Drug delivery devices: issues in drug development.

New techniques for delivery of drugs by inhalation are discussed in this article. Devices that promise to improve the efficiency of lung delivery are described along with some of the regulatory challenges faced by their development scientists. Although high delivery efficiencies are possible, such devices are expensive to develop and may only be feasible in the event that they are partnered with drugs whose therapeutic and economic value is truly enhanced by the effort invested in the process. Appropriate devices must also be selected after paying careful attention to the physicochemical and dosing demands associated with the drug substance to be inhaled. Even newly launched commercial products display large variations in dose delivery to the lung, in spite of increased global efforts to regulate and ensure the uniformity of delivered doses and their aerosol size distributions; this because of variations in the inspiratory maneuvers used by patients and the lack of control exercised over these maneuvers by most new inhalers. Sophisticated electromechanical techniques are discussed as possible ways of overcoming some of the common difficulties associated with ensuring reproducibility of dose and drug delivery to the lung.