Determination of plasma loratadine concentration with RP-HPLC and its pharmacokinetic study

Objective : To establish a RP-HPLC method for the determination and pharmacokinetic study of loratadine in Chinese healthy volunteers. Methods; Chrornatography was performed on a Hypersil-BDS with acetonitrile-water (65 : 35, pH was adjusted to 3. 8 with H3PO4) as mobile phase. The flow rate was 1. 0 ml/min and the UV wavelength was set at 248 nm. Results: Good linearity was found within 0. 506 0-50. 60 ng/ml of loratadine in human plasma(r = 0. 999 5). The mean relative recovery rate was more than 95% ; intra-day and inter-day RSD were less than 15. 0%. The limit of detection was 0. 506 ng/ml. The main pharmacokinetic parameters were as follows:t12 was (1. 57 ± 0. 18) h;MRT was (2. 46±0. 19) h;Cl/ F was (583. 7±215. 0) L/h;cmax, was (37. 40±8. 92) ng/ml;tmax was (1. 0±0. 20) h;AUC0-8h was (73. 24±21. 30) ng · h/ ml;.AUC/C0-∞ was (75. 57±21. 70) ng · h/ml. Conclusion: Our method has a good selectivity and sensitivity and can be used for further clinical pharmacokinetic study of loratadine.