Betadex Sulfobutyl Ether Sodium

Chemical Properties

β-Cyclodextrin, sulfobutyl ethers, sodium salts is a cyclic oligosaccharide containing seven D-(t)- glucopyranose units attached by α(1→4) glucoside bonds. Sulfobutylether b-cyclodextrin is an anionic bcyclodextrin derivative with a sodium sulfonate salt separated from the hydrophobic cavity by a butyl spacer group. The substituent is introduced at positions 2, 3, and 6 in at least one of the glucopyranose units in the cyclodextrin structure. Introducing the sulfobutylether (SBE) into b-cyclodextrin can produce materials with different degrees of substitution, theoretically from 1 to 21; the hepta-substituted preparation (SBE7-b-CD) is the cyclodextrin with the most desirable drug carrier properties. Sulfobutylether b-cyclodextrin occurs as a white amorphous powder.

Uses

β-Cyclodextrin with sulfobutyl ether groups and sodium ions substituted along the length of the molecule. β-Cyclodextrin is a cyclic oligosaccharide produced from starch via enzymatic conversion. β-Cyclodextrin is commonly used to produce HPLC columns allowing chiral enantiomers separation.

Uses

SBE- β –CD is a chemically modified cyclodextrin with a structure designed to optimize the solubility and stability of drugs.

Production Methods

Sulfobutylether β-cyclodextrin is prepared by alkylation of bcyclodextrin using 1,4-butane sultone under basic conditions. The degree of substitution in b-cyclodextrin is controlled by the stoichiometric ratio of β-cyclodextrin to sultone used in the process.

Pharmaceutical Applications

Cyclodextrins are crystalline, nonhygroscopic, cyclic oligosaccharides derived from starch (see Cyclodextrins). Sulfobutylether bcyclodextrin is an amorphous, anionic substituted b-cyclodextrin derivative; other substituted cyclodextrin derivatives are also available.
Sulfobutylether b-cyclodextrin can form noncovalent complexes with many types of compounds including small organic molecules, peptides, and proteins. It can also enhance their solubility and stability in water. The first application of sulfobutylether bcyclodextrin was in injectable preparations; it can also be used in oral solid and liquid dosage forms, and ophthalmic, inhalation, and intranasal formulations. Sulfobutylether bcyclodextrin can function as an osmotic agent and/or a solubilizer for controlled-release delivery, and has antimicrobial preservative properties when present at sufficient concentrations.
The amount of sulfobutylether β-cyclodextrin that may be used is dependent on the purpose for inclusion in the formulation, the route of administration, and the ability of the cyclodextrin to complex with the drug being delivered. The minimum amount required for solubilization is, in general, a cyclodextrin/drug molar ratio of approximately 1–5 (the exact ratio being experimentally determined from complexation data). The maximum use in a formulation may be limited by physicochemical constraints such as viscosity (e.g. syringeable concentrations may be considered up to 50% w/v), tonicity, or the total weight and size of solid dosage forms (e.g. less than a gram in an individual tablet). It may also be limited by pharmacokinetic/pharmacodynamic (PK/PD) considerations. As dilution of a cyclodextrin formulation leads to an increase in the amount of uncomplexed drug, formulations that are not diluted upon administration, such as ophthalmic formulations, are sensitive to cyclodextrin concentration. In formulations such as these, cyclodextrin concentrations greater than the minimum required for solubilization can reduce the availability of uncomplexed drug and thereby affect PK/PD expectations by producing effects such as slower onset, lower Cmax, and bioavailability.

Toxicity evaluation

Sulfobutylether b-cyclodextrin sodium (SBECD) has been associated with toxic effects in the kidney. Doses up to 1500 mg/kg produced no histopathological evidence of toxicity in dog kidneys.

Safety

Sulfobutylether b-cyclodextrin is derived from b-cyclodextrin, which is nephrotoxic when administered parenterally. However, studies have shown that sulfobutylether bcyclodextrin is well tolerated at high doses, when administered via intravenous bolus injections, orally, and by inhalation. Up to 9 g/day may be administered by IV infusion in a licensed voriconazole formulation. The safety following high doses of sulfobutylether β-cyclodextrin intravenous administration in humans is continually being investigated.
Sulfobutylether β-cyclodextrin has been subjected to an extensive battery of in vitro and in vivo genotoxicity and pharmacological evaluations. No genotoxic or mutagenic changes were observed with sulfobutylether β-cyclodextrin administration. Sulfobutylether β-cyclodextrin is biocompatible and exhibits no pharmacological activity. It is rapidly eliminated unmetabolized when administered intravenously.

storage

Sulfobutylether b-cyclodextrin(182410-00-0) is stable in the solid state and should be protected from high humidity. It should be stored in a tightly sealed container in a cool, dry place.
It will reversibly take up moisture without any effect on the appearance of the material at humidities up to 60% RH. Equilibration at RH values above 60% will result in deliquescence. Once in this state, the material can be dried, but will give a glasslike product. This water absorption behavior is typical of amorphous hygroscopic materials.
Sulfobutylether b-cyclodextrin is stable in aqueous solutions at values above about pH 1. It can degrade in highly acidic (pH < 1) solutions, particularly at elevated temperatures, producing the ring-opened form, followed by hydrolysis of the a(1-4) glucoside bonds.
Sulfobutylether b-cyclodextrin solutions may be autoclaved.

Incompatibilities

The preservative activity of benzalkonium chloride is reduced in the presence of sulfobutylether b-cyclodextrin.

Regulatory Status

Sulfobutylether β-cyclodextrin is included in IV and IM injectable products currently approved and marketed in the USA, Europe, and Japan. It is included in the FDA Inactive Ingredients Database for IM and IV use. Its use by other routes, including SC, oral, inhalation, nasal and ophthalmic, is being evaluated in clinical studies.