Pharmacokinetic and safety data related to the use of inhaled
insulin for the management of
diabetes mellitus are discussed. The various pulmonary
insulin delivery systems under development are also reviewed.
SUMMARY: Several
pharmaceutical companies are developing pulmonary
insulin delivery systems. These products fall into two main groups:
solution and
drug powder formulations, which are delivered through different patented
inhaler systems.
Exubera, a
rapid-acting insulin in
powder form, has been studied extensively in patients with type 1 and
type 2 diabetes mellitus. The AERx
Insulin Diabetes Management System delivers a liquid form of human
insulin. Preliminary data indicate that patients converting from
insulin injections to this system showed higher compliance to
therapy, demonstrated by improved
glycemic control. Other pulmonary
insulin delivery systems, including ProMaxx, AIR, Spiros, and Technosphere, are also under investigation. In humans, inhaled
regular insulin is more rapidly absorbed than
insulin from the
subcutaneous injection site. The efficiency of inhaled
insulin is lower than that of
subcutaneous injection because pulmonary delivery of
insulin involves some loss of
drug within the
inhaler or mouth during inhalation. A concern of many clinicians is the possibility of long-term effects from the intraalveolar deposition of
insulin within the lung, since
insulin is known to have growth-promoting properties. The long-term safety of these products has not been established.
CONCLUSION: