Development and validation of a high performance liquid chromatography quantification method of levo-tetrahydropalmatine and its metabolites in plasma and brain tissues: application to a pharmacokinetic study

Levo-tetrahydropalmatine (l-THP) is an alkaloid isolated from Chinese medicinal herbs of the Corydalis and Stephania genera. It has been used in China for more than 40 years mainly as an analgesic with sedative/hypnotic effects. Despite its extensive use, its metabolism has not been quantitatively studied, nor there a sensitive reliable bioanalytical method for its quantification simultaneously with its metabolites. As such, the objective of this study was to develop and validate a sensitive and selective HPLC method for simultaneous quantification of l-THP and its desmethyl metabolites l-corydalmine (l-CD) and l-corypalmine (l-CP) in rat plasma and brain tissues. Rat plasma and brain samples were processed by liquid-liquid extraction using ethyl acetate. Chromatographic separation was achieved on a reversed-phase Symmetry® C18 column (4.6 × 150 mm, 5 μm) at 25°C. The mobile phase consisted of acetonitrile-methanol-10 mm ammonium phosphate (pH 3) (10:30:60, v/v) and was used at a flow rate of 0.8 mL/min. The column eluent was monitored at excitation and emission wavelengths of 230 and 315 nm, respectively. The calibration curves were linear over the concentration range of 1-10,000 ng/mL. The intra- and interday reproducibility studies demonstrated accuracy and precision within the acceptance criteria of bioanalytical guidelines. The validated HPLC method was successfully applied to analyze samples from a pharmacokinetic study of l-THP in rats. Taken together, the developed method can be applied for bioanalysis of l-THP and its metabolites in rodents and potentially can be transferred for bioanalysis of human samples.

[Study on effect of oligochitosan in promoting intestinal absorption of protoberberine alkaloids in extracts from Corydalis saxicola total alkaloids]

OBJECTIVE

To investigate the effect of oligochitosan in promoting intestinal absorption of protoberberine alkaloids in extracts from Corydalis saxicola total alkaloids.

METHOD

The in vitro single-pass intestinal perfusion model in rats was established to study the changes in absorption kinetic parameters of dehydrocavidine, berberine hydrochloride and palmatine chloride in C. saxicola total alkaloids after the addition of different concentrations oligochitosan and evaluate the effect of oligochitosan in promoting intestinal absorption of the drugs.

RESULT

The concentration of oligochitosan had different effects on the absorption rate constant (Ka) and apparent permeability coefficient (Peff) of the three active component in rat intestines. Ka and Peff in 0.5% oligochitosan group significantly increased, indicating a stronger effect in promoting the absorption.

CONCLUSION

Oligochitosan has a certain effect in promoting the intestinal absorptions of protoberberine alkaloids in C. saxicola total alkaloids.

A UPLC-MS/MS method for simultaneous quantitation of three monoterpene glycosides and four alkaloids in rat plasma: application to a comparative pharmacokinetic study of Huo Luo Xiao Ling Dan and single herb extract

The objective of this study was to develop a sensitive and reliable ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous quantitation of three monoterpene glycosides (paeoniflorin, alibiflorin and oxypaeoniflorin) and four alkaloids (tetrahydropalmatine, corydaline, dehydrocorydaline and berberine), the main active ingredients of Radix Paeoniae Rubra extract (RPE) and Corydalis yanhusuo extract (CYE) in Huo Luo Xiao Ling Dan (HLXLD), and to compare the pharmacokinetics of these active ingredients in normal and arthritic rats orally administrated with HLXLD or RPE/CYE alone. The analytes and internal standard (IS) (geniposide) were separated on a XBridge C18 column (150 × 4.6 mm, 3.5 µm) using gradient elution with the mobile phase consisting of methanol and 0.01% formic acid in water at a flow rate of 0.6 ml/min. The detection of the analytes was performed on Acquity UPLC-MS/MS system with an electrospray ionization and multiple reaction monitoring mode via polarity switching between negative (for monoterpene glycosides) and positive (for alkaloids) ionization mode. The lower limits of quantification were 2.5, 1, 0.5, 0.2, 0.2, 0.02 and 0.01 ng/ml for paeoniflorin, alibiflorin, oxypaeoniflorin, tetrahydropalmatine, corydaline, dehydrocorydaline and berberine, respectively. Intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (15%). The mean extraction recoveries of analytes and IS from rat plasma were all more than 83.1%. The validated method has been successfully applied to determination of the analytes. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes between herbal formula and single herb group, normal and arthritic group.

Integrated pharmacokinetics of five protoberberine-type alkaloids in normal and insomnic rats after single and multiple oral administration of Jiao-Tai-Wan

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao-Tai-Wan (JTW), an important herbal formula consists of Rhizoma coptidis and Cortex cinnamomi powder, is a famous prescription which has been used for centuries to treat insomnia in Traditional Chinese Medicine. The purpose of this study is to compare the pharmacokinetic properties of five protoberberine-type alkaloids (i.e. berberine, palmatine, coptisine, epiberberine and jatrorrhizine), the main bioactive constituents in JTW, between normal and insomnic rats. We also investigate the differences between single-dose and multiple-dose pharmacokinetics of five protoberberine-type alkaloids.

MATERIALS AND METHODS

The insomnic rat models were induced by intraperitoneal injection of one-dose para-chlorophenylalanine acid (PCPA). Quantification of five protoberberine-type alkaloids in rat plasma was achieved by using a rapid LC-MS/MS method. Plasma samples were collected at different time points to construct pharmacokinetic profiles by plotting drug concentration versus time and estimate pharmacokinetic parameters. An unpaired Student׳s t test was used for comparisons with SPSS 17.0.

RESULTS

The five protoberberine-type alkaloids of single-dose normal groups had slow absorption and low bioavailability, as well as a delay of peak time. In the single-dose oral administration, the Cmax and Tmax of five ingredients in insomnic rats had significant differences compared with those of normal rats. In the multiple-dose oral administration, the pharmacokinetic parameters of five protoberberine-type alkaloids varied greatly in insomnic rats. In the normal rats, there were significant differences (P<0.05) in the principal pharmacokinetic parameters such as Cmax and Tmax between single-dose and multiple-dose oral administration. In the insomnic rats, the five ingredients of multiple-dose groups showed better absorption than the single-dose groups. Particularly, three peaks were observed in multiple-dose model group of plasma-concentration curves.

CONCLUSIONS

The pharmacokinetic behavior of five protoberberine-type alkaloids was described in this paper. In both normal groups and model groups, the pharmacokinetic behavior of multiple-dose had significant differences comparing with the single-dose; either single-dose or multiple-dose, the pharmacokinetic behavior of insomnic rats had significant differences comparing the normal rats. Multiple dosing may improve the absorption of JTW in insomnic rats, which will increase the bioavailability and bring into active role in therapeutical effect.

Plasma pharmacokinetics and lung distribution of tetrahydropalmatine after topical application of cold asthma recipe extract: Feishu (BL 13) versus Non-Feishu acupoint

ETHNOPHARMACOLOGICAL RELEVANCE

Acupoint application of cold asthma recipe (CAR) was a traditional Chinese medicine (TCM) method, widely used as an alternative medicine for clinical prevention of the common winter diseases of asthma and bronchitis. Tetrahydropalmatine (THP) was a main active ingredient of CAR extract. The aim of this study is to compare plasma pharmacokinetics and lung distribution of THP between Feishu (FS) acupoint (BL 13) and Non-Feishu (NFS) acupoint application of CAR extract by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

MATERIALS AND METHODS

The extract of CAR was topically administrated in FS and NFS acupoint of rats for plasma pharmacokinetics, and topically administrated in FS and NFS acupoint of mice for lung distribution. The plasma and lung homogenates were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on an ACQUITY UPLC BEH C18 column with a mobile phase consisted of 0.1% formic acid in acetonitrile and 0.1% formic acid in water. The detection was accomplished by multiple-reaction monitoring (MRM) scanning in the positive electrospray ionization (ESI(+)) mode. All pharmacokinetic parameters were estimated by non-compartmental analysis.

RESULTS

A sensitive, accurate and precise UPLC-MS/MS method was successfully established for determination of THP in 100 μL plasma and lung homogenate. The lower limit of quantification (LLOQ) of THP was 0.05 ng/mL and 0.072 ng/mL, respectively. The pharmacokinetic results manifested that THP was absorbed and eliminated slowly in plasma. Additionally, it was found that there was significantly higher amount of THP absorbed into blood and lung after FS acupoint application compared to NFS acupoint application.

CONCLUSIONS

Both of the rat plasma pharmacokinetics and mice lung distribution of THP could support that FS acupoint application of CAR extract has greater advantages of absorption into the blood circulation and distribution in target tissue over NFS acupoint application. The results might be helpful in providing a rational explanation for why the TCM chose the acupoint application and elucidating the underlying mechanism of this treatment.

Pharmacokinetic comparisons of berberine and palmatine in normal and metabolic syndrome rats

ETHNOPHARMACOLOGICAL RELEVANCE

San-Huang formula is a popular traditional Chinese medicine (TCM) preparation to replenish Qi, resolve phlegm, dissipate blood stasis, and therapy metabolic syndrome in China. Metabolic syndrome, which is accompanied by Qi and blood stasis, mainly arises from spleen deficiency in essence. There is limited information available for differences of pharmacokinetic properties of San-Huang formula between normal and metabolic syndrome rats. The present study was conducted to compare the pharmacokinetics of berberine as well as palmatine in normal and metabolic syndrome rats following oral administration of San-Huang formula extract.

MATERIALS AND METHODS

The animals were orally administered with San-Huang formula extract with the equivalent dose of 60.4 and 12.5mg/kg for berberine and palmatine, respectively. The blood samples were collected according to the time schedule. The concentrations of berberine and palmatine in rat plasma were determined by LC-ESI/MS. Various pharmacokinetic parameters were estimated from the plasma concentration versus time data using non-compartmental methods.

RESULTS

It was found that AUC0-t, Cmax, Vd and CL of berberine and palmatine in metabolic syndrome rats were significantly different (P<0.05) from normal rats.

CONCLUSIONS

The results indicated that berberine and palmatine have higher uptake and slower elimination in the rats with metabolic syndrome, which suggests that the rate and extent of drug metabolism were altered in metabolic syndrome rats.

Novel pharmacokinetic studies of the Chinese formula Huang-Lian-Jie-Du-Tang in MCAO rats

Our previous studies showed that after oral administration of an Huang-Lian-Jie-Du-Tang (HLJDT) decoction, there is a higher concentration of the pure components, berberine, baicalin and gardenoside in the plasma of Middle cerebral artery occlusion (MCAO) rats than in sham-operated rats, The aim of the present study was to determine whether these components could be reliably measured in MCAO rat tissues. First, the plasma concentration-time profiles of berberine, palmatine, baicalin, baicalein and gardenoside were characterised in MCAO rats after oral administration of the aqueous extract of HLJDT. Subsequently, liver, lung and kidney tissues were obtained from sudden death MCAO rats in the absorption phase (0.25 h), the distribution phase (1.0 h) and the elimination phase (8.0 h) after administration of the HLJDT aqueous extract. An HPLC method was developed and validated for the determination of the distribution characteristics of berberine, palmatine, baicalin, baicalein and gardenoside simultaneously from the above-mentioned rat tissues. The results indicated that berberine, palmatine, baicalin and baicalein distributed rapidly and accumulated at high levels in the lung, while gardenoside distributed widely in the lung and the kidney. To the best of our knowledge, this is the first report to describe the distribution of the active ingredients derived from HLJDT in MCAO rat tissues. The tissue distribution results provide a biopharmaceutical basis for the design of the clinic application of HLJDT in cerebrovascular disease.

[Study on in vitro release and percutaneous absorption for Zhitong cataplasm]

To evaluate in vitro release and transdermal behaviors of Zhitong cataplasm, modified Franz diffusion cell method was applied to investigate in vitro transdermal absorption of Zhitong cataplasm and the content of tetrahydropalmatine was determined by HPLC. In 24 hours, accumulative release rate of tetrahydropalmatine was 81. 9%, transmission rate was 2.26 microg x cm(-2) x h(-1). In 48 hours, accumulative transdermal rate and transmission rate of tetrahydropalmatine were 20.31%, 0.22 pg x cm(-2) x h(-1). So Zhitong cataplasm had a good release and transdermal properties and transdermal actions were consistent with zero-order kinetics process.

[In vitro transdermal delivery of the active fraction of xiangfusiwu decoction based on principal component analysis]

The objective of the present study was to establish a method based on principal component analysis (PCA) for the study of transdermal delivery of multiple components in Chinese medicine, and to choose the best penetration enhancers for the active fraction of Xiangfusiwu decoction (BW) with this method. Improved Franz diffusion cells with isolated rat abdomen skins were carried out to experiment on the transdermal delivery of six active components, including ferulic acid, paeoniflorin, albiflorin, protopine, tetrahydropalmatine and tetrahydrocolumbamine. The concentrations of these components were determined by LC-MS/MS, then the total factor scores of the concentrations at different times were calculated using PCA and were employed instead of the concentrations to compute the cumulative amounts and steady fluxes, the latter of which were considered as the indexes for optimizing penetration enhancers. The results showed that compared to the control group, the steady fluxes of the other groups increased significantly and furthermore, 4% azone with 1% propylene glycol manifested the best effect. The six components could penetrate through skin well under the action of penetration enhancers. The method established in this study has been proved to be suitable for the study of transdermal delivery of multiple components, and it provided a scientific basis for preparation research of Xiangfusiwu decoction and moreover, it could be a reference for Chinese medicine research.

[Study on metabolism of Coptis chinensis alkaloids from different compatibility of Wuji Wan in human intestinal flora]

OBJECTIVE

To study the metabolism of berberine and palmatine in prescription compatibility of Wuji Wan in human intestinal flora.

METHOD

The L9 (3(4)) orthogonal design was adopted to compare prescription compatibility of nine groups of Wuji Wan composed of Coptis chinensis, Evodiae and fried Radix paeoniae alba into and single ingredient of C. chinensis. They were cultivated with fresh human excrements under anaerobic conditions for 24 h. A HPLC-UV method was adopted for determining berberine and palmatine in bacteria culture medium, in order to compare the metabolism of the two components in different prescription compatibility.

RESULT

Metabolism of berberine was positively correlated with doses, whereas metabolism of palmatine was negatively correlated with doses in extracts from C. chinensis. Compound compatibility speeded up the metabolism of berberine in low dose, which was positively related to the doses of Evodiae and fried Paeoniae Alba Radix; meanwhile Compound compatibility slowed down the metabolism of berberine in high dose, which was negatively related to the dose of Evodiae. Compound compatibility speeded up the metabolism of palmatine in high dose, which was negatively related to the doses of Evodiae and fried Paeoniae Alba Radix.

CONCLUSION

The metabolism of the compatibility of Wuji Wan speeds up, when Coptis chinensis components metabolite rapidly in intestinal flora; while the metabolism of the compatibility of Wuji Wan slows down, when C. chinensis components metabolite slowly in intestinal flora. Therefore, they show a balanced effect. Additionally, different proportion of C. chinensis, Evodiae and fried Paeoniae Alba Radix cause difference in metabolism speed of berberine and palmatine to some extent.

[Biotransformation by human intestinal flora and absorption-transportation characteristic in a model of Caco-2 cell monolayer of d-corydaline and tetrahydropalmatine]

OBJECTIVE

To study the biotransformation by human intestinal flora, and the absorption and transportation characteristic in a model of human colon adenocarcinoma cell lines (Caco-2 cell) monolayer of d-corydaline (CDL) and tetrahydropalmatine (THP).

METHOD

CDL or THP was incubated with crude enzymes of human intestinal flora under the anaerobic environment and 37 degrees C conditions to transform CDL or THP. Caco-2 cell monolayer was used as an intestinal epithelial cell model for determination of the permeability of CDL or THP from apical side (AP side) to basolateral side (BL side) or from BL side to AP side. Transportation parameters and permeability coefficients (P(app)) were then calculated, and P(app) values were compared with the reported values for model compounds, propranolol as a well absorbed drug and atenolol as a poor absorbed drug. The concentration of CDL or THP was measured by HPLC coupled with photodiode array detector.

RESULT

CDL or THP in the human intestinal flora incubation system did not happen biotransformation. In the Caco-2 cell monolayer model, the P(app) magnitudes of both CDL and THP were 1 x 10(-5) cm x s(-1) in the bi-directional transport, which were identical with propranolol. And their transports were concentration dependent between 0-180 min.

CONCLUSION

Both CDL and THP may be stable in the human intestinal flora incubation system, and their absorption and transportation in the human Caco-2 cell monolayer model are mainly via passive diffusion mechanism.

A sensitive and selective liquid chromatography-tandem mass spectrometry method for simultaneous determination of five isoquinoline alkaloids from Chelidonium majus L. in rat plasma and its application to a pharmacokinetic study

Chelidonium majus L. is one of the most important medicinal plants of the family Papaveraceae. Its pharmacological effects have been primarily attributed to the presence of a number of alkaloids. In the present study, a sensitive and selective liquid chromatography-tandem mass spectrometry method for simultaneous determination of five isoquinoline alkaloids from Chelidonium majus L. was developed and validated. The analytes (protopine, chelidonine, coptisine, sanguinarine and chelerythrine), together with the internal standard (palmatine), were extracted from acidified rat plasma with ethyl acetate-dichloromethane (4:1, v/v). Chromatographic separation was carried out on a Diamonsil C(18) column with an isocratic mobile phase consisting of acetonitrile and water (adjusted to pH 2.3 with formic acid) (30:70, v/v) at a flow rate of 0.4 ml/min. Mass spectrometric detection was performed by selected reaction monitoring mode via electrospray ionization source operating in positive ionization mode. The assay exhibited good linearity (r ≥ 0.9933) for all the analytes. The lower limits of quantification were 0.197-1.27 ng/ml using only 50 µl of plasma sample. The intra- and inter-day precisions were less than 11.9%, and the accuracy was between -6.3% and 9.3%. The method was successfully applied to the pharmacokinetic study of the five alkaloids in rats after intragastric administration of Chelidonium majus L. extract.

[Impact on absorption of berberine and palmatine in different compatibilities of Wuji pill]

OBJECTIVE

To observe the impact on absorption of berberine and palmatine in different compatibilities of Wuji pill by the perfused rat intestine-liver preparation.

METHOD

Use L9 (3(4)) orthogonal design table, establish the perfused rat intestine-liver preparation, the twelve Wuji pill compatibilities duodenal administrated, collect the perfusate at different times points for LC-MS detection, calculate the absorbed score, Ka.

RESULT

Evodiae Fructus and the absorption score, Ka of berberine and palmatine are inverse correlated. The most superior portion which promote the absorption is Coptidis Rhizoma-Evodiae Fructus-Paeoniae Radix Alba 3:1:3.

CONCLUSION

Evodiae Fructus suppressed the absorption of berberine and palmatine. With the different portion the absorption also have big different.

[Tetrahydropalmatine's permeative properties of acupoint and non-acupoint transdermal administration of Baijiezi Tufang in vitro and in vivo]

OBJECTIVE

To study tetrahydropalmatine's permeative properties of acupoint and non-adupoint transdermal administration of baijiezi tufang in vitro and in vivo.

METHOD

Taking tetrahydropalmatine as an evaluative component to assess the permeative of baijiezi tufang in acupoint skin and non-acupoint skin with the modified Franz diffusion cell method and in vivo penetration studies. The content of tetrahydropalmatine was determined by a HPLC method.

RESULT

The 24 hours cumulative permeation amount through acupoint skin was (13.53 +/- 3.92) microg x cm(-2), about 4 times higher than non-acupoint skin. The steady-state infiltration rates of tetrahydropalmatine in acupoint skin was (0.659 1 microg x cm(-2) x h(-1)), 4.5 times higher than non-acupoint skin. The content in acupoint skin was signally higher than that in non-acupoint skin (P < 0.05). An accumulation of fluorescence can be clearly seen in the four layers: stratum corneum > viable epidermis > dermis > subcutaneous.

CONCLUSION

In vitro and in vivo studies show that the permeation of baijiezi tufang in acupoint skin was better than in non-acupoint skin, following a higher cumulative amount and skin content.

Effect of wine and vinegar processing of Rhizoma Corydalis on the tissue distribution of tetrahydropalmatine, protopine and dehydrocorydaline in rats

Vinegar and wine processing of medicinal plants are two traditional pharmaceutical techniques which have been used for thousands of years in China. Tetrahydropalmatine (THP), dehydrocorydaline (DHC) and protopine are three major bioactive molecules in Rhizoma Corydalis. In this study, a simple and reliable HPLC method was developed for simultaneous analysis of THP, DHC and protopine in rat tissues after gastric gavage administration of Rhizoma Corydalis. The validated HPLC method was successfully applied to investigate the effect of wine and vinegar processing on the compounds' distribution in rat tissues. Our results showed that processing mainly affect the T(max) and mean residence time (MRT) of the molecules without changing their C(max) and AUC(0-24)( )(h) Vinegar processing significantly increased the T(max) of DHC in heart, kidney, cerebrum, cerebrellum, brain stem and striatum and prolonged the T(max) of protopine in brain. No significant changes were observed on the T(max) of THP in rat tissues after vinegar processing. Wine processing reduced the T(max) of protopine and DHC in liver and spleen and T(max) of protopine in lung, but increased the T(max) of THP in all the rat tissues examined. To our knowledge, this is the first report on the effects of processing on the tissue distribution of the bioactive molecules from Rhizoma Corydalis.

[Studies on intestinal absorption of alkaloids in Coptis chinensis by in situ single-pass perfused rat intestinal model]

OBJECTIVE

To study the absorption characteristics of alkaloids in Coptis chinensis in rat intestinal.

METHOD

In situ single-pass perfused rat intestinal model was used and the concentrations of berberine and palmatine were determined by HPLC, the drug absorption rate constant (K(a)) and apparent absorption coefficient (P(app)) were tested to evaluate their absorption characteristics.

RESULT

The absorption of berberine and palmatine in different regions of rat intestinals was significantly different. From bigness to smallness, the P(app) value of berberine at 50 mg x L(-1) were ileum, duodenum, jejunum and colon, of palmatine at 50 mg x L(-1) were ileum, colon, jejunum and duodenum. The concentration of berberine and palmatine had distinctive effect on the K(a) value of berberine and palmatine were ordered from larger to little as in Wujiwan compatibility, Coptis chinensis extractive and single compound.

CONCLUSION

The berberine and palmatine were absroped at all regions of rat intestinal. The absorption characteristics of 2 alkaloids were not passive diffusion. The other ingredients in Wujiwan compatibility and Coptis chinensis extractive could promote the absorption of alkaloids.

Correlation between rheological properties, in vitro release, and percutaneous permeation of tetrahydropalmatine

The aim of the present work was to investigate the influence of formulation factors including different grades of Carbopol® matrices and penetration enhancers on the percutaneous permeation of tetrahydropalmatine (THP), rheological properties, and in vitro release; and the correlation behind rheological properties, in vitro release, and percutaneous permeation. Transdermal penetration of THP through excised rabbit skin and in vitro release of THP across transparent Cellophane® were performed by vertical Franz diffusion cell. Rheological analyses were proceeded in terms of "steady flow tests", "oscillation stress sweep", and "creep recovery". The result of percutaneous penetration of THP indicated that, the emulgel prepared with Carbopol® 971P (Cp 971P) as the matrix and N-methyl-2-pyrrolidone (NMP) as the penetration enhancer had the highest cumulative permeation amount (118.19 μg/cm(2)). All the experimental data showed a good fit to the Casson model in viscosimetric studies no matter what the types of matrices or the kinds of penetration enhancers were. The release profile fitted the zero-order release kinetics model with Cp 971P as the matrix without any penetration enhancers. However, when adding penetration enhancers, in vitro release of THP presented anomalous (non-Fickian) release kinetics. Clarifying the relationship behind percutaneous permeation of THP, rheological properties, and in vitro release will provide us with profound insights and facilitate the design of specific emulgel.

[Influence of penetration enhancers on in vitro transdermal permeation of L-tethrahydropalmatine]

OBJECTIVE

To study the effect of different penetration enhancers on the in vitro transdermal permeation of 1-tethrahydropalmatine (L-THP) through rat skin.

METHOD

Both natural and chemical synthesis penetration enhancers were applied singly or jointly to investigate the skin permeation rates of l-THP. The skin permeation profiles were evaluated by Valian-Chien permeation cells with isolated rat skin. HPLC-UV method was established to determine the concentration of l-THP in samples.

RESULT

As chemical synthesis penetration enhancer was used alone, 8% azone was observed to be the optimal penetration enhancer with the maximal penetration rate of 21.153 microg x cm(-20 x h(-1). Although 2% menthol crystal or 5% eucalyptus oil was effective as a natural penetration enhancer when used alone, the average penetration rate reached only half of that of 8% azone. The penetration potency of either menthol oil or menthol crystal combined with 8% azone was more effective than that of azone alone (P < 0.05).

CONCLUSION

Either menthol oil or menthol crystal combined with 8% azone is effective on transdermal penetration of l-THP in vitro. There is significant synergistic effect when natural penetration enhancers combined with chemical synthesis penetration enhancers.

[Enhancing effect of volatile oils of rhizoma zingiberis, flos magnoliae and fructus litseae on permeation of rotundine in vitro]

OBJECTIVE

To investigate the enhancing effect of volatile oils of Rhizoma Zingiberis (RZ), Flos Magnoliae (FM), Fructus Litseae (FL), Azone and pairwise combinations on the permeation of Rotundine in vitro.

METHODS

To screen out the volatile oils with the best percutaneous enhancing effect on Rotundine, a test of penetration through rats skin was conducted by using an improved Franz diffusion cell. The accumulative penetration amount of Rotundine was determined by UV and HPLC.

RESULTS

All of the 3 volatile oils had enhancing effect on Rotundine permeation. The average accumulative doses of Rotundine for 8 hours (Q8, mg/cm2) of 5% volatile oil of FL, 5% volatile oil of, RZ, 2.5% FL + 2.5% Azone were 6.0758, 6.1148, 6.5487, the enhancement ratios of 4 hours were 1.01, 1.00, 1.13 respectively.

CONCLUSION

2.5% FL + 2.5% Azone had the best effect of percutaneous enhancing on Rotundine.

[Comparison of pharmacokinetics about ermiao capsules and ermiao pellet]

OBJECTIVE

To compare the pharmacokinetics about Ermiao capsules and ermiao pellet, and observe the changes in plasma concentration with different formulations in animals from the perspective of pharmacokinetics.

METHODS

After the rabbits were administered with Ermiao capsules and ermiao pellet through ig. HPLC was used to determine berberine in blood plasma at different times, DAS 2.0 procedure was used to process concentration-time data.

RESULTS

In the rabbit plasma samples,the linear range of berberine was 0.00427-0.427 microg/mL, it has a high extract recovery rate,and day-day precision RSD was less than 10%. The whole blood concentration-time course of berberine in Ermiao capsules was fitted to be a two-compartment model, and berberine in Ermiao pellet was fitted to be a one-compartment model.

CONCLUSION

This essay establishes a method for determine berberine in rabbit plasma, provided the pharma cokinetic parameters for rational administration of ermiao capsules, and also provided the pharmacokinetic study method of compounds.

[Influence of combination of extractum Angelicae Dahuricae Siccum and total alkaloids of Rhizoma Corydalis on pharmacokinetics of tetrahydropalmatine in rats]

This paper is aimed to develop a rapid and sensitive HPLC-fluorescence detection (FLD) method for the determination of tetrahydropalmatine (TET) in rats' plasma. The influence of combinations of Extractum Angelicae Dahuricae Siccum (coumarin and volatile oil) and total alkaloids (TA) from Rhizoma Corydalis (TA) on pharmacokinetics of TET in rats was studied. Plasma samples were treated with hexane-isopropanol (95:5) to precipitate the protein, and were determined by HPLC-fluorescence detection. The calibration curve was linear in the range of 2.096-167.68 microg L(-1). The limit of quantification was 2.096 microg L(-1). The method recovery of TET was 94.0%-100.0%. The extract recovery was 72.0%-81.5%. RSDs ofintra- and inter-day precisions were all less than 7.0%. Pharmacokinetics of TET in rats was fitted to two compartments open model after oral administration of TA, TA-volatile oil (VO), TA-coumarin (Cou) and TA-VO-Cou. Compared with TA, AUC(0-t), AUC(0-infinity), MRT(0-t), and MRT(0-infinity) of TET had significant deviation when combined with VO and/or Cou. The determination method is sensitive, specific, accurate, and appropriate for determination of TET in vivo. Coumarin and/or VO combined with TA can prolong the resistance time of TET significantly, delay elimination and enhance bioavailability of tetrahydropalmatine.

[Pharmacokinetics of three alkaloids in Huanglianjiedu decoction in rat serum by LC-MS-MS]

OBJECTIVE

To develop a sensitive and reliable high-performance liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for simultaneous determination of jatrorrhizine, palmatine and berberine in rat serum, and study the pharmacokinetics of the three alkaloids in rat serum after an intragastrical (ig) administration of Huanglianjiedu decoction to rat.

METHOD

The optimal ionization and fragmentation conditions, as well as HPLC ones, to detect jatrorrhozine, palmatine and berberine were developed and validated. After the Huanglianjiedu decoction were administered to rats through ig route, LC-MS-MS method has been applied to the pharmacokinetic study of the three alkaloids in rat serum. DAS procedure was used to process concentration-time data.

RESULT

The detection was performed by MRM mode via electrospray ionization (ESI) source operating in the positive ionization mode. The precursor-to-product ion transitions were at m/z 338-322 for jatrorrhozine, m/z 351.9-308 for palmatine, m/z 336-319.8 for berberine and m/z 356.1-192.1 for tetrahydropalmatine (IS) respectively. The method was linear over the concentration range of 0.2-25 microg x L(-1) for jatrorrhozine, 0.4-50 microg x L(-1) for palmatine and berberine. The method was validated according to the requirements. The pharmacokinetic process of the three alkaloids after oral administration of Huanglianjiedu decoction was fitted to be a one-compartment model.

CONCLUSION

The fully validated LC-MS-MS method has been successfully applied to the pharmacokinetic study of the three alkaloids in rat serum after oral administration of Huanglianjiedu decoction.

[Study on vitro release and transdermal behaviors of Yulian cataplasm]

OBJECTIVE

To investigate the regularity of Yulian Cataplasm in vitro release and transdermal behaviors.

METHOD

Improved Franz diffusion devices was used with four index ingredients as evodiamine, rutaecarpine, palmatine and berberine that were determined by HPLC in one mobile phase.

RESULT

The release rates of evodiamine, rutaecarpine, palmatine and berberine were 0.0239, 0.0156, 0.0725, 0.8191 mg x cm(-2) x h(-1/2), respectivley. The transdermal rates of evodiamine, rutaecarpine, palmatine and berberine were 1.256, 1.0302, 2.8029, 20.919 microg x cm(-2) x h(-1), respectively.

CONCLUSION

The releasing process of all index is in accordance with Higuchi equation and the transdermal proccess is in accordance with zero-level equation.

[Absorption kinetics of dehydrocavidine in rats' stomachs and intestines]

OBJECTIVE

To study the absorption kinetics of dehydrocavidine in rats' stomachs and intestines.

METHOD

The absorption kinetics was investigated by the in situ perfusion in rats and the concentrations of drug perfusion solutions were determined by HPLC.

RESULT

The hourly absorption percentages of dehydrocavidine in stomach, small intestine were 8.88%, 2.08%, respectively. Although the absorption rate constants of dehydrocavidine in duodenum and jejunum are more than that in ileum and colon, there is no significance difference between them. The absorption rate constants kept at the same level when the concentrations of drug perfusion solution are at middle and high level. The increase of the pH of perfusion solution didnt significantly affect the absorption rate constants of the drug.

CONCLUSION

Dehydrocavidine was absorbed poorly at stomach and all segments of intestine in rats, but the absorptions in stomach are better than intestine. Dehydrocavidine was absorbed mainly via passive transport mechanism between middle and high concentration levels.

[Pharmacokinetic studies of tetrahydropalmatine and dehydrocorydaline in rat after oral administration of yanhusuo extraction by LC-MS/MS method]

A sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the quantification of tetrahydropalmatine (THP) and dehydrocorydaline (DHC) in rat plasma. The compounds were simply pretreated by protein precipitation using acetone. Chromatographic separation was achieved on a reversed-phase SB-C18 column with the mobile phase of acetonitrile-ammonium acetate (0. 1% acetic acid) and step gradient elution resulted at a flow rate of 0.80 mL x min(-1). A tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the positive ion mode. Quantification was performed using multiple reaction monitoring (MRM) of the transitions m/z 356. 2 --> m/z 191.9 and m/z 366. 2 --> m/z 350.2 for THP and DHC respectively. The method showed excellent linearity over the concentration range 1-1 000 ng x mL(-1) of two components (r = 0.994 for THP and r = 0.992 for DHC). The low limits of quantification were both 1 ng x mL(-1). The extract recoveries of analytes were from 71.71% to 91.59% for THP and from 83.27% to 103.15% for DHC. The precisions, the accuracy and the stability of the analytes meet the requirements. The method was applied to a pharmacokinetic study of THP and DHC after oral administration of the total alkaloid extraction of Rhizoma Corydalis (Yanhusuo). The AUC were (1.90 +/- 0.04), (2.58 +/- 0.08) and (4.34 +/- 0.19) mg x L(-1) h for low, medium and high doses of THP, respectively. While the DHC concentrations in plasma of low dose and medium dose were too lower to be detected, the AUC of high dose was (0.0896 +/- 0.0002) mg x L(-1) h.

[Absorption of extractive Rhizoma Coptidis in rat everted gut scas]

OBJECTIVE

Using in vitro everted gut seas to research the intestinal absorption of the extractive Rhizoma Coptidis at the different intestinal section and the different density.

METHOD

Berberine (BER) and palmatine (PAL) which are representative compositions of the extractive Rhizoma Coptidis in everted gut seas are detected by HPLC, and calculated the absorption parameter to describe the character of absorption.

RESULT

The absorption of BER and PAL is linearity in different intestine and different dose, and the square of coefficient correlation exceed 0.9, which consistent with zero order rate process. The K(a) of BER and PAL increases along with the raised dosage of the extractive Rhizoma Coptidis (P < 0.05), indicated it is the passive absorption. The absorption of BER and PAL in the jejunum is the most quick, the ileum and colon are slower.

CONCLUSION

In the different dosage of extractive Rhizoma Coptidis, the absorption of BER and PAL Conforms to the zero order rate process at the different intestine, and is the passive absorption.

[Comparison of pharmacokinetics of tetrahydropalmatine monomer and extractive of corydalis and corydalis processed with vinegar]

OBJECTIVE

To investigate the pharmacokinetics of tetrahydropalmatine monomer and extractive of corydalis and corydalis processed with vinegar in rats.

METHODS

The plasma concentrations of tetrahydropalmatine were determined by a reversed phase high performance liquid chromatographic. The plasma concentrations-time data were calculated with 3p97 program.

RESULTS

The main pharmacokinetic parameters of tetrahydropalmatine monomer and extractive of corydalis and corydalis processesd with vinegar as follows: T(1/2) was (5.66 +/- 1.92), (4.24 +/- l1.54), (4.35 +/- 1.34) h, Tmax was (1.5 +/- 0.5), (1.0 +/- 0.55), (0.5 +/- 0.68) h, Cmax was (0.71 +/- 0.29), (0.37 +/- 0.11), (0.67 +/- 0.35) microg/ml,AUC(o-t), was (2.58 +/- 0.85), (1.96 +/- 0.69), (2.95 +/- 1.61) microg/ml.

CONCLUSION

The T(1/2) of corydalis and corydalis processesd with vinegar is more shorter than tetrahydropalmatine monome, the effect of preventing pain is promoted in rats.

Determination of palmatine in canine plasma by liquid chromatography–tandem mass spectrometry with solid-phase extraction

A sensitive and specific high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method has been developed and validated for the determination of palmatine in canine plasma. Palmatine and jatrorrhizine (internal standard, I.S.) were extracted from plasma samples by solid-phase extraction (SPE) using Oasis HLB cartridges. The chromatographic separation was performed on a Waters XTerra MS C(18) reversed-phase column at 30 degrees C. The gradient mobile phase, delivered at 0.25 mL/min, was composed of a mixture of acetonitrile -0.1% (v/v) acetic acid aqueous solution adjusted to pH 2.8 with triethylamine. Positive electrospray ionization was utilized as the ionization source. Palmatine and the internal standard (I.S.) were determined using multiple reaction monitoring (MRM) of precursor-->product ion transitions at m/z 352-->336 and m/z 338-->322, respectively. The lower limit of quantification (LLOQ) was 0.1 ng/mL using 100 microL plasma samples and the linear calibration range was from 0.1 to 500 ng/mL. The inter-day and intra-day RSDs were lower than 9.9% and the recoveries of palmatine ranged from 87.3 to 100.9%. The mean extraction recoveries of palmatine and the I.S. were 99.2 and 96.8%, respectively. The method has been successfully applied to the pharmacokinetic studies of palmatine in beagle dogs after oral administration and intramuscular injection of palmatine.

[Difference absorption of l-tetrahydropalmatine and dl-tetrahydropalmatine in intestine of rats]

To investigate the difference in absorptive of tetrahydropalmatine (THP) and l-tetrahydropalmatine (l-THP) in rat intestine as well as the mechanism of the absorption of THP, in situ single pass perfusion model was used and the concentration of THP in perfusate was determined by HPLC. The absorption rate constant (k(a)) and effective permeability values (P(eff)) of THP had no significant difference (P > 0.05) at concentration of 8, 16 and 32 microg x mL(-1) in perfusion or in four different regions of intestine of rat (duodenum, jejunum, ileum, colon). The absorption of l-THP and THP in jejunum had significant difference (P < 0.05). The k(a) and P(eff) of THP increased obviously when verapamil was co-perfused with THP, while those of l-THP were not influenced by verapamil. The absorption of THP in intestine showed the passive diffusion process, and without a special absorption region. The stereoselective absorption difference may result from stereoselective combination of P-glycoprotein with d-THP.

Protopine inhibits serotonin transporter and noradrenaline transporter and has the antidepressant-like effect in mice models

The protopine isolated from a Chinese herb Dactylicapnos scandens Hutch was identified as an inhibitor of both serotonin transporter and noradrenaline transporter in vitro assays. 5-hydroxy-DL-tryptophan(5-HTP)-induced head twitch response (HTR) and tail suspension test were adopted to study whether protopine has anti-depression effect in mice using reference antidepressant fluoxetine and desipramine as positive controls. In HTR test, protopine at doses of 5, 10, 20 mg/kg dose dependently increase the number of 5-HTP-induced HTR. Protopine at doses of 3.75 mg/kg, 7.5 mg/kg and 30 mg/kg also produces a dose-dependent reduction in immobility in the tail suspension test. The present results open up new possibilities for the use of protopine in the treatment of mood disorders, such as mild and moderate states of depression.

Simultaneous determination of berberine and palmatine in rat plasma by HPLC–ESI-MS after oral administration of traditional Chinese medicinal preparation Huang-Lian-Jie-Du decoction and the pharmacokinetic application of the method

A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of berberine and palmatine in rat plasma. After the addition of the internal standard (IS) and alkalization with 0.5M sodium hydroxide solution, plasma samples were extracted by ethyl ether and separated by HPLC on a Shim-pack ODS (4.6 microm, 150 mm x 2.0mm i.d.) column using a mobile phase composed of A (0.08% formic acid and 2 mmol/l ammonium acetate) and B (acetonitrile) with linear gradient elution. Analysis was performed on a Shimadzu LC/MS-2,010A in selected ion monitoring (SIM) mode with a positive electrospray ionization (ESI) interface. [M](+)=336 for berberine; 352 for palmatine and [M+H](+)=340 for IS were selected as detecting ions, respectively. The method was validated over the concentration range of 0.31-20 ng/ml for berberine and palmatine. Inter- and intra-CV precision (R.S.D.%) were all within 15% and accuracy (%bias) ranged from -5 to 5%. The lower limits of quantification were 0.31 ng/ml for both analytes. The extraction recovery was on average 68.6% for berberine, 64.2% for palmatine. The validated method was used to study the pharmacokinetic profile of berberine and palmatine in rat plasma after oral administration of Huang-Lian-Jie-Du decoction.

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.

Chiral liquid chromatography resolution and stereoselective pharmacokinetic study of tetrahydropalmatine enantiomers in dogs

A selective chiral high performance liquid chromatographic (HPLC) method coupled with achiral column was developed and validated to separate and quantify tetrahydropalmatine (THP) enantiomers in dog plasma. Chromatography was accomplished by two steps: (1) racemic THP was separated from biological matrix and collected on a Kromasil C18 column (150 mmx4.6 mm, 5 microm) with the mobile phase acetonitrile-0.1% phosphoric acid solution, adjusted with triethylamine to pH 6.15 (47:53); (2) enantiomeric separation was performed on a Chiralcel OJ-H column (250 mmx4.6 mm, 5 microm) with the mobile phase anhydrous ethanol. The detection wavelength was set at 230 nm. (+)-THP and (-)-THP were separated with a resolution factor (Rs) of at least 1.6 and a separation factor (alpha) greater than 1.29. Linear calibration curves were obtained over the range of 0.025-4 microg/ml in plasma for each of (+)-THP and (-)-THP (R2>0.999) with a limit of detection (LOD) of 0.005 microg/ml and the recovery was greater than 88% for each enantiomer. The relative standard deviation (R.S.D.) and relative error values were less than 10% at upper and lower concentrations. The method was used to determine the pharmacokinetics of THP enantiomers after oral administration of racemic THP. The results presented herein showed the stereoselective disposition kinetics of THP in dogs and were a further contribution to the understanding of the kinetic behavior of THP analogues.

[Stereoselective pharmacokinetics of tetrahydropalmatine in rats]

AIM

To investigate the stereoselective pharmacokinetic process of tetrahydropalmatine (THP) in rats.

METHODS

The concentrations of tetrahydropalmatine enantiomers in rat plasma were determined by coupled achiral and chiral HPLC method. The differences in plasma concentrations and pharmacokinetic parameters between the two enantiomers were compared by paired t-test.

RESULTS

The plasma levels of l-THP were always higher than those of d-THP in eight rats. There was significant difference between the main pharmacokinetic parameters of the two enantiomers.

CONCLUSION

Tetrahydropalmatine showed significant stereoselective pharmacokinetics in rats after an ig dose of the racemate.

Iodination and radiolabeling of alpha-allocryptopine with iodine-125

A procedure for labeling of alpha-allocryptopine with 125I is reported in this article. Alpha-allocryptopine is first iodinated with largely excessive iodine monochloride, and then radiolabeled by isotopic exchange with Na125I in a dichloromethane-water two-phase system. The radiochemical purity and yield of the labeled product are typically as high as 94% and 72%, respectively. Further chromatographic purification gives a highly pure product (radiochemical purity > 99%). The distribution of 125I-labeled alpha-allocryptopine in mice at 2 h after injection shows that the uptake of radioiodine in thyroid is negligibly low.

Stereoselective pharmacokinetics of tetrahydropalmatine after oral administration of (?)-enantiomer and the racemate

Tetrahydropalmatine (THP) is a biologically active ingredient isolated from a traditional Chinese herb Rhizoma corydalis (yanhusuo). THP is a racemic mixture which contains 50% of the (+) and 50% of (-) enantiomer. The (-) enantiomer accounts for most of the analgesic effects. Plasma concentrations of THP enantiomers were analyzed by chiral high-performance liquid chromatography (HPLC) on a Chiralcel OJ column with quantification by UV at 230 nm. The method was used to determine the pharmacokinetics of THP enantiomers in rats and dogs after oral administration of rac-THP or (-)-THP. The pharmacokinetic profiles of the two enantiomers after dosing with rac-THP were significantly different both in rats and dogs. The mean C(max) and AUC(0-infinity) values in rats were 1.93 +/- 0.36 microg/ml and 6.65 +/- 2.34 microg x h/ml for the (-) enantiomer, and 1.11 +/- 0.25 microg/ml and 2.03 +/- 0.45 microg x h/ml for the (+) enantiomer. The mean C(max) and AUC(0-infinity) in dogs were 1.60 +/- 0.81 microg/ml and 9.88 +/- 2.58 microg x h/ml for the (-) enantiomer, while 0.36 +/- 0.21 microg/ml and 1.22 +/- 0.40 microg x h/ml for the (+) enantiomer. rac-THP at 40 mg/kg and (-)-THP at 20 mg/kg had very similar plasma concentration-time profiles, and C(max), AUC(0-infinity), and t(1/2) of the (-) enantiomer in both rats and dogs, indicating that the two treatments were equivalent with respect to the pharmacokinetic properties of the (-) enantiomer.

Transfer of cationic antibacterial agents berberine, palmatine, and benzalkonium through bimolecular planar phospholipid film and Staphylococcus aureus membrane

Some organic cations are known to be electrophoretically imported into bacterial cells and actively extruded from these cells by multidrug resistance (MDR) pumps. We have studied penetration of plant antimicrobial agents berberine and palmatine and synthetic antiseptic benzalkonium chloride through black planar phospholipid membrane (BLM) and membrane of Staphylococcus aureus cells. Gradients of these cations across BLM generated an electric potential difference. Penetrating anion tetraphenyl borate and phloretin (a plant substance decreasing membrane dipole potential) stimulated this effect. Under optimal conditions, the magnitude of the electric potential was close to theoretical, that is, 60 mV/10-fold cation gradient. Berberine accumulated in S. aureus cells as shown by direct measurement of berberine with a berberine-sensitive electrode. The berberine accumulation was prevented by protonophore CCCP and was stimulated by mutation in the MDR pump NorA. It is concluded that the plant alkaloids and benzalkonium are penetrating cations and substrates of an MDR pump.

[RP-HPLC method for determination of protopine in plasma and pharmacokinetics in rats]

AIM

To develop a reversed phase high performance liquid chromatographic method (RP-HPLC) for determination of protopine (Pro) in rat plasma and to investigate the pharmacokinetics of Pro in rats.

METHODS

The column was packed with 5 microns C18. The mobile phase (pH 5.6) was a mixture of methanol-water-10% acetic acid (80:20:2). After twice extracted with ether under basic condition, and reextracted with 0.02 mol.L-1 sulfuric acid, protopine in the plasma samples was isolated well. The content of protopine in the plasma sample was measured by UV detector at 285 nm.

RESULTS

The lowest limit of detection was 50 ng.mL-1. The intraday and interday precisions were 1.5%-3.0% and 2.1%-6.2%, respectively. The mean recovery was 80.6%-97.6%. A good linear relationship between the peak height and the concentration of protopine in rat plasma was observed. The pharmacokinetics of protopine had been investigated in rats after intravenous administration 10 mg.kg-1. The concentration-time curve of protopine in rat was confirmed to two-compartment open model. The T1/2 alpha, T1/2 beta, Ke, CL, Vd were 0.05 h, 1.85 h, 1.52 h, 6.41 L.h-1 and 17.27 L, respectively.

CONCLUSION

This method is suitable for studies on pharmacokinetics of protopine.