A rapid method for simultaneous quantification of berberine, berbamine, magnoflorine and berberrubine in mouse serum using UPLC-MS/MS.

Berberidis cortex, the dry bark of Berberis L., is used to treat diabetes and contains at least three bioactive components: berberine (BBR), berbamine (BBM) and magnoflorine (MGF). BBR in turn is metabolized into berberrubine (BRB). Although it is possible to quantify each of these components individually in serum, there are currently no methods for simultaneously quantifying all four. Here, we developed a specific and rapid method for simultaneously quantifying BBR, BBM, MGF and BRB in mouse serum using ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Samples were pretreated by protein precipitation, separated using an ACQUITY UPLC® BEH C18 column and detected by a triple quadrupole mass spectrometer with electrospray ionization. The compound [9,10-(OC2H3)2]-BBR (d6-BBR) was used as internal standard for BBR and BRB, boldine (BOL) for MGF and tetrandrine (TET) for BBM. The m/z transitions for precursor/product ion pairs were 336.1/320.2 for BBR, 305.2/566.3 for BBM, 342.0/297.1 for MGF, 322.1/307.2 for BRB, 342.2/294.3 for d6-BBR, 312.2/580.3 for TET and 328.1/265.2 for BOL. We validated our method in terms of selectivity, linearity and lower limit of quantification, accuracy, precision, matrix effect and recovery, dilution integrity and stability. This method showed good linearity from 0.1 to 40 ng/mL for BBR, 8 to 3200 ng/mL for BBM, 5 to 2000 ng/mL for MGF and 0.2 to 80 ng/mL for BRB. The chromatographic run time was 3.9 min, and sample preparation took approximately 15 min per batch. Finally, we used our method to measure BBR, BBM, MGF and BRB in serum from diabetic mice after gavage administration of BBR hydrochloride, BBM hydrochloride, and MGF. This method is precise, accurate and suitable for high-throughput sample analysis.

HPLC-MS/MS method for the determination and pharmacokinetic study of six compounds against rheumatoid arthritis in rat plasma after oral administration of the extract of Caulophyllum robustum Maxim.

Caulophyllum robustum Maxim (CRM) is a well-known traditional Chinese medicine (TCM) mainly present in the northeast, northwest and southwest regions of China, which is belong to the family Berberidaceae. The roots and rhizomes of CRM have been used as a famous TCM for the treatment of rheumatoid arthritis (RA). The selective, sensitive and accurate high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method for the determination and pharmacokinetic study cauloside H, leonticin D, cauloside G, cauloside D, cauloside C and magnoflorine in rat plasma was developed and validated in this paper. Chromatographic separation was achieved by using a Waters ACQUITY UPLC HSS T3 (100 mm × 2.1 mm, 1.7 µm) with gradient elution using a mobile phase consisting of acetonitrile and 0.1 % formic acid in water at a flow rate of 0.4 mL/min. The detection was performed in multiple reaction monitoring (MRM) mode and electrospray ionization (ESI) in positive and negative modes. The linearity, precision, accuracy, extraction recovery, matrix effects and stability were assessed to validate the current high-performance liquid chromatography/mass spectrometry (HPLC-MS) assay. Good linearity was achieved for each analyte with a correlation coefficient (r2) > 0.99). All the precision (RSD) data were less than 12.20 %, the accuracies ranged from -12.39 % to 10.55 %, the recovery rates from the rat plasma ranged from 85.48%-98.69 %, and the matrix effects ranged from 80.96 % to 91.35 %. The validated approach was successfully applied to study the pharmacokinetic characteristics of saponins and alkaloids in plasma after administering CRME to rats, and this assay provides a platform for studying the active components of multicomponent traditional Chinese medicines and provides useful information for further clinical studies.

Simultaneous determination of multiple components in rat plasma and pharmacokinetic studies at a pharmacodynamic dose of Xian-Ling-Gu-Bao capsule by UPLC-MS/MS.

Xian-Ling-Gu-Bao capsule (XLGB) is an effective traditional Chinese medicine prescription (TCMP) that is used for the prevention and treatment of osteoporosis in China. A rapid, simple, efficient and stable method based on UPLC-MS/MS technology was developed for simultaneous determination of multiple components of XLGB in rat plasma. Mass spectrometric detection was performed in multiple reaction monitoring (MRM) mode with electrospray ionization (ESI). For twenty-one selected quantitative prototypes, all calibration curves showed favourable linearity (r>0.9932) in linear ranges. The lower limits of quantification (LLOQs) were 2 ng/mL for psoralen (PL), 2.5 ng/mL for asperosaponin VI (AS), 1 ng/mL for isopsoralen (IPS) and sweroside (SW), 0.5 ng/mL for magnoflorine (MA), bavachinin (BVN), tanshinone IIA (TA), timosaponin BII (TBII) and icaritin (ICT), 0.1 ng/mL for epimedin B (EB) and epimedin C (EC), 0.05 ng/mL for icariin (IC), isobavachalcone (IBC), psoralidin (PD), bavachin (BV), bavachalcone (BC), epimedin A (EA) and isobavachin (IBV), 0.02 ng/mL for neobavaisoflavone (NEO) and icariside I (ICI) and 0.01 ng/mL for icariside II (ICII). The intra-day and inter-day (low, medium, high) precision (relative standard deviation) for all analytes was less than 8.63%, and the accuracies (as relative error) were in the range of -12.45% to 8.91%. Extraction recoveries and matrix effects of analytes and IS were acceptable. All analytes were stable during the assay and storage in plasma samples. The validated method was successfully applied to the pharmacokinetics (PK) studies of the twenty-one prototypes at pharmacodynamic doses (0.3 and 1 g/kg/day). In addition, dynamic profiles of 28 metabolites (phase II conjugates: 23 glucuronide conjugates, 2 sulfate conjugates and 3 glucuronide or sulfate conjugates) were also monitored by their area/IS area-time curves. As a result, coumarins, prenylated flavonoids from Psoraleae Fructus, alkaloids and prenylated flavonol glycosides from Epimedii Herba, and iridoid glycosides, triterpenoid saponins from Dipsaci Asperoidis Radix were considered to be the key effective substances of XLGB due to their high exposure and appropriate pharmacokinetic features. This is the first report to reveal pharmacodynamic ingredients by a reversed pharmacodynamic (PD) - pharmacokinetics (PK) study.

Use of magnoflorine-phospholipid complex to permeate blood-brain barrier and treat depression in the CUMS animal model.

To improve the liposolubility and blood-brain barrier permeability of magnoflorine, a new formulation of magnoflorine-phospholipid complex was prepared, characterized, and pharmacologically evaluated in the chronic unpredictable mild stress animal model. In this paper, the magnoflorine-phospholipid complex was synthesized and its characterization was determined. The antidepressant-like and antioxidant activity of magnoflorine-phospholipid complex was investigated by behavioral tests and western blotting analysis. As a result, the magnoflorine-phospholipid complex displayed high encapsulation efficiency and significantly improved the oil-water participate coefficient. In vivo blood-brain distribution study, the magnoflorine-phospholipid complex extended the duration of magnoflorine in blood and help magnoflorine to permeate the blood-brain barrier into brain. In behavioral tests, the magnoflorine-phospholipid complex significantly decreased immobility time compared to model control group in both FST and TST. Furthermore, the magnoflorine-phospholipid complex increased the expression of antioxidative stress-related proteins by the western blotting analysis. These findings strongly suggest that the phospholipid complex could significantly improve liposolubility, drug properties of magnoflorine and help magnoflorine permeate blood-brain barrier and exert the antidepressant effect.

Identify super quality markers from prototype-based pharmacokinetic markers of Tangzhiqing tablet (TZQ) based on in vitro dissolution/ permeation and in vivo absorption correlations.

BACKGROUND: A quality marker (Q-marker) is defined as an inherent chemical compound that is used for the quality control of a drug. Its biological activities are closely related to safety and therapeutic effects. Generally, a multiple-component herbal medicine may have many Q-markers. We therefore proposed a concept of "super Q-marker" satisfying both the criterion of Q-markers and PK-markers to be used in more effective quality control of herbal medicine. PURPOSE: The first aim was to find suitable prototype-based PK-markers from Tangzhiqing tablets (TZQ), a Chinese patent medicine. Then super Q-markers were expected to be identified from the prototype-based PK-markers based on an in vitro-in vivo correlation study. METHODS: Potentially eligible prototype-based PK-markers were identified in a single- and multiple-dose pharmacokinetic study on TZQ in 30 healthy volunteers. The in vitro dissolution and permeation profiles of the prototype-based PK-markers of TZQ were evaluated by the physiologically-based drug dissolution/absorption simulating system (DDASS). An in vitro-in vivo correlation analysis was conducted between the dissolution/permeation behaviors in DDASS and the actual absorption profiles in human to test the transferability and traceability of the promising super Q-markers for TZQ. RESULTS: In human, plasma paeoniflorin and nuciferine as prototype-based PK-markers exhibited the appropriate pharmacokinetic properties, including dose-dependent systemic exposure (AUC, Cmax) and a proper elimination half-life (1∼3h). In DDASS, it was predicted that paeoniflorin and nuciferine are highly permeable but the absorption rates are primarily limited by the dissolution rates. Moreover, the established in vitro-in vivo correlations of paeoniflorin and nuciferine were in support of the super Q-markers features. CONCLUSION: Paeoniflorin and nuciferine are identified as the super Q-markers from the prototype-based PK-markers of TZQ based on findings from a combination of in vitro, in vivo, and in vitro-in vivo correlation studies. This method is practical for optimal identification of qualified Q-markers, thus helping improve the quality control of herbal medicines.

Pharmacokinetics of boldine in control and Mrp2-deficient rats.

The aim of the present study was to describe the currently poorly understood pharmacokinetics (PK) of boldine in control rats (LW, Lewis rats), and Mrp2 transporter-deficient rats (TR(-)). Animals from the LW and TR(-) groups underwent a bolus dose study with 10 mg/kg of boldine applied either orally or intravenously in order to evaluate the major PK parameters. The TR(-) rats demonstrated significantly reduced total clearance with prolonged biological half-life (LW 12+/-4.6 versus TR(-) 20+/-4.4 min), decreased volume of distribution (LW 3.2+/-0.4 l/kg versus TR(-) 2.4+/-0.4 l/kg) and reduced bioavailability (LW 7 % versus TR(-) 4.5 %). Another set of LW and TR(-) rats were used for a clearance study with continuous intravenous administration of boldine. The LW rats showed that biliary and renal clearance formed less than 2 % of the total clearance of boldine. The treatment of samples with beta-glucuronidase showed at least a 38 % contribution of conjugation reactions to the overall clearance of boldine. The TR(-) rats demonstrated reduced biliary clearance of boldine and its conjugates, which was partly compensated by their increased renal clearance. In conclusion, this study presents the PK parameters of boldine and shows the importance of the Mrp2 transporter and conjugation reactions in the elimination of the compound.

Metabolism profiles of nuciferine in rats using ultrafast liquid chromatography with tandem mass spectrometry.

Nuciferine (NF) is one of the main aporphine alkaloids existing in the traditional Chinese medicine Folium Nelumbinis (lotus leaves). Modern pharmacological studies have demonstrated that NF has a broad spectrum of bioactivities, such as anti-HIV and anti-hyperlipidemic effects, and has been recommended as a leading compound for new drug development. However, the metabolites and biotransformation pathway of NF in vivo have not yet been comprehensively investigated. The present study was performed to identify the metabolites of NF for exploring in vivo fates. Rat plasma and urine samples were collected after oral administration and prepared by liquid-liquid extraction with ethyl acetate. A method based on ultrafast liquid chromatography with tandem mass spectrometry was applied to identify the metabolites. Q1 (first quadrupole) full scan combined with a multiple reaction monitoring (MRM) survey scan were used for the detection of metabolites. MRM-information-dependent acquisition of enhanced product ions was used for the structural identification of detected metabolites. A total of 10 metabolites were identified, including phase I (demethylation, oxidation and dehydrogenation) and phase II (glucuronidation, sulfation and glutathione) biotransformation products. Demethylation is the main metabolic pathway of NF in the body. These results can help in improving understanding of the disposition and pharmacological mechanism of NF in the body. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacokinetics of a multicomponent herbal preparation in healthy Chinese and African volunteers.

K-601 is an herbal formulation for influenza consisting of Lonicera japonica, Isatis indigotica, Rheum palmatum, Phellodendron chinense, and Scutellaria baicalensis. In this work, we characterized the chemical constituents in K-601, identified the absorbed compounds and determined their pharmacokinetics in 6 Chinese and African volunteers by liquid chromatography with time-of-flight mass spectrometry. Similarity evaluation for chromatographic fingerprint of nine different batches showed values above 0.983. Totally, 50 components were identified in K-601. Then, 15 major prototype compounds and 17 metabolites were identified in human plasma. Major metabolic pathways included glucuronidation, sulfation, methylation, demethylation, and reduction. The pharmacokinetics of the most abundant prototype compounds, berberine, jatrorrhizine, palmatine and magnoflorine were determined. Significant pharmacokinetic differences were observed between the African and Chinese subjects. The AUCs of the African is about 4-10 fold higher than that of the Chinese for the three benzylisoquinoline alkaloids. Magnoflorine, an aporphine alkaloid, was absorbed better in the Chinese than in the African. The biotransformation of K-601 by human intestinal microflora was also investigated. The major reactions included hydroxylation, methylation, demethylation, acetylation and reduction. Glucuronidation and sulfation were not observed with fecal flora. These results may be important and useful in linking data from pharmacological assays and clinical effects.

In vitro and in vivo identification of metabolites of magnoflorine by LC LTQ-Orbitrap MS and its potential pharmacokinetic interaction in Coptidis Rhizoma decoction in rat.

Magnoflorine, an important aporphine alkaloid in Coptidis Rhizoma, is increasingly attracting research attention because of its pharmacological activities. The in vivo and in vitro metabolism of magnoflorine was investigated by LC LTQ-Orbitrap MS. In vivo samples including rat urine, feces, plasma and bile were collected separately after both oral (50 mg kg(-1) ) and intravenous administration (10 mg kg(-1) ) of magnoflorine, along with in vitro samples prepared by incubating magnoflorine with rat intestinal flora and liver microsome. As a result, 12 metabolites were found in biological samples. Phase I metabolites were identified in all biological samples, while phase II metabolites were mainly detected in urine, plasma and bile. In a pharmacokinetic study, rats were not only dosed with magnoflorine via oral (15, 30 and 60 mg kg(-1) ) and intravenous administration (10 mg kg(-1) ) but also dosed with Coptidis Rhizoma decoction (equivalent to 30 mg kg(-1) of magnoflorine) by intragastric administration to investigate the interaction of magnoflorine with the rest of compounds in Coptidis Rhizoma. Studies showed that magnoflorine possessed lower bioavailability and faster absorption and elimination. However, pharmacokinetic parameters altered significantly (p < 0.05) when magnoflorine was administered in Coptidis Rhizoma decoction. Oral gavage of Coptidis Rhizoma decoction decreased the absorption and elimination rates of magnoflorine, which revealed that there existed pharmacokinetic interactions between magnoflorine and the rest of ingredients in Coptidis Rhizoma.

A novel UPLC-MS/MS method for sensitive quantitation of boldine in plasma, a potential anti-inflammatory agent: application to a pharmacokinetic study in rats.

Boldine is a potential anti-inflammatory agent found in several different plants. Published bioanalytical methods using HPLC with ultraviolet and fluorescent detection lacked enough sensitivity and required tedious sample preparation procedures. Herein, we describe the development of a novel ultra-high performance LC with MS/MS for determination of boldine in plasma. Boldine in plasma was recovered by liquid-liquid extraction using 1 mL of methyl tert-butyl ether. Chromatographic separation was performed on a C18 column at 45°C, with a gradient elution consisting of acetonitrile and water containing 0.1% (v/v) formic acid at a flow rate of 0.3 mL/min. The detection was performed on an electrospray triple-quadrupole MS/MS by positive ion multiple reaction monitoring mode. Good linearity (r(2) > 0.9926) was achieved in a concentration range of 2.555-2555 ng/mL with a lower limit of quantification of 2.555 ng/mL for boldine. The intra- and inter-day precisions of the assay were 1.2-6.0 and 1.8-7.4% relative standard deviation with an accuracy of -6.0-8.0% relative error. This newly developed method was successfully applied to a single low-dose pharmacokinetic study in rats and was demonstrated to be simpler and more sensitive than the published methods, allowing boldine quantification in reduced plasma volume.

Study on the PK profiles of magnoflorine and its potential interaction in Cortex phellodendri decoction by LC-MS/MS.

Magnoflorine, an aporphine alkaloid in Cortex phellodendri, is increasingly attracting research attention because of its antidiabetic effects. However, at present, little information on its pharmacokinetics (PK) in vivo is available. In this study, a sensitive, rapid, and selective method was developed to determine the magnoflorine content in rat plasma using liquid chromatography-tandem mass spectrometry. Following liquid-liquid extraction, the calibration curve showed good linearity within the concentration range of 2.93 to 1,500 ng ml(-1). The intra- and inter-day precisions were all below 7.8 %, and the accuracy ranged from 94.9 to 103.4 %. The method was successfully applied in investigating the PK of magnoflorine in rats. The compound had low bioavailability, a high absorption rate, and a high elimination rate. However, area under the curve, T 1/2, and MRT increased approximately twofold when the same dosage of the compound was administered in a C. phellodendri decoction (20.8 g kg(-1)). Moreover, T max was prolonged from 0.3 to 3.33 h. Furthermore, a comparison of coadministration of the mixture group, magnoflorine (40 mg kg(-1)) and berberine (696.4 mg kg(-1)), with the C. phellodendri decoction group, revealed that no statistical difference (P > 0.05) was found in the parameter AUC, and certain similar changes in the PK trend to the herbal medicine group were also observed. These results suggested that oral administration of the herbal medicine decreased the absorption and elimination rates of magnoflorine and increased its bioavailability. Berberine played a significant role in interacting with magnoflorine and in affecting the PK profiles of magnoflorine in the C. phellodendri decoction group.

Development and validation of a high-performance liquid chromatography coupled with ultraviolet detection method for the determination of isocorydine in rat plasma and its application in pharmacokinetics.

A new HPLC-UV method has been developed, validated and applied for the determination of isocorydine (CAS 475-67-2) in rat plasma after oral or intravenous (i. v.) administration. Caffeine was used as the internal standard (IS). The analyte and IS were extracted from rat plasma by liquid-liquid extraction (LLE) with methyl tert-butyl ether and they were separated on an XTerra C18 column (250×4.6 mm, 5 µm, pH 1-12) with UV detection at 264 nm. The mobile phase consisted of methanol and 0.02 mol/L potassium dihydrogen phosphate-phosphoric acid buffer solution (pH 3.2) (30:70, v/v) at a flow rate of 1 mL/min for 8.5 min. The retention times of isocorydine and caffeine were approximately 6.5 and 5.1 min, respectively. The good linearity of the calibration curves was observed over the concentration range of 0.05-8 µg/mL (n=8, r 2≥0.9995). The lower limit of quantification (LLOQ) was 0.05 µg/mL [signal to noise ratio (S/N)≥10], and the limit of detection (LOD) was demonstrated as 0.01 µg/mL (S/N≥3). The mean extraction recovery ranged from 83.7% to 89.5% at 3 quality control (QC) concentrations. Intra-day and inter-day precision (relative standard deviation, RSD%) were within 4.7% and accuracy (relative error, RE%) ranged from -1.2% to 4.5%. The developed method was successfully applied to determination of the pharmacokinetic properties of isocorydine in rats after oral administration at a dose of 20 mg/kg and i. v. injection at 5 mg/kg.

Orthogonal array design for optimization of hollow-fiber-based liquid-phase microextraction combined with high-performance liquid chromatography for study of the pharmacokinetics of magnoflorine in rat plasma.

In this work, a new sample-preparation method based on hollow-fiber liquid-phase microextraction (HF-LPME) was developed for analysis of magnoflorine in rat plasma. Analysis was accomplished by reversed-phase high-performance liquid chromatography (HPLC), with ultraviolet detection by use of a photodiode-array detector. An orthogonal array design (OAD) was found to be effective for optimization of major conditions which may affect the efficiency of HF-LPME. Under the optimized conditions (pH of donor and acceptor phases 12 and 2.0, respectively; extraction time 20 min; stirring speed 800 rpm; and addition of 10 % (w/v) salt), the preconcentration factor for magnoflorine was 355. Calibration curves with reasonable linearity (r(2)≥0.9994) were obtained in the range 10-1000 ng mL(-1). Intra-day and inter-day precision (RSD) were <5.5 % and the limit of detection (LOD) for the analyte was 3.0 ng mL(-1) (S/N=3). The validated method was successfully used for pharmacokinetic studies of magnoflorine in rat plasma after intravenous administration.

Rapid determination of isocorydine in rat plasma and tissues using liquid chromatography--tandem mass spectrometry and its applications to pharmacokinetics and tissue distribution.

A rapid and sensitive method for the determination of isocorydine in rat plasma and tissues was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The biological samples were processed by extracting with diethyl ether-dichloromethane (3:2, v/v) and tetrahydropulmatine was used as the internal standard (IS). Detection of the analytes was achieved using positive ion mode electrospray ionization in the multiple reaction monitoring mode. The MS/MS ion transitions monitored were m/z 342.0→279.0 and 356.0→191.9 for isocorydine and IS, respectively. The maximum plasma concentration (C(max) 2496.8 ± 374.4 µg/L) was achieved at 0.278 ± 0.113 h (T(max)) and the half-life (t(1/2)) of isocorydine was 0.906 ± 0.222 h after a 20 mg/kg oral administration. As for a 2 mg/kg intravenous (i.v.) administration, the C(max) and clearance (CL) were 1843.3 ± 338.3 µg/L and 2.381 ± 0.356 L/h/kg, respectively. Based on the AUC(0-∞) obtained from oral and i.v. administration, the absolute bioavailability (F) was estimated as 33.4%. Tissue distribution results indicated that isocorydine underwent a rapid and wide distribution into tissues and it could effectively cross the blood-brain barrier.

HPLC method for the pharmacokinetics and tissue distribution of taspine solution and taspine liposome after intravenous administrations to mice.

Taspine is a bioactive aporphine alkaloid, which has many potent pharmacological effects. A simple, rapid HPLC method to quantify taspine in mouse plasma and tissue homogenates containing either taspine solution or liposome was developed and validated. Sample preparation was achieved by liquid-liquid extraction with acetoacetate. Taspine was separated on a C(18) reversed phase HPLC column, and quantified by its absorbance at 245 nm. The pharmacokinetics and tissue distribution after intravenous administrations of taspine liposome (L-Ta) and taspine solution (Ta) to ICR mice were then compared. The area under the plasma concentration-time curve (AUC) was higher for L-Ta than for Ta. In contrast, the total body clearance (CL), apparent volume of distribution V(c) and plasma half-life for the distribution (t(1/2 alpha)) and elimination phase (t(1/2 beta)) were lower for L-Ta, in comparison to the respective parameter of Ta. The AUC values were higher in the lung than in other organs for both L-Ta and Ta. The AUC in the spleen, kidney and liver of L-Ta were higher than those of Ta. However, the heart and brain AUC of Ta was higher than that of L-Ta. It can thus be concluded that incorporation into liposomes prolonged taspine retention within the systemic circulation, increased its distribution to the spleen and liver but reduced its distribution to the heart and brain.

[Study on pharmacokinetics of crebanine injection in rabbits].

OBJECTIVE: To develop an HPLC method for the determination of serum level of Crebanine (Cre) and study on the pharmacokinetics of Cre injection in rabbits. METHOD: To sample blood serum from the rabbits' ears which were injected the Cre by 2.0 mg x kg(-1) at different time and use HPLC to determine the concentration of Cre in it, the pharmacokinetic parameters were accessed by the DAS software. RESULT: Cre was fitted to a two compartment open pharmacokinetic model in rabbits. There was no signifiant difference between the male and female rabbits'pharmacokinetic by t-test. The mainly pharmacokinetic parameters were: t1/2alpha = (3. 246 +/-0.222) min, t1/2beta = (36.67+/-5.52) min, Cmax = (1.401 +/- 0.062) mg x L(-1), Vd = (5.928 +/- 0.877) L x kg(-1), Cl = (0. 051 +/-0.003) L x min(-1) x kg(-1). CONCLUSION: This experiment can objectively show the pharmacokinetics regularity of Crebanine injection in rabbits. Crebanine injection was a speeding disposition drug (t1/2 <1 h) and disposed extensively and rapidly in rabbits.

Biological disposition of boldine: in vitro and in vivo studies.

Boldine is a natural compound with well-established free radical scavenger and hepatoprotective properties. The further exploration of its actual therapeutic potential as an antioxidant is, however, partially limited by the absence of knowledge on its pharmacokinetics. In the present studies, we provide information on the in vitro and in vivo biological disposition of boldine. The addition of 200 microM boldine to an isolated rat hepatocyte suspension was followed by a time-dependent (0-60 min) disappearance of boldine from the extracellular medium. This decline was associated with an early (first 2 min) and swift accumulation (1600 microM) of boldine within the cells. Although the intracellular concentration of boldine diminished, boldine was always found to occur within the cells at concentrations substantially higher than those initially added to the preparation. Boldine was also concentration-dependently removed from the extracellular medium by isolated rat livers portally perfused with the antioxidant. In vivo studies, conducted in rats, revealed that following either its oral or its intravenous administration, plasma boldine concentrations declined rapidly and according to an apparently first order type of kinetics. After its oral administration (50 or 75 mg/kg), boldine was rapidly (within 30 min) absorbed and preferentially concentrated in the liver, with substantially lower concentrations being found in the brain and heart. Maximal hepatic concentrations of boldine were found to be equal to or greater than those needed to afford antioxidant and hepatoprotective effects in vitro.

Toxicological evaluation of the hydro-alcohol extract of the dry leaves of Peumus boldus and boldine in rats.

The hydro-alcohol extract of the dry leaves of Peumus boldus and boldine, showed abortive and teratogenic action and changes in the blood levels of bilirubin, cholesterol, glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and urea in rats. The long term administration of the extract and boldine did not cause histological modification during a period of 90 days.

Determination of dicentrine in rat plasma by high-performance liquid chromatography and its application to pharmacokinetics.

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of dicentrine in rat plasma after 10 mg/kg intravenous administration. After addition of an internal standard (coumarin), plasma was deproteinized by acetonitrile for sample clean-up. The drugs were separated on a reversed-phase Nucleosil C18 column (250 x 4 mm I.D., particle size 5 microns) and detected by photodiode-array detection at a wavelength of 308 nm. Acetonitrile-water (35:65, v/v, pH 2.5-2.8, adjusted with orthophosphoric acid) was used as the mobile phase. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve.