Microbiological integrity pharmaceutical products

Other physical tests may allow routine in-place evaluation of the microbiological integrity of vials. Headspace gas analysis is one such method. Many sterile products are held under nitrogen or some other gas in vials. The gas content of the headspace should, with a perfect seal, remain constant over time rather than becoming equilibrated with the atmosphere under a less than perfect seal. This type of analysis is amenable to chemical methodology and is likely done routinely in pharmaceutical production for reasons other than evaluation of microbiological integrity. 

Allwood M.C. (1990) Package design and product integrity. In Guide to Microbiological Control in Pharmaceuticals (eds S. Denyer R. Baird), pp. 341-355. Chichester Ellis Horwood. 

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