What is Semax Nasal Spray?
Semax is H-Met-Glu-His-Phe-Pro-Gly-Pro-OH, CAS 80714-61-0, formula C37H51N9O10S, molecular weight 813.92, seven residues. The first four, Met-Glu-His-Phe, reproduce the 4 to 7 region of adrenocorticotropic hormone, the part of the parent hormone associated in the literature with central rather than steroidogenic activity. The Pro-Gly-Pro extension at the C-terminus is a stabilizing addition. The single sulfur atom in the formula belongs to the N-terminal methionine.
The spray is a delivery format rather than a distinct chemical entity. Mucosal formulation is a mature research area, since the nasal epithelium is thin, densely vascularized and avoids first-pass metabolism in absorption models, and part of that literature examines olfactory and trigeminal transport. Semax was developed in Russia in intranasal solutions, so much of the published rodent work on neurotrophic factor expression and ischemia models used this format.
What is not established is how much intact peptide crosses the epithelium under any given set of conditions. Reported absorption fractions for short peptides vary with pH, tonicity, viscosity and mucociliary clearance, and the direct nose-to-brain transport hypothesis remains an active argument rather than a settled finding.
Reconstitution & handling
No reconstitution applies, since the peptide arrives already dissolved in a buffered isotonic vehicle. Calculation starts from the label. The 10 mg total content divided by fill volume gives nominal concentration, and dividing again by the metered volume per actuation gives mass per actuation. The bottle should not be diluted, because buffer and tonicity affect both stability and absorption.
Storage & stability
Sealed bottles are kept refrigerated at 2 to 8 degrees Celsius and shielded from light, since a peptide in solution is less stable than the same molecule lyophilized at -20 degrees Celsius. Freezing is avoided because ice formation concentrates solutes. The dominant liability is the N-terminal methionine, which oxidizes to the sulfoxide on exposure to air and light, so headspace is limited and the bottle is inspected for yellowing or haze.
How it's tested
Solution lots are assayed by reverse-phase HPLC with detection at 214 and 220 nanometres, quantified against a reference standard to confirm the declared 10 mg content. The same gradient separates methionine sulfoxide from parent peptide, so the oxidation state is reported rather than assumed. Mass spectrometry confirms identity against the theoretical average mass of 813.92. Fill volume, pH, appearance and sterility are recorded, and a lot-matched certificate of analysis is available.