Description

Poly(styrene sulfonate) | MW ~142,800 Da

Poly(styrene sulfonate) is a high-purity, anionic polyelectrolyte polymer characterized by excellent water solubility and a strong density of negative sulfonate charges polysciences.com. With an average molecular weight of ~142,800 Da, this polymer serves as a versatile excipient in pharmaceutical formulations for controlled-release drug delivery and ionic stabilization of active compounds.

Key Features:

• Defined Molecular Weight: Average Mw ≈142,800 Da for consistent polymer performance and predictable viscosity in formulations.
• Strong Anionic Polymer: High sulfonate functional group content provides a high cation exchange capacity, enabling strong ionic binding with positively charged molecules (e.g., amines and metal cations).
• Water-Soluble & pH-Stable: Readily dissolves in aqueous systems; as a sulfonated polymer, its charge remains dissociated across a broad pH range (ensuring functionality independent of typical formulation pH).
• Pharmaceutical-Grade Purity: Produced with low residual monomers and solvents, suitable for sensitive applications. Each batch is quality-checked to meet compendial standards (e.g., USP for sodium polystyrene sulfonate) and high purity specifications.
• Biocompatible Excipient: Non-cytotoxic and biocompatible as demonstrated by decades of medical use (e.g., oral cation-exchange resins since 1958, making it suitable for internal use in drug delivery systems.

Applications:

Poly(styrene sulfonate) finds wide application in pharmaceutical formulation science, particularly where ionic interactions are leveraged. In controlled-release oral dosage forms (such as tablets, capsules, or suspensions), this polymer can bind cationic active pharmaceutical ingredients (APIs) and modulate their release profile via ion-exchange mechanisms. For example, ion-exchange resins of polystyrene sulfonate are used clinically to bind potassium ions in the gastrointestinal tract (treatment of hyperkalemia), illustrating the polymer’s high capacity to sequester cations. Formulators also incorporate polystyrene sulfonate into microencapsulated or nanoparticle delivery systems: the polyanion can form polyelectrolyte complexes or coatings that stabilize drug-loaded particles and prevent aggregation, thereby improving dispersion stability. This approach has been shown to prolong drug release – e.g. PSS-based nanomedicine complexes significantly extended the release duration of a model drug. In ophthalmic and mucosal delivery, crosslinked polystyrene sulfonate particles have been used as carriers to achieve sustained release and enhanced local bioavailability of therapeutic agents. Notably, a recent study validated a 3 μm sodium polystyrene sulfonate resin as a safe ocular drug carrier that doubled the retention and exposure of a cationic drug in eye tissue demonstrating the polymer’s value in advanced drug delivery systems. Additionally, polystyrene sulfonate’s strong ionic binding is being explored for drug stabilization, for instance by forming reversible complexes with sensitive cationic drugs to protect them from precipitation or degradation, releasing the drug in a controlled manner. Its broad utility is further evidenced by uses in technical fields (outside pharma) as an ion-exchange medium to remove unwanted ions from solutions—the same fundamental property that formulators harness to create novel pharmaceutical delivery mechanisms.

Detailed Description:

Chemically, poly(styrene sulfonate) is a sulfonated aromatic polymer derived from polystyrene, typically supplied in the sodium salt form (Poly(sodium 4-styrenesulfonate)) for ease of handling and solubility. Each repeating styrene unit carries a sulfonate group, imparting a permanent negative charge along the polymer backbone. This high charge density translates to a strong affinity for oppositely charged species and a high ion-exchange capacity. In practical terms, the polymer can bind and exchange ions readily: for instance, it can sequester metal cations like K^+, Ca^2+, or Na^+ from solution, or form ionic complexes with organic cations (such as protonated drug molecules). These properties underlie its functionality in pharmaceutical systems – acting as an ion–exchange excipient that can retain and slowly liberate an active drug. Because the sulfonate groups are strong acids (pK_a < 1), the polymer remains fully ionized in typical formulation pH ranges, ensuring consistent performance without relying on pH-triggered solubility. The moderate molecular weight (~142k Da) of this grade offers a balance between high binding capacity and manageable viscosity: it dissolves to form clear, stable solutions or gels, but is still large enough to be non-absorbable in the GI tract (if used orally, it passes through the gut unabsorbed, like other ion-exchange resins).

From a formulation perspective, poly(styrene sulfonate) is used to enhance the stability and delivery of cationic drugs. It can be blended into tablet matrices or bead formulations where drug-polyelectrolyte interactions slow down dissolution. In suspensions (oral or ophthalmic), it may be employed as a functional suspending agent that not only provides physical stability but also chemically binds APIs to prevent rapid release. The polymer’s ability to form multilayer polyelectrolyte films is also harnessed in novel drug coatings and implants, where alternating layers of PSS and oppositely charged polymers create a controlled barrier to drug diffusion. For example, polyelectrolyte multilayer coatings using PSS have been investigated to modulate membrane permeability and drug release rates. Moreover, its use as a drug carrier in controlled-release systems is well documented– it is considered a biocompatible additive that can improve the therapeutic index of drugs by releasing them more gradually and by localizing their action (as evidenced by improved ocular drug AUC in PSS-based eye drops. Because poly(styrene sulfonate) itself is non-toxic and not absorbed systemically (due to its polymeric nature), it has a favorable safety profile in the contexts where it’s used; in fact, pharmaceutical-grade sodium polystyrene sulfonate has been in therapeutic use for decades, underscoring its acceptability to regulatory bodies.

CarboMer offers poly(styrene sulfonate) as a reliable supplier for pharmaceutical and biotech needs, with this polymer available for purchase in both research and commercial quantities. B2B customers looking to buy high-quality poly(styrene sulfonate) will benefit from CarboMer’s manufacturing consistency and technical support. Our production process yields a consistently sulfonated polymer (with lot-to-lot uniformity in molecular weight distribution and functionality), allowing formulation scientists to confidently integrate the material without unexpected variability. The product is provided as a free-flowing powder (sodium salt form) that is readily soluble in water, simplifying its incorporation into various formulation processes (e.g., it can be dissolved for solution blending or dispersed for wet granulation). Whether used in developing a new controlled-release oral drug, a novel ophthalmic therapy, or a bioadhesive gel, poly(styrene sulfonate) from CarboMer delivers dependable performance aligned with the high standards of the pharmaceutical industry.

Regulatory & Quality Assurance:
Poly(styrene sulfonate) (Mw ~142,800) is manufactured under strict Good Manufacturing Practice (GMP) conditions in CarboMer’s certified facilities. Each batch undergoes comprehensive quality control to ensure it meets predefined specifications for purity, identity, and performance. The material can be provided with a Certificate of Analysis (CoA) for each lot, detailing all relevant quality attributes (e.g. assay of sulfonation, moisture content, residual solvents, heavy metals) to support your regulatory filings. The polymer conforms to relevant pharmacopeial standards where applicable (for instance, the sodium form aligns with the USP monograph for Sodium Polystyrene Sulfonate in terms of identity and functional assay). Full documentation is available, including an updated Safety Data Sheet and technical data sheet. For drug product developers, CarboMer can support regulatory submissions by providing a Technical Data Package reference upon request, ensuring you have the necessary data on sourcing, characterization, and impurity profiles. Our quality system emphasizes batch-to-batch consistency and traceability – every lot is identified and traceable back to raw material inputs and process parameters, which is critical for reproducibility in formulation development and commercialization. We also maintain GMP-certified quality management processes, reflecting our commitment to excellence and compliance.

Packaging & Availability:

CarboMer supplies poly(styrene sulfonate) in secure, pharma-grade packaging suitable for both laboratory and production environments. The product is typically shipped as a dry powder in airtight containers to protect it from moisture uptake. Standard pack sizes include small bottles (e.g., 10 g, 50 g, 100 g) for R&D use, as well as larger quantities (1 kg and above) for scale-up and manufacturing. We offer flexible order sizes accommodating projects from early development through commercial scale. Bulk packaging options are available for high-volume needs, and custom packaging can be arranged to suit specific requirements. Our logistics team ensures prompt shipment and can provide estimated lead times upfront (most standard quantities are ready to ship quickly, while bulk orders are fulfilled with minimal lead time thanks to our efficient production capabilities).