ABSTRACT
AIM To prepare the thermosensitive intestinal gels of Houttuynia cordata Thunb volatile oils hydroxypropyl-β-cyclodextrin (HPCD) inclusion compound.METHODS For the gels prepared by cold dissolving method,poloxamer 407 consumption and poloxamer 188 consumption were taken as influencing factors,together with phase transition temperature as an evaluation index,central composite design-response surface method was applied to optimizing the formulation.With 2-undecanone as an index component,the gels' dissolution rate and in vitro release rate were investigated by non-membrane dissolution method and dialysis bag method respectively,whose stability was then evaluated by high temperature (40,60 ℃),low temperature (4 ℃),strong light [(4 500 ±500) 1x] and acceleration (three months) tests.RESULTS The optimal conditions were determined to be 20.61％ for P407 consumption and 3.03％ for P188 consumption,the phase transition temperature was 36.5 ℃.Within the time range of 30-150 min,the HPCD inclusion compound gels exhibited higher accumulative dissolution rate than the volatile oils gels,which tended to be consistent in 150-210 min,but the former exhibited higher accmulative release rate (0-50 h) than the latter all the time.The obtained gels showed good stability at low temperature,whose appearance,characteristic (except for high temperature) and pH were stable at high temperature,strong light and acceleration with obviously decreased 2-undecanone content.CONCLUSION The thermosensitive intestinal gels of Houttuynia cordata Thunb volatile oils HPCD inclusion compound should be stored at low temperature (4 ℃).