Hydroxypropyl-sulfobutyl-²-cyclodextrin, the preparation method, analytical method, and the pharmaceutical application thereof The hydroxypropyl-sulfobutyl-²-cyclodextrin is a derivative of cyclodextrin which is substituted by a hydroxypropyl group and a sulfobutyl group: n-(2,3,6-O-2-hydroxypropyl)-m-(2,3,6-O-sulfobutyl)-²-cyclodextrin. The number of substituent groups per mole cyclodextrin is n hydroxypropyl groups and m sulfobutyl groups. "n" represents the average substituent degree of hydroxypropyl groups "m" represents the average substituent degree of sulfobutyl groups "n+m=z" is the gross average substituent degree, in which n is a random integer chosen from 1, 2, 3, 4, 5, 6, 7, 8, 9 m is a random integer chosen from 1, 2, 3, 4, 5 , 6, 7, 8, 9 and the gross average substituent degree z is a random integer chosen from 2, 3, 4, 5, 6, 7, 8, 9, 10. The present invention shows low hemolysis and low toxicity.
