[Comparison of the effectiveness of sodium azide and merthiolate as bacteriocidal agents--a NMR study]

The pseudohalogenide sodium azide (NaN3) and the organometallic mercury compound merthiolate (sodium salt of ethyl mercurithiosalicylate) are commonly used as preserving solutions for biomaterials. In the present paper, these preserving solutions were compared for their efficacy in preserving porcine articular cartilage. For this purpose, porcine articular cartilage was incubated with phosphate buffer containing the corresponding amounts of NaN3 or merthiolate. Supernatants were assayed using NMR spectroscopy, and the content of soluble saccharides was determined using the dye Alcian blue. The results obtained clearly indicate that merthiolate is more effective than sodium azide. This makes the former a more suitable preserving agent for the storage of cartilage. A significant decrease in the lactate concentration, and enhancement of the acetate and the N-acetyl resonances indicate degenerative changes in the cartilage. However, when a large excess of sodium azide is used, its efficacy approaches that of merthiolate.