Brain pharmacokinetics and tissue distribution of tetrahydropalmatine enantiomers in rats after oral administration of the racemate

Tetrahydropalmatine (THP), a racemic mixture, is a biologically active ingredient isolated from a traditional Chinese herb Rhizoma Corydalis (yanhusuo). The main objective of this study was to determine the brain pharmacokinetics and tissue distribution of THP enantiomers in rats after oral administration of racemic THP (rac-THP). Rats (5 animals/group/per time) were given a single oral dose of rac-THP and killed after different post-treatment times. The concentrations of THP enantiomers in plasma, cortex, cerebellum, diencephalon, brain stem, striatum and hippocampus were measured using a validated chiral high performance liquid chromatographic (HPLC) method coupled with an achiral column. The pharmacokinetic profiles of the two enantiomers in six brain regions were significantly different. The peak concentrations (Cmax) and AUC(0-infinity) values of the (-)-enantiomer were significantly greater than the corresponding values for the (+)-enantiomer while the striatum contained the highest peak concentrations compared with the plasma and other brain regions. The tissue distribution studies also revealed significant differences between the two enantiomers in all tissues except the lung. The highest concentrations of both enantiomers were found in the liver. The (-)/(+)-THP ratios in six brain regions and other tissues were consistent with that observed in plasma indicating that the stereoselective disposition of THP in rat brain and other tissues reflects the situation in plasma.     

Pharmacokinetics,bioavailability and tissue distribution of geniposide following intravenous and peroral administration to rats

In order to characterize the pharmacokinetics, bioavailability and tissue distribution of geniposide following intravenous and peroral administration to rats, a reliable gradient HPLC‐based method has been developed and validated. After p.o. administration of geniposide, the peak concentration of geniposide in plasma occurred at 1 h and plasma geniposide was eliminated nearly completely within 12 h. The AUC_{0→ ∞} values of geniposide were 6.99 ± 1.27 h · µg/ml and 6.76 ± 1.23 h · µg/ml after i.v. administration of 10 mg/kg and p.o. administration of 100 mg/kg of geniposide, respectively. The absolute oral bioavailability (%F) of geniposide was calculated as 9.67%. After p.o. administration of geniposide, the AUC_0→4h values in tissues were in the order of kidney > spleen > liver > heart > lung > brain. This study improved the understanding of the pharmacokinetics, bioavailability and tissue distribution of geniposide in rats and may provide a meaningful basis for clinical application of such a bioactive compound of herbal medicines. Copyright © 2013 John Wiley & Sons, Ltd.     

Simultaneous determination of tanshinones and polyphenolics in rat plasma by UPLC‐MS/MS and its application to the pharmacokinetic interaction between them

The aim of this study was to investigate the pharmacokinetic interaction between tanshinones and polyphenolics which act as the main bioactive compounds in Saliva miltiorrhiza Bunge (SMB). Thus, a rapid and highly sensitive ultra‐performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS) method was developed and validated to determine the concentrations of Tanshinone IIA (TSIIA), Tanshinone I (TI), Cryptotanshinone (CT), Salvianolic acid B (Sal B), Protocatechuic aldehyde (PAL), Rosmarinic acid (RA), and Danshensu (DSS) in rat plasma. The Sprague–Dawley rats were allocated to three groups which orally administered tanshinones (DST), polyphenolics (DFS), and a mixture of tanshinones and polyphenolics (DTF). These samples were processed by a simple liquid‐liquid extraction (LLE) method with ethyl acetate. Chromatographic separation was achieved on an Acquity BEH C₁₈ column (100 mm × 2. 1 mm, 1.7 µm) with the mobile phase consisting of 0.1% (v/v) formic acid and acetonitrile by gradient elution at a flow rate of 0.4 mL/min. The detection was performed on a triple quadrupole‐tandem mass spectrometer TQ‐MS/MS equipped with negative and positive electrospray ionization (ESI) interface in multiple reaction monitoring (MRM) mode. The statistical analysis was performed by the Student's t‐test with P ≤ 0.05 as the level of significance. The method showed good precision, accuracy, recovery, sensitivity, linearity, and stability. The pharmacokinetic profiles and parameters of these polyphenolics changed when co‐administrated with tanshinones. The tanshinones improved the bioavailability of DSS, accelerated the eliminating rate of RA and Sal B and promoted their distribution in vivo. They also contributed to promoting the biotransformation of Sal B to DSS. The polyphenolics could affect the pharmacokinetic of tanshinones, especially CT and TSIIA. Furthermore, the biotransformation of CT to TSIIA and the bioavailability of TSIIA were both improved. This study may provide useful information to avoid unexpected increase of the plasma drug concentration in the clinical practice. Copyright © 2015 John Wiley & Sons, Ltd.     

Circadian variations in the pharmacokinetics, tissue distribution and urinary excretion of nifedipine after a single oral administration to rats

Circadian variations in the pharmacokinetics, tissue distribution and urinary excretion of nifedipine were examined in fasted rats after administering a single oral dose at three different dosing times (08:00 am, 16:00 pm, 00:00 am). The plasma concentrations, the areas under the plasma concentration-time curve from zero to 6 h (AUC(0-6 h)) and the peak plasma concentration (C(max)) were significantly higher in the rats dosed at 08:00 am (immediately inactive), and was lower at 16:00 pm (most inactive) and 00:00 am (most active). The time to reach the C(max) (T(max)) was the shortest in the rats dosed at 08:00 am. It was very interesting to observe the double peak phenomena in the plasma concentration profiles, showing a larger peak followed by a smaller peak. There was a dosing time dependency on the tissue distribution 30 min after administration, showing a similar tendency to the pharmacokinetic behavior. However, there was no distinct dosing time dependency observed at 2 h after administration due to the extensive disposition. The cumulative urine excretion of nifedipine in the rats dosed at 08:00 am was significantly higher (about two-fold) than in those dosed at 16:00 pm and 00:00 am. The pharmacokinetics of nifedipine in the rats was consistent with that observed in human subjects in terms of the day-night clock time but the biological time was the opposite, as marked by the rest-activity cycles. These results may help to explain the circadian time-dependency of nifedipine pharmacokinetics.     

Biological activities and pharmacokinetics of aconitine,benzoylaconine, and aconine after oral administration in rats

Aconitine (AC), benzoylaconine (BAC), and aconine (ACN) are three representative alkaloids in Aconitum tubers. Knowing that the drug disposal process in vivo is closely related to the toxicity and efficacy of a drug, it is important to classify the disposal properties of these alkaloids. In this study, the pharmacokinetics of the three alkaloids was investigated. The results showed that the three alkaloids could be quickly absorbed, especially BAC, whose T_max was 0.31 ± 0.17 h. Their C_max was 10.99, 3.99, and 4.29 ng·mL^‐1 respectively, indicating that AC had better absorption than BAC and ACN. Subsequently, we further investigated their absorption mechanism using the Caco‐2 cell monolayer model in vitro. The results showed that they were poorly absorbed, and the absorption of AC and BAC was inhibited by P‐gp, while the absorption of ACN was in a form of passive diffusion. The t_1/2 of AC, BAC and ACN was 1.41, 9.49, and 3.32 h, respectively, indicating that the metabolic or excretion rate of AC was quicker than that of BAC and ACN. Therefore, their metabolic stability was further investigated by using rat liver microsomes in vitro, which showed that AC was easier to be metabolized than BAC and ACN. The excretion experiments showed that AC and ACN were primarily excreted in urine, while BAC was excreted in faeces. In addition, the results of tissue distribution experiments showed that the three alkaloids distributed throughout all the organs, although the distribution rate of AC was slower than that of BAC and ACN. Copyright © 2015 John Wiley & Sons, Ltd.     

Preparation,preliminary pharmacokinetics and brain tissue distribution of Tanshinone IIA and Tetramethylpyrazine composite nanoemulsions

Objective: Tanshinone IIA (TSN) and Tetramethylpyrazine (TMP) were combined in a composite, oil-in-water nanoemulsions (TSN/TMP O/W NEs) was prepared to prolong in vitro and vivo circulation time, and enhance the bioavailability of TSN.

Material and methods: Physicochemical characterization of TSN/TMP O/W NEs was characterized systematically. The in vitro dissolution and in vivo pharmacokinetic experiments of TSN/TMP O/W NEs were also evaluated.

Result: A formulation was optimized, yielding a 32.5?nm average particle size, an encapsulation efficiency of over 95 %, and were spherical in shape as shown by TEM. TSN/TMP O/W NEs were shown to extend the release and availability in vitro compared to raw compounds. In pharmacokinetic study, the AUC_0→∞ and t_1/2 of the TSN/TMP O/W NEs were 481.50?mg/L*min and 346.39?min higher than TSN solution, respectively. Brain tissue concentration of TSN was enhanced with TSN/TMP O/W NEs over raw TSN and even TSN O/W NEs.

Conclusions: Therefore, nanoemulsions are an effective carrier to increase encapsulation efficiency of drugs, improve bioavailability and brain penetration for TSN – which is further enhanced by pairing with the co-delivery of TMP, providing a promising drug delivery.     

Enhancing effects of different dosages of borneol on pharmacokinetics of salvanic acid B after oral administration to rats

The main purpose of this study was to illustrate the effect of borneol on pharmacokinetics of salvianolic acid B (SalB) in rats after oral administration of SalB with different doses of borneol. The concentrations of SalB in rat plasma were determined by an established and validated LC-MS/MS method. Our data showed that when 20, 40, and 80 mg kg^? 1 of borneol were orally administrated with SalB at 50 mg kg^? 1, C _max of SalB was increased by 18.4%, 55.8%, and 103.2% compared with that of SalB alone. And AUC_0 ? t of SalB in plasma was increased by 14.4%, 48.5%, and 123.3%, respectively. The results indicated that borneol is able to enhance the intestinal absorption and relative bioavailability of SalB, with a positive dose-dependent relationship. The described herb–drug interactions might prove the scientific rationality of the compatible ratio of traditional Chinese medicines.     

Preclinical factors affecting the pharmacokinetic behaviour of tanshinone IIA,an investigational new drug isolated from Salvia miltiorrhiza for the treatment of ischaemic heart diseases

Tanshinone IIA (TSIIA) is a major active triterpenoid isolated from Salvia miltiorrhiza. The purposes of this study were to investigate various preclinical factors that determined the pharmacokinetics of TSIIA. After oral dosing at 6.7, 20, and 60 mg kg^?1, TSIIA was detected mainly as glucuronidated conjugate (TSIIAG) with only small amounts of the unchanged in the plasma. TSIIA was predominantly excreted into the bile and faeces as TSIIAG, and urine to a minor extent. The C_max and AUC_0?t of TSIIAG after i.p. administration were significantly lower than those after intragastric administration. The plasma concentration–time profiles of TSIIA following oral dosing of TSIIA showed multiple peaks. The C_max and AUC_0?t of TSIIA and its glucuronides in rats with intact bile duct were significantly lower than those of rats with bile duct cannulation. Studies from the linked-rat model and intraduodenal injection of bile containing TSIIA and its metabolites indicate that TSIIA glucuronides underwent hydrolysis and the aglycone was reabsorbed from the gut and excreted into the bile as conjugates. TSIIA had a wide tissue distribution, with a very high accumulation in the lung, but very limited penetration into the brain and testes. TSIIA was metabolized by rat CYP2C, 3A and 2D, as ticlopidine, ketoconazole and quinidine all inhibited TSIIA metabolism in rat liver microsomes. Taken collectively, these findings indicate that multiple factors play important roles in determining the pharmacokinetics of TSIIA.     

不同给药方式在大鼠内对利巴韦林的药代动力学和组织分布的影响

目的:利用HPLC-QqQ-MS多反应监测(multiple reaction monitoring, MRM)技术检测方法探究口服和呼吸道给药方式对利巴韦林药代动力学及组织分布情况的影响。方法:实验建立了检测利巴韦林的高灵敏度液质联用分析方法,经过了线性、专属性、回收率、准确度、精密度的考察。用建立的方法对口服和呼吸道给药两种方式的药代动力学和组织分布情况进行考察。结果:呼吸道给药0-72 h血药浓度较高,药物吸收较快,呼吸道给药C_max(46.1±10.6)μg/L和AUC_(0-t)(276±68)μg·L^-1·h显著性高于口服给药C_max(8.9±3.8)μg/L和AUC_(0-t)(142±63)μg·L^-1·h。组织分布结果表明,呼吸道给药肺组织利巴韦林含量明显高于口服给药,同时呼吸道给药肝脏组织含量较低。结论:与口服给药相比,呼吸道给药具有较高的血药浓度,及在肺组织含量较高,揭示了吸入给药的组织靶向作用。HPLC-QqQ-MS检测方法简单有效、准确度高、重复性好、可用于大鼠血浆,组织利巴韦林的含量测定。     

Pharmacokinetics and tissue distribution of 8,9-epoxy brevifolin in rats, a hepatoprotective constituent isolated from Phyllanthus simplex Retz by liquid chromatography coupled with mass spectrometry method

8,9-Epoxy brevifolin (EBF) is a novel compound isolated from Phyllanthus simplex Retz (P. simplex) and has been demonstrated to possess a hepatoprotective effect. The purposes of the present study were to examine the in vivo pharmacokinetics and tissue distribution of EBF in rats using a liquid chromatography coupled with mass spectrometry quantitative detection method (LC-MS/MS), with luteolin-7-O-glucoside being employed as an internal standard (IS). The method was validated within the concentration range 20-15 000 ng/ml, and the calibration curves were linear with correlation coefficients of >0.999. The limit of quantitation (LOQ) for EBF was 20 ng/ml. The intra-assay accuracy and precision ranged from 98.7% to 100.2% and 2.19% to 6.25%, respectively, while the inter-assay accuracy and precision ranged from 97.5% to 100.3% and 3.35% to 7.28%, respectively. The method was further applied to assess the pharmacokinetics and oral bioavailability of EBF after intravenous and oral administration in rats. The oral bioavailability of EBF was 12.46 +/- 2.31%. In the tissue distribution assay, its concentration was higher in the heart (13.2 +/- 0.24 microg/g) and liver (14.5 +/- 0.19 microg/g) than in other tissues.     

Pharmacokinetics,tissue distribution and relative bioavailability of geniposide-solid lipid nanoparticles following oral administration

Abstract

Geniposide has various pharmacological effects; however, low oral bioavailability limits its clinical utility. This study explores the pharmacokinetics, tissue distribution and relative bioavailability of geniposide-solid lipid nanoparticles (SLNs) following oral administration. The geniposide solution and geniposide-SLNs were orally administered to the rats, respectively. The C_max value of geniposide in the geniposide-SLNs was significantly higher than that obtained with geniposide solution. Compared with the geniposide solution, the t_1/2 and MRT were prolonged; the CL and V1/F were increased with geniposide-SLNs. The AUC_0–∞values of geniposide-SLNs were 50 times greater than geniposide solution. The ratios of AUC_{0–8 h} in the liver, spleen, heart, kidney, brain and lung of the geniposide-SLNs to geniposide solution were 25.93, 4.28, 27.91, 10.15, 5.16 and 16.22, respectively. Prepared geniposide-SLNs are very helpful for increasing the bioavailability of geniposide. These data suggest that SLNs are a promising delivery system to enhance the oral bioavailability of geniposide.     

氢氯噻嗪在小鼠体内的组织分布及药动学研究

目的建立小鼠血浆及组织中氢氯噻嗪浓度测定的HPLC—MS／MS方法,研究氢氯噻嗪在小鼠体内的组织分布及药动学。方法在血浆样品及组织样品中加入内标布洛芬,分别采用乙醚和乙酸乙酯提取处理,以甲醇-水-氨水（90：10：1）为流动相,用C18柱分离,采用电喷雾电离源（Turbo Ionspray）,负离子方式检测,扫描方式为多反应监测（MRM）。以此方法测定72只雄性健康小鼠给予氢氯噻嗪后10个时间点的血浆及组织样品,并采用DAS2．0药动学程序计算主要药动学参数。结果氢氯噻嗪在血浆中线性范围为5．0～1000μg·L^-1,在组织中线性范围为0．05～50．0μg·g^-1,日内、日间RSD均〈15％。小鼠灌胃给予氢氯噻嗪后快速分布在各组织中,其中胃、肠、肝分布最多,心分布最少。结论本法快速、准确、专属、灵敏。氢氯噻嗪灌胃给药后吸收快,消除半衰期长,组织分布广泛。     

The in vivo pharmacokinetics,tissue distribution and excretion investigation of mesaconine in rats and its in vitro intestinal absorption study using UPLC-MS/MS

1. Mesaconine, an ingredient from Aconitum carmichaelii Debx., has been proven to have cardiac effect. For further development and better pharmacological elucidation, the in vivo process and intestinal absorptive behavior of mesaconine should be investigated comprehensively.

2. An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitation of mesaconine in rat plasma, tissue homogenates, urine and feces to investigate the in vivo pharmacokinetic profiles, tissue distribution and excretion. The intestinal absorptive behavior of mesaconine was investigated using in vitro everted rat gut sac model.

3. Mesaconine was well distributed in tissues and a mass of unchanged form was detected in feces. It was difficultly absorbed into blood circulatory system after oral administration. The insufficient oral bioavailability of mesaconine may be mainly attributed to its low intestinal permeability due to a lack of lipophilicity. The absorption of mesaconine in rat’s intestine is a first-order process with the passive diffusion mechanism.     

Assessement of the pharmacokinetics,tissue distribution and excretion studies of a novel antiplatelet agent S007‐867, following administration to rats

S007‐867 is a promising novel antiplatelet agent with better efficacy and lesser bleeding risk than existing agents. The present study investigated the absorption, tissue distribution, and excretion of S007‐867 in rat model for further advancement of the molecule. A simple and robust ultra fast liquid chromatography‐tandem mass spectrometry (UFLC‐MS/MS) bioanalytical method was used to determine S007‐867 in various matrices. Following oral administration, the compound was quickly dispersed in the various tissues and peak concentration levels were achieved within 0.5–1 h. Overall, exposure of drug, i.e., AUC in different tissues was found in the order of small intestine > liver > heart > spleen > lungs > kidney > brain. The total recoveries of the S007‐867 within 96 h were 3.36% in urine and faeces. This might be due to a first‐pass effect by the liver and intestine as most of the drug was eliminated in metabolite form. These findings provide a crucial information about further development of S007‐867 as antithrombotic agent. Copyright © 2015 John Wiley & Sons, Ltd.     

Dose-independent pharmacokinetics of torasemide after intravenous and oral administration to rats

After intravenous (at doses of 1, 2, 5, and 10 mg/kg) and oral (at doses of 1, 5, and 10 mg/kg) administration of torasemide, the pharmacokinetic parameters were dose-independent. Hence, the extent of absolute oral bioavailability (F) was also independent of oral doses; the values were 95.6, 98.8, and 97.3% for oral doses of 1, 5, and 10 mg/kg, respectively. The high F values indicated that the first-pass (gastric, intestinal, and hepatic) effects of torasemide in rats could be almost negligible. After intravenous administration, the total body clearances of torasemide were extensively slower than the reported cardiac output in rats and hepatic extraction ratio was only 3-4% suggesting almost negligible first-pass effects of torasemide in the heart, lung, and liver in rats. Based on in vitro rat tissue homogenate studies, the tissues studied also showed negligible metabolic activities for torasemide. Equilibrium of torasemide between plasma and blood cells of rat blood reached fast and plasma-to-blood cells concentration ratio was independent of initial blood concentrations of torasemide, 1, 5, and 10 microg/ml; the mean value was 0.279. Protein binding of torasemide to fresh rat plasma was 93.9 +/- 1.53% using an equilibrium dialysis technique.     

Pharmacokinetics and tissue distribution of chlorpheniramine in rabbits after intravenous administration

Intravenous studies of chlorpheniramine (CPM) were conducted in six New Zealand White male rabbits (mean wt. 3.88 kg). CPM and its two demethylated metabolites in arterial serum and urine were assayed by HPLC. Triexponential equations were needed to fit the i.V. CPM serum data in three rabbits, while biexponential equations were required in the other three rabbits. Harmonic mean of V₁, V_ss, V _area , CL,and terminal t _1/2 were 2.84, 10.8, and 15.5 liters/kg, and 4.14 liters/kg/hr and 2.57 hr, respectively. The average serum protein binding was 44%. The average blood to plasma concentration ratio was 1.85. Estimated mean hepatic blood extraction ratio based on i.v. studies was 0.88. Tissue distribution studies showed rapid and extensive uptake of CPM by various organs such as lung, kidneys, and brain after i.v. bolus injection, as their concentrations were 160-, 80-, and 31- fold higher than the plasma level. The amount of CPM in the muscle was calculated to represent about 50% of CPM present in the body near the steady state. Variation in plasma protein and tissue binding was postulated to be an important factor for the observed marked interspecies difference in the apparent volume of distribution of CPM. Only 2% of the dose was excreted unchanged in the urine.     

Pharmacokinetic properties of albiflorin and paeoniflorin after oral administration of pure compound,Radix Paeoniae alba extract and Danggui-Shaoyao-San extract to rats

This study compared the pharmacokinetics of albiflorin (ALB) and paeoniflorin (PAE), respectively, after oral administration of ALB, PAE, Radix Paeoniae alba (RPA) extract, and Danggui-Shaoyao-San (DSS) extract to rats on separate occasions. Analytes were detected simultaneously with liquid chromatography-tandem mass spectrometry. Noncompartmental pharmacokinetic parameters were calculated. After oral administration of RPA and DSS extract to rats, ALB reached maximum concentrations of 4637 ± 2774 ng/ml (0.40 ± 0.14 h) and 226 ± 122 ng/ml (0.35 ± 0.14 h) and PAE reached maximum concentrations of 2132 ± 560 ng/ml (0.40 ± 0.14 h) and 143 ± 65 ng/ml (0.45 ± 0.11 h), respectively. Compared to the AUC_0 ? t value (1122 ± 351 and 722 ± 158 ng h/ml for ALB and PAE, respectively) after administration of monomers, larger AUC_0 ? t value of ALB (4755 ± 2560 ng h/ml) and PAE (2259 ± 910 ng h/ml) after administration of RPA extract and smaller AUC_0 ? t value of ALB (411 ± 118 ng h/ml) and PAE (242 ± 126 ng h/ml) after administration of DSS extract were obtained. The C _max, AUC, and K _el of ALB and PAE were remarkably increased (P < 0.05, 0.01 or 0.005) during oral administration of RPA extract in comparison to that of DSS extract.     

Pharmacokinetics,tissue distribution,and excretion of FGF‐21 following subcutaneous administration in rats

As one of the fibroblast growth factor (FGF) superfamily, FGF‐21 has been extensively investigated for its functions and roles since its discovery. It has been demonstrated to be one of the key regulators for glucose and lipid metabolism, and exhibits beneficial effects on cardiovascular disease. However, studies focusing on its pharmacokinetic behavior in vivo as a novel therapeutic agent have not been reported. In the present study, rapid and sensitive analytical approaches including radioactivity assay and assay after precipitation/separation by high performance liquid chromatography (HPLC) were established to determine the content of FGF‐21 tagged with ¹²⁵I in plasma, tissue, and excrement. The results indicated that FGF‐21 were quickly absorbed into systematic circulation and slowly eliminated; C_max and exposure increased in a dose‐dependent manner, exhibiting a typical linear pharmacokinetic pattern. Tissue distribution also confirmed that the kidney is the primary organ for FGF‐21 to be distributed, even though radioactivity of FGF‐21 was recovered in all tissues examined. In addition, the results also supported that urinary excretion was the critical route for FGF‐21 to be eliminated. The study fully clarifies the pharmacokinetic behavior of FGF‐21 and can provide valuable information and support further safety and toxicology development.     

Pharmacokinetics and tissue distribution of ginsenoside Rh2 and Rg3 epimers after oral administration of BST204, a purified ginseng dry extract,in rats

Abstract

1. BST204, a purified ginseng dry extract containing a high concentration of racemic Rh2 and Rg3 mixtures, is being developed for supportive care use in cancer patients in Korea. This study investigates the pharmacokinetics and tissue distribution of BST204 in rats.

2. After oral administration of BST204, only the S epimers, S-Rh2 and S-Rg3, could be determined in rat plasma. The poor absorption of the R-epimers, R-Rh2 and R-Rg3, may be attributed to lower membrane permeability and extensive intestinal oxygenation and/or deglycosylation into metabolites. The AUC and C_max values of both S-Rh2 and S-Rg3 after BST204 oral administration were proportional to the administered BST204 doses ranged from 400?mg/kg to 2000?mg/kg, which suggested linear pharmacokinetic properties.

3. There were no statistically significant differences in the pharmacokinetics of S-Rh2 and S-Rg3 after oral administration of pure S-Rh2 (31.5?mg/kg) and S-Rg3 (68?mg/kg) compared with oral administration of BST204, 1000?mg/kg. These indicated that the presence of other components of BST204 extract did not influence the pharmacokinetic behavior of S-Rh2 and S-Rg3.

4. After oral dosing of BST204, S-Rh2 and S-Rg3 were distributed mainly to the liver and gastrointestinal tract in rats.

5. Our finding may help to understand pharmacokinetic characteristics of S-Rh2, R-Rh2, S-Rg3, and R-Rg3, comprehensively, and provide useful information in clinical application of BST204.

     

Tissue distribution and pharmacokinetics of brucine niosomal gels in rats after topical and oral application

Brucine has anti-inflammatory and analgesic effects and is the main active compound of the seeds of Strychnos nux-vomica L. To study brucine niosomal gels, a reliable and rapid LC-MS/MS method was established to quantify brucine levels in rats. Tissue distribution and pharmacokinetics of brucine were investigated after topical and oral application of brucine niosomal gels to rats. The plasma concentration versus time profiles suggested that systemic exposure of brucine for oral administration of brucine niosomal gels was higher than that for topical administration, and topical administration showed a relatively sustained release. There was a considerable amount of brucine distributed in the knee joint. These results provided a strong basis for the follow-up study of this preparation.