THE PROBLEM:

The manufacturing consistency in the distribution of pharmaceutical ingredients and coating thickness is vitally important. Applying coatings to the intricate geometry of arterial stents is a manufacturing challenge. Coatings containing particles in the 1 µm range must be uniform, free from holes and other defects, and the concentration of drug reproducible within a few weight percent from one stent to the next.

Verifying coating quality can be a challenge to manufacturers, and that’s where MVA Scientific Consultants steps in.

THE ANALYSIS:

Asked to verify the quality of a stent coating, MVA gathered data from sub-surface layers using Confocal Raman Microscopy (CRM).

Figure 1 shows a composite image of a section of a stent coated with three different components: blue – polymer on metal substrate; red – copolymer mixture; and yellow – active drug product. This distribution was obtained non-destructively, with no cross-sectioning or sample preparation.

Figure 2 shows plots of the Raman spectra associated with each component.

THE OUTCOME:

The results of the analysis confirmed that the distribution of the pharmaceutical ingredients and the coating thickness in the stent met standards.