NASAL ABSORPTION IN THE RAT .1. A METHOD TO DEMONSTRATE THE HISTOLOGICAL EFFECTS OF NASAL FORMULATIONS

A method is described which enables the controlled assessment of the effects of intranasal drug formulations on rat nasal epithelium. Damage to the nasal mucosa caused by the surfactant laureth-9 (1% w/v) was used as an indicator of the distribution of dose volumes (100, 50 and 20-mu-l) administered to one side of the nasal cavity. Only the 20-mu-l volume was retained exclusively in the dosed side. Using this dose volume therefore, the epithelium on the undosed side could be used as control tissue and a direct comparison made between experimental and control tissue in the same section. Errors due to inter-animal variablity and tissue sampling are thus minimised, and the total number of animals required for future studies reduced.