PREPARATION AND IN-VITRO EVALUATION OF TETRANDRINE-ENTRAPPED ALBUMIN MICROSPHERES AS AN INHALED DRUG-DELIVERY SYSTEM

Tetrandrine is a bisbenzylisoquinoline alkaloid extracted from the roo ts of Stephania tetrandra S. Moore. It has been used in China as a tre atment of silicosis which is an occupational disease caused by the inh alation of silica particles. Tetrandrine is reported to be metabolised slowly, accumulate in the liver and induce hepatic damage. Hence, the aim of the present study is to deliver and retain tetrandrine in the lung so as to promote any antisilicotic effects but to minimise its si de effects to other organs. Albumin microspheres (MS) may provide a su itable carrier for airway delivery because of their biocompatibility a nd biodegradability. The albumin MS were prepared with micronised tetr andrine by high speed homogenisation and heat denaturation. Factorial design was used to optimise the preparative process. The particle size was measured by laser light scattering and drug entrapment determined by HPLC. Albumin MS with mean diameter 4.41 +/- 0.45 mu m (n = 6) and drug entrapment 120.2 +/- 26.2 mu g drug per mg MS (n = 6) were prepa red. The tetrandrine recovered from the lower stage of a twin-stage im pinger operated under Pharmacopoeial conditions was 13.83 +/- 2.58% (n = 6). The results showed that albumin MS may have the potential to de liver tetrandrine to the lung via airways.