ABSTRACT
Aim To develop an UPLC-MS/MS method to determine the concentration of lorcaserin hydrochloride in beagle plasma, and study the pharmacokinetics of osmotic pump controlled-release tablets of lorcaserin hydrochloride. Methods A randomized crossover design was used, carbamazepine as the internal standard(IS), and plasma protein precipitation with acetonitrile. The chromatographic was Phenomenex Polar C18 column(100 mm×2. 1 mm, 3 μm), and acetonitrile - water(containing 10 mmol·L-1 ammonium acetate and 0.1% formic acid)(40:60, V/V)was mobile phase. Multiple reaction monitoring mode and electrospray positive ionization were used to detect lorcaserin hydrochloride. The MS/MS ion transitions were monitored at m/z 196.2→129.2 for lorcaserin hydrochloride and m/z 237→194.1 for carbamazepine, respectively. Results The linear range was 1 to 500 μg·L-1(r=0.999 2), the extraction recovery rate ranged from 87.70% to 89.70%, the precision RSD was 9.7%. The accuracy and matrix effect met the requirements, and the stability of lorcaserin hydrochloride was good in -20 ℃ refrigerator for 45 d, repeated freezing and thawing for three times, placed at room temperature for 24 h, and the disposed samples placed in automatsampler for 6 h were stable. The main pharmacokinetic parameters of the controlled-release tablet and immediate-release tablet were as follows:Tmax was(8.00±1.27)h and(1.00±0.13)h, Cmax was(70.56±3.73)μg·L-1 and(176.33±16.73)μg·L-1, and AUC0-t was(966.33±7.56)μg·h·L-1 and(973.05±69.09)μg·h·L-1, respectively. Conclusions The established UPLC-MS/MS method can be used to study the pharmacokinetics of lorcaserin hydrochloride in the plasma of beagle dogs, and osmotic pump controlled-release tablets has sustained release effect.
ABSTRACT
Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this paper. Raw materials and preparation procedure of the activated carbon have great influences on the compositions and surface structure of platinum/carbon catalysts. Platinum catalysts supported on activated carbon with high purity, high surface area, large pore volume and appropriate pore structure usually exhibit higher activities for hydrogenation of ortho-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene. The catalyst prepared from H(2)PtCl(6) with pH=3 shows greater catalytic performance than those prepared under other conditions.