Pharmacokinetics of salvianolic acid B, rosmarinic acid and Danshensu in rat after pulmonary administration of Salvia miltiorrhiza polyphenolic acid solution

A sensitive and accurate LC-MS/MS method was established for quantifying salvianolic acid B (Sal B), rosmarinic acid (Ros A) and Danshensu (DA) in rat plasma. Salvia miltiorrhiza polyphenolic acid (SMPA), active water-soluble ingredients isolated and purified from Salvia miltiorrhiza Bge included Sal B, Ros A and DA. The pharmacokinetic analysis of Sal B, Ros A and DA after pulmonary administration of SMPA solution to rat was performed by LC-MS/MS. Results from the pharmacokinetic studies showed that the peak concentration of DA was 21.85 ± 6.43 and 65.39 ± 3.83 ng/mL after pulmonary and intravenous administration, respectively. DA was not detected at 2 h after administration. The absolute bioavailabilities of Sal B and Ros A were respectively 50.37 ± 27.04 and 89.63 ± 12.16% after pulmonary administration of 10 mg/kg SMPA solution in rats. The absolute bioavailability of Sal B increased at least 10-fold after pulmonary administration, compared with oral administration. It was concluded that the newly established LC-MS/MS method was suitable for describing the pharmacokinetic characteristics of Sal B, Ros A and DA in rat after pulmonary administration of SMPA solution. The data from this study will provide a preclinical insight into the feasibility of pulmonary administration of SMPA.

Some pharmacokinetic parameters of salvianolic acid A following single-dose oral administration to rats

CONTEXT

Salvianolic acid A (Sal A) is a hydrophilic bioactive compound isolated from Salvia miltiorrhiza Bunge (Lamiaceae). It exerts beneficial effects after oral administration on diabetic complications.

OBJECTIVE

To systematically study the absorption, distribution and excretion of Sal A after single-dose oral administration.

MATERIALS AND METHODS

Animal experiments were conducted in Sprague-Dawley rats. Plasma was sampled at designated times after oral doses of 5, 10 and 20 mg/kg, and an intravenous dose of 50 μg/kg. Tissues were harvested at 10, 60 and 120 min postdosing. Bile, urine and feces were collected at specified intervals before and after dosing. Absorption and distribution characteristics were analyzed by LC-MS, and excretion characteristics were analyzed by UPLC-MS/MS. The Caco-2 cell model was applied to investigate potential mechanisms.

RESULTS

The C_max (5 mg/kg: 31.53 μg/L; 10 mg/kg: 57.39 μg/L; 20 mg/kg: 111.91 μg/L) of Sal A increased linearly with doses (r> 0.99). The calculated absolute bioavailability was 0.39-0.52%. Transport experiment showed poor permeability and the ratio of P_B-A to P_A-B was 3.13-3.97. The highest concentration of Sal A was achieved in stomach followed by small intestine and liver, and it could also be detected in brain homogenate. Approximately 0.775% of its administered dose was excreted via feces, followed by bile (0.00373%) and urine (0.00252%).

DISCUSSION AND CONCLUSIONS

These results support the future development of Sal A as an oral drug for the treatment of diabetic complications. Future research should be conducted to investigate the reason for its poor bioavailability and improve this situation.

High-Throughput Determination of Sodium Danshensu in Beagle Dogs by the LCMS/MS Method, Employing Liquid-Liquid Extraction Based on 96-Well Format Plates

Sodium Danshensu (sodium d-(+)-β-(3,4-dihydroxyphenyl) lactate), one of the water-soluble ingredients in Salvia miltiorrhiza, exhibits potent relaxation of the coronary artery and anticoagulation effection. A high-throughput, rapid, and sensitive method combining liquid chromatography with electrospray ionization tandem mass spectrometry to determine the sodium danshensu in beagle dog plasma was developed and validated, using gallic acid as an internal standard (IS). Acidified plasma samples were extracted using 96-well liquid-liquid extraction, and were eluted on a CNW Athena C18 column (3 μm, 2.1 × 100 mm) by using a gradient mobile phase system of methanol and water (containing 0.2% formic acid). The mass spectrometric detection was achieved using negative ion electrospray ionization mode and monitoring the precursor→production combinations of m/z 197→135 for sodium danshensu and 169→125 for IS, in multiple reaction monitoring modes. Good linearity was achieved, and the linear range was 10-1000 ng/mL (R² > 0.996) with a quantification limit of 10 ng/mL for sodium danshensu in beagle dog plasma. The intra- and inter-day precision (RSD) ranged from 2.1% to 9.0%. The accuracy (RE) was between -8.6% and 5.7% at all quality control levels. The validated method was successfully applied to the pharmacokinetics study of sodium danshensu in beagle dog plasma after intravenous injection and oral administration of sodium danshensu.

Quantitatively metabolic profiles of salvianolic acids in rats after gastric-administration of Salvia miltiorrhiza extract

Salvianolic acids, the well-known active components in Salvia miltiorrhiza, have been shown to possess markedly pharmacological activities. However, due to the complex in vivo course after administration, the pharmacologically active forms are still poorly understood. In present study, we evaluated the stability of eight major salvianolic acids from Danshen extract under different chemical and physiological conditions. We also quantitatively explained the absorption, metabolism and excretion of these salvianolic acids in rats after gastric-administration, which was carried out by simultaneously determining the amounts of salvianolic acids and their metabolites in the rat gastrointestinal contents, gastrointestinal mucosa, plasma, bile and urine. We found that: 1) protocatechuic aldehyde (PAL) was much stable whether in acidic environment (pH4.0) or in alkaline environment (pH8.0), while other salvianolic acids were stable in acidic environment and instable in alkaline environment; 2) PAL, salvianoli acid A (SAA) and salvianolic acid B (SAB) were instable whether in rat stomach or in small intestine, while other salvianolic acids were stable in rat stomach and instable in small intestine; 3) after gastric-administration, except PAL and Danshensu (DSS), other phenolic acids would be metabolized into DSS and caffeic acid (CA) in the rat gastrointestinal tract before absorption, and only free and glucuronidated PAL, CA and DSS were detected in rat plasma, bile and urine. In conclusion, it was the free and glucuronidated PAL, CA and DSS rather than the prototypes of other salvianolic acids that were present in plasma with considerable concentrations after gastric-administration.

Layered Double Hydroxide Nanotransporter for Molecule Delivery to Intact Plant Cells

Here we report a powerful method that facilitates the transport of biologically active materials across the cell wall barrier in plant cells. Positively charged delaminated layered double hydroxide lactate nanosheets (LDH-lactate-NS) with a 0.5‒2 nm thickness and 30‒60 nm diameter exhibit a high adsorptive capacity for negatively charged biomolecules, including fluorescent dyes such as tetramethyl rhodamine isothiocyanate (TRITC), fluorescein isothiocyanate isomer I(FITC) and DNA molecules, forming neutral LDH-nanosheet conjugates. These neutral conjugates can shuttle the bound fluorescent dye into the cytosol of intact plant cell very efficiently. Furthermore, typical inhibitors of endocytosis and low temperature incubation did not prevent LDH-lactate-NS internalization, suggesting that LDH-lactate-NS penetrated the plasma membrane via non-endocytic pathways, which will widen the applicability to a variety of plant cells. Moreover, the absence of unwanted side effects in our cytological studies, and the nuclear localization of ssDNA-FITC suggest that nano-LDHs have potential application as a novel gene carrier to plants.

Comparative pharmacokinetic and tissue distribution profiles of four major bioactive components in normal and hepatic fibrosis rats after oral administration of Fuzheng Huayu recipe

Fuzheng Huayu recipe (FZHY) is a herbal product for the treatment of liver fibrosis approved by the Chinese State Food and Drug Administration (SFDA), but its pharmacokinetics and tissue distribution had not been investigated. In this study, the liver fibrotic model was induced with intraperitoneal injection of dimethylnitrosamine (DMN), and FZHY was given orally to the model and normal rats. The plasma pharmacokinetics and tissue distribution profiles of four major bioactive components from FZHY were analyzed in the normal and fibrotic rat groups using an ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. Results revealed that the bioavailabilities of danshensu (DSS), salvianolic acid B (SAB) and rosmarinic acid (ROS) in liver fibrotic rats increased 1.49, 3.31 and 2.37-fold, respectively, compared to normal rats. There was no obvious difference in the pharmacokinetics of amygdalin (AMY) between the normal and fibrotic rats. The tissue distribution of DSS, SAB, and AMY trended to be mostly in the kidney and lung. The distribution of DSS, SAB, and AMY in liver tissue of the model rats was significantly decreased compared to the normal rats. Significant differences in the pharmacokinetics and tissue distribution profiles of DSS, ROS, SAB and AMY were observed in rats with hepatic fibrosis after oral administration of FZHY. These results provide a meaningful basis for developing a clinical dosage regimen in the treatment of hepatic fibrosis by FZHY.

[Pharmacokinetics of salvianolic acid A after single intravenous administration in Rhesus monkey]

Salvianolic acid A (Sal A) is one of the most effective compounds isolated from the root of Salvia miltiorrhiza. Up to now, several studies regarding the pharmacokinetic profiles of Sal A have been reported, however there is no such study reported in monkeys, the species which is more similar to human. The aim of this study is to develop a LC-MS method for the determination of Sal A in monkey plasma and apply it to the pharmacokinetic studies of monkeys. After single intravenous administration of Sal A, the plasma concentration-time curves were observed and the main pharmacokinetic parameters were calculated. The plasma concentration at 2 min (C2 (min)) values were (28.343 ± 6.426), (45.679 ± 12.301) and (113.293 ± 24.360) mg x L(-1) for Rhesus monkeys treated with Sal A at 2.5, 5 and 10 mg x kg(-1). The area under the concentration-time curve (AUC(0-∞)) values were (3.316 ± 0.871), (5.754 ± 2.150) and (13.761 ± 2.825) μg x L(-1) x h, respectively. Furthermore, this method was improved and applied to the simultaneous determination of Sal A, Sal B and Sal C, which provided useful information for preclinical studies and clinical trials of Sal A, Sal B and Sal C.

A UPLC-MS/MS method for simultaneous determination of danshensu, protocatechuic aldehyde, rosmarinic acid, and ligustrazine in rat plasma, and its application to pharmacokinetic studies of Shenxiong glucose injection in rats

A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of the four major active ingredients, danshensu, protocatechuic aldehyde, rosmarinic acid, and ligustrazine, in the traditional Chinese medicine Shenxiong glucose injection in rat plasma. Acidified and alkalized plasma samples were extracted using ethyl acetate, and separated on a Waters C18 column (2.1mm×50mm, 1.7μm) by using a gradient mobile phase system of acetonitrile-water containing 0.1% formic acid and luteoloside as an internal standard. Electrospray ionization in the positive-ion mode and multiple reaction monitoring were used to identify and quantitate the active components. All calibration curves showed good linearity (r>0.994) over the concentration range, with a lower limit of quantification (LLOQ) between 0.02 and 0.21μg/mL. The precision of the in vivo study was evaluated by intra- and inter-day assays, and the percentage of relative standard deviation was within 15%. Moreover, satisfactory extraction efficiency was obtained (between 83.94 and 117.81%) by liquid-liquid extraction. The validated method was successfully applied in a pharmacokinetic study in rats after intravenous administration of Shenxiong glucose injection. The results showed that the four bioactive ingredients in Shenxiong glucose injection have linear pharmacokinetic properties in rats after intravenous injection within the administered dose range and partially different ones compared to single ingredient.

[Simultaneous determination of six Salvia miltiorrhiza gradients in rat plasma and brain by LC-MS/MS]

To develop a LC-MS/MS method for the determination of protocatechuic acid, protocatechuic aldehyde, salvianolic acid A, salvianolic acid B, cryptotanshinone and tanshinone II(A) in rat plasma and brain. The plasma and brain samples were precipitated with ethyl acetate, then were separated on an Agilent eclipse plus-C18 column (2.1 mm x 50 mm, 3.5 microm) using acetonitrile (consisting of 0.1% formic acid) and water (consisting of 0.1% formic acid) as mobile phase in gradient elution mode. The mass spectrometer was operated under both positive and negative ion mode with the ESI source, and the detection was performed by MRM. The transition of 154.3/153.1 m/z for protocatechuic acid, 137.3/108 m/z for protocatechuic aldehyde, 493.0/295.2 m/z for Salvianolic acid A, 718.0/520.0 m/z for salvianolic acid B, 321.4/152.3 m/z for chloramphenicol, 297.4/254.3 m/z for cryptotanshinone, 295.5/249.3 m/z for tanshinone II(A) and 285.2/154.0 m/z for Diazepam. The calibration curves in the range of 0.625-1 000 microg x L(-1) for protocatechuic acid and protocatechuic aldehyde, 1.25-1 000 microg x L(-1) for salvianolic acid A, 2.5-1 000 microg x L(-1) for salvianolic acid B, 0.15-1 000 microg x L(-1) for cryptotanshinone, 0.625-1 000 microg x L(-1) for tanshinone II(A) are with good linearityin rat plasma and brain. The analysis method is sensitive, simple, and suitable enough to be applied in the pharmacokinetic study of the 6 main components. Animal testing gives the lgBB of the drugs and further studies of the 6 components cross the blood-brain barrier can be carried out.

[Pharmacokinetics study on Danshensu in rats by brain microdialysis and automated blood technique]

To research the pharmacokinetic of Danshensu in brain via microdialysis method and automated blood technique. A microdialysis probe was inserted into the left lateral ventricle, and then dialysate samples and blood samples were continuously collected after iv Danshensu. LC-MS/MS was used to determinate for Danshensu in the dialysate samples. The in vivo recovery was used for the calibration of probe. WinNonlin was used for analyzing all pharmacokinetic data. Pharmacokinetic parameters of DSS in blood and in brain showed that Ke, t1/2,, AUC0-t, MRT were 0.04, 0.018 min(-1), 16.64, 58.76 min, 812.59, 51.19 min x mg x L(-1), 15.28, 79.97 min, respectively. The results were indicated that the study was successfully established LC-MS/MS detection method for Danshensu. Microdialysis combined with automated blood technique could better reflect the dynamic characteristics of Danshensu in the rat brain, and it provides a new perspective for pharmacokinetic study.

[Drug dynamics research of salvia miltiorrhiza in rabbit plasma and aqueous humor after intravenous injection]

OBJECTIVES

To assess the permeability of Danshensu at blood-ocular barrier and its characteristics of pharmacokinetics by respectively measuring the concentrations of Danshensu in blood plasma and aqueous humor of the rabbit with the high performance liquid chromatography(HPLC).

METHODS

It was an experimental study. Seventy-two white rabbits were split into three groups: control group (6 rabbits), plasma group (6 rabbits) and aqueous humor group (60 rabbits). After 0.85% salt water (control group)or salvia miltiorrhiza (1.0 g/kg) (plasma and aqueous group) was injected into the vein of auris-edge. Samples of blood and aqueous humor were obtained for analysis . The analytical column was a BDS C18 stainless steed column(5 µm, 4.6 mm× 250 mm); Precolumn:YWGC18; the mobile phase consists of acetonitrile and 0.01 mol/L KH2PO4 (8:92, adjusted to pH = 2.8 with phosphoric acid). The UV detector was set at 279 nm; the flow rate was 1.0 ml/min;and the column temperature was ordinary temperature.

RESULTS

The plasma concentration-time curves of Salvia miltiorrhiza fitted three-compartment model. t1/2 β (elimination half time): 5.661 min; Cmax (peak concentration): 727.29 mg/L; Tmax(peak time ): 0 min. The aqueous humor concentration-time curves fitted two-compartment model. t1/2 β: 147.663 min; Cmax: 38.62 mg/L; Tmax: 25 min.

CONCLUSIONS

HPLC is a sensitive, specific and accurate method that can be used in pharmacokinetics research on ocular tissue of rabbit for Danshensu, Salvia miltiorrhiza that is dissolvable in water can pass through the blood-ocular barrier after intravenous injection with a relatively stable concentration of danshensu in aqueous humor resulting from a slow rate of removal.

Crucial residue involved in L-lactate recognition by human monocarboxylate transporter 4 (hMCT4)

Background

Monocarboxylate transporters (MCTs) transport monocarboxylates such as lactate, pyruvate and ketone bodies. These transporters are very attractive therapeutic targets in cancer. Elucidations of the functions and structures of MCTs is necessary for the development of effective medicine which targeting these proteins. However, in comparison with MCT1, there is little information on location of the function moiety of MCT4 and which constituent amino acids govern the transport function of MCT4. The aim of the present work was to determine the molecular mechanism of L-lactate transport via hMCT4.

Experimental approach

Transport of L-lactate via hMCT4 was determined by using hMCT4 cRNA-injected Xenopus laevis oocytes. hMCT4 mediated L-lactate uptake in oocytes was measured in the absence and presence of chemical modification agents and 4,4′-diisothiocyanostilbene-2,2′-disulphonate (DIDS). In addition, L-lactate uptake was measured by hMCT4 arginine mutants. Immunohistochemistry studies revealed the localization of hMCT4.

Results

In hMCT4-expressing oocytes, treatment with phenylglyoxal (PGO), a compound specific for arginine residues, completely abolished the transport activity of hMCT4, although this abolishment was prevented by the presence of L-lactate. On the other hand, chemical modifications except for PGO treatment had no effect on the transport activity of hMCT4. The transporter has six conserved arginine residues, two in the transmembrane-spanning domains (TMDs) and four in the intracellular loops. In hMCT4-R278 mutants, the uptake of L-lactate is void of any transport activity without the alteration of hMCT4 localization.

Conclusions

Our results suggest that Arg-278 in TMD8 is a critical residue involved in substrate, L-lactate recognition by hMCT4.

Pharmacokinetic study of salvianolic acid A in beagle dog after oral administration by a liquid chromatography-mass spectrometry method: a study on bioavailability and dose proportionality

ETHNOPHARMACOLOGICAL RELEVANCE

Salvianolic acid A (SAA) is one of the main water-soluble components isolated from Salvia miltiorrhiza Bunge. Pharmacological researches revealed that it had various curative activities after oral and intravenous administration, including beneficial effects on diabetes and its complications, cardioprotective effect, anti-platelet aggregation, and so on. However, there is no report regarding the pharmacokinetics of SAA in beagle dogs after oral administration up to now.

AIM OF THE STUDY

To study the pharmacokinetics of different doses of SAA in beagle dogs and figure out the absolute bioavailability and dose proportionality of SAA after oral administration.

MATERIALS AND METHODS

Male and female beagle dogs were orally administered SAA 5, 10 and 20mg/kg randomly. The plasma drug concentration was detected by a rapid, sensitive and reproducible liquid chromatography-mass spectrometry (LC-MS) method. The pharmacokinetic parameters were calculated from plasma concentration-time data using the DAS pharmacokinetic software Data Analysis System Version 3.0 program.

RESULTS

After single-dose oral administration of SAA, the mean peak plasma concentration (Cmax) values for groups treated with 5, 10 and 20 mg/kg doses ranged from 14.38 to 38.18 µg/L, and the mean area under the concentration-time curve (AUC(0-t)) values ranged from 38.77 to 130.33 (µg/L·h). SAA showed lack of dose proportionality over the dose range 5-20mg/kg, based on the power model. However, the increase in systemic exposure with dose appeared linear. The absolute bioavailability was calculated to range from 1.47% to 1.84%.

CONCLUSION

The pharmacokinetic properties of SAA in beagle dogs after oral administration were characterized as rapid oral absorption, quick clearance, and poor absolute bioavailability. Systemic exposure exhibited lack of dose proportionality over the dose range 5-20mg/kg. Furthermore, a readily preparative LC-MS method was demonstrated in this study for the research of traditional Chinese medicine.

[Study on pharmacokinetics of danshensu sodium in danshen dripping solution in Beagles]

OBJECTIVE

To detect pharmacokinetics of Danshensu Sodium in Danshen dripping solution in Beagles.

METHOD

Danshen dripping solution was dripped intravenously into healthy Beagles at a dose of 10 mL x kg(-1). Their plasma samples were extracted with acetic ether, the blood concentrations were determined by HPLC method.

RESULT

Danshensu Sodium showed a good linear relationship within the range of 0.225-18.000 mg x L(-1), with the lowest detectable limit of 0.113 mg x L(-1). Its pharmacokinetic parameters were as follows: tmax was 30 min, Cmax was (9.5742 +/- 2.3715) mg x L(-1), t1/2 was (19.23 +/- 2.97) min, CL was (0.0127 +/- 0.0030) L x min(-1) x kg(-1), AUC(0-tn) was (474.954 +/- 95.483) mg x min x L(-1) and AUC(0-infinity) was (482.494 +/- 95.353) mg x min x L(-1).

CONCLUSION

The accurate, stable and reliable blood concentration method shows a one-compartment mode of Danshensu Sodium in Beagles.

Using neural networks to determine the contribution of danshensu to its multiple cardiovascular activities in acute myocardial infarction rats

ETHNOPHARMACOLOGICAL RELEVANCE

Danshensu is an active water-soluble component from Salvia Miltiorrhiza, which has been demonstrated holding multiple mechanisms for the regulation of cardiovascular system. However, the relative contribution of danshensu to its multiple cardiovascular activities remains largely unknown.

AIM OF THE STUDY

To develop an artificial neural network (NN) model simultaneously characterizing danshensu pharmacokinetics and multiple cardiovascular activities in acute myocardial infarction (AMI) rats. The relationship between danshensu pharmacokinetics (PK) and pharmacodynamics (PD) were evaluated using contribution values.

MATERIALS AND METHODS

Danshensu was intraperitoneally injected at a single dose of 20mg/kg to AMI rats induced by coronary artery ligation. Plasma levels of danshensu, cardiac troponin T (cTnT), total homocysteine (Hcy) and reduced glutathione (GSH) were quantified. A back-propagation NN model was developed to characterize the PK and PD profiles of danshensu, in which the input variables contained time, area under plasma concentration-time curve (AUC) of danshensu and rat weights (covariate). Relative contribution of input variable to the output neurons was evaluated using neuron connection weights according to Garson's algorithm. The kinetics of contribution values was also compared and was validated using bootstrap resampling method.

RESULTS

Danshensu exerted significant cTnT-lowering, Hcy- and GSH-elevating effect, and these marker profiles were well captured by the trained NN model. The calculation of relative contributions revealed that the effect of danshensu on the PD marker could be ranked as cTnT>GSH>Hcy, while the effect of AMI disease on the PD marker could be ranked in the following order: cTnT>Hcy>GSH. The activity of transsulfuration pathway was quite obvious under the AMI state.

CONCLUSION

NN is a powerful tool linking PK and PD profiles of danshensu with multiple cardioprotective mechanisms, it provides a simple method for identifying and ranking relative contribution to the multiple therapeutic effects of the drug.

Comparative pharmacokinetic and bioavailability studies of three salvianolic acids after the administration of Salviae miltiorrhizae alone or with synthetical borneol in rats

Salviae miltiorrhizae is one of the most commonly used herbal plants in the treatment of numerous ailments including cardiovascular diseases for hundreds of years. According to the theory of traditional Chinese herbal medicine, S. miltiorrhizae is always used in combination with borneol to obtain better pharmacological effects. The purpose of this study was to investigate the effects of borneol on the pharmacokinetic and bioavailability of S. miltiorrhizae. The pharmacokinetics studying on rosmarinic acid, salvianolic acid A and salvianolic acid B which are the main active compounds of S. miltiorrhizae in rat plasma, was achieved using a optimal high-performance liquid chromatographic technique coupled with liquid-liquid extraction method. After administration of either single salvianolic acids or salvianolic acids in combination with borneol, plasma concentrations of rosmarinic acid, salvianolic acid A and salvianolic acid B of male Sprague-Dawley rats were determined at different time points (5, 10, 20, 30, 45, 60, 90, 120, 180, 240, 300, and 360 min). In comparison with salvianolic acid extract alone, there were statistically significant differences in pharmacokinetic parameters of rosmarinic acid, salvianolic acid B and salvianolic acid A, and the bioavailability of the three salvianolic acids increased by different degrees when the salvianolic acid extract and borneol were administered together. These results indicated that borneol could enhance the intestinal absorption, decrease the distribution and inhibit the metabolism of salvianolic acids.

Pharmacokinetics of phenolic compounds of Danshen extract in rat blood and brain by microdialysis sampling

AIM OF THE STUDY

To evaluate the pharmacokinetics of phenolic compounds after oral administration of Danshen extract in rat brain.

MATERIALS AND METHODS

Blood and brain microdialysis probes were inserted into jugular vein and cerebral cortex of rat under anesthesia and perfused with ringer's solution at the rate of 2.0 and 0.8 μL/min, respectively. Blank microdialysates were collected after 2h post-implantation equilibrium time. Danshen extract (danshensu 40 mg/kg BW, protocatechuic aldehyde 149 mg/kg BW, and salvianolic acid B 50mg/kg BW) was administrated intragastrically, and then blood and brain microdialysates were collected at 15 and 30 min time intervals for 4h, respectively. The concentrations of phenolic compounds were determined by high-performance liquid chromatography coupled with chemiluminescence detection. Pharmacokinetic parameters were estimated using non-compartmental methods.

RESULTS

Danshensu and protocatechuic acid could be detected in both blood and brain microdialysates, while protocatechuic aldehyde and salvianolic acid B were not detected. Brain-to-blood (AUC(brain)/AUC(blood)) distribution ratio were 0.25±0.04 and 0.09±0.02 for danshensu and protocatechuic acid, respectively.

CONCLUSIONS

Danshensu can readily permeate the blood brain barrier after oral administration of Danshen extract, and protocatechuic acid is a potential oxidative metabolite of protocatechuic aldehyde.

[Tissue distribution in mice of danshensu from sodium danshensu and Salvia miltiorrhiza injection]

OBJECTIVE

To determine the concentration in mice of danshensu from sodium danshensu and Salvia miltiorrhiza injection and undertake comparative study of them as well as to assess the effect of other components of S. miltiorrhiza injection on the tissue distribution of danshensu.

METHOD

Mice received intraperitoneal administration of sodium danshensu or S. miltiorrhiza injection (equal to danshensu 60 mg x kg(-1)) respectively, and was executed 30 minutes after administration. The concentration of danshensu in different tissues was separately determined by high performance liquid chromatographic method.

RESULT

The characteristic profiles of sodium danshensu in different tissues were C(kidney) > C(spleen) > C(lung) > C(heart) > C(liver). The characteristic profiles of danshensu from S. miltiorrhiza injection in different tissues were C(kidney) > C(lung) > C(spleen) > C(heart) approximately C(liver). The concentration of danshensu in S. miltiorrhiza injection in liver and kindey was higher than sodium danshensu itself.

CONCLUSION

It was suggested that the other components in S. miltiorrhiza injection influent the distribution profile in tissues of danshensu.

Simultaneous determination of six phenolic constituents of Danshen injection in rat plasma by LC-ESI-MS and its application to a pharmacokinetic study

Salvianolic acid A, salvianolic acid B, danshensu, protocatechuic aldehyde, rosmarinic acid and lithospermic acid are the six major active constituents in Danshen injection. In this study, a rapid, sensitive and specific liquid chromatographic-electrospray ionization-mass spectrometry method for the simultaneous quantitative determination of these compounds in rat plasma was developed. After a single step of liquid-liquid extraction with ethyl acetate, they were eluted by a Hypersil C18 column (5 µm, i.d. 4.6 × 200 mm) within 4 min with a mobile phase consisting of acetonitrile and 0.1% formic acid water solution (35:65, v/v). The assay was linear in the concentration range of 0.05-10 µg mL(-1). Absolute recoveries were above 60%. The precisions and accuracies determined within three consecutive days were within acceptable limits. The method was successfully applied to a pharmacokinetic study in rats after an intravenous administration of Danshen injection.

[Comparative pharmacokinetics and relative bioavailability of magnesium-containing drugs]

Pharmacokinetics of magnesium ions after single peroral administration of Magnelis B6 and Magne B6 coated tablets (magnesium dose, 48 mg) was studied in rabbits. In the blood plasma, the level of magnesium ions was very low compared to the endogenous level, which did not allow the drug bioavailability to be reliable evaluated. At the same time, the level of magnesium ions was reliable determined in the daily urine of test animals. The relative bioavailability of magnesium for Magnelis B6 versus Magne B6 was estimated at 98.93 +/- 12.45% (average +/- SD).

[Intestinal absorption properties of three components in salvianolic acid extract and the effect of borneol on their absorption in rats]

This study aimed to investigate the effects of concentration, intestinal section and borneol on the intestinal absorption of salvianolic acids. The experiment not only studied the intestinal absorption properties of three concentrations of rosmarinic acid, salvianolic acid B and salvianolic acid A at duodenum, jejunum and ileum, but also of salvianolic acids compatible with borneol at different concentrations using single-pass intestinal perfusion model in rat with phenol red as the marker. The results showed that salvianolic acids was stable under weak-acid condition and affected by metabolism enzyme; The Peff and Ka significantly different among three concentrations of rosmarinic acid and salvianolic acid B, whose intestinal absorption were saturated in high concentration, suggesting that the transport mechanisms of rosmarinic acid and salvianolic acid B were similar to active transport or facilitated diffusion; However, there was inconspicuousness in the Peff and Ka of salvianolic acid A at different concentrations, whose absorption was not saturated in high concentration, indicating that the transport mechanisms of salvianolic acid A was passive diffusion; The Peff and Ka in the ileum obviously higher than those in the duodenum and jejunum, namely the ileum was the best absorption section; When concentration of borneol increased, the enhancing effect of intestinal absorption of salvianolic acids increased, but significantly decreased when borneol increased to some degree. The enhancing effect of medium borneol concentration was the optimum. This implied that borneol can enhance the intestinal absorption of salvianolic acids, and the capacity of enhancing effect was influenced by the concentration of borneol.

Simultaneous determination of danshensu, rosmarinic acid, cryptotanshinone, tanshinone IIA, tanshinone I and dihydrotanshinone I by liquid chromatographic-mass spectrometry and the application to pharmacokinetics in rats

A sensitive and specific liquid chromatography-tandem mass spectrometry method (LC-MS) was developed and validated for the separation and simultaneous determination of danshensu, rosmarinic acid and tanshinone compounds including cryptotanshinone, tanshinone I, dihydrotanshinone I and tanshinone IIA in rat plasma. Chromatographic separation of the analytes was successfully achieved on a C(18) column using a mobile phase composed of acetonitrile-water containing 0.5% glacial acetic acid. This method demonstrated good linearity and did not have endogenous material interfering with the active compounds and I.S. peaks. The limit of quantification of danshensu, rosmarinic acid, cryptotanshinone, dihydrotanshinone I, tanshinone I and tanshinone IIA were 5, 0.75, 0.1, 0.1, 1 and 0.5 ng/mL. The average extraction recoveries of these analytes from rat plasma were all over 60%. The precisions determined from five days were all within 10%. This method has been successfully applied in the simultaneous quantification and the pharmacokinetic studies of these six compounds in animals which were orally administered with danshen preparations.

[Effects of combination of Salvia miltiorrhiza and Panax notoginseng on the pharmacokinetics of their major bioactive components in Beagle dog]

After oral administration of Salvia miltiorrhiza (Danshen in Chinese), Panax notoginseng (Sanqi in Chinese) and Danshen Sanqi combination suspensions to Beagle dogs, the plasma concentration-time profiles of danshensu, tanshinone II(A), cryptotanshinone, notoginsenoside R1, ginsenoside Rg1 and Rb1 were analyzed by LC-MS/MS. Pharmacokinetic parameters were calculated and analyzed with BAPP 2.0 software. The results showed that the Cmax and AUC of danshensu, notoginsenoside R1, ginsenoside Rg1 and Rb1 in Danshen Sanqi combination group all decreased in comparison with those of Danshen or Sanqi given alone, while the CLz/F and Vz/F increased to some extent. No significant differences of the pharmacokinetics of tanshinone II(A) and cryptotanshinone were observed between groups.

[Prescription compatibility effect on the major components absorption in danshen extract and their identification]

An improved everted gut sac method was applied to the study of prescription compatibility effect on the major components in Danshen extracts. With the separation and detection by HPLC-ECD, 5 major peaks could be detected in intestinal absorbed solution after prescription administration. Following the identification by HPLC-MS/MS, peak 2, 3, 4, and 5 were rosmaric acid, lithospermic acid, salvianolic acid B, and salvianolic acid A, respectively, which also confirmed with reference standards of those components. Through paralleling substance identification, peak 2, 3, 4, and 5 could be found as the major components in Danshen extracts, except Salvianolic acid E which is undetectable in intestinal solution. The contents of peak 2, 3, and 4 did not show difference before and after compatible prescription administrated, where the peak 5 had a significant increase in the same process. Those results revealed that peak 5, salvianolic acid A, might lead to an increasing pharmacological effect after prescription compatibility.

[Pharmacokinetic evaluation of danshensu with in vivo microdialysis in freely moving rat's jugular vein]

OBJECTIVE

To investigate the pharmacokinetics of Danshensu with in vivo microdialysis in freely moving rat's jugular vein.

METHOD

three days after a microdialysis probe introducer was implanted into the jugular vein, a microdialysis probe was introduced to the blood vessel, and began to sample following a single intravenous injection (40 mg x kg(-1)) or a single oral dose (40 mg x kg(-1)) of Danshensu. All the samples were analyzed with HPLC. The concentration of Danshensu in blood were calculated according to the recovery of microdialysis probe and the concentration in dialysates. Pharmacokinetic parameters were than calculated with the concentration-time curve.

RESULT

For intravenous administration, t(1/2 zeta) = (69.62 +/- 33.42) min, AUC(0-infinity) = (3416.24 +/- 779.80) min x mg x L(-1), MRT(0-infinity) = (38.15 +/- 8.61) min, and for oral administration, Cmax = (7.42 +/- 3.08) mg x L(-1), tmax = (31.50 +/- 8.57) min, t(1/2 zeta) = (83.25 +/- 37.35) min, AUC(0-infinity) = (793.19 +/- 101.32) min x mg x L(-1), MRT(0-infinity) = (125.89 +/- 58.27) min. The oral bioavailability of Danshensu F = 22.56%.

CONCLUSION

In vivo microdialysis in freely moving rat's jugular vein is a useful tool to obtain a complete set of free drug concentrations to determine reliable pharmacokinetic parameters.

[Comparative pharmacokinetic study of sodium Danshensu and Salvia miltiorrhiza injection in rat]

OBJECTIVE

To develop a HPLC method for determination of the concentration of Danshensu in rat plasma and undertake comparative pharmacokinetic study of sodium danshensu and Salvia miltiorrhiza injection in rat as well as to assess the effect of other components of Salvia miltiorrhiza injection on the pharmacokinetics of Danshensu.

METHOD

Rats received an iv. infusion of sodium Danshensu or S. miltiorrhiza injection (equal to Danshensu 30 mg x kg(-1)). Blood samples were collected from carotid artery. Plasma concentration of Danshensu extracted with perchloric acid was measured. The pharmacokinetic parameters were calculated with DAS2.0 software.

RESULT

A good linear relationship of Danshensu was obtained from the range of 0.5 to 80.0 mg x L(-1), and the lowest limit of determination was 0.2 mg x L(-1). The plasma concentration time curves of Danshensu were best fitted with two-compartment models for Danshensu itself and for Salvia miltiorrhiza injection as well. The pharmacokinetic parameters such as t1/2alpha, AUC, CL had significant differences.

CONCLUSION

The concomitant components in Salvia miltiorrhiza injection influence the pharmacokinetic properties of Danshensu and speed up its disposition and elimination.

[Effect of Santalum album on tissue distribution of danshensu in rabbits by HPLC]

OBJECTIVE

To investigate the influence of Shi herb (Santalum album, SA) to the tissue distribution of danshensu (DSS) which is the main hydrosoluble component of Jun herb (Salvia miltiorrhiza, SM) in rabbits by HPLC.

METHOD

Rabbits were oral administrated decoction of SM and SM-SA, respectively. Perchloric acid (10%) was used to precipitate the tissue samples of rabbits heart, brain, liver, kidney, acetic ether was used to extracte supernatant, and the internal standard was p-hydroxybenzoic acid. The content of DSS of SM in tissues was detected.

RESULT

The content of DSS reached the highest point close to 50 min in the mentioned tissues. Before and after co-administration, the sequences of average concentration of DSS in tissues were C(kidney) > C(heart) > C(brain) > C(liver) and C(kidney) > C(liver) > C(brain) > C(heart) respectively. Compared with SM administrated singly, the content of DSS in every tissues of co-administration was higher.

CONCLUSION

In Danshenyin Formulae, SA can increase concentration of DSS in target tissues significantly, and therefore therapeutic effect of SM for cardiovascular disease is raised.

Effect of sodium caprate on the oral absorptions of danshensu and salvianolic acid B

The current study aims to investigate the effect of sodium caprate on the intestinal absorption and bioavailabilities of danshensu and salvianolic acid B, the major active components in Salvia miltiorrhiza Bge (Danshen). Biopharmaceutics and pharmacokinetics properties of the two compounds have been characterized by in vitro, in situ models as well as in vivo in rats. Based on the identified biopharmaceutics characteristics of the two compounds, effect of sodium carparate as absorption enhancer on the intestinal absorption and pharmacokinetics of danshensu and salvianolic acid B in pure compound form as well as extract form were investigated both in vitro and in vivo. Both danshensu and salvianolic acid B demonstrated very limited intestinal permeabilities, leading to oral bioavailabilities of only 11.09% and 3.90% in rats, respectively. Results from both in vitro and in vivo studies consistently indicated that sodium caprate could significantly enhance intestinal permeabilities as well as the in vivo bioavailabilities of both danshensu and salvianolic acid B. The current findings not only identified the usefulness of sodium caprate for the improved delivery of Danshen product but also demonstrated the importance of biopharmaceutics characterization in the dosage form development of traditional Chinese medicine.

Characterization of metabolites in rat plasma after intravenous administration of salvianolic acid A by liquid chromatography/time-of-flight mass spectrometry and liquid chromatography/ion trap mass spectrometry

Salvianolic acid A (SalA) is one of the main active constituents in Salvia miltiorrhiza (Danshen). Although the pharmacokinetics of SalA in rats after intravenous (i.v.) administration of Danshen injection has been reported, the information relevant to the metabolites of SalA in vivo is absent so far. In this study, by means of liquid chromatography with time-of-flight mass spectrometry (LC/TOFMS) and liquid chromatography with ion trap mass spectrometry (LC/MS(n)) techniques, the unknown metabolites of SalA in rat plasma after i.v. administration of the purified SalA at the dose of 20 mg/kg body weight were identified. A liquid-liquid extraction method was established to separate the metabolites from the plasma and the chromatographic separations were performed on a Xterra MS C(18) column (100 mm x 4.6 mm i.d., 3.5 microm) with acetonitrile/methanol/water/formic acid (20.5:19.5:64: 0.05, v/v/v/v) as the mobile phase at a constant flow rate of 0.2 mL/min. Based on the data obtained from the LC/TOFMS determination (the total ion chromatograms, MS spectra and extracted ion chromatograms), in combination with the characteristic fragment ions acquired from the LC/MS(n) determination, five metabolites were identified as SalA-monoglucuronide, monomethyl-SalA-monoglucuronide, mono-methyl-SalA, dimethyl-SalA and dimethyl-SalA-monoglucuronide, and the possible chemical structures were deduced. The results indicated that SalA might mainly undergo two metabolic pathways in vivo in rats, which were methylation and glucuronidation. The present studies have laid a solid foundation for the metabolic mechanism of SalA in vivo.

Determination of caderofloxacin lactate in rat plasma by high-performance liquid chromatography–mass spectrometry and its application in rat pharmacokinetic studies

A sensitive liquid chromatography-electrospray ionization mass spectrometric (LC-ESI-MS) method for the quantification of a newly active quinolone carboxylic acid caderofloxacin lactate in rat plasma was developed and validated after precipitation method with methanol. Chromatographic separation was achieved on a reversed-phase Shimadzu 2.0 microm C18 column (150 mm x 2.00 mm) with the mobile phase of methanol-0.02% formic acid and step gradient elution resulted in a total run time of about 10.0 min. The analytes were detected by using an electrospray positive ionization mass spectrometry in the selected ion monitoring (SIM) mode. A good linear relationship was obtained in the concentration range studied (5-2000 ng/mL) (r=0.9998). The lowest limit of quantification (LLOQ) was 5 ng/mL and the lowest limit of detection (LLOD) was 2 ng/mL. Average recoveries ranged from 88.80 to 93.05% in plasma at the concentrations of 10, 100 and 1000 ng/mL. Intra- and inter-day relative standard deviations were 4.01-7.30 and 4.15-7.51%, respectively. This method was successfully applied in the pharmacokinetic studies in rats.

Determination of the main bioactive metabolites ofRadix Salvia miltiorrhizaein Compound Danshen Dripping Pills and the tissue distribution of Danshensu in rabbit by SPE-HPLC-MSn

A fast solid phase extraction-high performance liquid chromatography-ion trap mass spectrometry (SPE-HPLC-MSn) method is presented for quantitative determination of 3-(3,4-dihydroxyphenyl)-2-hydroxylpropionic acid (Danshensu, DSS) from Compound Danshen Dripping Pills (CDDP) in rabbits' heart, liver, kidney, and lung and for qualitative analysis of the bioactive metabolites of Radix Salvia miltiorrhizae (DS) from CDDP in these tissues. The proposed method was validated with a detection limit of 0.06 ng/mL and a linear range of 5.0-200 ng/mL for DSS. The main metabolites of DS were pyrocatechol, vanillic acid, isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate, and 2-hydroxyl-3-(3,4-dihydroxyphenyl)propinonic sulfuric anhydride. In vitro pharmacological experiments demonstrated that isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate had a distinct vasodilatating action.

Pharmacokinetic study of salvianolic acid A in rat after intravenous administration of Danshen injection

In order to research the pharmacokinetics of salvianolic acid A (SalA), a herbal ingredient isolated from Salvia miltiorrhiza Bunge, after intravenous administration to rats, a specific and accurate high-performance liquid chromatography (HPLC) was developed. The assay procedure involved simple liquid-liquid extraction of SalA and internal standard (IS, ethyl-p-hydroxybenzoate) from plasma into ethyl acetate. The organic layer was separated and evaporated under reduced pressure at 40 degrees C. The residue was reconstituted in the mobile phase and analyzed on an Inertsil C8 column, monitored at 285 nm. The mobile phase, which consisted of methanol-acetonitrile-water-formic acid (10:20:70:0.4, by vol), was used at a flow rate of 1.0 mL/min. The ratio of the peak area of the analyte to IS was applied to quantify the plasma samples. The standard curve for SalA was linear (r2 = 0.9999) in the concentration range of 0.75-150 microg/mL. The limit of quantitation (LOQ) of SalA was 0.75 microg/mL. The intra- and inter-day precisions (RSD) of the quality control (QC) samples were in the ranges of 2.17-3.29 and 1.24-5.28%, respectively. Accuracy in the measurement of QC samples ranged from 94.7 to 101.1%. This method was validated for specificity, accuracy and precision and was successfully applied to the pharmacokinetic study of SalA in rat plasma after intravenous administration of Danshen injection.

Fluoride concentrations in dental plaque and saliva after the use of a fluoride dentifrice preceded by a calcium lactate rinse

Plaque fluoride concentrations ([F]) are directly related to plaque calcium concentrations [Ca]. Attempts to increase plaque F uptake from dentifrices or rinses have used methods designed to increase plaque [Ca] but with inconsistent results. This double-blind, double-crossover study tested the effect of a 150 mM calcium lactate rinse used prior to brushing with placebo or fluoridated dentifrices (1030 p.p.m. as NaF) on plaque and salivary [F] and [Ca]. Sixteen children (8-10 yr of age) were randomly assigned to four different groups according to the four treatments (placebo dentifrice or fluoridated dentifrice preceded by calcium lactate or deionized water prerinses). Plaque and saliva were collected 1 and 12 h after brushing on day 7 after starting to use the dentifrices. F was determined using the electrode and Ca was determined using atomic absorption spectrometry. Plaque and salivary [Ca] were not significantly increased after use of the calcium lactate prerinse, except for plaque [Ca] 1 h after the use of the placebo dentifrice. A significant increase in salivary [F] was associated with the calcium lactate prerinse only at 1 h after the use of the fluoridated dentifrice. The the calcium lactate prerinse did not significantly affect plaque [F] under any condition.

[Transport mechanism of danshensu across Caco-2 monolayer model]

OBJECTIVE

To study the absorption mechanism of Danshensu by using Caco-2 monolayer model .

METHOD

Caco-2 cell monolayer model was used to study the bi-direction transport of Danshensu. An LC-MS method was developed to measure the concentration of Danshensu in cell culture medium and calculate the apparent permeability coefficients (P(app)). The effects of time, drug concentration and inhibitor on the absorption of Danshensu were studied.

RESULT

Transport of Danshensu was time and concentration dependent, and it was also effected by P-glycoprotein inhibitor. P(app) increased with time increase and tended to become saturated at some point. It, however,decreased while concentration of Danshensu increased. P(ratio) is larger than 1.5 . Verapamil can cause significantly effect on transport of Danshensu: P(app,A-B) increased and P(app,B-A) decreased .

CONCLUSION

The absorption of Danshensu in Caco-2 cell model may be an active transportation mediated by P-glycoprotein transporter.

Danshen: an overview of its chemistry, pharmacology, pharmacokinetics, and clinical use

Danshen, the dried root of Salvia miltiorrhiza, has been widely used in China and, to a lesser extent, in Japan, the United States, and other European countries for the treatment of cardiovascular and cerebrovascular diseases. In China, the specific clinical use is angina pectoris, hyperlipidemia, and acute ischemic stroke. The current review covers its traditional uses, chemical constituents, pharmacological activities, pharmacokinetics, clinical applications, and potential herb-drug interactions based on information obtained in both the English and Chinese literature. Although numerous clinical trials have demonstrated that certain Danshen products in China are effective and safe for the treatment of cardiovascular diseases, most of these lack sufficient quality. Therefore, large randomized clinical trials and further scientific research to determine its mechanism of actions will be necessary to ensure the safety, effectiveness, and better understanding of its action.

Does oxygenated water support aerobic performance and lactate kinetics?

It has been asserted that the consumption of oxygenated water can support physical working capacity. As this has not been accurately investigated yet we analyzed effects of a two-week period of daily O2-water ingestion on spiroergometric parameters and lactate metabolism in healthy adults. Twenty men (24 +/- 2.5 years of age) with comparable aerobic abilities performed four exhaustive bicycle spiroergometric tests. Applying a double-blind crossover study design 10 subjects drank 1.5 liters of highly oxygenated water every day during the two weeks between the initial two tests whereas the other group consumed 1.5 liters untreated water from the same spring. After a two-week wash-out period subjects underwent a second period consuming the opposite type of water. Spiroergometric parameters and lactate kinetics between both groups at submaximal and maximal levels were analyzed using a MANOVA. Results showed no significant influence on aerobic parameters or lactate metabolism, neither at submaximal nor at maximal levels (all p-values > or = 0.050). Merely increments of VEO2 at submaximal levels were demonstrable (p = 0.048). We conclude that the consumption of oxygenated water does not enhance aerobic performance or lactate kinetics in standardized laboratory testing.

Development of a novel high-concentration galantamine formulation suitable for intranasal delivery

The goal of the current study was to develop an intranasal (IN) formulation of the acetylcholinesterase inhibitor galantamine, an important therapeutic for treating Alzheimer's disease. To allow for delivering a therapeutically relevant dose, it was necessary to greatly enhance drug solubility. Various approaches were examined to this end, including adding co-solvents, cyclodextrins, and counterion exchange. Of these, the latter, for example, replacement of bromide ion with lactate or gluconate, resulted in a dramatic drug solubility increase, more than 12-fold. NMR confirmed the molecular structure of new drug salt forms. An in vitro epithelial tissue model was used to assess drug permeability and cellular toxicity. In vitro, galantamine lactate formulations performed as well as or better than their hydrobromide (HBr) counterparts with respect to drug permeation across the epithelial membrane with minimal toxicity. In vivo studies in rats compared pharmacokinetic (PK) profiles of different formulations. The in vivo studies confirmed that IN galantamine achieves systemic blood levels comparable to those of conventional oral administration. Both the in vitro and in vivo data support the feasibility of IN administration of this important drug.

Calcium Fortification Systems Differ in Bioavailability

The objective of this study was to compare the bioavailability of calcium from two fortification systems used in orange juice. The design was randomized crossover, within-subject. The subjects were 25 healthy premenopausal women in an academic health sciences center. Two commercially marketed calcium-fortified orange juices, ingested in an amount providing 500 mg calcium, were taken at breakfast after an overnight fast. The two fortification systems tested were calcium citrate malate and a combination of tricalcium phosphate and calcium lactate (tricalcium phosphate/calcium lactate). The main outcome measure was the area under the curve (AUC) for the increase in serum calcium from 0 to 9 hours after ingesting the test calcium source. Statistical analyses performed were repeated measures analysis of variance, testing source, and sequence. AUC 9 was 48% greater for calcium citrate malate than for tricalcium phosphate/calcium lactate ( P < .001); absorbed calcium calculated from AUC 9 values (mean+/-standard error of the mean) was 148+/-9.0 mg and 100+/-8.9 mg for calcium citrate malate and tricalcium phosphate/calcium lactate, respectively. The results indicate that equivalent calcium contents on a nutritional label do not guarantee equivalent nutritional value. Nutritionists and dietetics professionals should encourage manufacturers of fortified products to provide information on bioavailability.

Effect of salvianic acid A on lipid peroxidation and membrane permeability in mitochondria

Salvia miltorrhiza Bunge is a traditional Chinese medicine and has long been used for treating liver and heart diseases in China. Salvianic acid A is the main active component of Salvia miltorrhiza Bunge. In the present study, the ability of salvianic acid A in scavenging free radicals, inhibiting lipid peroxidation and mitochondrial membrane permeability transition, as well as respiration and protein thiol oxidation in rat liver mitochondria, was evaluated. The results show that salvianic acid A scavenges superoxide anions in a dose-dependent manner (IC50 52 microg/ml). Salvianic acid A could scavenge lipid free radicals and inhibit lipid peroxidation as effectively as Vitamin E. Salvianic acid A also inhibited the mitochondrial membrane permeability transition assessed as the extent of mitochondrial swelling. Salvianic acid A inhibited the oxidation of mitochondrial protein thiols involved in the mitochondrial membrane permeability transitions. We conclude that salvianic acid A is able to reduce lipid peroxidation in the mitochondrial membrane by scavenging free radicals, and inhibit mitochondrial membrane permeability transition by reducing protein thiol oxidation. These data indicated the pharmacological potential of salvianic acid A against pathological processes related to oxidative stress.

Iron absorption by human subjects from different iron fortification compounds added to Thai fish sauce

OBJECTIVES

(a) To measure iron absorption by human subjects from citric acid stabilized fish sauce fortified with ferrous sulfate, ferric ammonium citrate or ferrous lactate and (b) to identify the effect of added citric acid (3 g/l) on iron absorption from ferrous sulfate fortified fish sauce.

DESIGN

Iron absorption from the intrinsically labeled compounds was determined via erythrocyte incorporation of isotopic labels ((57)Fe and (58)Fe) using a randomized crossover design. In three separate absorption studies, 10 adult women each consumed a basic test meal of rice and vegetable soup seasoned with isotopically labeled, iron fortified fish sauce.

RESULTS

Iron absorption was significantly lower from ferrous lactate and from ferric ammonium citrate fortified fish sauce than from ferrous sulfate fortified fish sauce. Fractional iron absorption (geometric mean; -1s.d., +1s.d.) was 8.7(3.6; 21.4)% for ferrous lactate compared to 13.0(5.4; 31.4)% from ferrous sulfate, P = 0.003 (study 1) and 6.0(2.5; 14.3)% from ferric ammonium citrate relative to 11.7(4.4; 30.7)% from ferrous sulfate, P < 0.001, in study 2. Citric acid added at a molar ratio of approximately 2.5 to iron had no effect on iron absorption from ferrous sulfate (study 3). Iron absorption in the presence of citric acid was 14.1(6.4; 30.8)% compared to 12.0(5.8; 24.7)% in its absence (P = 0.26).

CONCLUSIONS

Iron absorption was 50-100% higher from ferrous sulphate fortified fish sauce than from fish sauce fortified with ferric ammonium citrate or ferrous lactate. In the presence of citric acid as a chelator, ferrous sulfate would appear to be a useful fortificant for fish sauce.

SPONSORSHIP

International Atomic Energy Agency (IAEA), Vienna, Austria.

Thermal characterization of poly(ethylene glycol)-poly(D,L-lactide) block copolymer micelles based on pyrene excimer formation

Poly(ethylene glycol)--poly(D,L-lactide) (PEG-PDLLA) block copolymers were prepared by anionic ring-opening polymerization, resulting in block sizes effectively controlled by initial monomer/initiator ratios and low molecular weight distributions (<1.12). A pyrene derivative (1-pyrenyl carbonyl cyanide--Py) was conjugated to the end of the hydrophobic block (PDLLA) in a quantitative manner, with coupling efficiencies >95%. The so-obtained PEG-PDLLA-Py copolymers displayed fluorescent properties that were associated with the pyrene monomers, when placed in good solvents for both the hydrophilic and hydrophobic blocks. When placed in selective solvents, these copolymers self-assembled into micelles in the 30-nm range, also with low particle size distributions (<0.09), within which Py could be readily entrapped in the hydrophobic PDLLA core. Py entrapment resulted in the formation of excimers, as evident from fluorescence measurements. Observation of excimer formation/dissociation further conveyed information on the physicochemical properties of the core. Thermal characterization of these systems showed that an increase in the temperature resulted in changes in the properties of excimer fluorescence, an occurrence attributed to a higher mobility of the otherwise glassy PDLLA. This, in turn, greatly affected the inter-molecular distance between pyrene molecules, a crucial factor for excimer formation. The glass transition of the PDLLA block, approximately 38 degrees C, defined the onset for increasing chain mobility and whence excimer dissociation. Excimer fluorescence appeared to be time-dependent. Based on these observations, chain exchange processes were clearly evidenced through the time-dependent dissociation of excimers into unimers, a process that was influenced by changes in temperature.

Transdermal delivery of mixnoxidil with block copolymer nanoparticles

We evaluated the effect of hydrodynamic size of self-assembled nanoparticles on skin penetration of minoxidil in vitro and in vivo. Self-assembled 40- and 130-nm nanoparticles, both containing minoxidil, were prepared by solvent evaporation of poly(-caprolactone)-block-poly(ethyleneglycol) and were applied onto the skin of both hairy and hairless guinea pigs in the Franz diffusion cell. In hairy guinea pig skin, the permeation of the minoxidil that incorporated in 40-nm nanoparticles was 1.5-fold higher in the epidermal layer and 1.7-fold higher in the receptor solution than that of 130-nm nanoparticles. Nanoparticle size dependence on the permeation behavior of minoxidil was not observed for hairless guinea pig skin in either the epidermal layer or the receptor solution. Phospholipid liposomes and ethanol-water admixture, on the other hand, containing the same amount of minoxidil did not show differences in the amount of permeation irrespective of the existence of hair follicles. Confocal microscopy coupled with in vivo and in vitro skin permeation results demonstrated that nanoparticles containing solutes penetrated mainly via shunt routes like hair follicles, resulting in skin absorption of solutes.

Accumulation of aluminum in ferritin isolated from rat brain

The neurotoxic effects of aluminum have been widely reported but the mechanism of action and detoxification is poorly understood. To investigate the toxic potential of aluminum, we found it necessary to detail the behavior of absorbed aluminum in brain. The aim of this study was to clarify the distribution of aluminum in the brain. Rats were exposed to aluminum lactate intraperitoneally for 7 weeks. Although no marked differences in aluminum content was observed in brain regions, aluminum was eluted by gel filtration chromatography of the ferritin fraction from aluminum-loaded brain extracts; 5.9% of the total brain aluminum was recovered in purified ferritin from aluminum-loaded rat brains. These results suggest that ferritin may function as an aluminum detoxicant in the cell.

Transport of PLA-PEG particles across the nasal mucosa: effect of particle size and PEG coating density

The aim of the study was to investigate the effect of the size and PEG coating density of Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nano- and microparticles on their transport across the nasal mucosa. Particles were made of PLA-PEG copolymers of two different molecular weights (Mw: 37 and 28 kDa) and also PLA of Mw 28 kDa, and prepared using different techniques (simple emulsion (o/w), double emulsion (w/o/w), and nanoprecipitation techniques). The particles were characterized for their size, zeta potential, morphology [Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM)], and PEG coating efficiency. Additionally, the transport of rhodamine 6G-labelled PLA-PEG and PLA particles across the rat nasal mucosa was investigated by Confocal Laser Scanning Microscopy (CLSM). The results showed that the size of PLA-PEG nanoparticles varied between 150 and 300 nm and their zeta potential between -10 and -22 mV depending on both the polymer Mw and the preparation technique. Moreover, the PEG coating efficiency (amount of PEG on the surface with respect to the total amount of PEG in the particles) was high (between 75% and 92%) and affected by the PLA Mw and also by the particles preparation technique. The greatest PEG surface density was achieved for lowest Mw PLA-PEG, using the O/W emulsification technique. The CLSM images of nasal epithelia from rats showed the importance of the PEG coating density and the size on the transmucosal transport of the fluorescent nanoparticles. More specifically, PLA-PEG particles with a high PEG coating density and a small size were more significantly transported than noncoated PLA nanoparticles and also than PLA-PEG nanoparticles with a lower coating density. In conclusion, these results showed the important role that the PEG coating has on the efficacy of PLA-PEG nanoparticles as nasal drug carriers.

Incorporation and release behavior of hydrophobic drug in functionalized poly(d,l-lactide)-block–poly(ethylene oxide) micelles

The poly(ethylene oxide)-poly(lactide) (PEO-PLA) block copolymers containing a small quantity of carboxylic acid in the PLA block were synthesized. The microscopic characteristics of nanoparticles with carboxylic acid content in the copolymer were analyzed, and the effect of specific interactions between the copolymer and the model drug on the drug loading capacity and the release behavior were investigated systematically. The sizes of nanoparticles prepared by a dialysis method are within the range of 30-40 nm. The nanoparticles prepared from functionalized block copolymers have a very low critical micelle concentration (CMC) value as low as approximately 10(-3) mg/ml, which indicates a good stability of the nanoparticles in spite of the presence of carboxylic acid. The drug loading efficiency of nanoparticles dramatically increased when carboxylic acid content was increased in the block copolymer. This result may be attributed to the increase of interactions between the copolymer and the drug. The release rate of the drug was much slower from nanoparticles containing higher amounts of carboxylic acid in the copolymer, which might be associated with the enhanced interaction between the carboxylic group of copolymers and the drug. These experimental results suggest that the nanoparticles prepared from functionalized PEO-PLA block copolymers could be a good candidate for an injectable drug delivery carrier.

Simultaneous determination of magnesium lithospermate B, rosmarinic acid, and lithospermic acid in beagle dog serum by liquid chromatography/tandem mass spectrometry

A rapid, sensitive and specific isocratic liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the simultaneous quantitative determination of magnesium lithospermate B (MLB), rosmarinic acid (RA), and lithospermic acid (LA) in beagle dog serum, with silibinin as internal standard. The serum samples were treated by liquid-liquid extraction and analyzed using LC/MS/MS with a TurboIonSpray source. A short run-time (3 min) fulfilled the need for monitoring serum levels of MLB, RA, and LA in large-scale studies. The calibration curves for MLB, RA, and LA were linear over the ranges 8-2048, 4-1024, and 4-1024 ng/mL, respectively, with coefficients of correlation >0.999. The intra- and inter-day precision (CV) of analysis was <10%, and accuracy ranged from 90-104%. This quantitation method was successfully applied to a pharmacokinetic study of salvianolate administrated by intravenous infusion with dosage of 6 mg/kg in beagle dogs.

Pharmacokinetics and distribution of 125I-PLA-b-PEO block copolymers in rats

The PLA-b-PEO block copolymers were studied as potential carriers for anti-inflammatory and anticancer drugs. The copolymers were labeled with 125I, and their micelles in physiological saline were prepared by dialysis. Copolymer 1, with Mw = 12,360 (PLA/PEO = 7000/5000), formed particles of about 300 nm in diameter (Rh was 150 nm), whereas copolymer 2, with Mw = 20,470 (6000/14,000), made up micelles of about 72 nm in diameter (Rh was 35.8 nm). Their pharmacokinetic and biodistribution profiles were compared in normal rats and rats with carrageenan-induced inflammation after intravenous application of about 5 mg/kg of each copolymer. Copolymer 2, forming smaller particles, showed longer distribution and elimination half-lives. Both copolymers under study exhibited significantly higher uptake by inflammatory tissue compared with noninflammatory one. The study indicates that PLA-b-PEO copolymers, having different molecular weight of the chains, have similar biological behavior in most organs and tissues. Differences in the uptake by some organs (mainly kidney and bowels) and in activity level in blood at later time intervals were found. Significantly different clearance values are due to different ratios of hydrophobic and hydrophilic chains of the copolymers.

[Determination of danshensu in urine and its pharmacokinetics in human]

AIM

To determine Danshensu in urine and study its pharmacokinetics in human.

METHODS

A solid phase extraction-HPLC method was used for determination of Danshensu in urine of human. HPLC separation is performed on a Shim-pack CLC-ODS column (150 mm x 6.0 mm ID, 5 microns) with a mobile phase composed of acetonitrile -0.01 mol.L-1 KH2PO4 (adjusted to pH 2.8 with phosphoric acid). The flow rate was 1.0 mL.min-1 and the UV detector was set at 280 nm. The linear range of Danshensu was 0.2-50 mg.L-1 (r = 0.9999), and its limit of detection was 1.5 ng. The mean recovery was 99.4% (RSD = 2.9%).

RESULTS

The pharmacokinetics of Danshensu after p.o. administration of two kinds of pharmaceutical preparations containing Danshen (with 20 mg of Danshensu) were investigated in 6 healthy human volunteers by determining the Danshensu in urine samples. The elimination half lives (T1/2) of Danshensu after p.o. administration of compound granule preparation A and decoction of Danshen were (0.92 +/- 0.16) h and (0.94 +/- 0.21) h, respectively. Their excretions of Danshensu in urine were (6.2 +/- 2.8)% and (14 +/- 4)% of the dose in 8 hours, respectively.

CONCLUSION

Under normal doses, Danshensu can be eliminated from kidney. There is no evident difference on elimination half lives of Danshensu after p.o. administration of the two doses, but the excretions of Danshensu by urine after p.o. administration of compound granule preparation A were lower than that of decoction of Danshen.

An effective and better strategy for reducing body burden of radiostrontium

In this study we have examined the effect of different calcium salts, Ca gluconate (CaG), Ca lactate (CaL), Ca carbonate (CaC) and Ca phosphate (CaP), on the clearance of radiostrontium (*Sr) administered either intraperitoneally (ip) (*Sr-ip group) or orally (*Sr-oral group) in rats. The influence of these Ca salts was examined in a group of animals administered *Sr ip, while the effect of three Ca salts (CaG, CaL and CaP) was studied in another group of rats given *Sr orally and compared with that of Ca alginate (CaA), normally advised for *Sr decorporation. Rats from both groups were subdivided into control and four experimental subgroups and were housed individually. The experimental subgroups were given the respective Ca salts (elemental Ca = 9 mg/rat/day) 2 h post 85Sr, and thereafter once daily. In the *Sr-ip group, CaG was administered ip while the other Ca salts were given orally. In the *Sr-oral group all Ca salts were administered orally. In addition, the diet of all the experimental subgroups was supplemented with the respective Ca salts to 2% elemental Ca. The whole-body retention (WBR) of *Sr in animals treated with Ca salts was found to be significantly reduced from 50-60% at 24 h to 20-30% at the end of 15 days compared with 70-80% at 24 h to 50-60% at the end of 15 days in the untreated control animals. The results strongly suggest that CaA could be replaced by any of the commonly used Ca salts for curtailing the WBR of *Sr. CaG which was administered ip, in the *Sr-ip group, was found to be more effective in reducing the WBR of *Sr.