CSMA Uses its Brains on Stains

The Problem

A manufacturer of Metered Dose Inhaler (MDI) drug delivery systems encountered a manufacturing issue, which left a slight stain on the product. The stain was introduced part way through the manufacturing process, with several subsequent processing steps before the final product is produced. The appearance of the product was degraded slightly but the main concern was whether the integrity of the surface chemistry had been compromised- did the chemistry of the stain differ from that of the main body? It was imperative to prove that the stains could not react with the drug contents, with potential health effects for the consumer. This was necessary before the quarantined batch of products (over 1 million parts) could be released.

The Solution

A rigorous analysis by ToFSIMS (Time-of-Flight Secondary Ion Mass Spectrometry) was performed. The technique interrogates the outer 1-2nm of the surface (the part that interacts with the environment) and provides detailed molecular information with the detection limits at ppm (parts-per-million) to ppb (parts-per-billion) levels.

The Conclusion

ToFSIMS analysis showed no difference in the surface chemistry of the stain area. The stains were inert and safely buried sub-surface. The product was safe for release.