Pharmacokinetic Properties of Oral Lafutidine Tablets and the Effect of Food on its Pharmacokinetics in Healthy Chinese Subjects

The aim of this study was to evaluate the pharmacokinetics (PK) of single and multiple doses of oral lafutidine tablets and the effect of food on the PK properties in healthy Chinese subjects. The tolerability and the effect of gender on the PK properties were also evaluated to acquire more PK information. Three PK studies were conducted in 12 healthy Chinese subjects (6 male, 6 female). Study 1 was a single-dose, three-period, three-dose level (10, 20, and 40 mg), three-sequence cross-over study under fasting conditions. Study 2 was a repeat-dose study (10 mg twice daily over 6 days; all 12 subjects). Study 3 was a two-period, two-sequence cross-over single-dose (10 mg) food interaction study. All randomizations (study 1, study 3) were done to ascertain 1:1 gender ratio per sequence. A validated liquid chromatography tandem mass spectrometry (LC/MS/MS) method was used to determine plasma lafutidine concentrations. PK parameters were calculated by the non-compartmental method. The area under the time-concentration curve (AUC) and maximum plasma concentration (C (max)) of lafutidine tablets were dose-independent in the single-dose study among these healthy volunteers. The PK parameters of the multiple-dose study were inconsistent with the single study. After administration of a single dose of 10 mg under either fed or fasting conditions, we found that food may not affect the degree of absorption of the lafutidine tablets, but it may slow down the absorption rate. This is shown by the fact that the AUC showed no significant difference while the peak time was significantly delayed under fed conditions. The PK of lafutidine showed dose proportionality. There was no significant accumulation of lafutidine tablets with multiple dosing. Food did not affect the degree of lafutidine absorption, but it did reduce the rate of absorption. Further study is needed regarding the effect of gender on lafutidine. Lafutidine was well tolerated within the dose range 10-40 mg, and no serious adverse events were observed.