Β - cyclodextrin by seven glucose units constitute each glucose residues of 2 - 3 -, 6 --hydroxy in hydroxypropyl hydrogen atom can be replaced. 2 - hydroxypropyl - β - cyclodextrin mainly 2 --hydroxy hydrogen atoms substituted product. Compared with β - cyclodextrin, its nature has undergone great change.

 

① appearance: β - cyclodextrin is white crystals, and 2 - hydroxypropyl - β - cyclodextrin as amorphous glass state body, after grinding for the white powder.

 

② solubility: β - cyclodextrin solubility smaller, at room temperature only 1.8 g / 100 g water, this also limits its application, and compared with β - cyclodextrin, 2 - hydroxypropyl - β - ring paste Solubility very fine, usually at room temperature> 50 g / 100 g of water, so it can not be in the alcohol solution crystallization.

 

③ Stability: β - cyclodextrin, 2 - HP-β - cyclodextrin molecules without reducing the thermal and light stability, tolerance 80 ℃ and 4500 lx illumination for 10 days, pressing its solution can be sterilized, in alkaline medium stability, strong acid instability, be strong acid decomposition 
④ the metabolic pathway in the body: 2 - HP-β - CD is not gastric acid and alpha-amylase hydrolyzed, almost not participate in the body metabolism, not cumulative. After oral administration to complete all basically in the form of feces excreted, non-intestinal administration basically in the form of integrity with urine excretion. 
⑤ toxicity and hemolytic: β - CD renal toxicity, hemolytic and irritating, it is not possible for non-intestinal administration, and 2 - HP-β - CD no renal toxicity, but also because of surfactant low, the role of hemolytic and irritating. 
 
⑥ the complex and the drug release: As chemical structure changes, 2 - HP-β - cyclodextrin and β - CD on the same drug complexation capacity and the main object will be different molecular ratio of β - cyclodextrin in the body of complexation of sustained-release drugs, and the 2 - HP-β - CD release on the role of promoting drugs, biological drugs in the body can prompt release.