The In Situ and In Vivo Study on Enhancing Effect of Borneol in Nasal Absorption of Geniposide in Rats

The objective of this research was to study the in situ and in vivo nasal absorption of Geniposide (Ge) co-administered with borneol. A rat in situ nasal perfusion technique with a novel volume-adjusted calculation was used to examine the absorption rate and extent of Ge. The influence of different experimental conditions such as purity of extract, drug concentration, co-administration with synthetic borneol or natural borneol were also investigated. Results indicated nasal absorption of Ge was primarily by passive diffusion that resembled first order kinetics. Following co-administration with borenol, the drug absorption was increased by 1.4 and 1.7 folds for natural borneol and synthetic borneol, respectively. However, the effect of other factors on drug absorption was not significant. In addition, it was also observed that there is a positive correlation between the absorption of water and Ge by the nasal route. In vivo studies carried out in rats where Ge was co-administered with NB and the pharmacokinetic profile obtained following intranasal administration were compared with those after intravenous administration. The bio-availability of Ge by intranasal was 101.5% and T-max was 2.04 +/- 0.64 min. MRT was 218.7 +/- 74.1 min and 44.4 +/- 8.9 min for intranasal and intravenous, respectively. Combined with the borneol, Ge can be promptly and thoroughly absorbed intranasally in rats.