Communications: Effects of Formulation Variables on the Pulmonary Delivery of Insulin

ABSTRACT

The effects of some formulation variables on the pulmonary absorption of insulin in presence of a bile salt, sodium glycocholate (NaGC), have been described in this report. Relationship between intratracheally administered insulin dose and pharmacodynamic response has been established. The data obtained from this study revealed that an increase in the viscosity of an aqueous formulation administered to pulmonary sacs can facilitate insulin absorption probably due to reduced mucocilliary clearance. A hypertonic formulation produced similar overall hypoglycemic effect to the isotonic solution. On the other hand, hypotonicity elicited significantly improved hypoglycemic response, probably due to membrane damage. The cumulative hypoglycemic effect of intratracheally administered insulin has been linearly correlated with the logarithmic doses.