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Identification of the precipitate in alkalinized solutions of mepivacaine and bupivacaine at 37 °C
Author(s) -
Bigeleisen P. E.,
Wempe M.
Publication year - 2001
Publication title -
journal of clinical pharmacy and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.622
H-Index - 73
eISSN - 1365-2710
pISSN - 0269-4727
DOI - 10.1046/j.1365-2710.2001.00339.x
Subject(s) - mepivacaine , bupivacaine , salt (chemistry) , chemistry , hydrochloride , base (topology) , chromatography , anesthesia , medicine , organic chemistry , mathematical analysis , mathematics
Commercial and control solutions of bupivacaine (0˙75%) and mepivacaine (1˙5%) were alkalinized with bicarbonate until cloudy at room temperature. The solutions were heated to 37 °C for 2˙5 h. The precipitates were filtered, lyophylized and analysed by fast atom bombardment mass spectrometry. Analysis showed the precipitates to be predominantly the free base of the local anaesthetic. The precipitate of the commercial bupivacaine solution also contained a small amount of the hydrochloride salt. The mepivacaine control crystals contained an unknown at molecular weight 528, which may represent a dimer of the free base and hydrochloride salt.