Slow Particle Velocity Improves Drug Deposition

Particle Velocity Is Important in Drug Delivery

Particle velocity depends on two main factors: (1) Particle Diameter and (2) IFR (Inspiratory Flow Rate)
Particle size is determined by drug formulation. HFA formulation results in finer particle size resulting in better drug deposition. CFC formulations are no longer available as of 2012.
Slow particle velocity is a key determinant in drug deposition.
Low flow rates allow small particles or the respirable particles (2-3 microns in size) to deposit more deeply into the lung.
High flow rates tend to allow the large non-respirable particles (greater than 3 microns in size) to be deposited mainly in the oral cavity.

Inspiratory flow rate determines the type of gas pattern that enters the respiratory tract.
High inspiratory flow rates produce turbulent flow patterns, low inspiratory flow rates produce laminar flow patterns.
Both in vitro and in vivo studies revealed that laminar flow patterns deposit inhaled medication deeper into the bronchi.
Turbulent air flow patterns repeatedly have been shown to result in deposition of most of the medication plume into the oral cavity or upper airways.
Prescribers of medications have no control over drug formulations. However, through the use of the RiteFlo™ you can obtain for your patients repeatedly the correct IFR, resulting in ideal respirable particle size deposition into your patients lungs.

Distal airways are a major site of airway caliber obstruction. They are also a site of airway hyper-responsiveness
Even with normal lung function tests, distal airways show high airflow resistance
Small airways in chronic asthmatics contribute 51% of total airway resistance compared to 24% in normal patients
Greater percentage of activated eosinophils and their mediators are found in the distal airways compared to the proximal airways
Disease of the small distal airways is more intense compared to central airways
Distal airways have a greater concentration of steroid receptors