BJA Advance Access originally published online on October 23, 2007
British Journal of Anaesthesia 2007 99(6):819-823; doi:10.1093/bja/aem296
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Analysis of the composition of original and generic sevoflurane in routine use
Department of Anesthesiology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan
* Corresponding author. E-mail: yamakage{at}sapmed.ac.jp, michiaki_yamakage{at}mac.com
Background: Original sevoflurane (Sevofrane) contains a small amount of water, which can inhibit the production of hydrofluoric acid. Hydrofluoric acid is highly pungent, and sevoflurane that contains a high concentration of hydrofluoric acid is not suitable for volatile induction of anaesthesia. Recently, generic sevoflurane (Sevoness) has become available in some countries. The generic product is produced by a different method and kept in a different kind of bottle. We questioned whether the original and generic sevoflurane differed in their composition and thus might differ in their resistance to degradation.
Methods: Sevoflurane from groups of three bottles of Sevofrane and three bottles of Sevoness was kept in the bottle at 24–37°C for 2 weeks or in two kinds of vaporizer for 3 days, and the resulting contents measured by gas chromatography.
Results: Both products contained sevoflurane concentrations exceeding 99.998%. Fluoride ion concentration did not differ between the products (0.043 ppm). The original sevoflurane contained more (0.07% w/v) water than the generic anaesthetic (0.003% w/v). Original sevoflurane contained 5 ppm compound A, 10 ppm sevomethylether, and 5 ppm of unknown materials. Generic sevoflurane contained 32 ppm hexafluoroisopropanol and 12 ppm of unknown materials. While stored in a vaporizer for 3 days, the water content in the original sevoflurane decreased by two-thirds but the water in the generic sevoflurane increased by a factor of three-fold.
Conclusions: Generic sevoflurane contains high-quality sevoflurane and only a small amount of fluoride ions, making it comparable with the original sevoflurane product.
Keywords: anaesthetics volatile, sevoflurane; measurement techniques, chromatography
These data were presented in abstract form at the 12th Asian Australasian Congress of Anaesthesiologists, Singapore, Singapore, November 6–10, 2006.