Adamax : Adamantane-Modified Semax Analogue, BDNF/TrkB Axis Potentiation, and Enhanced Neuroprotection in Research Models
Abstract & Overview Adamax (AcMEHFPGPAGNH₂; C₅₀H₆₉N₁₁O₁₁S; MW 1032.23 g/mol) is a synthetic octapeptide and the most structurally advanced member of the Semax analogue family, a class of neuropeptides derived from the ACTH(4–7) fragment of adrenocorticotropic hormone. Adamax was engineered through two key structural modifications to the parent compound Semax (MetGluHisPheProGlyPro): Nterminal acetylation, which enhances metabolic stability and membrane permeability, and Cterminal conjugation with an adamantanebased group, which substantially increases lipophilicity, resistance to enzymatic degradation, and bloodbrain barrier (BBB) penetration. The compound’s name is a portmanteau of ‘adamantane’ and ‘maximum,’ reflecting the design intent to maximise the pharmacological profile of the Semax scaffold [1][2]. The Semax family of peptides has a welldocumented research history originating from the Institute of Molecular Genetics at the Russian Academy of Sciences, where Semax was first described in 1991 as a synthetic analogue of the ACTH(4–7) tetrapeptide fragment MetGluHisPhe. Semax is an approved prescription medication in Russia and Ukraine, where it is used clinically for stroke, transient ischaemic attack, memory and cognitive disorders, optic nerve disease, and immune system support [3][4]. The extensive preclinical and clinical research base established for Semax provides the mechanistic framework from which Adamax’s proposed pharmacological profile is derived, with the adamantane modification anticipated to amplify and extend these effects through improved pharmacokinetic properties [1][5]. “Semax rapidly elevates the levels and expression of brainderived neurotrophic factor (BDNF) and its signaling receptor tropomyosin receptor kinase B (TrkB) in the hippocampus, and rapidly activates serotonergic and dopaminergic brain systems… it has been found to produce antidepressantlike and anxiolyticlike effects, attenuate the behavioral effects of exposure to chronic stress, and potentiate the locomotor activity produced by Damphetamine.” — Semax pharmacology, Wikipedia / Dolotov et al. (2006) [5][6]. Adamax is classified as a synthetic nootropic peptide, a cellpenetrating peptide, and a designer analogue of Semax. It has been identified in border seizures and has been submitted for classification as a prescription medicine in New Zealand (Medsafe, 2025). No dedicated peerreviewed clinical trials have been published specifically for Adamax; its proposed pharmacological profile is derived from the extensive Semax research literature combined with structural pharmacology reasoning regarding the contributions of the adamantane modification. All research applications of Adamax remain strictly preclinical and experimental in nature [1][2]. Molecular Identity and Structural Architecture Peptide Backbone: The ACTH(4–7) Core and Semax Scaffold The structural foundation of Adamax is the ACTH(4–7) tetrapeptide fragment MetGluHisPhe (MEHF), which constitutes the biologically active core of the Semax family. This fragment is derived from adrenocorticotropic hormone (ACTH), a 39aminoacid pituitary peptide, and retains the melanocortin receptorinteracting and neuroprotective properties of the parent hormone without the steroidogenic activity of the full ACTH molecule. In Semax, this tetrapeptide core is extended at the Cterminus with the tripeptide ProGlyPro (PGP), which confers resistance to enzymatic degradation and contributes additional neuroprotective properties through its own biological activity as a collagenderived peptide with antiinflammatory effects [3][4]. Adamax extends the Semax heptapeptide scaffold (MEHFPGP) with two additional residues at the Cterminus (AlaGly), yielding the octapeptide sequence MEHFPGPAG. The full Adamax sequence is therefore AcMetGluHisPheProGlyProAlaGlyNH₂ (AcMEHFPGPAGNH₂). The molecular weight of 1032.23 g/mol reflects the combined contributions of the octapeptide backbone, the Nterminal acetyl group, the Cterminal amide, and the adamantanebased Cterminal modification. The molecular formula C₅₀H₆₉N₁₁O₁₁S includes the single sulfur atom from the methionine residue at position 1 of the sequence [1][2]. The Adamantane Modification: Structure and Pharmacokinetic Rationale The defining structural feature of Adamax is the adamantane group conjugated to its Cterminus. Adamantane (C₁₀H₁₆) is a tricyclic diamondoid hydrocarbon with a cagelike structure composed of four fused cyclohexane rings in a chair conformation, forming the smallest unit of the diamond crystal lattice. This rigid, symmetrical cage structure confers exceptional lipophilicity, metabolic stability, and threedimensional bulk that profoundly alters the pharmacokinetic profile of any peptide to which it is conjugated. Adamantane is a wellestablished pharmacophore in CNS drug design: it is the core structural element of amantadine (Parkinson’s disease, influenza), memantine (Alzheimer’s disease), and rimantadine (influenza), all o
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