Validation and application of capillary electrophoresis for the analysis of lidocaine in a skin tape stripping study.
A fast and simple capillary zone electrophoresis method was developed and validated for the determination of lidocaine in skin using tape samples. Separation was performed in a 350 mm (265 mm to window) x 50 microm i.d. fused silica capillary using a background electrolyte of phosphoric acid-Tris pH 2.5. The extraction of lidocaine from tape samples was achieved using methanol, which was diluted to 50% with water before injection. Procaine was the internal standard. The migration times for procaine and lidocaine were 2.9 and 3.2 min, respectively. The limit of quantification for lidocaine was 50 microg, with signal to noise ratio greater than 10. The calibration curve was linear from 50 to 1000 microg with r(2) greater than 0.99. The CV for both within- and between-assay imprecision and the percentage of inaccuracy for the quality control samples including lower and upper limits of quantitation were <or=2% and <or=14%, respectively. The absolute recovery of lidocaine was >97%. The accuracy and selectivity of this method allowed the measurement of lidocaine in tape samples obtained from a skin tape stripping study of local anesthetics in healthy subjects.
Chik
Z
Z
Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur.
Johnston
A
A
Tucker
A T
AT
Burn
R T
RT
Perrett
D
D
D000779:Anesthetics, Local / Q000032:analysis*; D002138:Calibration; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D008012:Lidocaine / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012867:Skin / Q000737:chemistry*; D013048:Specimen Handling / Q000379:methods*
D000779:Anesthetics, Local; D008012:Lidocaine