The aim of this work is to understand the impact of carrier material and API processing on the preparation of adhesive mixtures for inhalation. Additionally, a surface phenomenon, that was observed in a prior study where spray dried salbutamol sulphate seemed to fuse with a specific mannitol carrier surfaces, is investigated further. Therefore, mixtures with two different mannitol carriers and spray dried and micronized salbutamol sulphate as model active pharmaceutical ingredient (API) were prepared. To evaluate the morphology of the different adhesive mixtures SEM images were taken and the air permeability was determined as parameter to detect changed in the powder mixtures resistance to airflow.
From the results, it can be assumed that the observed surface phenomenon is specific for P160C and spray dried salbutamol sulphate. When using micronized salbutamol sulphate no fusion of API and carrier surface occurred. Moreover, also when using a different type of mannitol (Pearlitol 300DC) no fusion occurred.