The Distribution of an Intranasal Insulin Formulation in Healthy Volunteers: Effect of Different Administration Techniques

The initial deposition pattern in the nasal passages and subsequent clearance of an insulin formulation labelled with 99mTc-human serum albumin have been determined in 12 healthy male volunteers. Four different administration modes from a novel aqueous spray device were compared, involving delivered volumes of 80-160 microL, and with either gentle or vigorous inhalation while firing the device. The entire dose was deposited in the nasal cavity, and no significant radioactivity was deposited in the lungs. A mean 25-33% of the radiolabel remained in the nose after 4 h. A significantly smaller area of the nasal mucosa was covered by the smallest (80 microL) bolus, but subsequent clearance rates did not vary significantly with mode of administration. Blood glucose levels fell after administration of the insulin formulation, but no serious episodes of hypoglycaemia occurred.