Chitosan and Randomly Methylated β-cyclodextrin Combined to Enhance the Absorption and Elevate the Bioavailability of Estradiol Intranasally: in situ and in vivo Studies

Chitosan and randomly methylated β-cyclodextrin were the most to be studied absorption enhancers for nasal administration recently. The enhancing absorption mechanisms of each other were different. Authors chosen estradiol as the model drug used in situ and in vivo methods to study whether or not they could combine to enhance the nasal absorption. In situ study data indicated that the optimal concentration and pH for chitosan to enhance the nasal absorption of estradiol in rats were 0.5% and 5, and in this condition the remaining percentage of estradiol was significant difference with RAMEB formulation after perfusion 30 min (P<0.05). The absolute bioavailabilities after intranasal administration were estradiol ethanol (70% w/w) solution: 22.24±7.88%; RAMEB: 58.78±11.19%; chitosan + RAMEB: 78.51± 23.13%. They were different significantly from each other (P<0.05). Based on the in situ and in vivo studies results, it’s clear that chitosan and randomly methylated β-cyclodextrin could combine to enhance the absorption and elevate the bioavailability of estradiol after nasal administration. [The Journal of American Science. 2006;2(1):61-65]