Study on the inclusion technic of hydroxypropyl-β-cyclodextrin in tea tree oil and evaluation of its included compounds

Abstract

Objective This study takes hydroxypropyl-β-cyclodextrin (HP-β-CD) as the inclusion materials to optimize the preparation technic of tea tree oil (TTO) and evaluate its pharmaceutical performance. Methods Take the production rate of HP-β-CD tea tree oil inclusion and entrapment rate as the evaluation index, taking the orthogonal test method to optimize the production technic of tea tree oil (HP-β-CD inclusion and using infrared (IR), differential thermal scanning (DSC) method to characterize the inclusion compound to analyze the stability of TTO-HP-β-CD. Results The best technic to produce HP-β-CD tea tree oil is as follow: the ratio of TTO and HP-β-CD should be equal to 1/10, at 40 ℃, within 1 h. The average drug loading shoud be 9.25% ± 3.25%. The IR, DSC characterization results showed that the characteristic peak of tea tree oil disappeared after the microspheres, which indicated the HP-β-CD encapsulated the tea tree oil with good compatibility. In 80 ℃ water bath, the TTO-HP-β-CD was stable with the retention rate 40% after 8 h, the retention rate was 4.32 times than that of the unwrapped tea tree oil. Conclusions The HP-β-CD tea tree oil obviously has higher rate of inclusion and stability. Therefore, it’s worth to promoting and being used in the pharmacy preparations and cosmetics field. Key words: Tea tree oil; Hydroxypropyl-beta-cyclodextrin; Inclusion complex; Drug stability; Orthogonal test; Dosage forms improving