Cyclodextrins as Sustained-Release Carriers

cyclodextrins (CDs) is a practical and economical way to improve the physicochemical and pharmaceutical properties of administered drug molecules. CDs can improve properties such as solubility, stability, and bioavailability of various drugs, thereby potentially serving as novel drug carriers. In addition, the hydrophobic and ionizable derivatives of CDs are being tested for use in the preparation of sustained-release or delayedrelease formulations. This review article describes the complexation of drug molecules with CDs to improve the properties of various formulations. yclodextrins (CDs) have immense potential as carrier molecules in the formulation of novel drug delivery systems. These substances can alter the physicochemical properties of guest molecules by forming inclusion complexes with the molecules that fit within the hydrophobic cavity of CDs (1,2). Commercially available CDs can be used for the complexation of drug molecules that are poorly soluble and unstable and hence difficult to formulate. Complexation with a CD results in improved wettability, dissolution, and stability of this type of drug (3). Despite these well-documented applications of CDs, few reports exist that document the use of CDs to develop sustained-release formulations. Hydrophobic CDs such as alkylated and acylated derivatives have been used as slow-release carriers for water-soluble drugs (4). This article summarizes the physicochemical properties of hydrophobic CDs and investigates their use in sustained drug delivery.