ARA-290 Reconstitution: Water, mg/mL and Units

ARA-290 reconstitution: water per 5 and 10 mg vial, the concentration each gives, the most water that keeps a 4 or 8 mg trial dose in one syringe, and units.

Medibact Guides · Published 2026-10-17

Illustration: A clear glass vial with pale blue liquid on a white lab bench. — Illustration

ARA-290 turns the usual reconstitution question around. Most compounds on this site are read in micrograms, and the worry is whether a small amount is readable on the syringe; ARA-290's trial doses are whole milligrams — 1, 2, 4 and 8 mg — and the worry is whether one amount fits in the syringe at all. No ARA-290 product has a label, so no document states how much water goes in. What the record does hold is a registry entry that describes its placebo as a 1 mL injection, and a terminated trial whose reason for stopping says something about the drug's shelf life. This page reports both, works the 5 mg and 10 mg vials at each water volume, and sets out the limits the milligram doses impose (all sources opened 2026-10-17). It reports; it suggests no dose.

The dose record itself — the four trials, their results and how many days a vial lasts at each figure — is on the ARA-290 dosage page. Any other vial and volume is worked by the ARA-290 calculator; the index of every compound is the reconstitution hub.

What the record says about the formulation

Source	What it states
NCT02039687 (Araim, phase 2, 64 enrolled, completed 2015-02)	1, 4 or 8 mg subcutaneously for 28 days; placebo is "formulation buffer", given as "1 mL placebo"
NCT01933529 (Karolinska investigator, phase 2)	"ARA 290, 4.0 mg, injected subcutaneously once every morning during 28 days"
NCT06626971 (Belfast, 9 enrolled, terminated)	4 mg subcutaneously daily for 84 days; stopped for "Expiry of study drug - no replacement available"
NCT02070783 (Leiden, phase 1/2)	2 mg intravenously once; placebo is 0.9% saline
PubChem CID 91810664	C51H84N16O21, 1,257.3 g/mol; N-terminal pyroglutamate

Two points come out of it. First, the trial product was a prepared formulation in a buffer, not a powder mixed by the participant, and no record names the buffer. Second, the dose-ranging trial's placebo was 1 mL. A blinded placebo is normally given in the same volume as the active doses, which would put the 1, 4 and 8 mg arms at 1, 4 and 8 mg/mL — this site's inference from the placebo line, not a stated figure. The subcutaneous trial products were therefore fixed-volume injections at different strengths; a research vial reverses that, with one fixed strength and a volume that changes with the amount.

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Water per vial and the concentration it gives

Vial	Water	Concentration	mcg per U-100 unit
5 mg	1 mL	5 mg/mL	50
5 mg	1.25 mL	4 mg/mL	40
5 mg	2 mL	2.5 mg/mL	25
5 mg	3 mL	1.67 mg/mL	16.7
10 mg	1 mL	10 mg/mL	100
10 mg	1.25 mL	8 mg/mL	80
10 mg	2 mL	5 mg/mL	50
10 mg	2.5 mL	4 mg/mL	40
10 mg	3 mL	3.33 mg/mL	33.3

On a U-100 syringe, 100 units is 1 mL. The 4 mg/mL and 8 mg/mL rows are the concentrations at which the registry's 4 mg and 8 mg arms would read as 100 units — the volume of the trial's placebo.

The trial amounts in syringe units

Concentration	1 mg	2 mg	4 mg	8 mg
10 mg/mL (10 mg in 1 mL)	10 units	20	40	80
8 mg/mL (10 mg in 1.25 mL)	12.5	25	50	100
5 mg/mL (5 mg in 1 mL, 10 mg in 2 mL)	20	40	80	160, two draws
4 mg/mL (5 mg in 1.25 mL, 10 mg in 2.5 mL)	25	50	100	200, two draws
3.33 mg/mL (10 mg in 3 mL)	30	60	120, two draws	240
2.5 mg/mL (5 mg in 2 mL)	40	80	160, two draws	more than the vial
1.67 mg/mL (5 mg in 3 mL)	60	120, two draws	240	more than the vial

A 5 mg vial never holds the 8 mg figure, whatever the water. For every other combination, the rule is the opposite of the one that applies to microgram compounds: adding water spreads the same milligrams over more volume, so a 4 mg amount goes from 40 units to more than a syringe as the water rises from 1 to 3 mL.

The most water that keeps one amount in one syringe

Amount	5 mg vial	10 mg vial
1 mg	5 mL	10 mL
2 mg	2.5 mL	5 mL
4 mg	1.25 mL	2.5 mL
8 mg	not possible	1.25 mL

Formula: maximum water (mL) = vial mg ÷ amount mg × 1 mL, the volume at which one amount is exactly 100 units. These are ceilings for fitting a draw on one barrel, not suggestions; a 0.5 mL or 0.3 mL syringe holds 50 or 30 units, so its ceiling is half or less of each figure. The insulin syringe units page shows how each barrel size reads.

Amounts per vial and per course

Whatever the water, the powder sets the count: at 4 mg, a 5 mg vial holds one amount with 1 mg left and a 10 mg vial two with 2 mg left; at 1 mg, five and ten. The trial courses were large by research-vial standards:

Course in the registry	Total ARA-290	10 mg vials
1 mg a day, 28 days (NCT02039687, low arm)	28 mg	2.8
4 mg a day, 28 days (NCT02039687, NCT01933529)	112 mg	11.2
8 mg a day, 28 days (NCT02039687, high arm)	224 mg	22.4
4 mg a day, 84 days (NCT06626971)	336 mg	33.6
2 mg IV three times a week, 4 weeks (Heij 2012)	24 mg	2.4

Mixing and storage

No ARA-290 label describes mixing. The general procedure for a lyophilised peptide — water down the side of the vial, swirled rather than shaken, checked for clarity — is on Medibact's how to reconstitute peptides page and is not repeated here. The only shelf-life fact in the registry is indirect: the Belfast study, which needed 84 days of daily 4 mg doses per participant, ended because its supply of the manufactured drug expired and could not be replaced. What labels and manufacturers say about storing mixed peptides is on Medibact's how to store peptides page.

What this page does not do

It does not state or suggest an amount, a water volume or a course. The 1, 2, 4 and 8 mg figures are reported because registered trials used them; ARA-290 has no approval anywhere, and no trial was phase 3. The 1 mL formulation volume is an inference from a placebo description and is labelled as one. The arithmetic is exact for the inputs given and says nothing about whether any input is appropriate. Medibact's ARA-290 guide covers the compound. Product and dose decisions belong with a clinician.

Sources and dates

Opened 2026-10-17: ClinicalTrials.gov v2 API records NCT02039687, NCT02070783, NCT06626971 and NCT01933529 (arms, interventions, status, reason stopped, enrolment); PubChem CID 91810664 (formula, weight, IUPAC name); the PubMed count for ARA-290 or cibinetide in title or abstract (76 records). The publisher's full texts of the 2012–2015 trials did not open unattended and were not used. From this site's dosage page (opened 2026-09-21): the trial results and Heij 2012 (PMID 23168581). Concentration, unit and per-vial arithmetic by this site. Corrections go to the contact page.

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Medibact Guides facts

ARA-290 (cibinetide) is an 11-amino-acid peptide, C51H84N16O21, molecular weight 1,257.3, whose first residue is a pyroglutamate ring, the '5-oxopyrrolidine-2-carbonyl' in its PubChem name (CID 91810664, read 2026-10-17). No label for it exists anywhere, so no document sets a water volume.
The dose-ranging trial's registry entry gives 1, 4 or 8 mg subcutaneously for 28 days and describes the placebo arm as '1 mL placebo administered subcutaneously', with the placebo itself 'formulation buffer' (NCT02039687, Araim Pharmaceuticals, 64 enrolled, completed 2015-02; read 2026-10-17).
If the active arms matched that 1 mL volume, as a blinded placebo normally does, the three doses were given at 1, 4 and 8 mg/mL; that is this site's inference from the placebo description, not a figure the record states.
At 4 mg the most water that keeps one dose within a 100-unit U-100 syringe is 1.25 mL in a 5 mg vial and 2.5 mL in a 10 mg vial; at 8 mg it is 1.25 mL in a 10 mg vial, and a 5 mg vial cannot hold the amount at all (arithmetic by this site).
In 1, 2 and 3 mL of water a 5 mg vial gives 5, 2.5 and 1.67 mg/mL and a 10 mg vial 10, 5 and 3.33 mg/mL; 4 mg is then 80, 160 and 240 units from the 5 mg vial and 40, 80 and 120 units from the 10 mg vial (arithmetic by this site).
The Belfast diabetic macular oedema study (NCT06626971), 4 mg subcutaneously every day for 84 days, enrolled 9 people and was terminated with the reason 'Expiry of study drug - no replacement available' (registry, read 2026-10-17).
At 4 mg a day, the 28-day trials used 112 mg per participant and the 84-day Belfast protocol 336 mg, which is 11.2 and 33.6 ten-milligram vials (arithmetic by this site).

Frequently asked questions

How much water goes into a 10 mg ARA-290 vial?

No label sets it. The arithmetic: 1 mL gives 10 mg/mL, 2 mL gives 5 mg/mL and 2.5 mL gives 4 mg/mL. Because the trial doses are whole milligrams, volume works against readability here: above 2.5 mL a 4 mg amount no longer fits in one 100-unit syringe.

How many units is 4 mg of ARA-290?

It depends on the concentration: 40 units at 10 mg/mL, 80 at 5 mg/mL, 100 at 4 mg/mL and 120 at 3.33 mg/mL. From a 5 mg vial it is 80 units in 1 mL and 160 units in 2 mL, more than one syringe.

What concentration did the ARA-290 trials use?

No published abstract or registry entry states it. The dose-ranging trial's registry describes its placebo as 1 mL of formulation buffer given under the skin, which suggests (this site's inference) that each active dose was also 1 mL, so 1, 4 and 8 mg/mL. The intravenous studies gave 2 mg and state no volume.

How many ARA-290 doses are in a vial?

The water does not change the count. At the 4 mg trial figure, a 5 mg vial holds one dose with 1 mg left and a 10 mg vial two with 2 mg left. At 1 mg a day, five and ten; at 8 mg a 10 mg vial holds one.

How long does reconstituted ARA-290 keep?

No ARA-290 label exists to say. The one stability fact in the registry is the Belfast trial's: it stopped because the study drug, a manufactured product, reached its expiry with no replacement. Storage of mixed peptides in general is covered on Medibact's storage page.