Abstract: AIM: To study the correlation of LTG concentrations between saliva and serum in children with epilepsy.METHODS: After informed consent was obtained from the parents or guardian of children, children with primary epilepsy were collected in Peking University First Hospital.When reaching the steady drug concentration,1.0 ml blood samples were obtained by phlebotomy,and 0.5 ml saliva sample were collected at the same time.Serum and salivary LTG concentrations were determined by reversed-phase high performance liquid chromatography(RP-HPLC).Statistics software SPSS11.5 was used for data analysis.RESULTS: Linear regression analysis was made by LTG concentration (C) and the peak area ratio (Y) of LTG vs.internal standard (flurazepam),and the regression equation of serum concentration and saliva concentration were Y =0.1824 C -0.0080, r =0.9998 and Y =0.1816 C -0.0119, r =0.9997, respectively.We collected 39 patients and 53 serum and saliva concentrations samples, of whom, 27 were male and 12 female, aged 1 to 15 years (the average was 7.86).The correlation between LTG serum concentration(x) and saliva concentration(y) was y =0.5607x-0.6074 (n =53, r =0.9501, p<0.001).Themean saliva/serum LTG concentration ratio was 0.42 ±0.11.CONCLUSION: A significant positive correlation was found between LTG serum and saliva concentrations.Saliva sample may be a useful alternative to serum for therapeutic monitoring of LTG treatment, because saliva collection is simpler, less painful and cheaper than blood drawing, thus children may particularly benefit from this method.

Key words: lamotrigine, saliva, therapeutic drug monitoring, RP-HPLC