Generation of Aerosolized Drugs

Abstract

The expanding use of inhalation therapy has placed demands on current aerosol generation systems that are difficult to meet with current inhalers. The desire to deliver novel drug entities such as proteins and peptides, as well as complex formulations including liposomes and microspheres, requires delivery systems of improved efficiency that will target the lung in a reproducible manner. These efforts have also been spurred by the phase out of chlorofluorocarbons (CFCs) and this has included a directed search for alternative propellants. Consequently, a variety of new aerosol devices and methods of generating aerosols are being studied. This includes the use of freon replacement propellants, dry powder generation systems, aqueous unit spray systems and microprocessor controlled technologies. Each approach has advantages and disadvantages depending upon each principle of action and set of design variables. In addition, specific drugs may be better suited for one type of inhaler device vs. another. The extent to which aerosol generation systems achieve their goals is discussed together with a summary of selected papers presented at the recent International Congress of Aerosols in Medicine.

Use of Respimat� Soft Mist? Inhaler in COPD patients

“…Standard pMDIs at best deposit 10%–15% of the delivered dose in the lungs and most of the inhaled dose is deposited in the oropharynx. To perform optimally, pMDIs require coordination of actuation with inhalation as well as a slow inspiratory flow rate and breath-holding (Wolff and Niven 1994). Poor coordination of pMDI actuation with inhalation has been shown to result in lower lung deposition of drug and reduced lung function response (Newman et al 2001).…”

Studies on Trans-Resveratrol/Carboxymethylated (1,3/1,6)-β-d-Glucan Association for Aerosol Pharmaceutical Applications

“…Sample stream was generated by a low pressure chamber inside the instrument (at approx. 80 mbar) which sucks air and sample from the sampling chamber [23,24,25]. To obtain statistically relevant data, at least 60,000 particles were analyzed for each sample.…”

Use of Aerosolized Antibiotics in Patients With Cystic Fibrosis

“…36 Classes of Inhalation Devices: There are five current classes of inhalation devices that can deliver drug to the respiratory tract: dry powder inhalers, metered dose inhalers, micronebulizers, ultrasonic nebulizers, and jet nebulizers. 37,38 In their current form, dry powder inhalers and metered-dose inhalers are impractical to deliver the mass of aminoglycoside antibiotics required for efficacy. Micronebulizers are devices that produce aerosols by forcing a solution through a sieve at high pressure and have not been clinically tested for antibiotic delivery.…”

“…The average cycle life of an ultrasonic nebulizer is 600 to 1,000 uses, which is easily reached within one year by a CF patient receiving multiple medications. 37 Jet Nebulizers: Jet nebulizers work by shearing the liquid solution by gas pressure. Larger particles are baffled out and recycled into the nebulizer solution.…”