环糊精是由6,7或8个吡喃葡萄糖单元组成的环状低聚糖，通常分别称为α-, β-,或γ-环糊精。这些化合物具有刚性的环形结构，使其成为天然的络合剂。这些化合物的独特结构的稳定性归功于相邻吡喃葡萄糖单元的C2-和C3-羟基之间的分子内氢键。该分子呈环状形状，其中C2-和C3-羟基位于较大的开口周围，而反应性较高的C6-羟基则在较小的开口周围排列。C6-羟基与氢键结合的C2-和C3-羟基的相对排列迫使氧空腔内键合至紧邻的邻位，从而产生了一个富电子的疏水内部。该疏水腔的大小与形成环糊精的吡喃葡萄糖单元数成函数关系。天然环糊精的溶解度极低。1960年代末期发现在2,3和6号羟基位点的化学性取代可极大提高溶解度。绝大多数化学改性的环糊精都能在水中达到50%(w/v)的浓度。空腔的大小是决定哪种环糊精用于络合的主要决定因素。#946;-环糊精或#946;-吡喃葡萄糖单元化合物的空腔直径非常适合用于激素、维生素和组织和细胞培养应用中常用的许多化合物大小的分子。处于这样的原因，β-环糊精最常用作络合剂。 (2-Hydroxypropyl)-β-cyclodextrin is the most widely used modified cyclodextrin. The compound has shown to change the physicochemical properties of lipophilic compounds when co-administered. (2-Hydroxypropyl)-β-cyclodextrin functions by forming an inclusion complex with the compound being administered for easier diffusion across biological membranes, and its popularity can be attributed to its large 7 glucose unit cavity size. Some advantageous effects are reduction of negative effects, increased aqueous solubility and increased stability. The effects of (2-Hydroxypropyl)-β-cyclodextrin have been observed to be dose dependent with both advantageous and disadvantageous results occurring at sporadic concentrations. The compound may also increase the antimicrobial effectiveness of chemical agents by increasing their release rate. A cyclodextrin that allows easier diffusion of lipophiles across biological membranes