:: Section 5
Factors affecting SVN performance
There are several factors that can influence the performance of a SVN. They are either related to the nebulizer design or the gas source.
1. Nebulizer design
- Baffles
- Large mists with large inertial force impact on the baffle and then fall back into the suspension.
- Fill volume
- The proportion of drug nebulized by an SVN increases as the fill volume increases.
- Residual or dead volume
- The greater the residual volume, the more drug is wasted and the less efficient is the delivery system.
- Position of the SVN
- Residual volume also depends on the position of the SVN. Some SVNs stop producing aerosol when tilted as little as 30 degrees from vertical.
- Viscosity
- The viscosity and density of a drug formulation affect both output and particle size. Some drugs, such as antibiotics, are so viscous that they cannot be effectively nebulized in some standard SVNs.
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