Characterization of pharmaceutical surfaces with white light interferometry

Pharmaceutical formulations today are notonly the traditional ones, such as ointments, liquids and tablets. The field ofpharmaceutical formulations has during the last decades rapidly grown, with newrecognized formulations such as orodispersible films, nanomedicines and three-dimensional(3D) printed tablets. Being an old or a new formulation, all these formulationshave surfaces with different topographical characteristics that affect thefunctionality of the dosage forms and the drug itself. Thus, the ability tovisualize and characterize these surfaces has become more and more of interest.

 

The main aim of this thesis was toinvestigate the possibilities and the potential of using scanning white lightinterferometry (SWLI) as a surface analytical tool to visualize and characterizesurfaces of different pharmaceutical formulations. The formulations studied inthis work ranged from traditional rotary press produced tablets to novelprinted formulations with nanoparticles.

 

The results obtained within this studyshowed that it was possible to both visualize and characterize different pharmaceuticalsurfaces and their topographies with SWLI. Based on the SWLI results, a deeperinsight into the understanding of different phenomena taking place on thesubstrate surface of the printed formulations was achieved. Studies of the 3Dprinted grid structures with smooth edges revealed weaknesses in the imagingpossibilities of round shapes with SWLI. Further investigations are suggestedto be done to overcome such problems. Moreover, the results from the printedformulations showed the possibilities to study drug-substrate interactions in multilayerprinted formulations with SWLI.

 

Thiswork shows that scanning white light interferometry as a non-invasive surfacetopographical technique can be applied to both visualize and characterizedifferent pharmaceutical surfaces.