Inhalation Drug Delivery – Understanding Basic Steps Involved in Pressurized Metered Dose Inhalation (pMDI) Development

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Drug delivery via the inhalation route is an efficient, safe and efficacious method for local and systemic administration of certain therapeutic agents. Many inhaled therapeutics are delivered to the lung tissue to elicit a local response, typically for asthma or other lung disorders. However, because of the large surface area and high vascularity of the lungs, it is also an excellent route of administration for systemic drug delivery. In recent years, researchers began developing inhalation products containing proteins and peptides (e.g. insulin and calcitonin), opioids, vaccines, hormones and other therapeutic agents intended for local and systemic absorption.

Inhalation drug delivery is advantageous for local delivery due to a reduction in systemic side effects. It is also advantageous for systemic delivery due to rapid and complete absorption by the alveolar capillaries as well as prevention of hepatic fist pass metabolism. Ideal drug candidates for this route of administration should be relatively potent (i.e. low dose), safe for pulmonary administration (i.e. not a pulmonary irritant) and should have chemical characteristics that allow for solubilization and absorption within the lung.

Development of inhaled therapeutics presents numerous challenges for researchers and commercial manufacturers. This white paper will provide insight into the aspects of formulation development, packaging development and analytical development associated with inhaled drug delivery as it relates to pressurized metered dose inhalers (pMDI).