LIQUID DOSE INHALER
To generate an aerosol from the air-jet nebuliser, compressed air is forced through an orifice over, or in co-axial flow around the open end of a capillary tube. The drug solution or suspension is drawn through the capillary by means of momentum transfer. In the nozzle region, shear forces disrupt the liquid into small particles that are entrained by the air towards the baffle. Only the smallest droplets, in the desired particle size range, are able to follow the streamlines of the airflow and pass the baffle, whereas larger droplets impact on the baffle and are returned to the liquid reservoir. Ultrasonic nebulisers generate aerosols using high-frequency ultrasonic waves by a ceramic piezoelectric crystal. Vibrating-mesh nebulisers employ perforated plates that vibrate to generate aerosols. There are two types of vibrating-mesh nebuliser, which include the passively vibrating and actively vibrating-mesh nebulisers.
The relationship between nebuliser design and formulation characteristics on the properties of generated aerosols is complex. However, it has been reported that inhaled mass and aerodynamic particle size of nebulised suspensions is influenced by the type of nebuliser. Since the inhaled mass of nebulised solution has been reported to be less dependent on nebuliser type suspensions are generally more difficult to nebulise compared to solutions.
Our services for liquid-dose development include:
Physicochemical characterisation and specification setting for raw materials and finished product
Device selection and optimisation
API and excipient selection
Solution or suspension Formulation prototyping
Analytical method development
Droplet size and aerodynamic particle size measurement
