In situ and in vivo study of nasal absorption of borneol in rats.

The aim of this work was to study the in situ and in vivo nasal absorption of borneol. A novel single pass in situ nasal perfusion technique was applied to examine the rate and extent of nasal absorption of borneol by rats. Experimental conditions, such as perfusion rate, pH and drug concentration, were investigated. The in situ experiments showed that the nasal absorption of borneol was not dependent on drug concentration, and fitted a first order process. The absorption rate constant, Ka, influenced with an increase in perfusion speed. The borneol was well absorbed in the conditions of the nasal cavity within the pH range and pH value of physiological conditions. In vivo studies of borneol absorption were carried out in rats and the pharmacokinetics parameters of intranasal (i.n.) was compared with intravenous (i.v.) administration. The bioavailabilities of borneol was 90.82% for i.n. while Tmax values were 10min. MRT (Mean Residence Time) were 262.55 +/- 67.35 min and 204.22 +/- 14.50 min for i.n. and i.v. methods, respectively. The results demonstrate that borneol could be absorbed promptly and thoroughly by i.n. administration in rats.