An N-terminal-acetylated, C-terminal-amidated variant of the heptapeptide nootropic Semax, designed to extend plasma and central nervous system exposure beyond both the parent and the simple N-acetyl variant.
Abstract
NA-Semax Amidate (N-acetyl-Met-Glu-His-Phe-Pro-Gly-Pro-NH2) is a doubly modified variant of Semax (the seven-residue ACTH(4-10) analog Met-Glu-His-Phe-Pro-Gly-Pro) developed at the Russian Academy of Sciences as a long-acting analog. Semax itself is registered in the Russian Federation as an intranasal nootropic and stroke treatment at 0.1 percent and 1 percent solutions, with a published pharmacological signature of BDNF and NGF transcriptional upregulation, neuroprotection in middle cerebral artery occlusion stroke models, and pro-cognitive effects in passive avoidance and operant conditioning paradigms. The parent Semax has a plasma half-life of minutes and a central nervous system exposure window of similarly short duration after intranasal administration. The N-acetyl variant of Semax (NA-Semax) extends plasma half-life by approximately 5-fold by blocking the aminopeptidase cleavage at the methionine N-terminus, and the C-terminal amidation in the Amidate variant additionally blocks the carboxypeptidase cleavage at the proline C-terminus, producing a peptide with the longest exposure in the Semax family. Comparative pharmacology in rodent models reports that NA-Semax Amidate at one-tenth the dose of parent Semax produces equivalent or greater BDNF mRNA elevation in cortex and hippocampus and equivalent neuroprotection in stroke models, with substantially longer duration of effect. Routes studied include subcutaneous, intramuscular, intranasal, and intraperitoneal administration. The compound is research-grade and not approved by any regulatory authority; the principal published record is in Russian-language journals from the Institute of Molecular Genetics RAS. Investigators should treat the extended-PK variant as a research tool for studying long-duration ACTH-derived heptapeptide pharmacology where the brief pulse from intranasal Semax is operationally limiting.
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.
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.
A six-residue acetylated peptide modeled on the N-terminal SNAP-25 sequence cleaved by botulinum neurotoxin, used in topical cosmetic formulations for expression-line reduction.
Abstract
Argireline (Acetyl hexapeptide-8; Ac-Glu-Glu-Met-Gln-Arg-Arg-NH2; CAS 616204-22-9 or 575826-37-6 acetate; molecular weight 888.97 free peptide) is a six-residue N-acetylated, C-amidated peptide developed by the Spanish company Lipotec (now part of Lubrizol) and marketed as Argireline since 2002. The peptide sequence corresponds to the N-terminus of SNAP-25, a key SNARE complex protein that mediates synaptic vesicle fusion at the neuromuscular junction; SNAP-25 is the substrate cleaved by botulinum neurotoxin type A (Botox) at the same N-terminal region. The pharmacological argument for Argireline as a topical cosmetic ingredient is that the peptide competes with endogenous SNAP-25 for assembly into the SNARE complex, weakening neurotransmitter release at the neuromuscular junction at the application site and reducing the muscular contraction that drives expression-line formation. The mechanism is qualitatively similar to botulinum toxin but operates at substantially lower potency and through a distinct molecular mechanism (competitive SNAP-25 mimicry rather than enzymatic cleavage of endogenous SNAP-25). Topical penetration of an intact polar hexapeptide through the stratum corneum is intrinsically poor; modern Argireline formulations use liposomal encapsulation or other delivery vehicles to improve penetration. Published clinical evidence is mixed and dominated by manufacturer-sponsored studies; independent academic studies report modest reduction in expression-line depth at 30 days of twice-daily 10 percent topical application, substantially less than the effect of intramuscular botulinum toxin. The compound is sold as a cosmetic ingredient (not a regulated drug) in essentially all major cosmetic markets including the United States, EU, and East Asia. Stability of formulated solutions is moderate; solid peptide stored at refrigerated conditions has multi-year shelf life.
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.
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.
Synthetic gonadotropin-releasing hormone superagonist nonapeptide with paradoxical chronic suppression of pituitary-gonadal axis through GnRH receptor desensitization and downregulation
A synthetic nonapeptide analog of endogenous gonadotropin-releasing hormone bearing a D-serine(tert-butyl) substitution at position 6 and an ethylamide C-terminal modification, conferring 20- to 170-fold greater potency than native GnRH and resistance to enzymatic degradation, developed at Hoechst AG in the mid-1970s as one of the first clinically viable GnRH superagonists and now registered in approximately 40 jurisdictions for hormone-dependent prostate cancer, endometriosis, uterine fibroids, premenopausal breast cancer, central precocious puberty, and pituitary downregulation in assisted reproduction protocols.
Abstract
Buserelin ([D-Ser(tBu)6,des-Gly-NH2-10]GnRH ethylamide; CAS 57982-77-1, free base; 68630-75-1, acetate salt) is a synthetic nonapeptide analog of the hypothalamic decapeptide gonadotropin-releasing hormone (GnRH, also designated luteinizing hormone-releasing hormone, LHRH) first described by Sandow and colleagues at Hoechst AG in 1976 and approved for clinical use in 1984 [1, 2]. The compound incorporates two structural modifications to native GnRH that collectively confer superagonist potency and metabolic stability: replacement of glycine at position 6 with D-serine bearing a tert-butyl ether on the side-chain hydroxyl, which eliminates the principal endopeptidase cleavage site and introduces conformational rigidity favorable to receptor binding; and replacement of the C-terminal glycinamide (position 10) with an ethylamide, which further resists carboxypeptidase degradation. The resulting peptide binds the type I GnRH receptor with affinity approximately 20- to 170-fold greater than native GnRH and produces a biphasic pharmacological response that is the mechanistic foundation for all clinical applications [3, 4]. Acute administration stimulates pituitary gonadotroph secretion of luteinizing hormone and follicle-stimulating hormone, producing transient elevations in gonadal steroid output (the “flare” phase, lasting 7 to 14 days). Chronic continuous administration produces homologous desensitization of the GnRH receptor through receptor internalization, uncoupling from Gq/11-phospholipase C signaling, and transcriptional downregulation of GnRH receptor expression, resulting in profound and sustained suppression of gonadotropin secretion and a hypogonadal state equivalent to surgical castration in both sexes [5, 6]. This medical castration is reversible on cessation of treatment. Buserelin was the first GnRH agonist demonstrated to achieve medical castration in humans via intranasal administration, an observation reported by Sandow and colleagues in 1980 that established the clinical viability of non-injectable GnRH agonist therapy [2]. The compound is registered in approximately 40 jurisdictions across Europe, the United Kingdom, Canada, New Zealand, South Africa, Latin America, and Asia, but is not approved in the United States or Australia. Registered indications include hormone-responsive prostate cancer, endometriosis, uterine fibroids, premenopausal breast cancer, and pituitary downregulation as an adjunct to controlled ovarian hyperstimulation in assisted reproduction [7, 8, 9]. The compound is additionally used off-label for central precocious puberty and as a component of gender-affirming hormone therapy. Pharmacokinetics are characterized by negligible oral bioavailability due to gastrointestinal peptidase degradation, approximately 2.5 to 3.3 percent intranasal bioavailability, and approximately 70 percent subcutaneous bioavailability [10]. The plasma elimination half-life is 50 to 80 minutes after intravenous or subcutaneous administration and approximately 1 to 2 hours after intranasal dosing. Protein binding is low (approximately 15 percent). Metabolism occurs principally through pyroglutamyl peptidase and chymotrypsin-like endopeptidase activity in the liver, kidneys, and gastrointestinal tract, with approximately 50 percent of the administered dose recovered unchanged in urine [10, 11]. Formulations include aqueous solution for subcutaneous injection and intranasal spray (requiring multiple daily administrations) and sustained-release subcutaneous implants providing 2- or 3-month depot delivery. The adverse-event profile is dominated by the pharmacological consequences of gonadal steroid suppression: hot flashes, reduced libido, erectile dysfunction or vaginal dryness, and long-term bone mineral density reduction. The initial flare phase carries specific risk in metastatic prostate cancer (bone pain exacerbation, spinal cord compression, ureteral obstruction), which is mitigated clinically by co-administration of an antiandrogen during the first 2 to 4 weeks of therapy. This monograph reviews the chemistry and synthesis, the biphasic GnRH receptor pharmacology, the comprehensive human pharmacokinetic record, the clinical evidence base across prostate cancer, endometriosis, uterine fibroids, breast cancer, precocious puberty, and assisted reproduction indications, sourcing and quality verification, reconstitution and handling, stack interactions, adverse-event signal, and a comparative assessment of five GnRH agonist candidates against buserelin 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.
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.
Endogenous peptide hormone and apelin receptor (APJ/APLNR) agonist of the apelinergic signaling system
A 32-amino-acid secreted peptide hormone discovered in 2013 as the second endogenous ligand of the apelin receptor (APJ/APLNR), essential for vertebrate cardiovascular morphogenesis, human embryonic stem cell self-renewal, placental angiogenesis, and renal fluid homeostasis, with preclinical cardioprotective, renoprotective, antihypertensive, and neuroprotective activity across multiple disease models.
Abstract
Elabela (ELA), also designated Apela, Toddler, and Ende, is a secreted peptide hormone encoded by the APELA gene on human chromosome 4q32.3. The gene encodes a 54-amino-acid preproprotein containing a 22-residue signal peptide; cleavage yields the 32-amino-acid mature peptide ELA-32 (sequence QRPVNLTMRRKLRKHNCLQRRCMPLHSRVPFP), which may be further processed by proprotein convertases to generate the bioactive isoforms ELA-21 and ELA-11 [1, 2]. Elabela was discovered independently by two groups in 2013 and 2014: Chng et al. (2013) identified the peptide in zebrafish as a hormone essential for heart development signaling through the apelin receptor (APLNR/APJ), while Pauli et al. (2014) characterized the same molecule as “Toddler,” an embryonic signal promoting mesodermal cell migration [1, 3]. The peptide is the second endogenous ligand of the apelin receptor, a class A G-protein-coupled receptor previously known to bind only apelin; despite sharing a common receptor, Elabela and apelin exhibit less than 25 percent sequence similarity and display distinct spatiotemporal expression profiles and partially divergent signaling bias [4, 5]. Elabela activates the apelin receptor through Gi/o-coupled inhibition of adenylyl cyclase, stimulation of ERK1/2 and PI3K/AKT/mTOR pathways, mobilization of intracellular calcium, and recruitment of beta-arrestin, functioning as a balanced agonist across G-protein-dependent and beta-arrestin-dependent pathways [5, 6]. The binding affinity of ELA-32 for the human apelin receptor is high, with reported IC50 values of approximately 0.27 nanomolar and Kd values of approximately 0.51 nanomolar [7]. Physiologically, Elabela is expressed at high levels during embryogenesis across vertebrate species and in adult tissues with restricted distribution, principally kidney (collecting ducts and loops of Henle), prostate, and vascular endothelium [2, 8]. The peptide is essential for vertebrate cardiovascular development: genetic ablation of Elabela in zebrafish produces severe cardiac malformations including rudimentary or absent hearts, phenocopying loss of the apelin receptor itself [1]. In mice, Elabela knockout produces preeclampsia-like symptoms during pregnancy including proteinuria, hypertension, defective placental angiogenesis, and reduced fetal weight, effects that are rescued by exogenous ELA infusion [9]. A separate demonstration by Ho et al. (2015) established that Elabela is an endogenous growth factor sustaining human embryonic stem cell self-renewal via the PI3K/AKT pathway, with CRISPR-mediated deletion causing loss of pluripotency and cell death [10]. In the adult cardiovascular system, Elabela functions as an endogenous agonist of the apelin receptor producing positive inotropy, vasodilation, increased cardiac output, and depressor responses comparable to apelin; expression is downregulated in pulmonary arterial hypertension, and exogenous administration attenuates right ventricular hypertrophy and pulmonary vascular remodeling in monocrotaline-exposed rats [11]. Preclinical cardioprotective activity has been demonstrated across myocardial infarction, ischemia-reperfusion injury, and hypertensive cardiac fibrosis models, operating through PI3K/AKT-mediated anti-apoptotic, anti-fibrotic, and pro-angiogenic mechanisms [12, 13, 14]. Renoprotective activity is characterized by antagonism of the intrarenal renin-angiotensin system, reduction of blood pressure and albuminuria in salt-sensitive hypertensive rats, and prevention of vasopressin-induced aquaporin-2 translocation in collecting duct principal cells, thereby promoting aqueous diuresis [15, 16]. Neuroprotective activity has been demonstrated in rodent models of ischemic stroke, where ELA attenuates neuronal apoptosis, ferroptosis, and pyroptosis through APJ-dependent signaling cascades [17, 18]. The in vitro plasma half-life of ELA-32 in human plasma is approximately 47 minutes, substantially longer than that of apelin-13 (approximately 5 minutes in vivo), though rapid degradation occurs in kidney homogenates (half-life approximately 44 seconds), and the short systemic half-life has motivated the development of Fc-fusion, PEGylated, and acylated analogs with extended duration of action [19, 20, 21]. No human clinical trials of exogenous Elabela administration have been completed as of the monograph revision date; the compound remains in the preclinical-to-translational research phase. This monograph reviews the chemistry, isoform biology, and synthesis of Elabela; the receptor pharmacology and signaling mechanisms in molecular detail; the pharmacokinetic profile including metabolism and stability-enhancement strategies; the preclinical evidence base across cardiovascular, renal, obstetric, stem cell, neurological, and oncological applications; sourcing and quality verification for research-grade material; reconstitution and handling; stack-interaction considerations; the adverse-event and safety signal from animal studies; and a comparative assessment of five apelinergic system candidates against Elabela 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.
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.
Sevoflurane is the inhalational anesthetic of choice for pediatric mask induction, owing to its non-pungent character and pleasant odor that allow children to breathe down to anesthesia without IV access first. Synthesized by Ross Terrell at Travenol in 1968, brought to clinical use in Japan in 1990, FDA-approved in 1995 (Ultane). Blood-gas partition coefficient of 0.65 gives faster kinetics than isoflurane and a favorable cardiovascular profile with preserved cardiac output. Mechanism mirrors other halogenated ethers: GABA-A potentiation, K2P channel activation, glycine and NMDA modulation. The classical concern is Compound A, a degradation product formed when sevoflurane reacts with CO2 absorbents at very low fresh gas flows; nephrotoxic in rats but not demonstrated in humans within recommended flow limits. Workhorse modern volatile. 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.
Halogenated ether volatile general anesthetic
A non-pungent fluorinated methyl isopropyl ether with a low blood-gas coefficient enabling fast induction and the dominant inhalational agent for pediatric mask induction.
Abstract
Sevoflurane (fluoromethyl 2,2,2-trifluoro-1-(trifluoromethyl)ethyl ether; CAS 28523-86-6; molecular formula C4H3F7O; molecular weight 200.05) is a fluorinated methyl isopropyl ether volatile anesthetic synthesized by Ross Terrell at Travenol Laboratories in 1968, brought to clinical use in Japan in 1990, and approved by the FDA in 1995 (Ultane, Sojourn). The minimum alveolar concentration (MAC) at age 40 is 1.8 percent in oxygen; the blood-gas partition coefficient is 0.65, faster than isoflurane (1.4) but slower than desflurane (0.42). The non-pungent character and absence of airway irritation make sevoflurane the agent of choice for inhalational induction of anesthesia, particularly in pediatric patients where intravenous access is established after induction. Mechanism parallels other halogenated ethers (GABA-A positive allosteric modulation, K2P channel activation, glycine and NMDA effects); the agent is achiral. Hepatic metabolism via CYP2E1 produces hexafluoroisopropanol and inorganic fluoride; the fluoride concentrations approach the historical nephrotoxic threshold associated with methoxyflurane (50 micromolar plasma) during prolonged exposure but published clinical data have not demonstrated nephrotoxicity in humans even with extended cases, attributed to the absence of intrarenal defluorination. The principal residual concern is degradation of sevoflurane in carbon dioxide absorbents (soda lime, Baralyme) at low fresh gas flows producing Compound A, which is nephrotoxic in rats but lacks demonstrated human renal injury within recommended fresh gas flow limits (1 to 2 L/min). Cardiovascular profile is favorable with preserved cardiac output, modest reduction in systemic vascular resistance, and minimal coronary steal physiology.
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.
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.
Benzocaine is the simplest ester local anesthetic, structurally just ethyl 4-aminobenzoate without the diethylamino-ethanol group of procaine. The simpler structure makes it lipophilic and poorly water-soluble, useful only for topical mucous membrane anesthesia. You know it as the active ingredient in Cepacol throat lozenges, Anbesol and Orajel oral gels, hemorrhoidal preparations, and topical ENT and bronchoscopy sprays. Onset is rapid (15 to 60 seconds on mucous membranes); duration is 5 to 15 minutes. The main safety concern is dose-dependent methemoglobinemia, more pronounced than with prilocaine, that has driven FDA boxed warnings against benzocaine spray and gel use in infants. The mechanism is hepatic conversion to nitroso and N-hydroxy metabolites that oxidize hemoglobin. The FDA advised against benzocaine teething gels in infants under two years in 2018. 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.
Ester local anesthetic (topical only)
The simplest ester local anesthetic, used as a topical mucous membrane anesthetic and the principal ingredient in over-the-counter sore-throat lozenges.
Abstract
Benzocaine (ethyl 4-aminobenzoate; CAS 94-09-7; molecular formula C9H11NO2; molecular weight 165.19) is an ester-class local anesthetic, structurally the simplest member of the para-aminobenzoate family (the primary aminobenzoate ester directly esterified to ethanol, lacking the diethylamino-ethanol group of procaine). The simpler structure produces a lipophilic, water-poorly-soluble compound suitable only for topical mucous membrane anesthesia; the absence of the tertiary amine restricts utility for infiltration and regional anesthesia. Benzocaine is the principal active ingredient in over-the-counter throat lozenges (Cepacol), oral analgesic gels (Anbesol, Orajel), topical preparations for hemorrhoidal and minor wound use, and topical ENT and bronchoscopy preparation. Mechanism is voltage-gated sodium channel block in surface nerve fibers contacted topically. Onset is rapid (15 to 60 seconds on mucous membranes); duration is 5 to 15 minutes. The principal safety concern is dose-dependent methemoglobinemia, more pronounced than with prilocaine, that has driven FDA boxed warnings against benzocaine spray and gel use in infants and limited topical doses in children and adults. The mechanism is hepatic conversion of benzocaine to nitroso and N-hydroxy metabolites that oxidize hemoglobin iron to the ferric state. Clinical methemoglobinemia is reported with topical mucosal application of as little as 250 mg in vulnerable individuals; the risk is amplified in G6PD deficiency, infancy (low NADH-methemoglobin reductase activity), and concurrent oxidant drug exposure. Methylene blue is the rescue therapy. The FDA advised in 2018 against benzocaine teething gels in infants under 2 years.
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.
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.
N-acetylated Selank derivatives with extended pharmacokinetics
N-terminal-acetylated and amidated variants of the heptapeptide anxiolytic Selank, designed to extend plasma and central nervous system exposure beyond the parent peptide.
Abstract
NA-Selank (N-acetyl-Thr-Lys-Pro-Arg-Pro-Gly-Pro) and NA-Selank Amidate (the same N-acetylated heptapeptide with C-terminal amidation, Pro-NH2) are N-terminal-modified derivatives of Selank, the seven-residue peptide anxiolytic developed at the Russian Academy of Sciences as an analog of the endogenous tetrapeptide tuftsin (Thr-Lys-Pro-Arg). The parent Selank is registered as a medicine in the Russian Federation as an intranasal anxiolytic at 0.15 percent solution; the principal pharmacological signature is anxiolysis without sedation, modest pro-cognitive activity, and immunomodulation through tuftsin-receptor binding on monocytes and natural killer cells. Selank itself has a short plasma half-life of minutes and is administered intranasally to leverage direct olfactory and trigeminal transport to the central nervous system; the N-acetyl modification at the threonine N-terminus blocks the principal aminopeptidase cleavage site and extends plasma half-life by approximately 5-fold, while the C-terminal amidation in the Amidate variant similarly blocks carboxypeptidase cleavage at the proline C-terminus. The combined modifications produce a heptapeptide with substantially extended exposure suitable for parenteral administration with central nervous system effect. Mechanism includes BDNF transcriptional upregulation, GABAergic and serotonergic modulation, and tuftsin-receptor immunomodulation. Both NA-Selank and NA-Selank Amidate are research-grade peptides without regulatory approval; published characterization is principally in Russian-language journals and is dominated by the originating Institute of Molecular Genetics RAS research group. Investigators should treat the extended-PK variants as research tools for studying parenteral Selank pharmacology and should consider that the immune-modulatory profile may be more pronounced with extended exposure than with the brief intranasal pulse achieved by the parent.
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.
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.
Matrikine cosmetic peptide blend (Pal-GHK and Pal-GQPR)
A topical cosmetic blend of two palmitoylated matrikine peptides, palmitoyl tripeptide-1 (Pal-GHK) and palmitoyl tetrapeptide-7 (Pal-GQPR), formulated for collagen synthesis stimulation in cosmetic anti-aging applications.
Abstract
Matrixyl 3000 is a cosmetic ingredient blend developed by the French company Sederma (Croda) consisting of two palmitoylated matrikine peptides: palmitoyl tripeptide-1 (Pal-Gly-His-Lys; Pal-GHK; molecular weight approximately 578 Da; the palmitoylated version of the well-characterized matrikine GHK that is the basis of GHK-Cu, KDC-MN-007) and palmitoyl tetrapeptide-7 (Pal-Gly-Gln-Pro-Arg; Pal-GQPR; molecular weight approximately 619 Da). The matrikine concept describes short bioactive peptides released by enzymatic degradation of extracellular matrix proteins (collagens, elastin, laminin) that signal to dermal fibroblasts to repair the matrix; the matrikine signal is interpreted as a tissue-damage marker that drives compensatory matrix synthesis. GHK is the canonical collagen-promoting matrikine; the GQPR sequence is derived from immunoglobulin and inhibits IL-6-induced inflammatory cytokine production. The palmitoylation of both peptides anchors them in the lipid bilayer of the stratum corneum, substantially improving topical retention relative to the unmodified peptides and providing sustained cutaneous delivery. The pharmacological argument for the blend over either peptide alone is the dual mechanism: collagen synthesis stimulation through GHK signaling combined with anti-inflammatory and matrix-protective signaling through GQPR. Published manufacturer-sponsored studies report measurable increases in skin firmness, reduced wrinkle depth, and improved skin tone at 8 weeks of twice-daily topical application of 3 percent or 4 percent Matrixyl 3000 solutions. Independent academic replication is limited. The blend is sold as a cosmetic ingredient (not a regulated drug) in essentially all major cosmetic markets. Distinct from the original Matrixyl (palmitoyl pentapeptide-4, also known as Pal-KTTKS), which is a separate Sederma matrikine ingredient.
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.
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.
Synthetic cyclic octapeptide somatostatin analog with preferential somatostatin receptor subtype 2 and 5 agonism
A cyclic octapeptide somatostatin analog developed by Beaufour-Ipsen as the second clinically available long-acting somatostatin receptor ligand, distinguished by a unique self-assembling supersaturated depot formulation, antiproliferative activity in gastroenteropancreatic neuroendocrine tumors demonstrated in the landmark CLARINET trial, and a three-indication regulatory portfolio spanning acromegaly, neuroendocrine tumor growth control, and carcinoid syndrome.
Abstract
Lanreotide (D-2Nal-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2; CAS 108736-35-2 free base; molecular formula C54H69N11O10S2; molecular weight 1096.33) is a synthetic cyclic octapeptide analog of native somatostatin-14, developed by Beaufour-Ipsen (now Ipsen) and introduced clinically in the early 1990s as the second somatostatin analog to reach the market after octreotide. The compound exhibits high-affinity agonism at somatostatin receptor subtypes 2 and 5 (SSTR2, Ki approximately 0.54 to 0.75 nM; SSTR5, Ki approximately 5.2 nM) with moderate affinity at SSTR3 and low affinity at SSTR1 and SSTR4, a selectivity profile that mediates suppression of growth hormone, insulin-like growth factor 1, and multiple gastrointestinal and pancreatic hormones through inhibition of adenylyl cyclase and reduction of intracellular cyclic adenosine monophosphate [1, 2]. The compound is formulated as lanreotide acetate in the Autogel (marketed as Somatuline Depot in the United States), a supersaturated aqueous gel in which lanreotide molecules self-assemble into hollow nanotubes of highly uniform diameter stabilized by beta-sheet hydrogen bonding, hydrophobic packing, and aromatic pi-pi stacking, producing a deep subcutaneous depot that releases active peptide over 28 days with a terminal elimination half-life of 23 to 30 days and absolute bioavailability of approximately 60 to 70 percent [3, 4]. The Autogel formulation, first approved in Europe in 2001 and in the United States in 2007, was the first marketed sustained-release pharmaceutical product produced by peptide self-assembly rather than by polymer microsphere encapsulation. Three indications are registered in the United States: long-term treatment of acromegaly in patients who have had an inadequate response to or cannot be treated with surgery and radiotherapy (FDA approved August 2007); treatment of unresectable, well- or moderately-differentiated, locally advanced or metastatic gastroenteropancreatic neuroendocrine tumors to improve progression-free survival (FDA approved December 2014, on the basis of the CLARINET trial); and treatment of carcinoid syndrome in adults to reduce the frequency of rescue somatostatin analog therapy (FDA approved February 2018, on the basis of the ELECT trial) [5, 6, 7]. In acromegaly, lanreotide Autogel at 60 to 120 mg every 28 days normalizes growth hormone to below 2.5 micrograms per liter in approximately 58 percent and age-adjusted insulin-like growth factor 1 in approximately 48 percent of treatment-naive patients, with tumor volume reduction in approximately 60 percent of evaluated patients on long-term treatment [8, 9]. In the CLARINET trial, lanreotide 120 mg every 28 days versus placebo produced a hazard ratio for progression or death of 0.47 (95 percent confidence interval 0.30 to 0.73; P less than 0.001) in 204 patients with nonfunctioning, somatostatin-receptor-positive, grade 1 or 2 enteropancreatic neuroendocrine tumors, with estimated 24-month progression-free survival of 65.1 percent versus 33.0 percent [6]. In the ELECT trial, lanreotide 120 mg every 28 days significantly reduced the need for rescue short-acting octreotide for symptomatic carcinoid syndrome control and reduced patient-reported days with moderate or severe diarrhea and flushing [7]. The principal adverse events at registered doses are gastrointestinal (diarrhea 26 to 65 percent, abdominal pain 7 to 34 percent, nausea 5 to 11 percent), cholelithiasis and gallbladder sludge (14 to 20 percent), injection site reactions (5 to 22 percent), dysglycemia (hyperglycemia 5 to 14 percent, hypoglycemia 2 to 7 percent), and sinus bradycardia (3 to 8 percent) [10]. This monograph reviews the chemistry, synthesis, and self-assembly of lanreotide; the somatostatin receptor pharmacology in molecular detail; the comprehensive human pharmacokinetic record; the preclinical antiproliferative pharmacology; the clinical evidence base across acromegaly, neuroendocrine tumor, and carcinoid syndrome indications; reconstitution and handling; sourcing and quality verification; stack-interaction considerations; adverse-event signal; and a comparative assessment of five somatostatin receptor ligands against lanreotide 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.
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.
Synthetic tetrapeptide bioregulator of pancreatic endocrine and exocrine cell differentiation and function
A synthetic tetrapeptide (Lys-Glu-Asp-Trp) developed at the Saint Petersburg Institute of Bioregulation and Gerontology as a tissue-specific epigenetic modulator of pancreatic cell differentiation, glucose homeostasis, and beta cell functional recovery in aging and type 2 diabetes mellitus.
Abstract
Pancragen (Lys-Glu-Asp-Trp-NH2; KEDW) is a synthetic tetrapeptide bioregulator developed by Vladimir Khavinson and colleagues at the Saint Petersburg Institute of Bioregulation and Gerontology (Russia) as a tissue-specific modulator of pancreatic endocrine and exocrine cell differentiation and function. The compound belongs to the Khavinson class of ultrashort (two to four amino acid) bioregulatory peptides, a pharmacological category defined by the hypothesis that short peptides penetrate cell nuclei, bind complementary DNA sequences in promoter regions through electrostatic and hydrogen-bond interactions, and modulate gene expression in a tissue-specific manner without engaging classical cell-surface receptors. Pancragen was derived from fractionation of bovine pancreatic tissue extracts; the tetrapeptide Lys-Glu-Asp-Trp was identified as the minimal active sequence responsible for the pancreotrophic activity of the parent extract preparation Suprefort. The compound has a molecular formula of C26H36N6O9 (free acid form) and a molecular weight of 576.60 g/mol. Physical-chemical characterization by ultraviolet-visible absorption spectroscopy, circular dichroism, and molecular modeling has demonstrated that the KEDW tetrapeptide binds double-stranded DNA in the major groove at sequences containing the ACCT motif, which is found in promoter regions of genes responsible for pancreatic cell differentiation and function [1]. The principal downstream molecular consequence of this interaction is upregulation of transcription factors that govern pancreatic endocrine cell fate, including PDX1 (the earliest marker of pancreatic progenitor cells and the master regulator of beta cell identity), NGN3, PAX6, PAX4, FOXA2, NKX2-2, and NKX6.1 [2, 3]. In organotypic pancreatic cell cultures from young and aged rats, Pancragen stimulated the expression of differentiation factors of both acinar cells (Pdx1, Ptf1a) and islet of Langerhans cells (Pdx1, Pax6, Pax4, Foxa2, Nkx2.2), with the inducing effect more pronounced in aged cultures, consistent with a geroprotective mechanism [3]. Preclinical pharmacology in streptozotocin-induced diabetic rats demonstrated that oral Pancragen produced a pronounced hypoglycemic effect during the treatment period and that intramuscular administration normalized the adhesion properties of mesenteric capillary endothelium without modifying capillary permeability, suggesting homeostatic and endothelioprotective activity in early diabetes [4]. In a study of biological activity using immunoenzyme and high-performance liquid chromatography methods, the tetrapeptide modulated metabolic parameters characterizing apoptosis, including caspase-3 activity, in pancreatic beta cells and hepatocytes from streptozotocin-treated animals [5]. Primate studies in aged female rhesus monkeys demonstrated that a 10-day intramuscular course of Pancragen at 50 micrograms per day markedly increased the glucose disappearance rate, decreased basal insulin and C-peptide levels, and normalized glucose, insulin, and C-peptide dynamics during intravenous glucose tolerance testing, with partial persistence of these effects for three weeks after cessation of treatment [6, 7]. A comparative study in the same primate model demonstrated that Pancragen normalized insulin and C-peptide levels (suggesting recovery of disturbed glucose tolerance) while glimepiride produced a stronger but delayed blood-glucose-lowering effect without substantially affecting insulin secretion, indicating mechanistically distinct activity [7]. In a clinical study of 33 elderly patients with type 2 diabetes mellitus, Pancragen administered against a background of constant-dose glibenclamide significantly decreased fasting plasma glucose and glucose concentrations at two hours during oral glucose tolerance testing, reduced plasma insulin levels, and decreased the HOMA insulin resistance index; an additional glucose-lowering effect persisted for two weeks after cessation of Pancragen in 60 percent of patients who continued glibenclamide at unchanged doses [8]. Organotypic tissue culture studies confirmed that Pancragen at concentrations as low as 0.05 ng/mL stimulated tissue growth in pancreatic explants from both young and aged rats, with the stimulating effect tissue-specific (no effect on non-pancreatic tissue explants at the same concentration) [9]. The compound has not been approved by the United States Food and Drug Administration, the European Medicines Agency, or any major Western regulatory authority. It is marketed in Russia as a dietary supplement (Pancragen capsules) and is available internationally as a research-grade peptide from multiple suppliers. Formal toxicology studies meeting International Council for Harmonisation or FDA regulatory standards have not been published. The existing safety data, derived exclusively from the Khavinson research network, report no significant adverse events in preclinical or clinical studies at the doses and durations studied. This monograph reviews the chemistry, synthesis, and structural class of Pancragen; the epigenetic and transcriptional mechanism of action; the available pharmacokinetic considerations for ultrashort peptides; the preclinical pharmacology in cell culture, rodent, and primate models; the clinical evidence base in type 2 diabetes; sourcing and quality verification; reconstitution and handling; stack interactions; adverse events and safety signals; and a comparative assessment of five alternative pancreatic bioregulatory or beta cell-active compounds against Pancragen 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.
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.
