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Influence of micronization method on the performance of a suspension triamcinolone acetonide pressurized metered-dose
1College of Pharmacy, University of Texas at Austin 78712-1074, USA. williro@mail.utexas.edu
Abstract:
The purpose of this study was to investigate the influence of micronization technique on performance and stability of the model drug formulated in a suspension-based pressurized metered-dose inhaler (pMDI). The model drug, triamcinolone acetonide (TAA), was subjected to ball milling or air-jet milling prior to formulation of the pMDI. The dose delivery characteristics of the emitted aerosol cloud were monitored for the ball-milled, air-jet-milled, and unmicronized TAA pMDI formulations prior to and after storage at 25 and 40 degrees C. Cascade impaction was used to determine the aerodynamic particle size distribution of the emitted dose. Both micronization techniques reduced the drug particle size distribution and the polydispersity of the drug particles to a similar extent, but the ball-milling technique reduced the crystallinity of the drug to a greater degree compared to the air-jet-milling technique. The air-jet-milled and unmicronized TAA pMDI displayed similar aerodynamic particle size distributions of the emitted aerosol and respirable fractions over the storage period. The ball-milled TAA resulted in a pMDI formulation with the smallest aerodynamically sized particles and the highest respirable fraction compared to the air-jet-milled or unmicronized TAA pMDI formulations. The micronization techniques significantly influenced the dose delivery characteristics as a result of different initial particle size distributions, amorphous contents, and surface energies.
Insights
Ball milling triamcinolone acetonide (TAA) for pressurized metered-dose inhalers (pMDIs) yielded smaller particles and higher respirable fractions than air-jet milling. Micronization technique significantly impacts TAA pMDI performance.
Area of Science:
- Pharmaceutical Technology
- Drug Delivery Systems
- Particle Engineering
Background:
- Pressurized metered-dose inhalers (pMDIs) are crucial for delivering drugs to the lungs.
- Micronization is essential for optimizing pMDI performance by controlling particle size.
- The choice of micronization technique can influence drug properties and subsequent aerosolization.
Purpose of the Study:
- To evaluate the impact of ball milling versus air-jet milling on the performance and stability of triamcinolone acetonide (TAA) in suspension-based pMDIs.
- To compare the dose delivery characteristics and aerodynamic particle size distribution of TAA pMDIs formulated with different micronization methods.
Main Methods:
- Triamcinolone acetonide (TAA) was micronized using ball milling and air-jet milling.
- pMDI formulations were prepared with micronized and unmicronized TAA.
- Dose delivery characteristics were assessed using cascade impaction before and after storage at 25°C and 40°C.
Main Results:
- Both milling techniques reduced particle size and polydispersity; ball milling decreased crystallinity more than air-jet milling.
- Ball-milled TAA pMDIs exhibited smaller aerodynamic particle sizes and higher respirable fractions compared to air-jet milled or unmicronized TAA.
- Air-jet milled and unmicronized TAA pMDIs showed similar aerodynamic particle size distributions and respirable fractions post-storage.
Conclusions:
- Micronization technique significantly influences TAA pMDI dose delivery characteristics.
- Ball milling is a superior technique for achieving optimal particle size and respirable fraction for TAA in pMDIs.
- Differences in particle size, amorphous content, and surface energy arising from micronization impact pMDI performance.