ARA-290 10mg Nasal Spray

ARA 290 nasal spray supplies cibinetide, the 11-residue peptide pGlu-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser at roughly 1257 daltons. Written either with or without the hyphen, the compound is a fragment of erythropoietin engineered to do the one thing the parent hormone is famous for not at all, which is an unusual design objective worth understanding.

Specification Table

Why Was ARA 290 Nasal Spray Designed to Lose an Activity?

Most peptide fragments are made to concentrate what the parent does. ARA 290 nasal spray was made to discard part of it, which is the reverse of the usual objective.

Erythropoietin is a 165-residue glycoprotein best known for driving red blood cell production. That activity is the reason it is a household name.

Work at Araim Pharmaceuticals identified that the tissue-protective signalling attributed to erythropoietin runs through a different receptor arrangement than the erythropoietic signalling does.

Erythropoietic activity is reported to require a homodimer of the erythropoietin receptor. The tissue-protective signalling is attributed to a heterodimer pairing that receptor with CD131.

Two different receptor assemblies reading the same hormone means the two activities can in principle be separated by a ligand that engages one and not the other.

This peptide is that ligand. Derived from the helix B surface domain, it is reported to engage the heterodimer while not driving erythropoiesis.

That separation is the entire point of the compound, and it makes the molecule interesting as a pharmacological tool independent of any application.

For an experiment the implication is direct. Comparing this fragment against intact erythropoietin is the design that tests the separation claim, and it is the comparison the compound exists to enable.

Why Does the Missing Chromophore Complicate Everything?

This compound contains no tryptophan, no tyrosine and no phenylalanine, which is unusual for an eleven-residue peptide and has a practical consequence.

The standard concentration measurement for a peptide is absorbance at 280 nanometres, which reads aromatic side chains. With none present, that method returns nothing usable.

Detection during chromatography has to run at 214 nanometres on the amide bond instead. That is less specific and more sensitive to mobile phase composition.

A certificate quoting 280 nanometre detection for this compound has a problem worth raising, since there is nothing at that wavelength to detect.

Concentration by ultraviolet absorbance is therefore unavailable, and quantification has to rest on amino acid analysis, gravimetry corrected for counterion and water, or a colorimetric total-peptide assay.

Each of those is more laborious than a spectrophotometer reading. That is why concentration figures for compounds like this one are worth scrutinising.

The upside is that the absence of aromatic residues removes the photodegradation and oxidation routes that dominate storage for the tryptophan-containing compounds in this range.

So the molecule trades easy measurement for genuine chemical stability, which is a reasonable trade for a product held in solution.

What Is the Asn-Ser Deamidation Risk?

The carboxy-terminal region carries a specific chemical liability that a purity figure will not report.

Asparagine at position 9 is followed immediately by serine, and asparagine followed by a small residue is the classic deamidation motif in peptide chemistry.

Deamidation converts asparagine to aspartate, adding one dalton and introducing a negative charge where there was none.

One dalton on a molecule of roughly 1257 is a shift a low-resolution instrument will not separate, so the reaction is silent on a nominal-mass report.

The reaction proceeds through a cyclic succinimide intermediate that can open to either aspartate or isoaspartate, and isoaspartate shifts the backbone by one carbon while leaving the mass identical to aspartate.

Mass spectrometry cannot distinguish those two at all, so even a high-resolution instrument reports only that deamidation occurred rather than which product formed.

Deamidation accelerates in aqueous solution and under alkaline conditions, which makes it the principal time-dependent concern for this product rather than oxidation.

Since the reaction adds a negative charge to a molecule already carrying three acidic residues, ion-exchange chromatography separates the products better than reversed-phase does, which is worth knowing before choosing a method.

How Does the Pyroglutamate Terminus Compare Here?

Three compounds in this batch open with pyroglutamate, and the residue does something slightly different in each context.

In the two GnRH compounds the pyroglutamate is part of the native hormone sequence, present because evolution put it there.

Here it appears at the amino terminus of a fragment cut out of a larger protein, where the parent had an ordinary glutamine or glutamate in a folded context.

Cyclisation blocks aminopeptidases in the same way regardless of origin, so the functional consequence is the same even though the provenance differs.

The verification consequence is also shared. An uncyclised preparation sits 17 daltons heavier, near 1274, and that check applies here exactly as it does for gonadorelin and triptorelin.

What differs is that this compound has a free carboxy terminus rather than an amide, so only one end is protected rather than both.

Carboxypeptidases therefore have an entry point here that they do not have on the GnRH compounds. The terminal serine is not a difficult residue for them.

In an aqueous product with no enzyme present that is irrelevant, but it matters for any experiment involving biological fluid or cell culture medium containing serum.

How Does 1257 Daltons Affect the Nasal Route?

ARA 290 nasal spray sits above the size range where transnasal transport works well, in company with several others in this catalogue.

Passage between epithelial cells stops being efficient somewhere near 1,000 daltons. That is the practical transition point.

At roughly 1257 daltons this compound is above that line, comparable to kisspeptin-10 at 1,302 and gonadorelin at 1,182.

Charge works in its favour relative to those two. Three acidic residues against one arginine give a net negative charge, and an anionic molecule is not held by a negatively charged mucosal surface the way a cation is.

That reduces mucoadhesion, which cuts both ways. Less binding means less retention at the surface as well as less obstruction to transit.

No aromatic residues means low hydrophobicity, which limits the transcellular route across the lipid membrane as an alternative to paracellular passage.

Published intranasal pharmacokinetic data for this compound is not established, and the published work used parenteral administration.

Anyone working by this route should measure delivered amount rather than infer it, which is the same conclusion that applies to every compound above the threshold here.

What Should an ARA 290 Nasal Spray Certificate Contain?

The panel here differs from the generic one in three places. Each follows from the chemistry above.

Measured mass against roughly 1257, with the resolution stated so that a one dalton deamidation shift would have been visible.

A specific check for a species near 1274, which indicates uncyclised glutamine at the amino terminus rather than the intended pyroglutamate.

Purity by chromatography with the detection wavelength stated. It must be 214 nanometres, since this compound has no aromatic residue and 280 nanometre detection sees nothing.

Sequence stated explicitly, since the compound circulates under both ARA-290 and cibinetide and neither name carries chemical information.

Counterion identity, reported beside net peptide content. At roughly 1257 daltons a single trifluoroacetate at 114 is roughly 9 percent of the associated mass, and this molecule has three acidic residues that can each carry one.

Water content by Karl Fischer where the material was supplied as a powder before formulation, since a hygroscopic peptide carries water that counts on the balance.

A CAS number is not stated on this page because none was traced to a primary source during preparation. A supplier quoting one should be asked for the registry entry rather than taken at their word.

How Should ARA 290 Nasal Spray Be Stored and Recorded?

ARA 290 nasal spray is among the more chemically stable products in this range, which narrows the storage requirements to one thing that matters.

Hold the bottle between 2 and 8 degrees Celsius, out of the light, and never freeze a solution-state product.

Light protection is a precaution here rather than a requirement, since there is no aromatic residue to photodegrade, which distinguishes this product from the tryptophan-containing sprays.

Deamidation at the Asn-Ser motif is the reaction that actually proceeds. It is pH dependent, accelerating under alkaline conditions.

A periodic pH check on an opened bottle is therefore more informative here than a visual inspection, since the degradation produces no visible change.

Because the failure mode is silent on both appearance and nominal mass, elapsed time in solution is the practical variable to control.

Date the bottle when opened and record that date alongside the lot, the stated concentration, the storage temperature and the actuation count.

Any study running past a few weeks should re-measure rather than assume, which is the only defensible approach with a silent degradation route.

Published Literature

Selected references verified against the publisher record.

1. (‘Brines M, Patel NS, Villa P, et al. Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin. Proc Natl Acad Sci USA. 2008;105(31):10925-10930.’, ‘https://doi.org/10.1073/pnas.0805594105’)
2. (‘Brines M, Cerami A. Erythropoietin-mediated tissue protection: reducing collateral damage from the primary injury response. J Intern Med. 2008;264(5):405-432.’, ‘https://doi.org/10.1111/j.1365-2796.2008.02024.x’)
3. (‘Brines M, Grasso G, Fiordaliso F, et al. Erythropoietin mediates tissue protection through an erythropoietin and common beta-subunit heteroreceptor. Proc Natl Acad Sci USA. 2004;101(41):14907-14912.’, ‘https://doi.org/10.1073/pnas.0406491101’)
4. (‘Robinson NE, Robinson AB. Molecular clocks. Proc Natl Acad Sci USA. 2001;98(3):944-949.’, ‘https://doi.org/10.1073/pnas.98.3.944’)

Frequently Asked Questions