Paeoniflorin In Rat Plasma Research Articles

Comparative Study on the Pharmacokinetics of Paeoniflorin, White Peony Root Water Extract, and Taohong Siwu Decoction After Oral Administration in Rats

Taohong Siwu Decoction (TSD) is a classic traditional Chinese medicine (TCM) compound with pharmacological effects such as vasodilation and hypolipidemia. Paeoniflorin (PF) is one of the active ingredients of TSD. The aim of this study was to evaluate the pharmacokinetics of PF in herbal extracts and their purified formsin rats. A sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method for the determination of PF in rat plasma was developed. Rats were divided into three groups, and given PF solution, water extract of white peony root (WPR), or TSD by gavage. At different predetermined timepoints after gavage, blood was collected from the orbital vein. The pharmacokinetic parameters of PF in the plasma of rats in the three groups was determined. The pharmacokinetic studies showed that the time to reach maximum concentration (Tmax) of PF in the purified forms group was relatively high, while the half-lives (T½) of PF in the TSD and WPR groups were longer. Among the three groups, PF in the purified forms group had the maximum area under the concentration-time curve (AUC0-t=732.997µg/L·h) and the largest maximum concentration (Cmax=313.460µg/L), which showed a significant difference compared with the TSD group (P<0.05). Compared with the purified group, the clearance (CLz/F=86.004L/h/kg) and the apparent volume of distribution (Vz/F=254.787L/kg) of PF in the TSD group increased significantly (P<0.05). A highly specific, sensitive, and rapid HPLC-MS-MS method was developed and applied for the determination of PF in rat plasma. It was found that TSD and WPR can prolong the action time of paeoniflorin in the body.

Simultaneous determination of calycosin, prim-O-glucosylcimifugin, and paeoniflorin in rat plasma by HPLC-MS/MS: application in the pharmacokinetic analysis of HQCF

ObjectiveThis study aimed to develop and validate a high-performance liquid chromatography–tandem mass spectrometry method to simultaneously determine three bioactive components of the Huangqi Chifeng decoction (HQCF) in rat plasma.MethodsTaxol was used as an internal standard in the developed method. Chromatographic separation was performed on a C18 column using a gradient elution with 0.1% formic acid in acetonitrile (v/v) and 0.1% formic acid in water (v/v) as the mobile phases at a flow rate of 0.4 mL·minute−1. All compounds were monitored via selected reaction monitoring with an electrospray ionization source.ResultsThe lower limits of quantification of paeoniflorin, calycosin, and prim-O-glucosylcimifugin were 15.0, 0.75, and 0.75 ng·mL−1, respectively. The calibration curves indicated optimal linearity (r > 0.99) across the concentration ranges. The specificity, precision, accuracy, recovery, matrix effect, and stability of the method were validated. This method was successfully applied in a pharmacokinetics study of the three compounds in rat plasma.ConclusionThe pharmacokinetics results provide insights into the mechanisms of HQCF in vivo and its future clinical application.

Simultaneous determination of curcumin, tetrahydrocurcumin, quercetin, and paeoniflorin by UHPLC-MS/MS in rat plasma and its application to a pharmacokinetic study

Curcumin (CUR) is a bioactive compound present in many composite prescriptions of traditional Chinese medicine together with quercetin (QR) and paeoniflorin (PF). Little is known about the influence of QR and PF on the absorption and metabolism of CUR when the three compounds are orally co-administered. In this study, a rapid, sensitive, and reliable ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the simultaneous determination of CUR, tetrahydrocurcumin (THC), QR, and PF in rat plasma by using tinidazole as the internal standard (IS). A liquid-liquid extraction method with ethyl acetate was used to pre-treat the plasma samples. Chromatographic separation was conducted on a C18 column with isocratic elution using acetonitrile and 0.1% formic acid water solution (80:20, v/v) as the mobile phase at the flow rate of 0.3 mL/min. A TSQ Quantum Access Max API mass spectrometer equipped with electrospray ionisation (ESI) source in selection reaction monitoring (SRM) mode was employed to determine transitions of m/z 369.0 → 176.9, 373.1 → 137.0, 303.0 → 228.9, 478.9 → 120.9, 248.1 → 121.0 for CUR, THC, QR, PF, and IS, respectively. The selectivity, precision, accuracy, extraction recovery, matrix effect, and stability of the method were validated. This developed and validated method was successfully applied in the pharmacokinetic study of CUR, THC, QR, and PF in rats. The effects of QR and PF on the pharmacokinetics of CUR and its metabolite, THC, were evaluated in the plasma of Sprague-Dawley rats that were orally co-administered CUR, QR, and PF. The results showed that the combined use of QR, PF, and CUR has a possible influence on the metabolism and excretion of CUR. Our work provides a fundamental method for the rapid simultaneous determination of CUR, THC, QR, and PF in rat plasma. Furthermore, this study will provide a basic method for the analysis of pharmacokinetic interaction of CUR, QR, and PF and offer a scientific basis for a possible combination therapy with the three compounds.

Simultaneous HPLC-MS Determination of Loganin, Morroniside and Paeoniflorin in Rat Plasma; Pharmacokinetics of Liuwei Dihuang Pills

A novel high performance liquid chromatography-mass spectrometry method for simultaneous determination of loganin, morroniside and paeoniflorin in rat plasma was developed, validated and applied to pharmacokinetic study of Liuwei Dihuang pills. Samples were prepared by liquid-liquid extraction with ethyl acetate. Separation was performed on a Wondasil C18 column (150×4.6 mm, 5 μm) using a mixture of methanol and 0.02 % formic acid water solution (28:72, v/v) as the mobile phase. The flow rate and column temperature were set at 0.7 ml/min and 30°. The compounds were detected in selected ion monitoring mode using an ESI source in the negative mode. The method was linear over the ranges of 5-1000 ng/ml for the three analytes, with all determined correlation coefficients exceeding 0.993. All of the lower limits of quantification of the three analytes were 5 ng/ml. The intra-day and inter-day precisions were less than 7.50 %, and the accuracy ranged from –6.57 to 7.90 %. The mean recoveries of the analytes were higher than 68.86 %, and the matrix effects were between 92.35 and 103.54 %. This method was simple, sensitive and reliable, and could be used to monitor pharmacokinetics of loganin, morroniside and paeoniflorin. Moreover, this study might be helpful for quality control and guiding the clinical application of Liuwei Dihuang pills.

Determination of Paeoniflorin in Rat Plasma by Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry and its Application to a Pharmacokinetic Study.

In this study, a rapid and highly sensitive ultra-high performance liquid chromatography-tandem mass spectrometry method was established for the quantification of paeoniflorin in rat plasma. The analyte and the internal standard (IS), hyperoside, were extracted from rat plasma via liquid-liquid extraction with ethyl acetate. LC separation was carried on a Phenomenex Luna C18 column within 2.5 min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operated in the multiple reaction monitoring and negative ion modes. The precursor to product ion transitions monitored for paeoniflorin and the IS were m/z 524.8→449.0 and 463.1→300.0, respectively. The assay was validated with a linear range of 0.02~25.6 μg/mL for paeoniflorin. The intra- and inter-day precisions (relative standard deviation%) were within 9.7%, and the recoveries were greater than 65.2%. Paeoniflorin was proven to be stable during all sample storage, preparation and analytical procedures. The method was successfully applied to a pharmacokinetic study of the Baixiangdan Capsule in eight female rats.

Simultaneous determination of paeonilactone A and paeonilactone B in rat plasma after oral administration of albiflorin by UPLC/TOF/MS following picolinoyl derivatization.

A new highly sensitive analytical method was developed to investigate the in vivo metabolism of albiflorin, one of the most principal components in traditional Chinese medicine. After hydrolyzation with sulfatase, the main metabolites paeonilactone A and paeonilactone B of paeoniflorin in rat plasma were successfully detected for the first time by liquid chromatography mass spectrometry following picolinoyl derivatization. Borneol was used as the internal standard compound to quantify paeonilactone A and paeonilactone B in rat plasma. Paeonilactone A and paeonilactone B show different pharmacokinetic behaviors. The maximum plasma concentration of paeonilactone A reached 36.4±5.6ng/mL at about 8h after oral administration of albiflorin at a dose of 5mg/kg, while the maximum plasma concentration of paeonilactone B reached 12.4±3.4ng/mL at about 2h. The total metabolic pathway of albiflorin in rats was proposed. Albiflorin was found to be metabolized to the sulfate of paeonilactone A and paeonilactone B which may be responsible for the biological effect of albiflorin. The new analytical method may help to elucidate the clinical efficacy of traditional Chinese formula containing albiflorin.

New analytical method for determination of epimer metabolites in rat plasma after oral administration of Paeoniflorin by UPLC-TOF-MS following picolinoyl derivatization

A highly sensitive analytical method was developed to study the in vivo metabolism of paeoniflorin, one of the most principal components in traditional Chinese medicine. After hydrolyzation with sulfatase, the epimer metabolites 7S-paeonimetabolin I and 7R-paeonimetabolin I of paeoniflorin in rat plasma were successfully detected and well separated by LC–MS following picolinoyl derivatization for the first time. Borneol was used as the internal standard to quantify 7S-paeonimetabolin I and 7R-paeonimetabolin I in rat plasma. 7S-paeonimetabolin I and 7R-paeonimetabolin I show similar but different pharmacokinetic behavior. 7S-paeonimetabolin I reached the maximum mean plasma concentration of 45.7±4.6ng/mL at about 1.5h after oral administration of paeoniflorin at a dose of 5mg/kg, while 7R-paeonimetabolin I reached the maximum mean plasma concentration of 39.2±3.5ng/mL at about 1.5h. The full metabolic pathway of paeoniflorin in rats was proposed. The monoterpene compound paeoniflorin was found to be metabolized to the sulfate of 7S-paeonimetabolin I and 7R-paeonimetabolin I in vivo which maybe responsible for the pharmacological effect of paeoniflorin.

Enhancement of Exposure and Reduction of Elimination for Paeoniflorin or Albiflorin via Co-Administration with Total Peony Glucosides and Hypoxic Pharmacokinetics Comparison.

There is evidence suggesting that herbal extracts demonstrate greater bioactivities than their isolated constituents at an equivalent dose. This phenomenon could be attributed to the absence of interacting substances present in the extracts. By measuring the pharmacokinetic parameters of paeoniflorin (PF) and albiflorin (AF) after being orally administered to rats in isolated form, in combination with each other and within total peony glucosides (TPG), respectively, the current study aimed to identify positive pharmacokinetic interactions between components of peony radix extracts. Moreover, the pharmacokinetic profiles of PF and AF under normoxia and hypoxia were also investigated and compared. In order to achieve these goals, a highly sensitive and reproducible ultra-peformance liquid chromatography–mass spectrometry (UPLC-MS) method was developed and validated for simultaneously quantitation of PF and AF in rat plasma. This study found that compared with that of single component (PF/AF), the exposure of PF in rat plasma after combination administration or TPG administration was significantly increased, meanwhile the elimination of PF/AF was remarkably reduced. It was also noticed that AUC and Cmax of PF in hypoxia rats were significantly decreased compared with that of normaxia rats, suggesting that there was a decreased exposure of PF in rats under hypoxia. The current study, for the first time, revealed the pharmacokinetic interactions between PF/AF and other constitutes in TGP and the pharmacokinetic profiles of PF and AF under hypoxia. In view of the current findings, it could be supposed that the clinical performance of total peony glucosides would be better than that of single constitute (PF/AF). The outcomes of this animal study are expected to serve as a basis for development of clinical guidelines on total peony glucosides usage.

UPLC-PDA determination of paeoniflorin in rat plasma following the oral administration of Radix Paeoniae Alba and its effects on rats with collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic disabling autoimmune disease with characteristics of chronic, progressive inflammatory joint synovial damage, which mainly encroaches upon the synovium of the joint. The use of traditional medicine to treat RA slows the development of RA to a certain extent; however, it often has numerous side-effects. Therefore, the focus of RA research is the identification of a new, safe and effective medicine. The aim of the present study was to use an ultra performance liquid chromatography and photo diode array (UPLC-PDA) method to detect the paeoniflorin component in a Radix Paeoniae Alba decoction and in rat plasma following the oral administration of Radix Paeoniae Alba decoction. In addition, the effects of paeoniflorin on collagen-induced arthritis (CIA) in rats were investigated. The results indicate that a UPLC-PDA method for determining the presence of paeoniflorin in the Radix Paeoniae Alba decoction was successfully established. The method was fast, simple, sensitive, precise and valid. Paeoniflorin was shown to be a bioactive component of the Radix Paeoniae Alba decoction that was absorbed into rat plasma. Paeoniflorin significantly improved the disease resistant ability of RA rats and reduced the levels of the inflammatory cytokines, IL-1β and TNF-α, thereby inhibiting inflammation and bone erosion in the rats with CIA. The observations are likely to lay the foundation for further study of the mechanism of paeoniflorin in the treatment of RA.

Simultaneous determination of five phenolic components and paeoniflorin in rat plasma by liquid chromatography–tandem mass spectrometry and pharmacokinetic study after oral administration of Cerebralcare granule®

A simple, sensitive and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS) method was developed for simultaneous determination and pharmacokinetic study of six active components, protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid rosmarinic acid and paeoniflorin in rat plasma after oral administration of Cerebralcare granule® for the first time. The method involves a simple liquid–liquid extraction with ethyl acetate. The separation was performed on a Luna C18 column (2.0×100mm i.d., 3.0μm, particle, Phenomenex, USA) with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.2ml/min. Electrospray ionization (ESI) in negative ion mode and selective reaction monitoring (SRM) was used for the quantification of six active components and internal standard (IS, Chloroamphenicol). The method was linear for all analytes over investigated range with all correlation coefficients greater than 0.9914. The lower limits of quantification (LLOQ) were 1.0ng/ml for protocatechuic acid, 1.0ng/ml for chlorogenic acid, 1.0ng/ml for caffeic acid, 5.0ng/ml for ferulic acid, 1.5ng/ml for rosmarinic acid and 6.0ng/ml for paeoniflorin, respectively. The intra- and inter-day precisions (R.S.D.%) were less than 6.60% and 11.68%, and accuracy (RE %) between −3.26% and 1.13% (n=6). The developed method was applied for the first time to the pharmacokinetic study of protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid, rosmarinic acid and paeoniflorin in rat plasma after oral administration of Cerebralcare granule®.

UHPLC-MS Simultaneous Determination and Pharmacokinetic Study of Three Aromatic Acids and One Monoterpene in Rat Plasma after Oral Administration of Shaofu Zhuyu Decoction

We developed a sensitive and rapid method for determination of ferulic acid, caffeic acid, vanillic acid, and paeoniflorin in rat plasma based on ultra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The separation of the four compounds was carried out on an AcQuity UHPLC™ BEH C18 column using a mobile phase consisting of acetonitrile and water (containing 0.1% formic acid). Electrospray ionization in positive and negative ion mode and multiple reaction monitoring was used to identify and quantify active components. All calibration curves gave good linearity (r > 0.991) over the concentration range from 4.24-2875 ngmL(-1) for all components. The precision of the in vivo study was evaluated by intraday and interday assays and the percentages of RSD were all within 10.6%. The recovery ranged from 60.2 to 77.9%. The method was successfully applied to pharmacokinetic study of all three aromatic acids and one monoterpene in rat plasma. Furthermore, we compared the pharmacokinetics profile of the four compounds in normal and primary dysmenorrhea rats' plasma following oral administration of Shaofu Zhuyu decoction (SFZYD) and its ethanol supernatant extract (SFE).

HPLC–MS/MS Analysis of a Traditional Chinese Medical Formulation of Bu-Yang-Huan-Wu-Tang and Its Pharmacokinetics after Oral Administration to Rats

Bu-yang-huan-wu-tang (BYHWT) is one of the most popular formulated traditional Chinese medicine prescriptions, and is widely for prevention of ischemic cardio-cerebral vascular diseases and stroke-induced disability. A specific high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has been developed and validated for simultaneous quantification of the nine main bioactive components, i.e., astragaloside I, astragaloside II, astragaloside IV, formononetin, ononin, calycosin, calycosin-7-O-β-d-glucoside, ligustilide and paeoniflorin in rat plasma after oral administration of BYHWT extract. This method was applied to investigate the pharmacokinetics in conscious and freely moving rats. No significant matrix effects were observed. The overall analytical procedure was rapid and reproducible, which makes it suitable for quantitative analysis of a large number of samples. Among them, three astragalosides and four isoflavones in A. membranaceus, ligustilide in Radix Angelicae Sinensis and Rhizoma Ligustici Chuanxiong and paeoniflorin in Radix Paeoniae Rubra were identified. This developed method was then successfully applied to pharmacokinetic studies of the nine bioactive constituents after oral administration of BYHWT extracts in rats. The pharmacokinetic data demonstrated that astragaloside I, astragaloside II, astragaloside IV and ligustilide presented the phenomenon of double peaks. The other herbal ingredients of formononetin, ononin, calycosin, calycosin-7-O-β-d-glucoside and paeoniflorin appeared together in a single and plateau absorption phase. These phenomenona suggest that these components may have multiple absorption sites, regulation of enterohepatic circulation or the gastric emptying rate, or there is ingredient-ingredient interaction. These pharmacokinetic results provide a constructive contribution to better understand the absorption mechanism of BYHWT and to support additional clinical evaluation.

LC‐MS/MS determination and pharmacokinetic study of albiflorin and paeoniflorin in rat plasma after oral administration of Radix Paeoniae Alba extract and Tang‐Min‐Ling‐Wan

A rapid, sensitive and selective liquid chromatography/tandem mass spectrometry method (LC-MS/MS) was developed and validated for simultaneous determination of albiflorin and paeoniflorin in rat plasma using geniposide as an internal standard. Plasma samples were extracted by solid-phase extraction. Chromatographic separation was carried out on a Zorbax SB-C(18) analytical column (150 × 2.1 mm × 5 µm) with 0.1% formic acid-acetonitrile (70:30, v/v) as the mobile phase. Detection was performed by multiple reaction monitoring mode using electrospray ionization in the positive ion mode. The total run time was 3.0 min between injections. The calibration curves were linear over a range of 1-1000 ng/mL for albiflorin and 2-2000 ng/mL for paeoniflorin. The overall precision and accuracy for all concentrations of quality controls and standards were better than 15%. Mean recovery was determined to be 87.7% for albiflorin and 88.8% for paeoniflorin. The validated method was successfully applied to the pharmacokinetic study of albiflorin and paeoniflorin in rat plasma after oral administration of Radix Paeoniae Alba extract and Tang-Min-Ling-Wan. The pharmacokinetic parameters showed that albiflorin and paeoniflorin from Tang-Min-Ling-Wan were absorbed more rapidly with higher concentrations in plasma than that from Radix Paeoniae Alba extract. The results provided a meaningful basis for evaluating the clinical applications of traditional Chinese medicine.

Comparative pharmacokinetic study of paeoniflorin after oral administration of decoction of Radix Paeoniae Rubra and Radix Paeoniae Alba in rats

An investigation was designed and conducted to compare the pharmacokinetics difference of paeoniflorin after oral administration of the extracts of Radix Paeoniae Rubra and Radix Paeoniae Alba to rats on separate occasions. Quantification of paeoniflorin in rat plasma was achieved using a simple and rapid HPLC method for pharmacokinetic study. After oral administration of decoctions of Radix Paeoniae Rubra and Radix Paeoniae Alba, paeoniflorin was absorbed and reached a maximum concentration of 3.69 ± 1.46 and 1.46 ± 0.29 ( p < 0.05) μg/ml at 1.67 ± 0.43 and 0.80 ± 0.35 h ( p < 0.05), respectively. Compared to the AUC (18.85 ± 7.54 μg h/ml) after oral administration of the paeoniflorin solution, a smaller AUC (10.61 ± 1.51 μg h/ml, p < 0.05) and a larger AUC (24.89 ± 7.41 μg h/ml) of paeoniflorin after oral administration of the decoctions of Radix Paeoniae Alba and Radix Paeoniae Rubra were obtained, respectively. There were statistically significant differences in pharmacokinetic parameters of paeoniflorin including the t max, C max, AUC, t 1/2, CL, and V d among the animals orally administered the decoctions of Radix Paeoniae Rubra and Radix Paeoniae Alba. In particular, the parameters of t max, C max, and AUC of paeoniflorin were remarkably increased ( P < 0.05, P < 0.001) when oral administering paeoniflorin in the decoctions of Radix Paeoniae Rubra, but t 1/2, V d, and CL were decreased ( P < 0.05 or P < 0.01), in comparison of the decoction of Radix Paeoniae Alba.

HPLC Analysis and Pharmacokinetic Study of Paeoniflorin after Intravenous Administration of a New Frozen Dry Powder Formulation in Rats

A simple and specific high performance liquid chromatographic (HPLC) method with UV detection using picroside II as the internal standard was developed and validated to determine the concentration of paeoniflorin in rat plasma and study its pharmacokinetics after an single intravenous administration of 40 mg kg−1 paeoniflorin to Wistar rats. The analytes of interest were extracted from rat plasma samples by ethyl acetate after acidification with 0.05 mol L−1 NaH2PO4 solution (pH 5.0). Chromatographic separation was achieved on an Agilent XDB C18 column (250 × 4.6 mm I.D., 5 μm) with a Shim-pack GVP-ODS C18 guard column (10 × 4.6 mm I.D., 5 μm) using a mobile phase consisting of acetonitrile–water–acetic acid (18:82:0.4, v/v/v) at a flow rate of 1.0 mL min−1. The UV detection was performed at a wavelength of 230 nm. The linear calibration curves were obtained in the concentration range of 0.05–200.0 μg mL−1 in rat plasma with the lower limit of quantification (LLOQ) of 0.05 μg mL−1. The intra- and inter-day precisions in terms of % relative standard deviation (RSD) were lower than 5.7 and 8.2% in rat plasma, respectively. The accuracy in terms of % relative error (RE) ranged from −1.9 to 2.6% in rat plasma. The extraction recoveries of paeoniflorin and picroside II were calculated to be 69.7 and 56.9%, respectively. This validated method was successfully applied to the pharmacokinetic study of a new paeoniflorin frozen dry power formulation. After single intravenous administration, the main pharmacokinetic parameters t1/2, AUC0-∞, CLTOT, VZ, MRT0-∞ and Vss were 0.739 ± 0.232 h, 43.75 ± 6.90 μg h mL−1, 15.50 ± 2.46 L kg−1 h−1, 1.003 ± 0.401 L kg−1, 0.480 ± 0.055 h and 0.444 ± 0.060 L kg−1, respectively.

Determination of paeoniflorin in rat plasma by a liquid chromatography‐tandem mass spectrometry method coupled with solid‐phase extraction

A rapid, sensitive and selective liquid chromatography-tandem spectrometry method was developed and validated for determination of paeoniflorin in rat plasma using geniposide as the internal standard. The samples were pretreated with solid-phase extraction using Extract-Clean cartridges. Separation of paeoniflorin and IS was achieved on a reversed-phase C18 column (50x4.6 mm i.d.) with a mobile phase made up of acetonitrile and 0.05% formic acid (25:75, v/v) at a flow rate of 0.5 mL/min. Detection was carried out on a triple quadrupole tandem mass spectrometer by multiple-reaction monitoring and an electrospray ionization source was employed as the ionization source. The lower limit of quantification obtained was 4 ng/mL (n=6) using 200 microL plasma with an accuracy of -3.67% (relative error) and a precision of 4.13% (relative standard deviation). A good linearity was found in the range of 4-1000 ng/mL. The intra- and inter-day relative standard deviations in the measurement of quality control samples 10, 150 and 800 ng/mL ranged from 3.73 to 4.94% and from 4.31 to 6.56%, respectively. The accuracy was from -3.93 to -1.11% in terms of relative error. The analyte and IS were stable in the battery of stability studies. This method was successfully applied to a pharmacokinetic study of paeoniflorin after a single oral administration of 53.36 mg/kg paeoniflorin to rats.

Effects of cerebral ischemia-reperfusion on pharmacokinetic fate of paeoniflorin after intravenous administration of Paeoniae Radix extract in rats

The objective of the present study was to investigate the effects of cerebral ischemia-reperfusion on pharmacokinetics of paeoniflorin after intravenous administration of Paeoniae Radix extract (PRE) in rats. The cerebral ischemia-reperfusion rats were induced by occluding the bilateral carotid arteries of normal rats for 2 h, followed by reperfusion. The resultant animals were immediately administrated by PRE (at a dose of 60 mg/kg of paeoniflorin) via the femoral vein, whilst the same dose was injected to the normal rats. Plasma samples were collected at different time to construct pharmacokinetic profiles by plotting drug concentration versus time. Quantification of paeoniflorin in rat plasma was achieved by using a simple and rapid high-performance liquid chromatographic method. In normal rats, the major parameters of distribution half-life ( t 1/2α), elimination half-life ( t 1/2β), area under the plasma concentration–time (AUC), mean retention time (MRT), and clearance (CL), estimated by an open two-compartmental model, were 0.69, 18.77 min, 5338.71 (μg min)/ml, 18.13 min and 0.0162 mg/(kg min), respectively. However, in ischemia-reperfusion rats, the corresponding parameters were 2.04, 24.51 min, 9626.00 (μg min)/ml, 29.75 min and 0.0071 mg/(kg min), respectively. The results showed that ischemia- reperfusion significantly increased AUC values, decreased CL values, and prolonged the terminal half-life of paeoniflorin. These findings suggest that the injuries of ischemia-reperfusion could play an important role in pharmacokinetic process of paeoniflorin.