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Published on: December 15, 2014
Controlled dissolution from wax-coated aerosol particles in canine lungs
R S Pillai1, D B Yeates, I F Miller
1Department of Chemical Engineering, University of Illinois at Chicago 60612, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|February 26, 1998
Summary
Paraffin wax coating enhances drug aerosol dissolution times, improving pulmonary drug delivery. This method increases drug absorption half-time, reducing toxicity for treating lung diseases.
Area of Science:
- Pharmaceutical Sciences
- Drug Delivery Systems
- Pulmonary Medicine
Background:
- Pulmonary drug delivery offers targeted treatment for respiratory and systemic diseases.
- Optimizing aerosol dissolution is crucial for improving therapeutic efficacy and reducing systemic toxicity.
- Current aerosol formulations may have rapid dissolution, limiting sustained drug release in the lungs.
Purpose of the Study:
- To develop and evaluate drug-containing aerosols with delayed dissolution properties for improved pulmonary drug delivery.
- To investigate the impact of paraffin wax coating on the dissolution characteristics and pulmonary absorption of disodium fluorescein and pentamidine aerosols.
- To assess the safety and efficacy of these modified aerosols in a preclinical model.
Main Methods:
- Aqueous disodium fluorescein and pentamidine aerosols were prepared and condensation coated with paraffin wax.
- Particle size (mass median aerodynamic diameter) and wax-to-drug ratios were characterized.
- Dissolution half-times were measured using a single-pass flow system.
- In vivo studies in canine models assessed the absorption half-time of wax-coated fluorescein aerosols using 99mTc-labeled iron oxide colloid.
Main Results:
- Paraffin wax coating significantly increased the dissolution half-times of both fluorescein (1.5 to 5.3 min) and pentamidine (0.8 to 2.6 min).
- Coated fluorescein particles had aerodynamic diameters of 2.8-4.0 microns, suitable for pulmonary deposition.
- In vivo, wax-coated fluorescein aerosols showed a 3.4-fold increase in absorption half-time (11.2 to 38.4 min) in canine lungs.
- No adverse changes in pulmonary function were observed after inhalation of wax-coated aerosols.
Conclusions:
- Paraffin wax coating effectively delays the dissolution of drug aerosols, enhancing pulmonary drug absorption.
- These modified aerosols offer a promising platform for improved therapeutic outcomes in pulmonary and systemic diseases.
- The combination of high drug load, delayed release, and preserved pulmonary function supports future clinical applications.
