Pentosan Polysulfate Sodium (PPS)

1 Identity

Biological and semi-synthetic preparations of undefined composition. Not a peptide and not a small molecule: a semi-synthetic, polydisperse, sulfated polysaccharide made by chemically sulfating beechwood-derived xylan, supplied as the sodium salt. It contains no amino acids, no peptide bonds and no nitrogen at all. It has no single molecular formula and no single molecular weight; the literature describes a weight-average molecular weight of roughly 4,000-6,000 Da across a broad distribution with approximately 1.6-2.0 sulfate groups per xylose unit. and UNII F59P8B75R4 / 914032762Y. Approved products containing the moiety, which are not this article and are not interchangeable with it: Elmiron, pentosan polysulfate sodium capsules.

Sequence

No defined sequence, and none can exist. This is not a peptide: there are no amino acids and no peptide bonds. There is no sequence to state, no terminus to cap and no end-group to certify, and any document offering a sequence, an amino acid analysis, a net peptide content or an endotoxin figure calculated per peptide mass for this article is describing something else. What replaces a sequence, and what a genuine specification would state, is a molecular-weight distribution with its measurement method, a monosaccharide composition, and a degree of sulfation per sugar unit.

Molecular formula

Not established, and no single formula describes a lot. Structure databases index an IDEALIZED disaccharide-repeat representation, C10H18O21S4, which is a drawing convention for a repeating unit and not the composition of anything in the bottle. The xylose monomer is C5H10O5 at 150.130 average. Two reagent catalogs list the article and both leave molecular formula blank, recording "no data available"; that is the correct answer and this record gives the same one.

Average mass

Not established. The article is a distribution, not a compound. Two facts bound the question and neither is a molecular weight. First, the idealized repeat unit C10H18O21S4 computes to 602.473 average and 601.92234 monoisotopic on the IUPAC 2021 abridged table (S 32.06); 602.50 also circulates, which is that same formula on the pre-2021 table (S 32.065, C 12.0107, H 1.00794, O 15.9994) and returns 602.497 exactly. The basis sits on the face of the number, as it does on every mass in this catalog, and the figure remains a drawing convention either way. Second, the literature describes a weight-average molecular weight of roughly 4,000-6,000 Da across a broad distribution with about 1.6-2.0 sulfate groups per xylose unit; that Mw is a distribution parameter obtained by SEC-MALS and cannot be printed as a molecular weight. Sulfur content computed in-house from that substitution range works out at roughly 17.4-19.1 percent w/w.

Monoisotopic mass

None. A polydisperse polymer has no monoisotopic mass; the concept does not apply, and a certificate reporting one has run a small-molecule or peptide template against a polysaccharide. The 601.92234 figure above is the monoisotopic mass of an idealized repeat-unit formula, which is a number about a drawing and not about a lot.

Salt / variant note

Substitution risk is high and the arithmetic that detects it is elemental, not mass-spectral. (1) dextran sulfate sodium at 5 kDa nominal size is the closest and cheapest substitute: a commodity item, polydisperse in the same 4-6 kDa window, with a sulfur content near 17 percent w/w that is indistinguishable from this article's calculated 17.4-19.1 percent. It passes every size-exclusion and sulfur check a naive specification would run. What separates them is the SUGAR — pentosan polysulfate is a pentose (xylose, C5) polymer and dextran sulfate is a hexose (glucose, C6) polymer — so acid hydrolysis followed by monosaccharide compositional analysis is the discriminating test and nothing else will do it. (2) heparin sodium and (3) CHONDROITIN sulfate sodium are the next tier and are caught by one cheap number: both are amino-sugar polymers carrying roughly 2-3 percent w/w nitrogen, whereas this article contains NO nitrogen at all, so an elemental nitrogen determination reading materially above zero is a substituted lot. Heparin separates twice over, at a 15-19 kDa weight-average against this article's 4-6 kDa and at an anti-factor-Xa activity orders of magnitude higher. (4) unsulfated beechwood xylan is the under-sulfation failure rather than a deliberate swap: it is the starting material, costs a fraction of the product and contains essentially no sulfur. (5) registry and grade axes that are genuinely different articles under the same words: the free acid (CAS 37300-21-3) against the sodium salt (CAS 140207-93-8); the human drug substance behind NDA 020193 against the equine article; and, most practically, the assay basis — two reagent catalogs both ship this article at 43 percent w/w, meaning a stated 100 mg unit contains roughly 43 mg of polymer, so any content calculation that treats the unit mass as polymer mass is out by a factor of 2.3.

2 Class & testing panel

Form

Single article

Testing panel

P7 — panel definition

3 Primary sources & evidence

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

A substantial regulated-drug literature exists behind the approved oral product, including the controlled human trials that supported NDA 020193 and decades of post-approval pharmacovigilance, together with a large body of litigation-linked observational analysis generated since 2018 and a 2020 revision to the approved labeling. That literature belongs to a finished approved drug product studied by an oral route under an NDA, and it is not evidence about a research-grade bulk polymer of undeclared molecular-weight distribution and undeclared polymer content. What does not exist is a non-clinical research literature that a research-grade offering would serve: no meaningful in-vitro or animal research program was identified that depends on obtaining this material from a research supplier. Literature volume by study type is printed at the head of the research page so a reader sees which body of work is being pointed at.

4 Storage & specification

Storage

Hygroscopic amorphous sodium-salt powder at 15-25 degrees C in a tightly closed container with desiccant, protected from moisture.

Shelf life

No stability-derived retest interval is issued. The attribute that limits this article is its molecular-weight distribution rather than an assay value: depolymerization shifts Mw without changing any purity number, so the property that would have to be trended over time is the distribution itself, measured by SEC-MALS against a matched standard. Each container is dated from receipt, and moisture control is the practical limit on that date, because the powder is hygroscopic.