Two Intranasal Administration Techniques Give Two Different Pharmacokinetic Results
Minor changes in the administration technique used for intranasal instillation of clonazepam, have been found to influence the results significantly. A simple study was performed, where rabbits received 0.5 mg clonazepam intranasally. One group received the drug while fixed in a sitting position, where the other group was fixed in a supine position. The results show that both techniques where able to provide a rapid absorption with a tmax around 3-4 min. The Cmax and AUC, however, were very different. The Cmax was found to be 40 ng/ml and 86 ng/ml, respectively, and the AUC was found to be 891 and 2249 (ng/ml/min), respectively, for the sitting and the supine position. The relative bioavailability for sitting/supine was found to be 38%. These results show that the administration technique is very important and should not be underestimated.