Semaglutide Acetate

1 Identity

Acylated lipopeptide, isolated as an acetate salt. A counter-ion is not part of a molecular class and does not create one. The molecular entity is identical to the preceding record: a 31-residue GLP-1(7-37) backbone with Aib8 and Arg34, acylated on the Lys26 epsilon-amine through a gamma-Glu-AEEA-AEEA linker to octadecanedioic acid, free-acid C-terminal glycine, no cysteine, no disulfide, no sulfur. and under three separate sellers' own item numbers. AcOH' to the parent name. The same active moiety as the preceding record and the same CAS for the free acid, 910463-68-2, with the salt traded under its own catalog numbers rather than its own identity.

Sequence

The same molecule as the preceding record and not a distinct product: H-{Aib}EGTFTSDVSSYLEGQAAKEFIAWLVRGRG-OH, 31 residues, GLP-1(7-37) with Aib8 and Arg34, carrying Lys26-N(epsilon)-(AEEA-AEEA-gamma-Glu-C18 di-acid) and a free-acid C-terminal glycine, isolated as an acetate salt rather than the sodium form used in the approved drug substance. A counter-ion is not part of a sequence and does not change one; it changes net peptide content per unit mass and nothing else about the molecule, its acylation site or its degradation profile.

Molecular formula

C187H291N45O59 - XC2H4O2 — the notation the supplier itself uses for the article, with the stoichiometry left as X because it is a measured quantity and not a constant. Writing a fixed subscript in place of X is an assertion the supplier has not made and the buyer cannot check.

Average mass

4113.641 Da for the free acid (C187H291N45O59) on the IUPAC 2021 abridged table. The salt has no single average mass: it has a free-acid mass plus a measured counter-ion stoichiometry. At 1 mol acetate the formula weight is 4173.69 (acetate 1.44 percent w/w), at 2 mol 4233.75 (2.84 percent), at 3 mol 4293.80 (4.20 percent). The seller quotes 4113.6 against a formula containing X, which is the correct way to state it and the way this catalog states it.

Monoisotopic mass

4111.11538 Da free acid; [M+H]+ 4112.12265; [M+4H]4+ 1028.78612. Acetate is not carried on the peptide molecular ion under standard electrospray conditions, so the mass spectrum of an acetate lot, a trifluoroacetate lot and a sodium lot look the same — which is exactly why the counter-ion is established by ion chromatography or 19F NMR and never inferred from MS. Reporting a monoisotopic mass for the salt would be reporting a formula unit that no instrument observes.

Salt / variant note

On this record the substitution vector is the product name itself, and what makes the merge defensible rather than merely tidy is that the salt IS separately traded. One reagent catalog alone sells four counter-ion articles under the one name at four different prices: free acid; acetate; trifluoroacetate, written C187H291N45O59 - XCF3COOH; and the sodium salt, listed through a European channel. A second seller likewise splits semaglutide, the acetate, the trifluoroacetate and the sodium salt across four item numbers, and a third splits the parent from a listing that appends '. AcOH' to the same name. So the counter-ion is a real commercial dimension carrying a 2.3-fold price spread at identical molecular identity, and it is still not a second molecule. Every confusable from the preceding record carries over undiluted, because a counter-ion changes none of them: des-acyl semaglutide C152H230N42O47, 3397.759 avg / 3395.68985 mono, a 715.88 Da shortfall that passes area-percent purity; the His7 alpha-amine positional isomer at identical mass to the last decimal, separable only by Lys-C or tryptic mapping; di-acylated species C222H352N48O71, 4829.523 avg; liraglutide C172H265N43O51, 3751.262 avg / 3748.94646 mono; the des-(7-13) impurity standard at a supplier-stated C156H246N38O45 / 3373.905 whose formula does not reconcile with the deletion its name implies. Salt arithmetic: 1 mol acetate 1.44 percent w/w, 2 mol 2.84 percent, 3 mol 4.20 percent; 1 mol trifluoroacetate 2.70 percent, 2 mol 5.25 percent, 3 mol 7.68 percent. A vial labeled acetate whose certificate reports a fluorine-bearing counter-ion is mislabeled, and 19F NMR settles it in one experiment.

2 Class & testing panel

Form

Single article

Testing panel

P2 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

No literature exists on 'semaglutide acetate' as a distinct article, and none should be expected: a counter-ion is not a subject of clinical investigation. The evidence base is that of the preceding record and attaches to the approved finished products. A duplicate citation index page is not built, because two pages of identical references presented as two products is itself a form of overstatement and inflates the apparent evidential weight of the catalog.

4 Storage & specification

Storage

The storage requirement of the preceding record applies unchanged: low-adsorption or siliconized vials, -20 degrees C plus or minus 5 degrees C, desiccated and protected from light, with the recovery check performed on the container-closure system in use. A counter-ion does not alter the adsorption behavior, the light sensitivity or the temperature requirement of the peptide it accompanies.

Shelf life

Dated on the same basis as the preceding record and limited by the same attributes, with counter-ion identity and stoichiometry confirmed by ion chromatography or 19F NMR at release, since net peptide content per unit mass moves with it. No second retest interval is created for a salt form of a molecule that already has one; that is how two expiry dates end up on one material.