HPBCD 2-Hydroxypropyl-beta-Cyclodextrin CAS 128446-35-5 Water Soluble Powder HP-β-CD

2-Hydroxypropyl-β-cyclodextrin (HP-β-CD / HPBCD), CAS 128446-35-5

Medical grade solubilizing excipient · Freely water soluble · Ph. Eur. / USP-NF compliant

1. Product Introduction

2-Hydroxypropyl-β-cyclodextrin (abbreviated HP-β-CD, HPBCD, or hydroxypropyl betadex) is a hydroxyalkylated derivative of β-cyclodextrin, produced by etherifying the hydroxyl groups of β-cyclodextrin with propylene oxide. The introduction of hydroxypropyl groups breaks the intramolecular hydrogen-bond network of native β-cyclodextrin, converting the crystalline, poorly soluble parent molecule into an amorphous, freely water-soluble material.

Native β-cyclodextrin dissolves to only about 18.5 g/L at 25 °C and is limited by nephrotoxicity concerns in parenteral use. HP-β-CD dissolves to more than 600 g/L at 25 °C, is well tolerated by the oral, parenteral, ophthalmic, nasal and topical routes, and holds a well-established safety profile supported by the Ph. Eur. and USP-NF monographs. Its amphiphilic cavity encapsulates poorly soluble molecules through host–guest inclusion complexation, and the hydroxypropyl shell keeps the complex in true solution.

Our HP-β-CD is manufactured under controlled etherification and multi-stage purification, then spray-dried into a white to off-white, free-flowing amorphous powder with a consistent degree of substitution (DS) from batch to batch. Every lot is released against a full specification covering assay, DS, water content, pH, related substances, heavy metals, residual solvents and microbial limits, and is supplied with a batch-specific Certificate of Analysis.

Typical dosage levels in finished formulations range from 5% to 40% w/w depending on the solubility gap that must be closed and the route of administration. HP-β-CD is the preferred choice when the target molecule is poorly soluble in water, when a clear aqueous concentrate is required, or when a parenteral or ophthalmic presentation must be developed without organic co-solvents.

2. Physical and Chemical Specification

Custom specifications — including pH range, DS window, residual propylene glycol, endotoxin and parenteral grade — can be developed against your dossier requirements.

3. Product Functions

• Solubility enhancement. Forms water-soluble host–guest inclusion complexes with poorly soluble actives, lifting apparent aqueous solubility by one to three orders of magnitude and delivering optically clear solutions instead of suspensions.
• Bioavailability improvement. By presenting the molecule in dissolved form at the absorption site, HP-β-CD raises the dissolution rate and the fraction absorbed of BCS Class II and Class IV compounds, often allowing dose reduction.
• Stabilization. The cyclodextrin cavity shields the guest from hydrolysis, oxidation, photodegradation, heat and metal-catalysed degradation, extending shelf life of labile vitamins, oils and volatile flavours.
• Taste and odour masking. Bitter, astringent or fishy notes are hidden inside the cavity, which is critical for chewables, sachets, effervescents and oral liquids.
• Irritation reduction. Encapsulation lowers the free concentration of aggressive molecules at the tissue surface, reducing gastric irritation and injection-site pain.
• Volatility and sublimation control. Prevents loss of volatile actives and flavour components during drying, tabletting and storage.
• Wettability and dispersibility. Improves powder wetting, dispersibility and content uniformity in dry blends, granulations and direct compression.
• Lyo- and cryo-protection. Acts as an amorphous bulking and stabilizing agent during freeze-drying and spray-drying of peptides, proteins and nano-suspensions.
• Compatibility and anti-aggregation. Reduces adsorption to container surfaces and prevents recrystallization or particle aggregation in liquid formulations.
• Release modulation. Adjusting the DS and the cyclodextrin ratio allows tuning of dissolution and release profiles.

4. Application Areas

5. Manufacturing Process

1. Raw material selection. β-Cyclodextrin (CAS 7585-39-9) is released against an incoming specification for assay, loss on drying and heavy metals.  
2. Alkaline dissolution. β-Cyclodextrin is dissolved in dilute sodium hydroxide solution to form a clear alkaline liquor, then filtered and cooled under nitrogen.
3. Hydroxypropylation. Propylene oxide is dosed into the liquor at a controlled rate and temperature in a pressure reactor. The molar ratio of propylene oxide to β-cyclodextrin is fixed per grade and is the key control lever for the target degree of substitution.
4. Neutralization. The reaction mass is cooled and neutralized with hydrochloric acid to pH 6–7, giving a crude hydroxypropyl betadex solution.
5. Decolourization and clarification. Activated carbon treatment followed by fine filtration removes colour bodies, unreacted residues and particulate matter.
6. Purification and desalting. Ion-exchange resin, ultrafiltration and nanofiltration remove sodium chloride, free propylene glycol, residual β-cyclodextrin and low-molecular-weight by-products, and concentrate the purified liquor.
7. Drying. The purified liquor is spray-dried (or freeze-dried for special grades) into an amorphous, free-flowing white powder, which is the physical form required for maximum complexation performance.
8. Milling and sieving. The powder is milled and classified to the agreed particle-size window.
9. Quality release. Each lot is tested for assay, DS, water content, pH, related substances, heavy metals, microbial limits and residual solvents; the batch is released only when the full specification is met.
10. Packing. Packed in a clean, controlled area into double polyethylene-lined bags with batch number, production date and expiry date; retained samples are archived for the full shelf life.

6. Why Choose Us

• Direct manufacturer. Cyclodextrin production is our core business, not a traded item, so we control the etherification and purification steps that determine DS consistency and solubility performance.
• Batch-to-batch consistency. DS, pH, water content and particle size are held inside tight windows, so your formulation performs the same from pilot batch to commercial scale.
• Complete documentation. COA, TDS, MSDS, specification sheet, residual solvent statement, heavy metal and microbial data, allergen and GMO statements, plus ISO 9001, Halal and Kosher certificates are available for your registration file.
• Custom grades. Adjustable DS, particle size, bulk density, pH and purity; low-endotoxin and parenteral grades are available on request.
• Formulation support. Our technical team advises on cyclodextrin ratio, complexation routes (kneading, co-precipitation, spray-drying, hot-melt extrusion) and analytical verification of complex formation.
• Fast sampling. Small trial quantities are shipped within 3–5 working days so your feasibility study is never delayed.
• Scale and continuity. Multi-ton monthly capacity, stable raw material contracts and safety stock let us support both pilot and long-term commercial demand.
• Export experience. Documented shipments to North America, Europe, Southeast Asia, the Middle East and Latin America, with packaging and labelling prepared for smooth customs clearance.

7. FAQ

Q1. What is 2-Hydroxypropyl-β-cyclodextrin used for?

It is a solubilizing and stabilizing excipient. It dissolves poorly water-soluble actives into clear aqueous solutions, improves bioavailability, protects sensitive molecules from degradation and masks bitter or unpleasant taste.

Q2. How does HP-β-CD differ from native β-cyclodextrin?

Native β-cyclodextrin is crystalline and dissolves to only about 18.5 g/L, and its parenteral use is restricted by renal tolerance. Hydroxypropylation makes the molecule amorphous and freely soluble (> 600 g/L), markedly better tolerated systemically and far more effective at keeping a complex in solution.

Q3. Is your HP-β-CD suitable for medical and food use?

Yes. Our standard grade is produced to the Ph. Eur. / USP-NF hydroxypropyl betadex monograph and is supplied with full analytical documentation. For food and dietary supplement applications, please confirm the regulatory status in your target market; we provide the supporting statements your dossier needs.

Q4. What degree of substitution can you supply?

Our standard grade is DS 4.5–7.0, within the compendial range of 4.0–9.0. Other DS windows can be produced to order, which is useful when you need to tune solubility, complexation efficiency or viscosity.

Q5. What is the recommended dosage in a formulation?

Typical use levels are 5%–40% w/w of the finished formulation, set by the molar ratio needed to solubilize the active. We can recommend a starting ratio once you share the active, its solubility and the target concentration.

Q6. Can I get a sample before ordering?

Yes. Samples of 100 g to 1 kg are available for feasibility and validation work, normally dispatched within 3–5 working days with the COA of the same batch.

Q7. What is your MOQ and lead time?

MOQ is 25 kg for standard grades. Stock items ship in 3–5 working days; bulk production orders are typically ready in 15–20 days after confirmation.

Q8. How is the product packed and shipped?

25 kg net in kraft paper bags with double food-grade PE liner, or 1 kg / 5 kg aluminium foil bags in cartons for small lots. Packaging is palletized, shrink-wrapped and moisture-protected for sea or air freight.

Q9. How should I store it and how long does it keep?

Store in a cool, dry, ventilated area, sealed and protected from light and moisture. Shelf life is 24 months in unopened original packaging; reseal opened bags and use them promptly.

Q10. Can you support custom specification or OEM supply?

Yes. We routinely develop custom specifications, custom particle sizes and private-label packaging. Send us your target specification and we will respond with a feasibility assessment and quotation.