Preparation of pH-Sensitive β-Cyclodextrin Derivatives and Evaluation of Their Drug-Loading Properties

Abstract

Hydroxypropyl β-cyclodextrin (HP-β-CD) is widely used in the encapsulation of drugs and the increase of solubility of poorly soluble drugs. The modified hydroxypropyl cyclodextrin can make cyclodextrin have pH and temperature sensitive and other characteristics. The purpose of this study was to oxidize and crosslink HP-β-CD to prepare a derivative of the network structure and evaluate its drug-loading properties. First, the βcyclodextrin with aldehyde group was obtained by periodate oxidation, and then crosslinked with different ratios of ethylenediamine (EN) to obtain a network structure of hydroxypropyl β-cyclodextrin derivative (EN-HP-β-CD). The β-cyclodextrin derivatives were characterized by FT-IR, DSC, XRD and SEM. Vitamin E (VE) was used as a model drug to study the solubilization effect, phase solubility and in vitro release behaviour under different pH conditions. The results showed that EN-HP-β-CD could significantly improve the solubility of VE, and 1:1 EN-HP-β-CD could increase the solubility by 25 times. In vitro release experiments under different pH conditions within 24 h showed that the cumulative release at pH 4.5 was 78.25%, which was significantly higher than the pH 7 release effect (43.94%). The result indicated that EN-HP-β-CD had solubility increasing effect and pH-sensitive properties.