Cardarine (GW501516)

1 Identity

Non-peptide small molecules. CAS 317318-70-0. CAS 317318-84-6 is GW0742, a different compound.

Sequence

No defined sequence. Not A peptide: no residues, no termini, no counterion in the peptide sense, no net peptide content. The article is the small molecule {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]-2-methylphenoxy}acetic acid, given in one reagent catalog as 2-[2-methyl-4-[[[4-methyl-2-[4-(trifluoromethyl)phenyl]-5-thiazolyl]methyl]thio]phenoxy]acetic acid. A thiazole-bearing phenoxyacetic acid, achiral, supplied as the free acid. It contains two sulfur atoms in chemically distinct environments — a benzylic thioether and the thiazole ring sulfur — and it is the thioether that governs the impurity profile. It is not a peptide and must not be classified as one.

Molecular formula

C21H18F3NO3S2

Average mass

453.494 Da (C21H18F3NO3S2) on IUPAC 2021 conventional atomic weights. Two reagent catalogs print the figure as 453.5 and as 453.50, and 453.49 also circulates; all are roundings of 453.494.

Monoisotopic mass

453.0680 Da neutral. Working ions: [M-H]- m/z 452.0607, [M+H]+ m/z 454.0753. As a carboxylic acid it is normally run in negative electrospray, and the certificate must state the ionization mode — the two ions are 2.01 m/z apart, and a mode-unstated mass on this molecule is ambiguous by more than the sulfoxide-to-GW0742 gap it is supposed to resolve.

Salt / variant note

A single parent molecule commercially, with one close structural analogue and two mass-shifted oxidation products that a thioether-bearing compound will generate on the shelf. (1) GW0742, CAS 317318-84-6, C21H17F4NO3S2, 471.49 avg / 471.0586 mono — the fluorinated congener from the same GlaxoSmithKline series, carried by three independent reagent catalogs, +18.0 Da and routinely shelved beside it. (2) the benzylic sulfoxide, C21H18F3NO4S2, 469.49 avg / 469.0629 mono, +16.0 Da — the first oxidation product and the predictable storage degradant. (3) the sulfone, C21H18F3NO5S2, 485.49 avg / 485.0578 mono, +32.0 Da. Note the trap: the sulfoxide at 469.49 and GW0742 at 471.49 sit 2 Da apart, so low-resolution mass alone will not separate an oxidized lot from a mis-shipped analogue, and the two failures have entirely different causes. (4) The sodium salt of the carboxylic acid, +21.98 Da on the free acid. (5) consumer-channel presentations are additionally sold as capsules and as "10 mg/ml" solutions, where the article of commerce is a formulation and no purity figure on the neat compound is recoverable at all.

2 Class & testing panel

Form

Single article

Testing panel

P6 — panel definition

3 Primary sources & evidence

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

Rodent and in-vitro literature including sponsor toxicology, together with a small number of early human pharmacology studies conducted before the program was terminated. The two-year rodent carcinogenicity work that preceded termination in 2007 is the central item in the record and is the reason the sponsor stopped. There is no completed controlled efficacy trial in humans, no approval anywhere, and no active development program by any sponsor. WADA issued a public notice concerning the compound in 2013, which is a regulatory communication rather than a study.

4 Storage & specification

Storage

Crystalline solid, 15 to 25 degrees C, desiccated, protected from light, container kept closed under an inert headspace because the benzylic thioether is oxidation-sensitive.

Shelf life

Provisional 36 months at 15 to 25 degrees C for a small-molecule solid. The interval is provisional because it rests on the class behavior of a crystalline small-molecule solid rather than on a completed dataset, and it is confirmed or shortened on this company's own stability data. The benzylic sulfoxide at 469.49 average / 469.0629 monoisotopic is the stability-indicating impurity that limits it.