Distribution of liposomal breviscapine in brain following intravenous injection in rats

Aim: To investigate distribution of breviscapine in brain after intravenous (i.v.) injection of liposomes. Methods: Breviscapine liposomes were prepared by rotary evaporation-sonication method. Particle size, encapsulation efficiency and stability of liposomes were respectively examined. In vitro drug release was investigated in 0.9% sodium chloride at 37 degrees C. Rats were divided into two groups. Liposomes were given to one group and commercial injection (Injectio Breviscapine) was given to the other at a single dose of 28.1 mg kg(-1) i.v., respectively. Scutellarin in rat brain at different sampling time was determined by RP-HPLC. The brain concentration-time curves of breviscapine liposomes and commercial injection were constructed and pharmacokinetic parameters were calculated and compared by statistic analysis. Results: The average liposome diameter was 735 59 run and encapsulation efficiency was 85.1 +/- 2.3%. The average accumulative release percentage of breviscapine liposomes in 0.9% sodium chloride was less than 30% within 24 h. The mean concentration-time curves of breviscapine liposomes and commercial injection were both fitted to one-compartment model. There are significant difference of parameter T-1/2 and AUC(0-360) between liposome and commercial injection (p < 0.05). T-1/2 Of breviscapine liposomes and commercial injection were 23.13 +/- 7.71 and 6.27 +/- 1.84 min, respectively. The brain AUC ratio of breviscapine liposomes to commercial injection was 443.4 +/- 92.3%. Conclusion: Compared with the commercial injection, liposomes delivered more drugs into the brain and have longer elimination time. (c) 2005 Elsevier B.V. All rights reserved.