pharmaceuticals (later acquired by GSK). It was designed as a more potent and drug-like successor to resveratrol, the natural compound that started the sirtuin-aging story. Sirtuins are NAD+-dependent enzymes that deacetylate metabolic and stress-response targets, hypothesized to mediate calorie-restriction-like longevity effects. SRT2104 activates SIRT1 allosterically and produced metabolic and inflammatory benefits in mouse studies. Phase 2 trials in diabetes, ulcerative colitis, and cardiovascular disease showed modest signals at best, and GSK shut down Sirtris in 2013 amid skepticism about the sirtuin-activator concept. Of mainly historical interest as a flagship compound of a faded program. Not stocked by Kodiac. This monograph is provided for research and educational reference.

    Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

    Selective small-molecule allosteric activator of NAD-dependent protein deacetylase sirtuin 1 (SIRT1)

    A second-generation imidazothiazole-scaffold sirtuin 1 activator developed by Sirtris Pharmaceuticals and advanced through multiple Phase 2 clinical programs by GlaxoSmithKline, distinguished from first-generation sirtuin-activating compounds by high target selectivity and favorable oral pharmacokinetics.

    Abstract

    SRT2104 (GSK2245840) is a synthetic, orally bioavailable, small-molecule allosteric activator of the NAD-dependent protein deacetylase sirtuin 1 (SIRT1, silent mating type information regulation 2 homolog 1), developed at Sirtris Pharmaceuticals and subsequently advanced into clinical trials by GlaxoSmithKline following the 2008 acquisition of Sirtris for approximately 720 million United States dollars. The compound is a second-generation sirtuin-activating compound (STAC) built on an optimized imidazo[2,1-b]thiazole scaffold and is reported to activate SIRT1 deacetylase activity approximately 1000-fold more potently than the natural polyphenol resveratrol in fluorophore-tagged peptide substrate assays, with minimal activity against a panel of more than 180 non-SIRT1 targets including kinases, G-protein-coupled receptors, nuclear receptors, ion channels, enzymes, and transporters [1, 2]. The allosteric mechanism involves binding to the N-terminal domain of SIRT1, lowering the Michaelis constant (Km) for the acetylated protein substrate without competing with either the NAD cofactor or the substrate acetyl-lysine site [3]. Downstream consequences of SIRT1 activation by SRT2104 include deacetylation and functional modulation of the transcription factor p53, the RelA/p65 subunit of nuclear factor kappa B (NF-kB), forkhead box protein O3 (FOXO3), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1alpha), and signal transducer and activator of transcription 3 (STAT3), producing composite anti-inflammatory, metabolic, and cytoprotective effects that have been characterized across a broad range of preclinical disease models [4, 5].

    Pharmacokinetics in humans are characterized by oral absorption with time to peak plasma concentration of 1 to 3 hours after single dosing, a terminal elimination half-life of 8 to 24 hours depending on dose, and substantial inter-individual variability that is not dose-proportional across the studied range of 0.03 to 3.0 grams [6]. The variable and non-dose-proportional pharmacokinetic profile has been identified as a principal limitation of the compound for clinical development in its current oral formulation. SRT2104 is poorly soluble in water and is formulated as a lipid-based oral capsule to improve bioavailability.

    Clinical evaluation has spanned at least seven registered clinical trials across multiple indications. In a Phase 1 trial in healthy elderly volunteers (60 to 80 years of age), 28 days of oral SRT2104 at 0.5 or 2.0 grams daily produced reductions in serum cholesterol, low-density lipoprotein, and triglycerides, with trends toward improved mitochondrial oxidative phosphorylation capacity as measured by phosphorus-31 magnetic resonance spectroscopy of skeletal muscle [7]. A Phase 2 randomized, placebo-controlled trial in 37 subjects with type 2 diabetes mellitus treated for 28 days at doses of 0.25, 0.5, 1.0, or 2.0 grams daily did not demonstrate improved glycemic control but produced a statistically significant reduction in total cholesterol and triglycerides at the 1.0 gram dose [8]. A separate cardiometabolic study in type 2 diabetic subjects reported trends toward improved endothelial function and arterial stiffness [9]. A Phase 2 trial in 40 subjects with moderate to severe psoriasis treated for 84 days at escalating doses of 250, 500, or 1000 milligrams daily reported 35 percent of SRT2104-treated patients achieving good to excellent histological improvement on skin biopsy, but three serious adverse events were reported including pneumonitis and pancreatitis [10]. A trial in mild to moderate ulcerative colitis (31 subjects, 50 or 500 milligrams daily for 8 weeks) demonstrated tolerability but limited clinical efficacy, with only 3 of 26 evaluable subjects achieving endoscopic remission [11]. In a human endotoxemia model, SRT2104 pretreatment significantly reduced lipopolysaccharide-induced cytokine release (interleukin-6, interleukin-8) and coagulation activation, representing the first human demonstration of anti-inflammatory and anticoagulant activity consistent with pharmacological SIRT1 activation [12].

    Preclinical pharmacology is extensive. The Mercken et al. (2014) study at the National Institute on Aging demonstrated that SRT2104 extends both mean and maximum lifespan of male mice fed a standard diet by 9.7 percent and 4.9 percent respectively, with preserved bone mineral density, muscle mass, motor coordination, and insulin sensitivity [13]. The Jiang et al. (2014) study demonstrated blood-brain barrier penetration, attenuation of brain atrophy, improvement of motor function, and extension of median lifespan by approximately 16 percent in N171-82Q Huntington disease model mice [14]. Additional preclinical evidence spans emphysema, sepsis, neonatal white matter injury, microglia polarization, dendritic outgrowth, and auditory cell senescence. GlaxoSmithKline discontinued active clinical development of SRT2104 following the 2013 closure of the Sirtris unit, though the compound remains widely used as a reference SIRT1 activator in academic and preclinical research. This monograph reviews chemistry, molecular pharmacology, pharmacokinetics, the complete clinical evidence base, sourcing and handling, stack interactions, adverse events, and a comparative assessment of five SIRT1 modulators against SRT2104 on five competency standards.

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    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.

  • Pridopidine

    Plain-language summaryIntrigue 62 / 100

    Pridopidine started life as a dopamine stabilizer for Huntington disease and was later reclassified as a high-affinity sigma-1 agonist when its true binding profile was characterized. Originally developed at NeuroSearch and now at Prilenia Therapeutics, it failed the phase 3 PRIDE-HD trial in Huntington but has continued in ALS development based on encouraging phase 2 signals in that population. The reclassification story is interesting because it changed how investigators think about both pridopidine and the sigma-1 target itself. Whether the current ALS program produces meaningful efficacy remains an open question. Not stocked by Kodiac. This monograph is provided for research and educational reference.

    Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

    Selective sigma-1 receptor agonist with low-affinity dopamine D2 receptor antagonism and CYP2D6 auto-inhibition

    A 4-phenylpiperidine sigma-1 receptor agonist originally developed as a dopaminergic stabilizer, repositioned on the basis of high-affinity sigma-1 binding and neuroprotective activity in Huntington disease and amyotrophic lateral sclerosis models, with Phase 3 clinical data in Huntington disease and an FDA-cleared Phase 3 program in ALS.

    Abstract

    Pridopidine (ACR16; 4-[3-(methylsulfonyl)phenyl]-1-propylpiperidine; CAS 346688-38-8; molecular formula C15H23NO2S; molecular weight 281.41) is a selective sigma-1 receptor (S1R) agonist with a binding affinity (Ki) of approximately 57 nM at the human sigma-1 receptor and substantially lower affinity at the dopamine D2 receptor (Ki approximately 2950 nM), the dopamine D3 receptor (Ki approximately 1630 nM), the adrenergic alpha-2C receptor (Ki approximately 1580 nM), and the sigma-2 receptor (Ki approximately 5450 nM). The compound was synthesized at A. Carlsson Research (later NeuroSearch) as part of a structure-activity exploration of 4-phenylpiperidine dopamine D2 receptor ligands with fast dissociation kinetics and was originally classified as a “dopaminergic stabilizer” on the basis of its state-dependent modulation of dopaminergic tone in behavioral models. Subsequent binding, functional, and positron emission tomography studies established that the principal pharmacological target at clinically relevant concentrations is the sigma-1 receptor, an endoplasmic reticulum chaperone protein located at the mitochondria-associated membrane that regulates calcium homeostasis, mitochondrial function, brain-derived neurotrophic factor (BDNF) trafficking and secretion, endoplasmic reticulum stress responses, autophagy, and synaptic plasticity. Pridopidine has demonstrated neuroprotective and neurorestorative activity in preclinical models of Huntington disease (YAC128 transgenic mice, R6/2 mice), amyotrophic lateral sclerosis (SOD1G93A mice), Parkinson disease (6-OHDA lesioned mice), and glaucoma (optic nerve crush and microbead occlusion models), with effects dependent on sigma-1 receptor activation and abolished in sigma-1 receptor knockout animals.

    Clinical development has focused primarily on Huntington disease. Four randomized controlled trials (Lundin 2010, MermaiHD, HART, PRIDE-HD) evaluated pridopidine at doses of 20 to 112.5 mg per day in a combined population of over 1,100 patients. The Phase 3 MermaiHD trial (437 patients, 26 weeks) did not meet its primary motor endpoint (modified Motor Score) but demonstrated nominally significant improvement on the total Unified Huntington’s Disease Rating Scale (UHDRS) Total Motor Score. The Phase 2 PRIDE-HD trial (408 patients, 52 weeks) reported that pridopidine 45 mg twice daily was associated with maintenance of Total Functional Capacity (TFC) compared to placebo at 52 weeks, a finding extended to five years in the Open-HART open-label extension. The Phase 3 PROOF-HD trial (499 patients, 65 weeks) did not meet its primary endpoint (TFC change) in the overall population but demonstrated statistically significant benefit on TFC, composite UHDRS score, and multiple secondary endpoints in the pre-specified subgroup of participants not receiving antidopaminergic medications. A European Marketing Authorisation Application was submitted in 2024 for the treatment of adults with Huntington disease; the Committee for Medicinal Products for Human Use recommended refusal in July 2025, and Prilenia Therapeutics has announced plans for a confirmatory global Phase 3 study.

    In amyotrophic lateral sclerosis, pridopidine was evaluated in the Phase 2 HEALEY ALS Platform Trial (121 participants, 24 weeks). The primary endpoint (ALSFRS-R total score change) was not met in the full analysis set, but subgroup analyses in patients with early and rapidly progressive disease demonstrated a 32 percent slowing of ALSFRS-R decline, a 62 percent slowing of respiratory decline, and a prolongation of median survival from approximately 300 to 600 days. The United States Food and Drug Administration cleared a pivotal Phase 3 trial (PREVAiLS, 500 patients) in December 2025, with recruitment planned for early 2026.

    Pharmacokinetics are characterized by oral absorption, hepatic CYP2D6-mediated N-depropylation, and a single-dose elimination half-life of approximately 6 hours in extensive CYP2D6 metabolizers and 15 hours in poor metabolizers. Pridopidine is a metabolism-dependent inhibitor of CYP2D6, producing auto-inhibition that extends the effective half-life to 10 to 14 hours regardless of CYP2D6 genotype on repeated dosing, an unusual pharmacokinetic property that reduces inter-individual variability at steady state and eliminates the requirement for CYP2D6 genotype-based dose adjustment. The compound is well tolerated at doses up to 112.5 mg per day; the most common adverse events are insomnia, diarrhea, nausea, and dizziness, with no clinically significant differences from placebo in serious adverse event rates across pooled trial data. QTc prolongation at the 45 mg twice daily dose is not considered clinically relevant.

    This monograph reviews the chemistry and synthesis of pridopidine; the sigma-1 receptor mechanism in molecular and cellular detail; the comprehensive pharmacokinetic record including CYP2D6 auto-inhibition; the preclinical neuroprotective evidence across multiple disease models; the clinical evidence base across Huntington disease, amyotrophic lateral sclerosis, and exploratory indications; sourcing and quality verification considerations; reconstitution and handling; stack-interaction implications; adverse-event signal; and a structured comparative assessment of five sigma-1 receptor candidates against pridopidine on five competency standards (novelty, effect size, promising potential, side-effect profile, and overall validation). The compound is not approved by any regulatory authority as of the monograph revision date. It is available as a research-grade preparation from multiple chemical suppliers; investigators should obtain analytical confirmation of identity and purity on every lot.

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  • 7,8-Dihydroxyflavone

    Naturally occurring flavone and selective small-molecule tropomyosin receptor kinase B (TrkB) agonist with BDNF-mimetic neurotrophic activity

    A naturally occurring dihydroxylated flavone identified through cell-based TrkB receptor screening as the first orally bioactive small-molecule brain-derived neurotrophic factor mimetic, distinguished by selective TrkB agonism, blood-brain barrier penetration, and broad preclinical neuroprotective and procognitive efficacy across neurodegenerative, neuropsychiatric, and metabolic disease models.

    Abstract

    7,8-Dihydroxyflavone (7,8-DHF), also designated tropoflavin, is a naturally occurring flavone first isolated from the leaves of Godmania aesculifolia and subsequently identified in Tridax procumbens, Primula vulgaris, and other plant species. The compound was characterized in 2010 by Jang et al. at Emory University as the first orally bioactive, blood-brain-barrier-penetrant small-molecule agonist of the tropomyosin receptor kinase B (TrkB), the principal high-affinity signaling receptor for brain-derived neurotrophic factor (BDNF) [1]. 7,8-DHF binds the extracellular domain of TrkB with a dissociation constant of approximately 320 nM by filter binding assay and approximately 15.4 nM by surface plasmon resonance, triggering receptor dimerization, autophosphorylation at tyrosine residues 706/707, and activation of the downstream PI3K/Akt and MAPK/ERK signaling cascades that mediate neuronal survival, synaptic plasticity, and long-term potentiation [1, 2]. The compound displays selectivity for TrkB over the related neurotrophin receptors TrkA and TrkC and does not activate TrkB kinase-dead mutants, confirming that the phosphorylation signal arises from the receptor itself rather than from off-target tyrosine kinases [2].

    Pharmacokinetic characterization in rodents reveals oral bioavailability of approximately 4.6 percent, a plasma half-life of approximately 134 minutes, rapid brain penetration with peak brain concentrations at 10 minutes after oral dosing, and primary hepatic metabolism through glucuronidation, sulfation, and catechol-O-methyltransferase-mediated methylation [3, 4]. The O-methylated metabolites (7-methoxy-8-hydroxyflavone and 7-hydroxy-8-methoxyflavone) retain TrkB agonist activity in vitro and in vivo, extending the effective pharmacodynamic window beyond the parent compound [5]. The modest oral bioavailability prompted the development of the prodrug R13 (a carbamate ester derivative) by the Ye laboratory, which increases oral bioavailability to approximately 10.5 percent and extends the plasma half-life to approximately 220 minutes [6]. R13 has entered Phase 1 clinical evaluation for Alzheimer’s disease, representing the most advanced clinical translation of TrkB agonist pharmacology from this scaffold.

    Preclinical pharmacology is extensive. In Alzheimer’s disease models, 7,8-DHF reduces BACE1 elevation, decreases amyloid-beta deposition, restores hippocampal synaptic density, and rescues spatial and working memory deficits in 5XFAD, APP/PS1, and Tg2576 transgenic mice at oral doses of 5 mg/kg/day [7, 8, 9]. In Parkinson’s disease models, the compound protects dopaminergic neurons from MPTP- and rotenone-induced degeneration and improves motor function [10]. In depression models, 7,8-DHF reverses learned helplessness, chronic mild stress, and social defeat stress phenotypes through restoration of hippocampal and prefrontal cortical TrkB-BDNF signaling [11, 12]. Additional preclinical efficacy has been demonstrated in models of Huntington’s disease, amyotrophic lateral sclerosis, traumatic brain injury, post-traumatic stress disorder, Rett syndrome, fragile X syndrome, retinal ganglion cell degeneration, and diet-induced obesity [13, 14, 15, 16, 17, 18, 19].

    Safety characterization in chronic rodent studies at 5 mg/kg/day for periods up to 6 months has revealed no pathological changes in major organs, no hematological abnormalities, and no observable toxicity at doses producing robust TrkB activation [2]. A 7-month oral dosing study in a non-human primate model of Parkinson’s disease similarly reported no toxic reactions [20]. No human clinical trial data for the parent compound 7,8-DHF have been published; clinical development has proceeded through the prodrug R13. This monograph reviews the chemistry, natural sources, and structure-activity relationships of 7,8-DHF; the TrkB receptor pharmacology in molecular and cellular detail; the pharmacokinetic profile including metabolism and prodrug development; the preclinical evidence base across neurodegenerative, neuropsychiatric, and metabolic indications; sourcing and quality verification; reconstitution and handling; stack-interaction considerations; adverse-event and safety characterization; and a comparative assessment of five TrkB-targeted candidates against 7,8-DHF on five competency standards.

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  • P7C3-A20

    Aminopropyl carbazole neuroprotective agent functioning as a nicotinamide phosphoribosyltransferase (NAMPT) positive allosteric modulator

    A synthetic 3,6-dibromocarbazole derivative discovered through target-agnostic in vivo neurogenesis screening, distinguished by its activation of the NAD+ salvage enzyme NAMPT and broad neuroprotective efficacy across preclinical models of traumatic brain injury, ischemic stroke, Parkinson disease, amyotrophic lateral sclerosis, and Alzheimer disease.

    Abstract

    P7C3-A20, the fluorinated and methoxylated analog of the parent aminopropyl carbazole P7C3, is a synthetic neuroprotective compound identified through iterative structure-activity optimization of a chemical series originally discovered in a target-agnostic in vivo screen for enhancers of adult hippocampal neurogenesis conducted by Pieper, McKnight, and colleagues at the University of Texas Southwestern Medical Center [1]. The parent compound P7C3 was one of eight hits from a library of approximately 1,000 small molecules screened for their ability to augment the survival of newborn neurons in the subgranular zone of the murine dentate gyrus. Subsequent medicinal chemistry optimization, principally the replacement of the central hydroxyl with fluorine and the introduction of a methoxy substituent on the aniline ring, yielded P7C3-A20, which demonstrated approximately ten-fold greater proneurogenic potency than the parent compound while retaining favorable oral bioavailability, blood-brain barrier penetration, and tolerability in chronic dosing studies in rodents and nonhuman primates [2, 3]. The molecular target of P7C3-A20 was identified by Wang et al. (2014) as nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the nicotinamide adenine dinucleotide (NAD+) salvage pathway [4]. P7C3-A20 functions as a positive allosteric modulator of NAMPT, enhancing the conversion of nicotinamide to nicotinamide mononucleotide (NMN) and thereby augmenting intracellular NAD+ levels under conditions of metabolic stress without elevating NAD+ to supraphysiologic concentrations. This mechanism distinguishes P7C3-A20 from direct NAD+ precursor supplementation strategies (nicotinamide riboside, nicotinamide mononucleotide) by preserving endogenous feedback regulation of the salvage pathway. The downstream consequences of NAMPT activation and NAD+ restoration include maintenance of sirtuin deacetylase activity (particularly SIRT1 and SIRT3), protection of mitochondrial bioenergetics, suppression of oxidative stress and DNA damage, attenuation of neuroinflammation through microglial modulation, and enhancement of the survival of newly generated neurons during adult hippocampal neurogenesis. The preclinical pharmacology of P7C3-A20 has been characterized across an unusually broad spectrum of neurodegenerative and neurotraumatic disease models. In the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson disease, P7C3-A20 substantially preserved dopaminergic neurons in the substantia nigra [5]. In the G93A-SOD1 transgenic mouse model of amyotrophic lateral sclerosis (ALS), P7C3-A20 reduced motor neuron cell death in the spinal cord [6]. In models of traumatic brain injury (TBI), P7C3-A20 blocked axonal degeneration and preserved neurological function when administered acutely [7], and, in a landmark 2020 study, restored blood-brain barrier integrity, arrested chronic neurodegeneration, and recovered normal cognitive function when treatment was initiated a full twelve months after the initial injury [8]. In rat models of focal ischemic stroke, P7C3-A20 promoted post-ischemic neurogenesis, restored cortical NAD+ levels, and improved chronic sensorimotor and cognitive outcomes [9]. In retinal degeneration models, the P7C3 class protected retinal ganglion cells from optic nerve injury [10]. In 2025, Vazquez-Rosa et al. published a study in Cell Reports Medicine demonstrating that P7C3-A20 treatment of 5xFAD and PS19 transgenic mice with advanced Alzheimer-like pathology produced comprehensive reversal of tau phosphorylation, blood-brain barrier deterioration, oxidative stress, DNA damage, and neuroinflammation, with full cognitive recovery and normalization of the clinical biomarker p-tau217 [11]. P7C3-A20 has not entered human clinical trials as of the most recent monograph revision. The compound is not approved by any regulatory authority for any indication. It is available as a research-grade preparation from multiple chemical suppliers at high purity. This monograph reviews the chemistry, synthesis, and structure-activity relationships of P7C3-A20; the NAMPT-mediated mechanism of action; the preclinical pharmacokinetic profile; the extensive preclinical pharmacology across neurodegenerative and neurotraumatic models; the current clinical development status; sourcing and quality considerations; reconstitution and handling; stack interactions; the adverse-event and safety profile from preclinical studies; and a comparative assessment of five neuroprotective or NAD-augmenting compounds against P7C3-A20 on five competency standards.

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  • PRE-084

    Selective sigma-1 receptor agonist derived from phencyclidine with neuroprotective, nootropic, and neurotrophic activity

    A phencyclidine-derived sigma-1 receptor agonist developed as a pharmacological tool compound, distinguished by high selectivity over sigma-2 and PCP receptors and by a broad preclinical literature spanning neuroprotection in motor neuron disease, stroke, Parkinson’s disease, cognitive impairment, and antidepressant activity.

    Abstract

    PRE-084 (2-(4-morpholino)ethyl 1-phenylcyclohexane-1-carboxylate) is a selective agonist of the sigma-1 receptor (sigma-1R) originally identified in 1991 by Su and colleagues at the National Institute on Drug Abuse through a systematic structure-activity program that sought to separate sigma receptor affinity from phencyclidine (PCP) receptor binding in the parent cyclohexylamine scaffold [1]. The compound binds the sigma-1 receptor with an IC50 of approximately 44 nM in radioligand displacement assays and exhibits selectivity ratios exceeding 2000-fold over the PCP binding site (IC50 greater than 100,000 nM) and approximately 300-fold over the sigma-2 receptor subtype (IC50 approximately 13,091 nM), establishing it as one of the most widely used pharmacological tools for interrogating sigma-1 receptor function in vitro and in vivo [1, 2]. The sigma-1 receptor itself is a ligand-regulated chaperone protein resident at the mitochondria-associated endoplasmic reticulum membrane (MAM), where it modulates calcium signaling through interactions with inositol 1,4,5-trisphosphate receptors, regulates protein folding and endoplasmic reticulum stress responses, and participates in diverse signal transduction cascades including the NF-kappaB, ERK/CREB, and protein kinase C pathways [3, 4]. PRE-084 has not been advanced to human clinical trials and carries no regulatory approval in any jurisdiction; its utility is exclusively as a research-grade pharmacological probe. The preclinical literature on PRE-084 is nonetheless substantial and spans multiple therapeutic domains. In amyotrophic lateral sclerosis, daily administration of PRE-084 to SOD1-G93A transgenic mice from eight weeks of age preserved spinal motoneuron survival, maintained compound muscle action potential amplitudes, improved locomotion, and extended overall survival, with neuroprotective effects attributed to protein kinase C-mediated phosphorylation of the NMDA receptor NR1 subunit and reduction of microglial reactivity [5, 6]. Comparable neuroprotection was demonstrated in the wobbler mouse model of motor neuron disease not linked to SOD1 mutation, broadening the mechanistic generalizability [7]. In ischemic stroke models, PRE-084 at 5 mg/kg intraperitoneally reduced infarct volume and neurological deficit scores after embolic middle cerebral artery occlusion in rats, with the mechanism involving suppression of pro-inflammatory cytokines (interleukin-1 beta, tumor necrosis factor alpha) and enhancement of anti-inflammatory cytokines [8]. In Parkinson’s disease models, PRE-084 administration normalized motor dysfunction and prevented dopaminergic neuron loss in both 6-hydroxydopamine and MPTP paradigms through sigma-1 receptor-mediated promotion of PINK1/Parkin mitophagy and enhancement of dopamine transporter expression [9, 10]. Cognitive and nootropic effects have been characterized across multiple paradigms: PRE-084 attenuated MK-801-induced amnesia, amyloid-beta peptide-induced learning impairment, and spatial learning deficits in aged rats, with mechanisms involving upregulation of NMDA receptor expression in the hippocampus and activation of the ERK/CREB/BDNF signaling axis [11, 12, 13]. Antidepressant-like activity has been demonstrated in the forced swim test in multiple mouse strains at doses of 30 to 60 mg/kg, with enhanced efficacy in amyloid-beta-treated animals [14, 15]. Additional preclinical applications include cardioprotection in myocardial ischemia-reperfusion injury, neuroprotection in perinatal excitotoxic brain injury, glial modulation in spinal muscular atrophy, protection against Huntington’s disease-associated cellular degeneration through NF-kappaB-mediated calpastatin upregulation, and attenuation of sepsis-associated encephalopathy [16, 17, 18, 19, 20]. Pharmacokinetic characterization in mice after intraperitoneal administration at 10 mg/kg reveals rapid central nervous system penetration (brain concentration 773.6 ng/g at five minutes), a plasma elimination half-life of approximately 195 minutes, and stability in biological matrices for at least 24 hours [2]. The compound is supplied as the hydrochloride salt by multiple research chemical vendors at greater than 98 percent purity and is reconstituted in aqueous solution or dimethyl sulfoxide for experimental use. This monograph reviews the chemistry, synthesis, and selectivity of PRE-084; the sigma-1 receptor chaperone pharmacology in molecular detail; the pharmacokinetic profile; the full preclinical evidence base across neurodegenerative, cerebrovascular, cognitive, affective, and cardioprotective domains; sourcing and quality verification; reconstitution and handling; stack interaction considerations; adverse event and safety signal from preclinical data; and a comparative assessment of five sigma-1 receptor candidates (SA4503/cutamesine, ANAVEX2-73/blarcamesine, pridopidine, igmesine, and fluvoxamine) against PRE-084 on five competency standards.

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