Effect of Alkyl Chain Length And Degree of Substitution on Complexation of Sulfoalkyl β-Cyclodextrins with Testosterone and Progesterone

Abstract

This study was designed to test how the sulfoalkyl ether (SAE) modification of β-cyclodextrin (β-CD) enhances the binding capacity of some water insoluble drugs, thereby enhancing their solubility. The SAE-β-CD derivatives contain either sulfopropyl ether (SPE) or sulfobutyl ether (SBE) groups in the 2-, 3-, and 6-hydroxyl positions of the glucose moieties. SAE-β-CD is a mixture of positional and regional isomers containing from one to as many as twelve sulfoalkyl ether (SAE) groups per cyclodextrin. The effect of chain length and the degree of substitution on complexation behavior was investigated using a miniaturized phase solubility method. Unlike the parent β-CD, linear increases in the apparent solubilities of these medicinal agents were observed with binding potentials being comparable to those of β-CD and better. Generally, the binding potential of these derivatives increase with increasing alkyl chain length and reach a maximum with increasing degree of sulfoalkyl substitution.