The determination of lidocaine and its metabolites by a direct injection LC method using large sample volumes of untreated plasma.
Lidocaine and its N-dealkylated metabolites (glycylxylidide and monoethyl-glycylxylidide) have been determined at their therapeutic levels. The plasma samples were centrifuged and then injected directly into a liquid chromatograph containing a reversed-phase column with LiChrosorb RP-Select B as solid phase and 1-propanolaqueous buffer containing decanesulphonate as eluent. A pre-column venting plug technique was used, in which the chromatographic system consisted of two injector valves, a precolumn, a valve and a separation column. Lidocaine and its dealkylated metabolites were detected in the eluent by UV detection (210 nm) and the quantitations were performed by measurement of the peak areas of the samples and external standards. Lidocaine and its metabolites were determined in the therapeutic range with a percentage recovery close to 100% and inter-assay precision (RSD) of 1.0-2.2%.
Daoud
N
N
Department of Analytical Pharmaceutical Chemistry, Biomedical Center, University of Uppsala, Box 574, S-751 23 Uppsala, Sweden.
Arvidsson
T
T
Wahlund
K G
KG