Pharmacokinetics of a Natural Self-emulsifying Reversible Hybrid-Hydrogel (N'SERH) Formulation of Full-Spectrum Boswellia serrata Oleo-Gum Resin Extract: Randomised Double-Blinded Placebo-Controlled Crossover Study.

The oleo-gum-resin of Boswellia serrata, an Ayurvedic herb for the treatment of chronic inflammatory diseases, contains both volatile (terpenes) and nonvolatile (boswellic acids) molecules as responsible for its bioactivity. The present randomized, double-blinded, placebo-controlled, crossover study evaluated the human pharmacokinetics of a 'natural' hybrid-hydrogel formulation of a unique full-spectrum boswellia extract (BFQ-20) (standardized for both volatile and nonvolatile bioactives) in comparison with unformulated extract (U-BE), for the first time. Mass spectrometry coupled with LC (UPLC-MS/MS) and gas chromatography (GC-MS/MS) measurements of the plasma concentration of boswellic acids and α-thujene at different post-administration time points followed by a single dose (400 mg) of U-BE and BFQ-20, to healthy volunteers (n = 16), offered 4-fold enhancement in the overall bioavailability of boswellic acids from BFQ-20, [area under the curve (AUC) (BFQ-20) = 9484.17 ± 767.82 ng * h/mL vs. AUC (U-BE) = 2365.87 ± 346.89 ng * h/mL], with the absorption maximum (Tmax) at 6.3 h post-administration and elimination half-life (T1/2) of 15.5 h (p < 0.001). While plasma α-thujene was not detectable upon U-BE administration, BFQ-20 provided significant absorption, [AUC (BFQ-20): 298.60 ± 35.48 ng * h/mL; Cmax: 68.80 ± 18.60 ng/mL; Tmax: 4.12 ± 0.38 h; T1/2: 16.24 ± 1.12 h]. Further investigation of the anti-inflammatory effect revealed 70.5% inhibition of paw edema in rats compared to 38.0% for U-BE. In summary, the natural self-emulsifying reversible hybrid-hydrogel (N'SERH) formulation of boswellia extract using fenugreek mucilage (FenuMat®) significantly increased the solubility (58-fold), stability, and bioavailability of both the volatile and non-volatile bioactives which in turn improved the anti-inflammatory efficacy of Boswellia extract.

Population Pharmacokinetic of the Diterpenes ent-Polyalthic Acid and Dihydro-ent-Agathic Acid from Copaifera Duckei Oil Resin in Rats.

Copaifera duckei oleoresin is a plant product extensively used by the Brazilian population for multiple purposes, such as medicinal and cosmetic. Despite its ethnopharmacological relevance, there is no pharmacokinetic data on this important medicinal plant. Due to this, we determined the pharmacokinetic profile of the major nonvolatile compounds of C. duckei oleoresin. The diterpenes ent-polyalthic acid and dihydro-ent-agathic acid correspond to approximately 40% of the total oleoresin. Quantification was performed using LC-MS/MS, and the validated analytical method showed to be precise, accurate, robust, reliable, and linear between 0.57 and 114.74 µg/mL plasma and 0.09 to 18.85 µg/mL plasma, respectively, for ent-polyalthic acid and dihydro-ent-agathic acid, making it suitable for application in preclinical pharmacokinetic studies. Wistar rats received a single 200 mg/kg oral dose (gavage) of C. duckei oleoresin, and blood was collected from their caudal vein through 48 h. Population pharmacokinetics analysis of ent-polyalthic and dihydro-ent-agathic acids in rats was evaluated using nonlinear mixed-effects modeling conducted in NONMEN software. The pharmacokinetic parameters of ent-polyalthic acid were absorption constant rate = 0.47 h-1, central and peripheral apparent volume of distribution = 0.04 L and 2.48 L, respectively, apparent clearance = 0.15 L/h, and elimination half-life = 11.60 h. For dihydro-ent-agathic acid, absorption constant rate = 0.28 h-1, central and peripheral apparent volume of distribution = 0.01 L and 0.18 L, respectively, apparent clearance = 0.04 L/h, and elimination half-life = 3.49 h. The apparent clearance, central apparent volume of distribution, and peripheral apparent volume of distribution of ent-polyalthic acid were approximately 3.75, 4.00-, and 13.78-folds higher than those of dihydro-ent-agathic.

Nanoparticle formation by using shellac and chitosan for a protein delivery system.

The potential of using two natural polymers (chitosan and shellac) for the formation of nanoparticles by the process of ionic cross-linking to encapsulate bovine serum albumin, a model protein was investigated. Depending on the concentrations of chitosan, shellac and bovine serum albumin, three physical states - nanoparticle, aggregation, and solution could be observed as a result of the electrostatic force. The formation of nanoparticles was due to the balance between the repulsion force and attractive force while the imbalance between both forces resulted in the formation of aggregation and solution. The Fourier transform infrared spectroscopy and differential scanning calorimetry were applied to prove the nanoparticle formation. The particle size was characterized by the light scattering technique and was found in the range between 100 and 300 nm. The morphology of the particles, detected by transmission electron microscopy was spherical shape. The result showed that the zeta potential of the nanoparticles possessed positive charges. The concentrations of chitosan, shellac and bovine serum albumin had an influence on the physicochemical properties of the nanoparticles such as the particle size, the zeta potential, the encapsulation, the loading efficiencies and the cumulative release. Therefore, chitosan and shellac could be used to form nanoparticles for protein delivery by the ionic cross-linking method.

[Effect of dragon's blood powder with different grain size on transdermal absorption and adhesion of ZJHX paste].

OBJECTIVE: To study the effect of dragon's blood powder with different grain size on the transdermal permeability and adhesion of ZJHX paste. METHOD: Dragon's blood powder with grain sizes of 4, 19, 55 microm were got by ultrafine grinding technology, and then prepared into rubber pastes A, B, C and D, together with dragon's blood powder with grain size of 93 microm of original description. Franz diffusion cell method was adopted to compare the difference in transdermal permeability of dragon's blood powder with different grain sizes, with dracorhodin as the index, and compared their effect on the adhesion of pastes with initial adhesion, permanent adhesion and peel strength as the indexes. RESULT: Q(s)-t equations of pastes A, B, C, D were as follows: Q(s)=1.369 6t + 3.985 5, Q(s) = 1.262 8t +3.738 1, Q(s) = 1.192 3t + 3.320 6, Q(s) = 1.152 2t + 2.366 1, respectively, which showed that the adhesion of A was the best good. CONCLUSION: With the decrease in the grain size of dragon's blood powder, accumulative penetration of dracorhodin increases, which facilitates transdermal permeability and adhesion.

Oral administration of chios mastic gum or extracts in mice: quantification of triterpenic acids by liquid chromatography-tandem mass spectrometry.

Chios mastic gum, the resin obtained as an exudate from the trunk and branches of Pistacia lentiscus L var. chia, is used extensively as a constituent of herbal drugs or functional foods. The oral absorption of its major constituents still remains unclear. In the context of identifying the features of mastic gum that are responsible for either therapeutic effects or effects of nutritional value, a methodology based on high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (MS/MS) was developed and applied for the quantification of mastic gum triterpenic acids, 24Z-isomasticadienonic acid (IMNA), and 24Z-isomasticadienolic acid (IMLA) in mouse plasma. The specific compounds were selected based on their biological activity and potential against Helicobacter pylori. Concentrations were determined simultaneously in mouse plasma after oral administration of mastic gum or total mastic extract without polymer (TMEWP) in order to evaluate the role of the natural polymer, poly-ß-myrcene, in the absorption process. Following TMEWP administration in mice, circulating IMNA and IMLA plasma levels were significantly higher (approximately 10-fold) in comparison to IMNA and IMLA plasma levels following total mastic gum administration (CMG), suggesting that the polymer plays a critical role in the absorption process. More specifically following TMEWP administration, Cmax plasma values were 3300 ± 859 ng/mL for IMNA and 163 ± 58 ng/mL for IMLA. In comparison, following CMG administration, Cmax plasma values were 329 ± 57 ng/mL for IMNA and 28 ± 8 ng/mL for IMLA. The methodological approaches presented in this study, along with the findings, offer valuable information on the availability of bioactive components following ingestion of mastic and facilitate the uses of mastic either as an ingredient of functional foods or as a herbal drug.

Novel biopolymers as implant matrix for the delivery of ciprofloxacin: biocompatibility, degradation, and in vitro antibiotic release.

The purpose of this study was to investigate the in vitro-in vivo degradation and tissue compatibility of three novel biopolymers viz. polymerized rosin (PR), glycerol ester of polymerized rosin (GPR) and pentaerythritol ester of polymerized rosin (PPR) and study their potential as implant matrix for the delivery of ciprofloxacin hydrochloride. Free films of polymers were used for in vitro degradation in PBS (pH 7.4) and in vivo in rat subcutaneous model. Sample weight loss, molecular weight decline, and morphological changes were analyzed after periodic intervals (30, 60, and 90 days) to monitor the degradation profile. Biocompatibility was evaluated by examination of the inflammatory tissue response to the implanted films on postoperative days 7, 14, 21, and 28. Furthermore, direct compression of dry blends of various polymer matrices with 20%, 30%, and 40% w/w drug loading was performed to investigate their potential for implant systems. The implants were characterized in terms of porosity and ciprofloxacin release. Biopolymer films showed slow rate of degradation, in vivo rate being faster on comparative basis. Heterogeneous bulk degradation was evident with the esterified products showing faster rates than PR. Morphologically all the films were stiff and intact with no significant difference in their appearance. The percent weight remaining in vivo was 90.70 +/- 6.2, 85.59 +/- 5.8, and 75.56 +/- 4.8 for PR, GPR, and PPR films respectively. Initial rapid drop in Mw was demonstrated with nearly 20.0% and 30.0% decline within 30 days followed by a steady decline to nearly 40.0% and 50.0% within 90 days following in vitro and in vivo degradation respectively. Biocompatibility demonstrated by acute and subacute tissue reactions showed minimal inflammatory reactions with prominent fibrous encapsulation and absence of necrosis demonstrating good tissue compatibility to the extent evaluated. All implants showed erosion and increase in porosity that affected the drug release. Increase in drug loading significantly altered the ciprofloxacin release in extended dissolution studies. PPR produced drug release >90% over a period of 90 days promising its utility in implant systems. The results demonstrated the utility of novel film forming biopolymers as implant matrix for controlled/sustained drug delivery with excellent biocompatibility characteristics.

Simultaneous determination of ten bioactive constituents of Sanjie Zhentong Capsule in rat plasma by ultra-high-performance liquid chromatography tandem mass spectrometry and its application to a pharmacokinetic study.

Sanjie Zhentong capsule, a well-known traditional Chinese medicine prescription, are used for the treatment of endometriosis-related diseases. In this study, a simple, rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of ten bioactive constituents, including peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4'-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, and notoginsenoside R1 in rat plasma after oral administration of Sanjie Zhentong capsule. The sample preparations for protein removal was accomplished using a simple methanol precipitation method. The analytes were completely separated from the endogenous compounds on an Agilent Poroshell 120 SB-C18 column (4.6mm×150mm, 2.7µm) using an isocratic elution with methanol - 0.1% formic acid aqueous (4/1, v/v) as a mobile phase. The single-run analysis time was as short as 14.0min. The inter-day and intra-day precision of the quality control samples exhibited relative standard deviations (RSD) <9.5% and the accuracy values ranged from -8.6% to 15.0%. The lower limits of quantification (LLOQ) were 10, 10, 10, 10, 10, 10, 5, 10, 10 and 20ng/mL for peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4'-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, notoginsenoside R1, respectively. The analytical method was successfully applied to a pharmacokinetic study of the multi-components after oral administration of Sanjie Zhentong Capsule in rats.

Molecular insights into shellac film coats from different aqueous shellac salt solutions and effect on disintegration of enteric-coated soft gelatin capsules.

The purpose of this investigation was to study the effect of using different salts of shellac on the disintegration properties of shellac-based enteric coatings. In the last two decades, shellac has been increasingly used as an aqueous solution for enteric coating purposes, with the ammonium salt being the form typically used. Little investigation has been performed on using other salts, and therefore, this was the focus of our work. Enteric coatings, based on different shellac salts (ammonium, sodium, potassium and composite ammonium-sodium), were applied onto soft gelatin capsules. Disintegration testing of the coated soft gelatin capsules showed that alkali metal salts promote faster disintegration than ammonium salts. In order to determine the causes behind these differences, the solubility, thermal and spectroscopic properties of films cast from the different salts were investigated. The results show that films cast from ammonium-based salts of shellac are, unlike those cast from alkali metal-based salts, water-insoluble. Spectroscopic evidence suggests that this might be due to partial salt dissociation resulting in loss of ammonium as ammonia and reduced degree of shellac ionization during drying. In addition, oxidation of shellac aldehyde groups of the ammonium-based shellac salts could also play a role. And possible higher extent of shellac hydrolysis during the preparation of alkali metal salts might also be a factor. Therefore, the nature of the shellac salt used in the preparation of shellac-based aqueous coating solutions is a significant formulation factor affecting product performance.

Improvement in the disintegration of shellac-coated soft gelatin capsules in simulated intestinal fluid.

Shellac is a natural enteric polymer, which results in good gastric resistance; however, it often dissolves too slowly in intestinal fluids. The objective of this study was to improve the disintegration of shellac-coated soft gelatin capsules in simulated intestinal fluids (phosphate buffer pH 6.8) through the addition of pore-formers, such as organic acids and hydrophilic polymers, while retaining gastric resistance. The mechanical properties (% elongation at rupture, puncture strength at break and modulus at puncture), media uptake and weight loss of shellac films were determined upon exposure in 0.1 N HCl and/or phosphate buffer pH 6.8. Organic acids (e.g., sorbic acid) acted as plasticizers, they reduced the glass transition temperature of ethanol-cast shellac films. The addition of additives effectively decreased the disintegration times in phosphate buffer pH 6.8, while the behavior in 0.1 N HCl remained unchanged. In addition, the hardness and disintegration of shellac-coated soft gelatin capsules were monitored through the whole disintegration experiments. The best disintegration was achieved with sorbic acid as pore-former. Sorbic acid remained in the shellac coating at low pH, but leached in pH 6.8 buffer, thus resulting in good gastric resistance and rapid disintegration in simulated intestinal fluids. The disintegration time of ethanolic shellac-coated soft gelatin capsules decreased with increasing amount of pore-former. The slow disintegration of aqueous shellac-coated soft gelatin capsules could be also improved by the addition of hydrophilic polymers, such as hydroxypropyl methylcellulose (HPMC). However, higher HPMC concentrations were required when compared to sorbic acid.

Use of natural plant exudates (Sanguis Draxonis) for sustained oral insulin delivery with dramatic reduction of glycemic effects in diabetic rats.

Sanguis Draxonis (SD), a kind of natural plant exudates, has been prescribed for handling diabetic disorders as a Chinese traditional herb. Surprisingly, SD was found to be a good material for oral insulin delivery. The Insulin-loaded Sanguis Draxonis nanocapsules (ISDN) were prepared by deposition technique. The average size and width of distribution of ISDN were 184+/-24 and 110+/-16 nm, respectively. The insulin encapsulation efficiency of ISDN reached up to 69.6+/-5.6%. In vitro the release profile of insulin from ISDN can be well modeled using an exponential function [Y=1-exp(-0.0275t)], showing that there was no initial burst release of insulin. The stability studies indicated that the majority of initial amount of insulin in ISDN was preserved not only after incubation of ISDN in three kinds of proteolytic enzyme solutions at 37 degrees C for 30 min, but also after its storage at 25 degrees C for 6 months. After a single oral administration of ISDN at the dose of 25, 50, and 75 IU/kg in STZ-induced diabetic rats, the blood glucose level was depressed to 60.5+/-2.7%, 52.6+/-2.3% and 47.3+/-3.1% of the initial value at time point 8 h, respectively, and these marked decreases lasted 2-4 days. When 125I-labeled ISDN was administered orally, the distribution sequence of isotope intensity of 125I radioactivity in rat organs was as follows: liver, kidney, heart, spleen and lung. In addition, 125I radioactivity disappeared progressively as a function of time, parallel to the biological effect. In conclusion, the results demonstrate that ISDN elicits a long-term hypoglycemic effect significantly after oral administration in STZ-induced diabetic rats and it can be considered as a stable and effective system for oral insulin delivery.

Dry polymer powder coating and comparison with conventional liquid-based coatings for Eudragit) RS, ethylcellulose and shellac.

Drug-layered pellets were coated with micronized polymer powders (Eudragit) RS, ethylcellulose, and shellac) by a dry powder coating technique as an alternative to organic- and aqueous-based coatings (Eudragit) RS 30D, Aquacoat) ECD) were investigated. High plasticizer concentrations (40%) and a thermal after-treatment (curing) were necessary for the coalescence of the polymer particles and good film formation. Ethylcellulose required a higher curing temperature and time than Eudragit) RS because of its higher glass transition temperature (133 versus 58 degrees C). A smaller polymer particle size also promoted film formation. In general, pellets coated with polymer powders required higher coating levels to obtain similar drug release patterns as pellets coated with organic polymer solutions and aqueous polymer dispersions.

Preparation and in vivo evaluation of mucoadhesive microparticles containing amoxycillin-resin complexes for drug delivery to the gastric mucosa.

In this work, microparticles consisting of amoxycillin-loaded ion-exchange resin encapsulated in mucoadhesive polymers (polycarbophil and Carbopol 934) were prepared with the aim of increasing the efficacy of amoxycillin in the treatment of peptic ulcers by achieving targeted delivery to the gastric mucosa and prolonged drug release. An oil-in-oil solvent evaporation technique was conveniently modified in order to obtain polymer microparticles containing multiple amoxycillin-resin cores. Polycarbophil microparticles were spherical, Carbopol 934 microparticles irregular. In vitro release of amoxycillin was rapid with or without a polymer coating. Gastrointestinal transit in rats was investigated by fluorescence microscopy using particles loaded with fluorescein instead of amoxycillin: gastric residence time was longer, and the distribution of the particles on the mucosa apparently better, without any polymer coating.

Description and simulation of a multiple mixing tank model to predict the effect of bile sequestrants on bile salt excretion.

A nonlinear, multicompartment mixing tank model based on human physiologic parameters from the literature and in vitro bile salt sequestrant binding parameters was integrated numerically to simulate bile salt excretion. The model focuses on the transit of bile salts and resin, bile salt binding, and bile salt reabsorption as a means of gaining insight into the functioning of bile sequestrants in the gastrointestinal tract and the effect of reabsorption of bile salts on the sequestering process. The series of compartments through the ileal region were tested over a range of parameter values, and the results were compared with bile salt output from ileostomy patient data to validate the model without resin. In simulations incorporating resin with a reversible binding scheme, fecal bile salt output was 2.37 (+/- 0.6) x 10(-3) mol/day compared with 2.64 (+/- 1.1) x 10(-3) mol/day for human data. Assuming irreversible bile salt binding resulted in predictions of fecal bile salt excretion greater than three times physiologic values. The results of these simulations support the hypothesis that the lack of efficacy of bile sequestrants is due to the displacement of bound bile salts from the sequestrant as a consequence of anion competition and bile salt reabsorption. Gastric emptying effects and the timing of resin doses have also been investigated with the model.

Modification of physicochemical and mechanical properties of shellac by partial hydrolysis.

The shellac was modified by partial hydrolysis with 2.0% (w/w) NaOH for different times. The hydrolysed shellac was then evaluated for physicochemical and film properties in comparison with native shellac. The tablets coated with native and hydrolysed shellac were also evaluated. The results demonstrated that acid value (AV) of shellac increased with prolongation of hydrolysis time. The solubility of shellac in buffer solution (pH < or = 7) gradually increased with increasing hydrolysis time. The films prepared from hydrolysed shellac were more flexible and soft than those prepared from native shellac. The increasing of flexibility was correlated with the increasing of soft resin in shellac. The water vapor permeability of hydrolysed shellac film was lower than that of native shellac film. The higher acid permeability of the tablet coated with hydrolysed shellac was observed. In ethanol-based film coating, shellac had lower solubility and thus lower drug dissolution from coated tablets was observed. In ammonia-based film coating, the solubility of shellac was improved higher nearby pH 7.0 by an ammonium neutralisation method because of forming well-soluble salts, thereby higher drug dissolution was obtained. Partial hydrolysis provided modified shellac, which is more effective for ammonium salt formation, thus very higher drug dissolution was achieved in the ammonia-based coated tablets.

Polymerized rosin: novel film forming polymer for drug delivery.

Polymerized rosin (PR) a novel film forming polymer is characterized and investigated in the present study for its application in drug delivery. Films were produced by a casting/solvent evaporation method from plasticizer free and plasticizer containing solutions. Films prepared from different formulations were studied for their mechanical (tensile strength, percent elongation and Young's modulus), water vapour transmission and moisture absorption characteristics. Neat PR films were slightly brittle and posed the problem of breaking during handling. Hydrophobic plasticizers, dibutyl sebacate and tributyl citrate, improved the mechanical properties of free films with both the plasticizers showing significant effects on film elongation. Release of diclofenac sodium (model drug) from coated pellets was sustained with high coating levels. Concentration of plasticizer was found to affect the release profile. PR films plasticized with hydrophobic plasticizers could therefore be used in coating processes for the design of oral sustained delivery dosage forms.

The use of sediment analogues to study the uptake of pollutants by chironomid larvae.

A technique is described that uses artificial resin beads with known surface properties to investigate the factors influencing the bioaccumulation of pollutants from sediments. One advantage of this technique is that it provides a standard procedure against which it is possible to calibrate natural sediments with their diverse properties. The method has been used on third instar larvae of the midge Chironomus riparius and the results are compared with previous studies on the worm Lumbriculus variegatus. The use of a standard test using resin beads as a substitute for natural sediment allows comparisons to be made between species and substrates. Thus, the bioaccumulation factors for the midge larvae are much smaller than those of the worm and this correlates with the ability of the insect larva to detoxify many pollutants. It is also possible to use the test to identify if ingestion of the sediment increases the bioaccumulation of contaminants and whether this involves the release of pollutants by digestive processes or not.

Effect of atropine on nasal mucociliary clearance.

To investigate the effect of atropine on mucociliary function, nasal mucociliary clearance was measured with two methods in eight healthy men before and after subcutaneous injection of atropine sulphate. The movement of two different tracers placed 1.5 cm posterior to the inferior turbinate tip was measured. The transport rate of a resin particle tagged with 99mTc was measured. The clearance of 10 microliters saline labelled with 99mTc was monitored and the clearance rate calculated. Whereas atropine lowered the resin particle transport rate, the saline method did not reveal any difference in clearance rate after injection of atropine. Since the former method measures the transport of particles in the gel phase (the outer mucous layer) and the latter measures the clearance of both gel and sol (periciliary fluid) layers, it is postulated that the slowing of mucociliary transport by atropine is due to alterations in the gel layer.

An HPLC-ESI-MS method for analysis of loureirin A and B in dragon's blood and application in pharmacokinetics and tissue distribution in rats.

A sensitive HPLC-ESI-MS method for the simultaneous determination of loureirin A (LA) and loureirin B (LB) in rat plasma and tissues was developed, and the pharmacokinetic and tissue distribution characteristics of LA and LB were investigated after gavage administration. The samples were pretreated by protein precipitation with ethyl acetate and then separated on a Welch Ultimate XB-C18 column with water-acetonitrile (42:58, v/v) containing 0.1% glacial acetic acid as the mobile phase. The analytes were detected with no interference in multiple reaction monitoring (MRM) mode on an electrospray ionization ion trap mass spectrometer. The analytes showed good linearity over a wide concentration range and the lowest limit of quantification (LLOQ) was 5 ng/mL for LA and 2ng/mL for LB in matrices. The pharmacokinetic curves of both analytes were best fitted to one-compartment model. It suggested that the analytes absorbed and distributed very quickly in rats. Tissue distribution results showed that the analytes had a wide distribution in tissues and the highest levels for LA and LB were observed in liver followed by kidney, lung, spleen, heart and cerebrum. This work provided the pharmacokinetics and tissue distribution characteristics of LA and LB, which would be instructive for their clinical regiment design.

A sensitive LC-MS/MS method to quantify loureirin B in rat plasma with application to preclinical pharmacokinetic studies.

A novel method for the quantification of loureirin B in rat plasma using high-performance liquid chromatography/tandem mass spectrometry (LC-MS/MS) was developed. Loureirin B and internal standard (buspirone) were extracted by liquid-liquid extraction and separated on a Agilent XDB C18 column (50 mm x 4.6 mm, 5 microm). As mobile phase a binary mixture of methanol (containing 0.1% formic acid)-water (containing 0.1% formic acid) was delivered by a Shimadzu LC-20AD pump in gradient mode at a flow rate of 0.4 ml/min in a run time of 5.0 min. The detector was a Q-trap mass spectrometer with an electrospray ionization (ESI) interface operating in the multiple reaction monitoring (MRM) mode. The calibration curve of loureirin B in plasma showed good linearity over the concentration range of 0.08-100 ng/ml. The limit of detection and limit of quantification were 0.03 ng/ml and 0.08 ng/ml, respectively. Intra- and inter-day precisions (as relative standard deviation) in all samples were both within 15%. The validated method was successfully applied to a preliminary pharmacokinetic study of loureirin B in rats. After oral administration of 16 g/kg longxuejie to rats, the main pharmacokinetic parameters tmax, Cmax, t(1/2), Ke and AUC(0-T) were 0.8 h, 7.99 microg/l, 1.94 l h, 0.365/h, and 22.21 microg h/l, respectively.