Pharmacokinetics of dimemorfan phosphate tablets in healthy Chinese volunteers

Investigate the pharmacokinetic properties of the antitussive dimemorfan phosphate tablets in healthy male and female Chinese volunteers after single and multiple-dose administration; and to evaluate the food-effect on pharmacokinetics of dimemorfan.

12 subjects received a single dose of 10 mg and 40 mg dimemorfan phosphate tablets, respectively in study stage 1. Another 12 subjects received a single dose of 20 mg dimemorfan phosphate tablets under fed conditions, a single dose of 20 mg dimemorfan phosphate tablets under fasting conditions and multiple-dosing of 20 mg dimemorfan phosphate tablets 3 times per day, respectively in study stage 2. The washout between each treatment was 1 week. Plasma dimemorfan was quantified by a high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method.

After single-dosing of 10 mg, 20 mg and 40 mg dimemorfan phosphate tablets, C_max, AUC_0-t and AUC_0-∞ were dose proportional, which achievd 6.19 ± 7.61 ng·mL^-1, 101 ± 171 and 117 ± 210 ng·mL^-1·h, respectively after single-dosing of 40 mg dimemorfan phosphate tablets. T_max ranged from 2.75 to 3.96 h and t_1/2 ranged from 10.6 to 11.4 h. After multiple-dosing of 20 mg dimemorfan phosphate tablets, the Accumulation Index (AI) was 2.65 ± 1.11. The pharmacokinetic parameters after single-dosing of 20 mg dimemorfan phosphate tablets under fed conditions were similar with those under fasting conditions. Sex did not affect the pharmacokinetics of dimemorfan phosphate tablets.

Single-dosing of dimemorfan phosphate tablets exhibited linear kinetic characteristics. Multiple-dosing of 20 mg dimemorfan phosphate tablets 3 times per day caused obvious accumulation. No food effect or sex effect on the pharmacokinetics of dimemorfan phosphate tablets was observed. Chictr.org identifier: ChiCTR-ONC-14004851.