The mode of drug particle detachment from carrier crystals in an air classifier-based inhaler.

Purpose: To investigate the mode of drug particle detachment from carrier crystals in an air classifier as a function of the carrier size fraction, payload, and the circulation time in the classifier.

Methods: Laser diffraction analysis of the aerosol cloud from the classifier has been performed at 10, 20, 30, and 60 l/min, using a special adapter, for different adhesive mixture compositions.

Results: A significant part of the drug particles is detached from carrier crystals during inhalation as small agglomerates.

The rate of drug particle detachment from carrier crystals in an air classifier-based inhaler.

Purpose: To investigate the rate with which drug particles are detached from carrier particles in adhesive mixtures when the action of the separation forces during inhalation is sustained by circulation of the powder dose in an air classifier.

Methods: Residual drug on retained carrier particles from different adhesive mixture compositions has been analyzed after different circulation times in the classifier (0.5 to 6 s).

The use of 13C labeling to enhance the sensitivity of 13C solid-state CPMAS NMR to study polymorphism in low dose solid formulations.

(13)C labeling was used to enhance the sensitivity of (13)C solid-state NMR to study the effect of tabletting on the polymorphism of a steroidal drug. The steroidal drug Org OD 14 was (13)C labeled and formulated into tablets containing only 0.5-2.