SBECD

Sulfobutyl ether beta-cyclodextrin (SBECD) is a modified cyclodextrin used as an excipient in pharmaceutical formulations. It is derived from beta-cyclodextrin by attaching sulfobutyl ether substituents to the glucose units, producing a highly water-soluble, anionic molecule. Commercial preparations are mixtures with varying degrees of substitution, rather than a single defined compound.

Chemistry and production: SBECD is typically formed by reacting beta-cyclodextrin with sulfobutane reagents such as 1,4-butane sultone to introduce sulfobutyl ether groups. The resulting material contains multiple substituted cyclodextrin molecules, which increases solubility and imparts a negative charge under physiological conditions. The product’s solubility-enhancing properties arise from both the hydrophobic cavity of the cyclodextrin and the ionic sulfobutyl groups.

Function and use: SBECD acts as a solubility-enhancing excipient for hydrophobic drugs, enabling intravenous administration and improving formulation stability. It forms inclusion complexes with drug molecules, thereby increasing apparent aqueous solubility and, in some cases, influencing drug release and stability.

Regulatory and safety: As an excipient, SBECD is not approved as a standalone therapeutic agent. Its use is described in the labeling of specific drug products. In patients with significant renal impairment, accumulation of SBECD has been reported, which can necessitate alternative formulations or dosing considerations. Overall, SBECD has a favorable safety profile when used as directed in parenteral drug products.

See also: Cyclodextrin derivatives; sulfobutyl ether derivatives are among several cyclodextrin-based solubility enhancers used in pharmaceutical development.