Dry powder inhalation aerosol

Podczeck F. The influence of particle size distribution and surface roughness of carrier particles on the in vitro properties of dry powder inhalations. Aerosol Sci Technol 1999 31 (4) 301 321. 

Chi Lip Kwok P, Chan HK (2008) Effect of relative humidity on the electrostatic charge properties of dry powder inhaler aerosols. Pharm Res 25 (2) 277-288... 

Park C-W, Li X, Vogt FG et al. (2013) Advanced spray-dried design, physicochemical characterization, and aerosol dispersion performance of vancomycin and clarithromycin multifunctional controlled release particles for targeted respiratory delivery as dry powder inhalation aerosols. International Journal of Pharmaceutics 455 374—392. 

USP24. <601 > Aerosols, Metered Dose Inhalers, and Dry Powder Inhalers. The United States Pharmacopoeia and National Formulary 1895-1912, 2000. 

Liquid instillation and nebulised aerosols are the most common methods for pulmonary administration to experimental animals [22, 54, 109, 134], The use of pressurised metered dose inhaler (pMDIs) and dry powder inhaler (DPIs) in preclinical studies is limited by the need for formulation development, which often cannot be performed in early drug discovery due to short supply of test materials. A number of alternative techniques for intra-tracheal administration of coarse sprays and powder formulations have been described [9, 15, 21, 36, 71, 80, 99, 138],... 

To measure lung deposition by imaging, the aerosol must be first labelled or tagged with a suitable radionuclide. Radiolabelling techniques have been developed for current inhalation products including nebulizers, propellant-driven metered dose inhalers, and dry powder inhalers. 

As described in Section 3.3 in more detah, particles in the aerosol cloud should preferably have an aerodynamic diameter between 0.5 and 7.5 pm. Currently three different types of devices are used to generate aerosol clouds for inhalation nebulizers (jet or ultrasonic), (pressurized) metered dose inhalers (pMDIs) and dry powder inhalers (DPIs). The basic function of these three completely different devices is to generate a drug-containing aerosol cloud that contains the highest possible fraction of particles in the desired size range. 

Aerosolized medications are available as pressurized or breath-actuated metered-dose inhalers (MDIs), dry powder inhalers (DPIs), and nebulized or wet aerosols. Most inhaled medications currently used are available as metered-dose inhalers (Table 3). For the patient who has difficulty to coordinate activation of a MDI, a spacer improves delivery. Spacers reduce deposition of the drug in the... 

Meakin BJ, Ganderton D, Panza I, Ventura P. The effect of flow rate on drug delivery from the Pulvinal, a high-resistance dry powder inhaler. J Aerosol Med 1998 ll(3) 143-52. 

Ross DL, Schulz RK. Effect of inhalation flow rate on the dosing characteristics of dry powder inhaler (DPI) and metered dose inhaler (MDI) products. J Aerosol Med 1996 9(2) 215-26. 

In an attempt to increase the amount of particles retained in the lungs, large porous particles with low density (p < 0.1 g/cm2) have been designed (Edwards et al. 1997). The particles were composed of 50% lactide and 50% glycolide. Porous and nonporous particles loaded with testosterone were aerosolized into a cascade impactor system from a dry powder inhaler (DPI) and the respirable fraction was measured. Nonporous particles (d = 3.5 pm, p = 0.8 g/cm3) exhibited a respirable fraction of 20.5 3.5%, whereas 50 + 10% of porous particles (d = 8.5 pm, p = 0.1 g/cm3) were respirable, even though the aerodynamic diameter of the two particle types were nearly identical. Porous particles as a consequence of their large size and low mass density can... 

Aerosols can be generated by three main drug delivery systems nebulizers, pressurized metered dose inhaler (pMDI), and dry powder inhaler (DPI). 

Inhalation drug products include inhalation aerosols (metered dose inhalers) inhalation solutions, suspensions, and sprays (administered via nebulizers) inhalation powders (dry powder inhalers) and nasal sprays. The CMC and preclinical considerations for inhalation drug products are unique in that these drug products are intended for respiratory tract-compromised patients. This is reflected in the level of concern given to the nature of the packaging components that may come in contact with the dosage form or the patient. 

At present, dry powder inhalers (DPIs) are not used as commonly in the United States as are pMDIs. DPIs have been the last pharmaceutical inhalation aerosol system developed. Although the concept of operation is readily envisioned for these devices, the development of an efficient dry powder dispersion device intended for lung delivery has been notoriously difficult. Most of these devices function by using interactive mixtures of fine drug particles (1-5 pm diameter) and carrier excipient particles (usually 75 200 pm). Some evidence suggests that DPI performance is dictated largely by the physicochemical properties of the excipients used (5). However, as will be discussed, the availability of different choices of excipients is very limited, particularly in the United States. 

Larhrib H, Martin GP, Prime D, Marriott C. Characterization and deposition studies of engineered lactose crystals with potential for use as a carrier for aerosolized salbutamol sulfate from dry powder inhalers. Eur J Pharma Sci 2003 19(4) 211-221. 

Dry-powder inhalers (DPIs) deliver the drug to the respiratory tract in aerosol form. An aerosol is by definition a suspension of free liquid or solid fine particles in a gas phase, which is air in the case of DPIs (and a compressed gas in the case of needle-free injection). The most prominent characteristic that determines the delivery of drug particles to the lungs is the particle size, although particle shape and density are also of considerable importance for the behavior of an aerosol in the respiratory tract (Brain and Blanchard 1993 Gonda 1992 Heyder et al. 1986 Agnew 1984 Heyder et al. 1980). 

Byron, P. R., Peart, J., and Staniforth, J. N. Aerosol electrostatics I. Properties of fine powders before and after aerosolization by dry powder inhalers. Pharm. Res. 14(6) 698—705, 1997. 

Staniforth, J. N. Improvements in dry powder inhaler performance Surface passivation effects, in Proceedings of Drug Delivery to the Lungs VII. London Aerosol Society, 1996. 

B. J. Lipworth, and D. J. Clark, Lung delivery of salbutamol given by breath activated pressurized aerosol and dry powder inhaler devices, Pulm. Pharmacol. Ther. 70 211 (1997). 

Key Words Dry powder inhalers (DPI) Pulmonary drug delivery Insulin Particle engineering Spray drying Liposomes Aerosol solvent extraction system (ASES) Technosphere insulin. 

At least 24 hours before discharge the patient should have been changed to aerosol or dry powder inhalers. 

Finlay, W. H., and Gehmlich, M. G. (2000), Inertial sizing of aerosol inhaled from two dry powder inhalers with realistic breath patterns versus constant flow rates, Int. J. Pharm., 210, 83-95. 

Pitcairn, G. R., Lankinen, T., Seppala, O. P, and Newman, S. P (2000), Pulmonary drug delivery from the taifun dry powder inhaler is relatively independent of the patient s inspiratory effort, J. Aerosol Med., 13, 97-104. 

Pitcairn, G, Reader, S., Pavia, D., and Newman, S. (2005), Deposition of corticosteroid aerosol in the human lung by respimat soft mist inhaler compared to deposition by metered dose inhaler or by turbuhaler dry powder inhaler, J. Aerosol Med., 18, 264-272. 

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