Investigations on the humidity-induced transformations of salbutamol sulphate particles coated with L-leucine.

Purpose: The crystallization and structural integrity of micron-sized inhalable salbutamol sulphate particles coated with L-leucine by different methods are investigated at different humidities. The influence of the L-leucine coating on the crystallization of salbutamol sulphate beneath the coating layer is explored.

Methods: The coated particles are prepared by an aerosol flow reactor method, the formation of the L-leucine coating being controlled by the saturation conditions of the L-leucine.