Evaluation of the Interaction of Micronized Salbutamol Sulphate Particles with a Polymer Surface

The interaction between micronized Salbutamol Sulphate molecules and the internal surface of the constant volume chamber of a Metered Dose Inhaler (MDI) were studied using Chromatographic methods, a Scanning Electron Microscope (SEM) and Spectroscopic methods. The extensive usage of the MDI to deliver the micronized Salbutamol Sulpate results in the systematic decrease of both the shot weight and the concentration of delivered drug, as the number of the actuations increases. Micronized Salbutamol Sulphate particles were attached onto the internal surface as single crystals and layers of the drug particles. Spectroscopic analysis of the attached particle confirms that it is Salbutamol Sulphate and that there are no new bands disappearing or arising as a result of the interaction between drug molecules and the internal surface, which indicates that this interaction is Physisorption.