PPK-V versus Cortexin, Semax and Dalargin: rat peptide-profile study

What the PPK-V comparison establishes

PPK-V (ППК «В») is the cortex-derived experimental mixture in Shustov and colleagues’ 2020 paper. PPK-B (ППК «Б») comes from brainstem. These letter codes identify different preparations. Their composition is not established as equivalent to commercial Cortexin.

The related experimental preparations

“Analogue” here describes a related research preparation. It does not establish a shared active sequence, potency, manufacturing process or interchangeable clinical product. See the PPK research card ↗.

Why the raw values do not prove superiority

The paper pools separately performed experiments and transforms their observations to T-scores using experiment-specific controls. Hypoxia and swimming were also measured in different sexes. The displayed control values therefore should not be treated as a verified shared concurrent control for every row.

A T-score is a shifted, standardized value: T = 50 + 10Z. Its zero is arbitrary. A ratio or percentage of T-scores is not a proportional change in seconds, exercise capacity or clinical benefit. No preparation-specific pairwise test establishes that PPK-V is superior to Cortexin.

The preparations also received unequal doses. Methods give 2.5 mg/kg for experimental complexes, but the discussion describes a maximum of 8.06 mg/kg for PPK-E. The study does not reconcile every complex’s actual exposure, so an apparent potency ratio would be unreliable. Combining two drugs without reducing component doses also does not demonstrate pharmacological synergy.

What 5–10 kDa means

This is a molecular-mass range of 5,000–10,000 daltons. Using an approximate average of 110 daltons per amino-acid residue gives roughly 45–90 residues for a simple peptide; this is an illustration, not sequence identification. A mixture’s chromatography bin can contain different molecules.

The reported fraction association concerns hypoxia resistance. The swimming analysis for the same bin was neutral. PPK-V and Cortexin also had similar reported 5–10 kDa fractions, despite different outcome means. The fraction alone cannot explain their difference or establish a generally optimal human peptide size.

Rectal administration is not evidence of nose-to-brain delivery

This experiment used one rectal exposure an hour before testing. It measured functional outcomes, not intact-peptide concentrations in brain, nasal absorption or blood–brain-barrier transport. Molecular mass by itself cannot establish delivery by another route.

Two distinct Cortexin sources provide context: a 2011 rat seizure study used intranasal nanoparticles or intraperitoneal solution and reported both neutral acute and favorable chronic findings; a 2002 human report combined nasal Cortexin with sensory/vestibular training. Neither establishes intranasal PPK-V delivery, and the human abstract does not isolate the drug’s contribution.

The 2019 book contains matching data

Pages 295–296 of Work Capacity, Fatigue, Correction contain Tables 109–110 with the same mass fractions and outcome values as Tables 1–2 of the 2020 article. The recovered book pages were visually inspected. These are linked reports from one research program, rather than independent replication.

The journal’s indexed full text was checked, but its PDF page images could not be retrieved. Visual table checking used the recovered monograph. The public links point to the original journal article ↗ and the book’s author-upload record ↗.

What would resolve the remaining questions?

Priority gaps are preparation-specific dose records, original experiment identifiers and controls, matched-exposure replication, sequence and batch characterization, and route-specific pharmacokinetics. No adverse-event denominator or long-term PPK-V safety program is established by this acute study.