Glutathione (liposomal)

The active in this listing is reduced L-glutathione (GSH), the tripeptide gamma-L-glutamyl-L-cysteinyl-glycine, C10H17N3O6S, molecular weight 307.3, CAS 70-18-8. Its unusual gamma-peptide bond — glutamate joined to cysteine through the side-chain carboxyl rather than the alpha-carboxyl — protects it from ordinary peptidases, and the free cysteine thiol is the functional centre of the GSH/GSSG couple that acts as the cell's principal low-molecular-weight redox buffer. What Thovek supplies here, though, is not the bare tripeptide. It is that tripeptide carried in the aqueous core of phosphatidylcholine bilayer vesicles, offered as a spray-dried powder and as a liquid concentrate. The plain crystalline material is a separate listing in this catalogue and is specified, priced and classified differently — buyers should not treat the two as interchangeable on a purchase order. Encapsulation exists because free oral glutathione is a difficult delivery problem. The systemic availability of orally administered glutathione is poor: the tripeptide is degraded in the gut lumen and there is no dedicated membrane transporter to carry the intact molecule across the enterocyte. A liposome puts a phospholipid bilayer between the peptide and that environment. The bilayer here is built from phosphatidylcholine-rich lecithin, and the choice of lecithin is a labelling decision as much as a technical one. Sunflower lecithin is Thovek's default because it carries no allergen declaration; soy lecithin is available, but soy is a listed allergen under EU Regulation 1169/2011 Annex II and under US FALCPA, so any soy-lecithin lot ships with a soy declaration and has to appear in the buyer's finished-label allergen statement. The powder is spray-dried onto a declared food carrier; the liquid is a glycerol and water dispersion. Two things drive handling. Glutathione is hygroscopic and its thiol oxidises to the disulphide GSSG on contact with air, moisture and warmth; the phospholipid shell is itself oxidisable, so peroxide value belongs on the specification alongside GSH assay. Material ships in foil-laminate barrier packing, nitrogen-flushed on request, and holds specification for 24 months at 2-8 °C. Origin is clean for most buyers: the glutathione is made by yeast fermentation on Saccharomyces cerevisiae or Candida utilis rather than by synthesis, so it is vegan and non-animal with no bovine, porcine, marine or egg input, and yeast-fermented glutathione is the subject of US FDA GRAS Notice GRN 293, filed by Kohjin Co., Ltd. and closed with a no-questions letter on 22 December 2009. Because the article as supplied is a preparation rather than a separate chemically defined compound, it classifies in chapter 21 rather than chapter 29 — India ITC-HS 21069099.