Preloaded Autoinjector | Cartalax | 3ml Pen | 20mg

The Cartalax pen is a preloaded 3ml research autoinjector containing the tripeptide L-alanyl-L-glutamyl-L-aspartic acid (Ala-Glu-Asp, laboratory code T-31) in solution at 20/3 mg/ml, giving 20mg of total peptide. With no oxidisable, deamidating or aromatic residue in any of its three positions, this molecule ages in water by hydrolysis alone, and every product of that hydrolysis has a different mass from the parent.

Specification Table

What Changes When Cartalax Ships in Solution?

Dissolving Ala-Glu-Asp puts a tripeptide with one free amine and three carboxylates into water at a pH that sets its rate of loss, and the only chemistry available to it there is hydrolysis of its two peptide bonds.

Start with what is absent. No asparagine or glutamine, so no deamidation. No methionine, cysteine, tryptophan, histidine or tyrosine, so nothing to oxidise, no disulfide to scramble and no chromophore to absorb bench light. What remains is the backbone, and a backbone of 333.30 g/mol has two ways to fail.

The first is diketopiperazine formation. The free amine of Ala1 folds back onto the carbonyl of Glu2 and severs the Glu-Asp bond by transamidation, releasing cyclo(Ala-Glu) at about 200 Da together with free aspartic acid at 133 Da. This is the characteristic loss pathway of any tripeptide with an unprotected N-terminus; it runs fastest when residue 2 is proline or glycine and comparatively slowly when residue 2 is glutamic acid. Slow is not zero, and nobody has published the rate for this sequence.

The second is acid-catalysed cleavage. Bonds flanking an aspartate are the most acid-labile in any peptide, because the side-chain carboxyl assists hydrolysis of its own backbone amide. Here the aspartate is C-terminal, so only the Glu-Asp bond qualifies, and cutting it yields the dipeptide Ala-Glu at about 218 Da plus free aspartic acid. The rate climbs steeply as pH falls, and the free acid in unbuffered water sits near pH 3 at tens of millimolar, so the pH of the fill is the one formulation number that decides how this device ages.

Earlier product notes described the C-terminal aspartate forming a succinimide slowly. That is a fair expectation for Asp inside a chain and a wrong one here: succinimide formation needs a backbone amide nitrogen on the C-terminal side of the aspartate, and a terminal aspartate with a free carboxylate has none. The isoaspartate problem that shadows the tetrapeptides Cardiogen (Ala-Glu-Asp-Arg) and Bronchogen (Ala-Glu-Asp-Leu) is absent from Cartalax, with one useful consequence: every degradation product of Ala-Glu-Asp has a mass different from the parent. The 333 Da signal declines and signals near 200, 218 and 133 Da appear. For most peptides a purity-by-mass figure tells part of the story; for this one it tells all of it.

Charge state governs the rest. Four ionisable groups are present: the N-terminal amine (pKa about 8), the Glu gamma-carboxyl (about 4.3), the Asp beta-carboxyl (about 3.9) and the C-terminal carboxyl (about 3). At pH 7.4 the net charge is about -2 and the estimated isoelectric point is around 3.2, unpublished. An anionic molecule is repelled by the anionic silanols of a glass cartridge, and a single methyl group gives it almost no drive toward elastomer or polypropylene. A 333 Da tripeptide carrying three carboxylates does not form fibrils, so particulate in this device would mean contamination or precipitated counter-ion, never aggregated peptide.

No approved product containing Ala-Glu-Asp exists anywhere to borrow a formulation from; in Russia the products of this class are oral capsules sold as dietary supplements, which says nothing about an injectable solution. No validated pH, buffer, preservative or in-use period exists for this molecule in any solution format.

What Is Known About Cartalax Solution Stability?

Nothing quantitative has been published on cartalax solution stability: a Crossref search in September 2026 found no forced-degradation, shelf-life or formulation study for Ala-Glu-Asp in any journal.

The only handling data in the literature is Caputi 2019 holding AED at 0.01 µg/ml in phosphate-buffered saline with medium replaced every 3 days, a culture schedule at a millionth of a pen fill’s concentration. The chemistry predicts slow loss cold and near neutral pH, faster loss in the unbuffered acid, but no rate constant exists for either, and cartalax degradation in solution has never been followed over the weeks a device stays in use.

One risk is independent of chemistry. Every approved multi-dose peptide pen contains phenol or metacresol, because a solution pierced repeatedly over weeks is exposed to microbes whatever its chemical stability. Whether this fill is preserved is not stated.

Concentration and Increment Arithmetic for the Cartalax Autoinjector

At 20mg in 3 ml the concentration is 20/3 mg/ml, and because the molecular weight is 333.30 g/mol that is almost exactly 20 millimolar: 1 mg in 3 ml is 1.00 mM, and 20 mg in 3 ml is 20.0 mM.

Each 0.01 ml step holds 20/300 mg of compound, so 0.1 ml holds 20/30 mg. At a 20 mg fill that is 66.7 µg per 0.01 ml, or 200 nanomoles, and 667 µg per 0.1 ml; at a 1 mg fill the smallest increment carries 3.33 µg, or 10 nanomoles.

The published work sits far below any of that. The Khavinson group’s systematic review gives 2-200 ng/ml as the effective culture window for this family, which for a 333 Da molecule is 6-600 nM, and Caputi 2019 used 0.01 µg/ml, which is 30 nM. Reaching 30 nM from a 20 mM fill takes a 667,000-fold dilution; from 1 mM, 33,000-fold. One increment of a 20 mg fill would make 6.67 litres of medium at Caputi’s concentration, so an actuation supplies an intermediate stock, never a working solution, and the serial dilutions that follow reintroduce every pipetting variable the pen was bought to remove.

Does Cartalax Come in a Pen?

Cartalax does come in a pen: this preloaded 3 ml autoinjector holds Ala-Glu-Asp in solution and sits alongside the lyophilized Cartalax vial in the PrymaLab catalogue, so the open question is which presentation an experiment needs, not whether the pen form exists.

The phrase “does cartalax come in a pen” arrives here mostly from people who have seen the vial and want a ready-to-use alternative. Fixed concentration at fill, the degradation clock starting at the fill line and the six fields to verify before ordering are covered on the preloaded autoinjector category page. What is specific to cartalax in pen form is that the one thing that cannot be inspected, the fill pH, is the one thing that controls its loss rate.

Cartalax Pen vs Vial: Which Presentation Suits the Tripeptide?

The cartalax pen vs vial decision turns on one fact: Ala-Glu-Asp is so soluble and so resistant to adsorption that reconstituting the vial is unusually forgiving, which removes the pen’s main advantage for difficult peptides and leaves consistency across sessions as its remaining case.

The pen suits work that draws from one lot repeatedly over weeks and needs each draw to match the last, such as a dose-response series prepared from one stock on six separate days. Weighing a small hygroscopic acetate salt is where most vial error lives for a 333 Da molecule, and the pen removes the balance from the procedure.

It does not suit work that must choose its own conditions. The fill pH is fixed and unpublished, so a study that needs the tripeptide at pH 7.4 in a defined buffer, or as the free acid, or above the fill concentration, starts from powder; cartalax solution vs lyophilized is a solution of unknown age against a powder whose clock starts when water is added. The peptide pen versus vial article covers the trade-offs common to every compound in this format; for this tripeptide the cartalax autoinjector vs vial question is less about stability than about whether a fixed, unpublished pH suits the assay in hand.

What the Product Record Does Not State

Five values are missing from the record for this preloaded Cartalax pen, and for a tripeptide whose loss rate is set by acidity, the first matters more than the other four together.

Solution pH is not stated. The unbuffered free acid sits near pH 3, buffered fills of short peptides sit anywhere from 4 to 7, and the Glu-Asp cleavage rate differs by orders of magnitude across that range. A pH meter and 50 µl settle the question in a minute; make that measurement on receipt.

The excipient system is not stated; buffer, tonicity agent and any preservative enter the assay with the peptide. The salt form is not stated; trifluoroacetate is not inert in cell culture at the concentrations a 20 mM stock carries. The fill date and the stability over shelf life are not stated. Ask for the first; nobody has the second.

Verifying the Cartalax Pen Before Use and Confirming the Contents

Inspect the solution before each draw against a dark background: it should be clear, colourless and free of particulate, and because a 333 Da tripeptide with three carboxylates does not aggregate, anything visible is contamination, precipitated counter-ion or excipient rather than peptide.

Let the cartridge reach room temperature before actuating, since a refrigerated solution is more viscous and a spring-driven pen delivers by displacement, and check delivered volume gravimetrically on the first day across several actuations; the actuation-to-actuation spread is the number that matters.

Confirming the contents is easier for this molecule than for most, with one exception. Ultraviolet absorbance at 280 nm is useless: with no tryptophan or tyrosine the peptide has no absorbance there, so detection must use the peptide bond at 205-215 nm, in practice reversed-phase HPLC at 214 nm, or mass spectrometry.

Mass spectrometry sees everything. The intact tripeptide gives a protonated ion near 334 Da (monoisotopic mass 333.117 Da); cyclo(Ala-Glu) appears near 201 Da, the Ala-Glu dipeptide near 219 Da and free aspartic acid near 134 Da. There is no mass-silent product to miss, no fibril for thioflavin T to bind and no aromatic ring for a 280 nm scan to excite. A same-day solution from the lyophilized vial run on the same column is the comparator, and the ratio of the 334 Da peak areas gives the fraction still intact.

Cartalax Pen Storage and Handling in the Laboratory

Cartalax pen storage is 2-8°C, protected from light and never frozen, with the device returned to the refrigerator between sessions, because warmth drives the hydrolysis described above and freezing threatens the cartridge and plunger rather than the tripeptide.

Light is the least of this molecule’s concerns: with no chromophore above roughly 220 nm, photodegradation is not available to it, and the protect-from-light instruction guards against lamp heat and excipient photochemistry. Temperature is the variable that matters, because diketopiperazine closure and Glu-Asp cleavage both accelerate with heat.

Freezing is prohibited for the device, not the peptide. A triacidic tripeptide survives freeze-thaw without aggregating, but 3 ml of solution expanding inside a glass cartridge sealed by an elastomer plunger cracks glass and displaces plungers, so keep the device away from the cooling element. Record fill date if supplied, date of first actuation, volume drawn at each session and any excursion outside 2-8°C; no in-use period has been established by anyone, so refrigeration history is the only substitute for stability data. The peptide storage and stability guide covers the general principles.

One downstream point is specific to a triacidic peptide: adding a 20 mM stock to weakly buffered medium at 1:100 brings 200 µM of carboxylate into the medium, enough to shift the pH of a bicarbonate-buffered culture measurably, so check medium pH after addition rather than assuming it.

What Does the Cartalax Literature Actually Report?

Every peer-reviewed data point on Ala-Glu-Asp comes from kidney tissue, skin fibroblasts or stem-cell cultures, none from cartilage and none from a human, which is the reverse of what the product positioning would lead a reader to expect.

“T-31 (AED)” appears in a 2015 abstract from the Khavinson group; the trade name Cartalax appears in no peer-reviewed abstract reachable through Crossref, so the identification rests on the institute’s product literature and secondary sources. The T-31 background article covers that history.

Chalisova and colleagues (2015) grew organotypic kidney cultures from young and old rats; T-31 raised Ki-67 and lowered p53, less strongly than the whole kidney polypeptide complex it derives from. Lin’kova and colleagues (2016) found that KE, KED, AED and AEDG all suppressed MMP-9 and raised Ki-67 and CD98hc in ageing human skin fibroblasts, and that AED and AEDG suppressed caspase-dependent apoptosis. Caputi and colleagues (2019) treated human periodontal-ligament stem cells at 0.01 µg/ml; the significant GAP43 and nestin increases were for KED and the mixture, not AED alone. Ashapkin and colleagues (2020) reported IGF1 up 3.5-5.6-fold and TERT up to 8-fold at nanomolar concentration in an ageing FetMSC line.

The single in vivo study is Zamorskii and colleagues (2019): old rats received a kidney polypeptide complex or one of AED, EDL or AEDG, and AED and EDL raised diuresis 1.2-1.4-fold, reduced urinary protein, improved sodium handling and raised antioxidant enzyme activity, with no nephrotoxicity reported. Route and dose are not in the abstract, and Khavinson is a co-author here as on the Italian and Moscow papers.

No receptor has been identified. Docking assigned AED to an “acct” DNA tetranucleotide (Khavinson 2016) and scored it at -28.14 kcal/mol against the LAT1 transporter (Khavinson 2023); no binding constant has been measured. No pharmacokinetic study, no chondrocyte or joint model, no injectable route, no toxicology and no replication outside the institute exist, and the institute’s own 2014 review of clinical results for peptide bioregulators covers seven other preparations and omits Cartalax. The bioregulator research overview sets this record beside the better-studied members of the family.

What Is the Safety and Regulatory Position?

No safety study of Ala-Glu-Asp exists in any species, and no regulator has approved a product containing it: not the FDA, EMA, PMDA, TGA or Health Canada, and the compound is absent from the FDA Orange Book.

In Russia the products of this class are marketed as dietary supplements rather than medicines, a status not verified against the Russian register. The compound is not on the FDA section 503A bulk-substance list nor the Category 1 or 2 lists (FDA page updated 22 April 2026), is not a component of any approved drug and has no USP monograph, so no lawful basis exists for compounding it in the United States. It is not named on the WADA Prohibited List as far as the dossier could establish; the 2026 list was not retrievable.

No adverse finding has been reported, because no study designed to find one has been run. Claims about cartilage, joints or lifespan have no study behind them for this sequence; the rodent lifespan work belongs to other Khavinson peptides such as AEDG and KE. Nothing in the published record describes what this reagent does after injection into anything.

Published Literature

The entries below concern the tripeptide Ala-Glu-Asp; nothing has been published on this delivery format.

1. Chalisova NI, Lin’kova NS, Nichik TE, et al. Bulletin of Experimental Biology and Medicine. 2015;159(1):124-127. DOI: 10.1007/s10517-015-2906-9
2. Lin’kova NS, Drobintseva AO, Orlova OA, et al. Bulletin of Experimental Biology and Medicine. 2016;161(1):175-178. DOI: 10.1007/s10517-016-3370-x
3. Khavinson VK, Lin’kova NS, Tarnovskaya SI. Bulletin of Experimental Biology and Medicine. 2016;162(2):288-292. DOI: 10.1007/s10517-016-3596-7
4. Caputi S, Trubiani O, Sinjari B, et al. International Journal of Immunopathology and Pharmacology. 2019;33:2058738419828613. DOI: 10.1177/2058738419828613
5. Ashapkin V, Khavinson V, Shilovsky G, et al. Molecular Biology Reports. 2020;47(6):4323-4329. DOI: 10.1007/s11033-020-05506-3
6. Zamorskii II, Shchudrova TS, Zeleniuk VG, et al. Advances in Gerontology. 2019;9(1):75-80. DOI: 10.1134/S207905701901017X
7. Khavinson VK, Popovich IG, Linkova NS, et al. Molecules. 2021;26(22):7053. DOI: 10.3390/molecules26227053. PMID: 34834147

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