Improvement of generic sevoflurane by a new production process

Background: Anesthesiologists can choose from several generic sevoflurane products available. Although both original and generic products contain high-purity sevoflurane, their minor components appear to be subtly different. We previously reported that original sevoflurane products contain a greater amount of water and smaller amount of related substances than generic sevoflurane. Since then, the manufacturer has developed a new type generic sevoflurane product by improving the method of production. The aim of this study was to analyze and compare the compositions of the original, new generic and old generic sevoflurane products. Materials and Methods: Twenty-four bottles of sevoflurane were prepared. In the first two tests, two bottles of each type of sevoflurane were stored in two types of vaporizers for 3 days each. In the third test, the same number of bottles of each sevoflurane type were stored at room temperature (24°C) for 3 days. In the fourth test, the bottles were incubated at a high temperature (40°C) for 3 days. Thereafter, the contents of sevoflurane, water, soluble fluoride and related substances were measured via gas chromatography. Results: Original sevoflurane contained a larger amount of water than the new and old types of sevoflurane. The new sevoflurane had significantly smaller amounts of related substances than the old sevoflurane. When stored in vaporizers for 3 days, the amount of related substances in the original and new type of sevoflurane was in the same range. Conclusions: Our results suggest that the quality of the new and original sevoflurane products is similar under common clinical conditions.