Investigation of the dispersibility for softpellets and the beneficial effect of artificial dispersing aids
Melvin Wostry and Regina Scherließ
Department of Pharmaceutics and Biopharmaceutics, Kiel University, Grasweg 9a, 24118 Kiel, Germany
Summary
In this study, the new approach utilizing softpellets as dry powder formulation for inhalation in combination with an inhaler containing a dispersing aid was investigated. The preparation of the softpellets was done by controlled agglomeration of micronised particles of lactose via vibration. While the micronised powders with a x50 value of 2.86 μm are suitable for inhalation into the deep lung, they are prone to uncontrolled cohesion and bad flowability behaviour. Contrary, the softpellets with an x50 value of 363.17 μm are round agglomerates with beneficial handling characteristics. The characterisation of dispersing behaviour was performed by laser diffraction using the HELOS with either the RODOS module for optimal dispersion or the INHALER module. With the RODOS micronised powder and softpellets showed an equivalent dispersing behaviour. Inhaled from the Cyclohaler, the softpellets showed a relative deagglomeration of 48.98 % compared to the optimal dispersed micronised powder. The micronised powders in the inhaler created a relative deagglomeration of 41.21 %. Therefore, the agglomeration into softpellets did not hinder the dispersibility. Additionally, the effect of dispersing aids for the generation of a fine aerosol was analysed. The dispersing aid was a 3D printed complex geometry with a diameter of 3 mm. It was placed in the mouthpiece of the inhaler. During inhalation, the dispersing aid was lifted with the airflow and due to the additional collision with the softpellets the relative deagglomeration of the softpellets was increased to 81.74 %. It was proven that dispersing aids have a beneficial effect on the generation of fine particles from softpellets.
Key Message
An artificial dispersing aid was utilised for a significant increase of the dispersion of softpellets, loose agglomerates of micronised powders produced by vibration, in the capsule based Cyclohaler.