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??OBJECTIVE To develop a highly sensitive and specific LC-MS/MS method to explore the pharmacokinetic properties of araloside A. METHODS Araloside A was administered in a dose of 50 mg??kg^-1 via gastric in fusion and 5 mg??kg^-1 by intravenous injection in rats.Araloside A was analyzed by a validated LC-MS/MS method in plasma after intravenous and intragastric administration. The pharmacokinetic parameters were evaluated by software DAS 3.0. RESULTS The RESULTS of pharmacokinetic study showed that the linear range of araloside A was good in 1.0-10 000.0 ??g??L^-1(r>0.994 8). The specificity, precision and accuracy, matrix effect and extraction recovery rate and stability all meet the requirements. The main pharmacokinetic parameters for intragastric administration with araloside A 50 mg??kg^-1 and intravenous injection of araloside A 5 mg??kg^-1 were as follows:t_1/2 was(8.65??3.22) and(2.00??0.21)h, AUC_0-t was(277.14??101.00) and (21 194.59??4 385.13)ng??h??L^-1, MRT_0-t was (7.88??0.64) and (1.21??0.11)h, Vd/F was (2 229.99??1 013.97) and (0.71??0.20)L??kg^-1, CL/F was(149.11??62.28) and (0.24??0.05) L??h^-1??kg^-1, respectively; ??_max was (32.68??10.74) ??g??L^-1 for intragastric administration and t_max reached(1.21??0.70) h, oral bioavailability of araloside A was about 0.14%. CONCLUSION The LC-MS/MS method established is specific and sensitive, and can be successfully applied in basic pharmacokinetic study of araloside A in rat plasma.     

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??OBJECTIVE To study the pharmacokinetics and bioequivalence of hydroxysafflor yellow A (HSYA) and hydroxysafflor yellow A nanoemulsion (HYAN) in rats.METHODS Twelve male rats were randomly divided into two groups. The rats were administered intragastrically with HSYA or HYAN, respectively, and then blood was collected from the venous plexus at different time points. HPLC method was used for the determination of HSYA blood concentration.RESULTS The main pharmacokinetic parameters of HYAN were as follows: the area under curve (AUC_{0-24 h}), peak concentration (??_max), peak time (t_max) and clearance (CL) were (31.56??4.58) mg??L??h^-1, (12.75??2.64) mg??L^-1, (0.83??0.54) h and (1.89??0.93) L??h^-1??kg^-1, respectively. The AUC_{0-24 h}, ??_max and t_max of HYAN increased by 5.49, 10.22 and 2.50 times, respectively, and the CL of HYAN was only 1/4 of that of HSYA. The 90% confidence intervals for AUC_{0-24 h} and ??_max were not within the prescribed range of bioequivalence criteria.CONCLUSION Relative to HSYA, the high plasma concentration and prolonged peak time of HYAN in vivo can significantly improve the oral bioavailability of HSYA. HSYA solution and HYAN are not bioequivalent.     

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??OBJECTIVE To assess the impact of chrysin and naringenin on the pharmacokinetics (PK) of saquinavir (SQV), a substrate of P-glycoprotein (P-gp), in rats. METHODS Fifteen rats were randomized into 3 groups of equal size, and administered orally 30 mg??kg^-1 SQV with or without 40 mg??kg^-1 chrysin or naringenin. The PK of SQV was assessed using non-compartmental analysis and the plasma concentrations of three groups were determined by LC-MS/MS. RESULTS The PK parameters values of SQV, SQV+ naringenin, SQV+ chrysin are as follows:AUC_0-t,882.91,861.32,934.84 ng??h??mL^-1; AUC_0-??,903.97,865.90,947.92 ng??h??mL^-1; ??_max,177.72,89.8,130.72 ng??mL^-1; t_max,1,2,0.5 h;t_1/2,11.73,12.61,13.33 h; MRT_0-??,27.09,31.63,26.60 h; CL/F,21.65,21.45,20.62 mL??kg^-1??h^-1. CONCLUSION Double peak phenomenon is observed in the plasma SQV profiles. Our study demonstrates that chrysin and naringenin can not significantly affect the SQV oral bioavailability and SQV PK profiles in rats.     

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??OBJECTIVE To study the pharmacokinetics of pirfenidone in Chinese healthy volunteer after a single dose and multiple-dose administration. METHODS Twelve Chinese healthy volunteers were randomly divided into low, medium and high dose groups(200, 400, 600 mg). The multiple-dose group was administrated with pirfenidione 400 mg three times daily for 5 d. Intensive blood sampling was performed from 12 volunteers within 12 h after the single dosing and the last dose of the multiple dosing. HPLC-MS/MS was used to determine the plasma concentrations of pirfenidone. The pharmacokinetic parameters were calculated by DAS software. RESULTS The main pharmacokinetic parameters of pirfenidone after single-dose administration of 200,400,600 mg qd as follows: ??_max were(5.00??1.42),(9.43??2.74)and(14.14??3.36)mg??L^-1;t_max were(0.57??0.33),(0.60 ??0.30)and(0.60??0.38)h;t_1/2 were(2.16??0.77),(2.15??0.75)and(2.01??0.76)h; AUC_0-?? were(13.87??7.79),(29.26??12.02)and(45.85??20.25)mg??h??L^-1;AUC_0-12 were?(13.27??7.08),(27.92??10.56)and(43.98??18.14)mg??h??L^-1,respectively. The main pharmacokinetic parameters after 400 mg tid for 5 d were as follows: ??_max was(9.46??2.77)mg??L^-1,??_min was(1.14??1.11)mg??L^-1,t_max was(0.52??0.34)h,t_1/2 was(1.93??0.63)h,AUC_0-?? was(26.74??13.49)mg??h??L^-1,AUC_0-12 was (25.79 ??12.34)mg??h??L^-1,AUC_sswas(23.53??10.59)mg??h??L^-1.CONCLUSION The pharmacokinetic parameters of pirfenidone show that ??_max and AUC were linear in the dose range from 200-600 mg and the pharmacokinetic parameters were similar as reference.
     

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??OBJECTIVE To investigate the pharmacokinetic characteristics of enteric-coated sodium mycophenolate(EC-MPS) or mycophenolate mofetil (MMF) dispersible tablets after multiple oral doses in early renal transplant patients, providing references for the rational use of the study drugs in clinical practice. METHODS Thirty-eight first-time renal transplant patients were selected and randomly divided into EC-MPS group (n=18) or MMF dispersible tablets group (n=19). The patients received EC-MPS (540 mg, q12h) or MMF dispersible tablets (750 mg, q12h), combined with tacrolimus and methylprednisolone to prevent acute rejection, respectively. Blood samples were collected at pre-dose, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12 h after oral administration on the postoperative day 5. Enzyme multiplied immunoassay technique (EMIT) was employed to determine the plasma concentration of MPA. The main pharmacokinetic parameters of the two durgs were assessed. RESULTS Pharmacokinetic parameters on the postoperative day 5 of EC-MPS and MMF dispersible tablet were as follows: AUC_{0-12 h} were(43.62??16.20) and(42.02??14.40)mg??h??L^-1(P>0.05);??_max were (17.85??11.32) and (13.96??5.11) mg??L^-1(P>0.05);t_max were (2.72??1.74) and(1.32??0.42)h(P<0.05); ??₀ were (1.63??1.18) and (1.66??0.93) mg??L^-1(P>0.05); ??₁₂ were(1.84??2.09) and (1.81??1.76) mg??L^-1(P>0.05); CL were (14.12??5.30) and (19.66??5.99) L??h^-1(P<0.05). Most of the patients revealed a second small peak in the 4-12 h after taking MPA in the two study groups. CONCLUSION There are large individual differences of pharmacokinetic between EC-MPS and MMF dispersible tablets in early renal transplant patients. It is necessary to carry out therapeutic drug monitoring of MPA to guide the adjustment of drug dosage.     

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??OBJECTIVE To prepare compound aspirin and esomeprazole magnesium enteric-coated pellet capsules and evaluate the drug release in vitro/in vivo. METHODS The aspirin pellet cores were prepared by using extrusion-spheronization method, and the esomeprazole magnesium-containing drug pellets were prepared with fluidized bed. By using fluidized bed coating method, the two kinds of drug-containing pellets were respectively coated with enteric layer to obtain enteric-coated pellets. After determining the loading capacity by measuring drug content, the two kinds of drug-containing pellets were filled into No.1 capsules. In vitro release was evaluated by measuring release percentage. The in vivo release behavior was evaluated by determination of pharmacokinetic parameters in rats. RESULTS The cumulative release percentage of the two drugs was less than 5% in 2 h in 0.1 mol??L^-1 hydrochloric acid solution. The cumulative release percentage of aspirin was more than 70% in 45 min in pH 6.8 PBS and it was more than 80% in 30 min for esomeprazole magnesium. Aspirin was metabolized to salicylic acid in plasma and its main pharmacokinetic parameters were as follows:t_1/2=9.47 h, MRT_0-??=14.43 h, t_max=3.00 h, ??_max=51.34 mg??L^-1, AUC _0-24=703.39 mg??h??L^-1, AUC _0-??=860.52 mg??h??L^-1. The pharmacokinetic parameters for esomeprazole magnesium were as follows:t_1/2=3.72 h, MRT_0-??=7.44 h, t_max=1.50 h, ??_max=2.71 mg??L^-1, AUC_0-24=11.89 mg??h??L^-1, AUC_0-??=13.79 mg??h??L^-1. CONCLUSION The formulation of compound enteric-coated pellet capsules is reasonable, and the preparation technology has good reproducibility. The drug release is located in the intestinal tract, thus esomeprazole magnesium can antagonize the gastrointestinal side effects of aspirin and aspirin can produce better antithrombotic effect .     

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??OBJECTIVE To establish an HPLC-UV method for the simultaneous determination of valsartan and nifedipine in rats plasma, so as to study the pharmacokinetic interaction between valsartan and nifedipine and to provide useful information for clinical practice. METHODS Eighteen male Wistar rats were divided into three groups: valsartan group(16 mg??kg^-1), nifedipine group (4.2 mg??kg^-1) and combined group (containing valsartan 16 mg??kg^-1, nifedipine 4.2 mg??kg^-1). Plasma samples were collected at 0, 0.08, 0.16, 0.25, 0.5, 0.75, 1, 2, 4, 8, 10, 24 h after the drug administration. An HPLC with UV detection method was developed to determine the concentration of valsartan and nifedipine in rat plasma, and the pharmacokinetic parameters were calculated using non-compartment model. RESULTS Compared with single valsartan group, the pharmacokinetic parameters ??_max and AUC_0-t of the combined group had a significant increase(P<0.05), while Tmax and CLz/F had a significant decrease(P<0.05). Compared with single nifedipine group, the pharmacokinetic parameters t_1/2z/h had a significant decrease(P<0.05), while other pharmacokinetic parameters had no significant differences. CONCLUSION Combination of valsartan and nifedipine could significantly improve the valsartan in rats plasma concentration and bioavailability, increase absorption and decrease excretion , while nifedipine shows no pharmacokinetic change in rats except shortened half-life.     

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??OBJECTIVE To investigate the pharmacokinetics of matrine injection by different routes of administration. METHODS Twenty healthy SD rats were enrolled in this study. They were randomly divided into two groups and received intraperitoneal and intravenous administration of matrine injection at dose of 15 mg??kg^-1 respectively. Blood samples (0.3-0.4 mL) were immediately collected into heparinized tubes before injection and at 0.033, 0.083, 0.167, 0.333, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12 h after injection. Plasma sample concentrations were determined by a validated LC-MS/MS method. The pharmacokinetic parameters including AUC_0-12, AUC_0-??, MRT_0-12, MRT_0-??, t_1/2, Vd, CL and ??_max were calculated. RESULTS The main pharmacokinetic parameters for matrine after intraperitoneal and intravenous administration at dose of 15 mg??kg^-1 were as follows:AUC_0-12 (10 166??2 426), (12 217??2 968) ng??mL^-1??h;AUC_0-?? (10 230??2 432), (12 300??3 031)- ng??mL^-1??h;MRT_0-12 (1.91??0.41), (2.14??0.54) h;MRT_0-?? (2.01??0.41), (2.26??0.64) h; t_1/2(2.26??0.89), (2.60??1.25) h;Vd(4 998??2 010), (6 175??2 540) mL;CL (1 531??315.0), (1 727??475.6) mL??h^-1??kg^-1; ??_max (5 246??1 187), (8 503??1 101) ng??mL^-1, respectively. The bioavailability of intraperitoneal administration is 83.21%. CONCLUSION No significant differences were observed in AUC, MRT, t_1/2 and CL values of matrine between different administrations except for ??_max and Vd.     

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??OBJECTIVE To establish an LC-MS/MS method for the determination of levetiracetam to investigate the pharmacokinetics of levetiracetam extended-release tablets at fasted and fed states. METHODS The separation was achieved on a Waters Symmetry C₁₈ column (3.9 mm??150 mm,5 ??m) with mobile phase consisting of acetonitrile-5 mmol??L^-1 ammonium acetate and 0.3% formic acid aqueous solution (10/90, V/V). Two subjects were randomly assigned to receive single oral dose of levetiracetam extended-release tablets 1 000 mg after being fasted and fed by a randomized crossover design. The plasma concentrations of levetiracetam were measured by LC-MS/MS. RESULTS The calibration curve of levetiracetam in human plasma was linear over the concentration rang of 0.100 0-80.00 ??g??mL^-1. Under fasted and fed conditions, the main pharmacokinetic parameters of levetiracetam were as follows:??_max were 20.50 and 19.09 ??g??mL^-1, AUC_{0-48 h} were 345.4 and 336.3 ??g??h??mL^-1, t_max were 4.5 and 7.0 h, respectively. CONCLUSION The method is proved to be convenient, accurate and sensitive, and suitable for the pharmacokinetic study of 1 000 mg levetiracetam extended-release tablets in healthy Chinese volunteers after being fasted and fed. The result suggests that high fat and calories diet has effect on the pharmacokinetics of levetiracetam extended-release tablets, with t_max being delayed.     

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??OBJECTIVE To establish a LC-MS/MS method for determining F1 in rat plasma and study the pharmacokinetic properties of F1. METHODS Ten healthy SD rats were enrolled in this study. They were randomly divided into two groups and received intragastric(10 mg??kg^-1) and intravenous administration(5 mg??kg^-1) of F1. After receiving F1, the concentrations of F1 in plasma were determined. Blood samples(0.1 mL)were immediately collected into heparinized tubes before injection and at 0,0.08, 0.25,0.5,0.75,1,2,4,6,8,10,12,24 h after injection. The pharmacokinetic parameters were determined by DAS2.0 software, absolute bioavailability of F1 was calculated based on AUC and dose administered. RESULTS The main pharmacokinetic parameters after intragastric and intravenous administration of F1 were as follows: ACU_0-t(27.052??10.068),(153.878??88.777)ng??h??mL^-1;AUC_0-??(31.425??9.261),(179.054??116.794)ng??h??mL^-1;MRT_0-t(10.722??4.335), (2.398??1.344)h; MRT_0-?? (15.651??5.917),(6.925??7.013)h;t_1/2(4.294??1.534),(6.052??3.633)h;??_max(18.394??17.856),(219.079??142.207)ng??mL^-1,respectively. Absolute bioavailability value was 8.79%. CONCLUSION This method can be used to determine the content of F1 in rat plasma. The experimental results can guide the structural optimization of F1, improve the pharmacokinetics of F1 in vivo and provide experimental basis for improving bioavailability of F1.