Comparison of the distribution of breviscapine in the brain by different administration routes

By comparing the drug distribution of breviscapine administered intranasally, orally and intrgvenous injected in rats’ brain.  After 0.4 mg·kg^-1 breviscapine was given by tail vein, intranasal and gastric perfusion administration to SD rats, cerebrospinal fluid was obtained by erebellomedllery cisternal puncture at different times. ¹²⁵I labeling was used to determine the drug content of cerebrospinal fluid, cerebrum, cerebellum, medulla oblongata, olfactory region, olfactory bulb and blood in rats.  AUCs were calculated by trapezoidal rule.  The results showed that AUCs_{0-240 min} (μg·min·g^-1) of brain tissues were 11.686 ± 1.919, 5.676 ± 1.025, 7.989 ± 0.925, 7.956 ± 1.159, 17.465 ± 2.136, 24.2 ± 2.906 and 78.51 ± 12.05, respectively, in the intranasal administration group; while those in the tail vein administration groups were 6.79 ± 0.661, 6.251 ± 0.40, 10.805 ± 1.161, 9.146 ± 1.04, 9.892 ± 1.532, 7.871 ± 0.842 and 173.91 ± 10.02; and oral administration group were 0.868 ± 0.167,  1.708 ± 0.266, 2.867 ± 0.725, 2.067 ± 0.313, 1.361 ± 0.308, 1.206 ± 0.255 and 45.2 ± 7.52, respectively.  AUCs_{0-240 min} of the brain tissues after oral, tail vein and intranasal administration were 22.29%, 29.18%, 95.49% of that of blood, respectively, it means that the absorption rate and drug distribution in the brain tissues after intranasal administration were higher than those of oral and tail vein administration.  It is worth to investigate further the pharmacodynamic relationship.