New CDDO Arylboronate Ester Derivatives with High Selectivity and Low Toxicity.

As an oleanolic acid derivative, CDDO-Me lacks selectivity for tumors. Based on the high reactive oxygen species (ROS) level in cancer cells, compound 4 was selected from 17 new CDDO arylboronate ester derivatives. A preliminary study revealed that 4 displayed the highest selectivity for cancer cells. Furthermore, 4 could be transformed to 4H by ROS to increase its covalent binding ability and antiproliferation effect (IC50 of 2.11 vs 0.37 µM) in BGC-823 cells. Interestingly, 4 increased ROS levels to induce apoptosis in BGC-823 cells. Moreover, the LD50 of 4 (91.2 mg/kg) was much greater than that of CDDO-Me (61.7 mg/kg) in ICR mice. A pharmacokinetic study indicated that 4 could be transformed to 4H in vivo. In addition, 4 exhibited a greater tumor inhibition rate (86.2%) than CDDO-Me (51.7%). Overall, the design of 4 provided an effective modification strategy for CDDO to increase the selectivity for cancer cells.

Enhanced bioaccessibility of interfacial delivered oleanolic acid through self-constructed Pickering emulsion: Effects of oil types.

Pentacyclic triterpenes have attracted much attention because of their many bioactivities, but their bioaccessibility is low. Oleanolic acid (OA) was used in this study as a typical edible pentacyclic triterpene. In this work, we proposed an OA interfacial delivery model based on W/O Pickering emulsion, and investigated the effects of different oil types on the emulsion properties and OA bioaccessibility of the OA W/O Pickering emulsion interfacial delivery system (EIDS). Medium chain triglyceride (MCT), long chain triglycerides (LCT) and MCT/LCT (1:1, w/w) were selected as carrier oils for the preparation of emulsions, respectively. The results showed that the emulsions formed from LCT had smaller particle sizes, which increased the deformation resistance of the emulsions and exhibited good stability during the simulated in vitro digestion. The extent of free fatty acid (FFA) release during oil digestion was MCT (103.32 ± 3.74 %) > M/L (97.89 ± 2.89 %) > LCT (71.41 ± 6.64 %). Of interest, the bioaccessibility of OA was influenced by the carrier oil: LCT (59.34 ± 2.55 %) > M/L (47.35 ± 6.25 %) > MCT (13.11 ± 1.40 %) ＞ PBS (7.11 ± 1.74 %), and such a difference was mainly attributed to the greater solubilisation of OA in mixed micelles consisting of long-chain fatty acids. In summary, the size of hydrophobic domains in the mixed micelles produced a greater effect than the effect of FFA release on OA bioaccessibility. This study provides a theoretical basis for the interfacial delivery of OA and the enhancement of OA bioaccessibility based on W/O Pickering emulsions with different oil types.

Targeted codelivery of doxorubicin and oleanolic acid by reduction responsive hyaluronic acid-based prodrug nano-micelles for enhanced antitumor activity and reduced toxicity.

Chemotherapy remains one of the most commonly used strategies in cancer treatment but suffers from damages to healthy tissues and organs. How to precisely co-deliver two or more drugs with different mechanisms of action to the tumors for synergistic function is a challenge for chemotherapy. Herein, Oleanolic acid (OA)-conjugated Hyaluronic acid self-assembled nano-micelles loaded with Doxorubicin (DOX) (HSO NPs/DOX) were constructed for CD44 positive cancer targeted codelivery of DOX and OA. HSO NPs/DOX exhibited reduction triggered drug release under high concentration of glutathione, more efficient uptake by 4T1 breast cancer cells than free DOX leading to higher cytotoxicity, pro-apoptotic, and migration inhibitory activities against 4T1 cells. The ex vivo biodistribution experiment demonstrated more HSO NPs/DOX were accumulated in the tumor tissues than free DOX and less in the non-tumor tissues after injections in 4T1 tumor bearing mice. More importantly, synergistic anti-tumor effects of DOX and OA were obtained using HSO NPs/DOX in 4T1 breast tumor-bearing mice and toxicity of DOX to liver and heart were circumvented through regulating the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Silent Information Regulator 1 (Sirt1) expressions. Taken together, HSO NPs/DOX may become a promising codelivery system for chemotherapeutics in cancer therapy.

Alendronate-functionalized porous nano-crystalsomes mitigate osteolysis and consequent inhibition of tumor growth in a tibia-induced metastasis model.

Bone is one of the most prevalent sites of metastases in various epithelial malignancies, including breast cancer and this metastasis to bone often leads to severe skeletal complications in women due to its osteolytic nature. To address this, we devised a novel drug delivery approach using an Alendronate (ALN) functionalized self-assembled porous crystalsomes for concurrent targeting of Oleanolic acid (OA) and ALN (ALN + OA@NCs) to bone metastasis. Initially, the conjugation of both PEG-OA and OA-PEG-ALN with ALN and OA was achieved, and this conjugation was then self-assembled into porous crystalsomes (ALN + OA@NCs) by nanoemulsion crystallization. The reconstruction of a 3D single particle using transmission electron microscopy ensured the crystalline porous structure of ALN + OA@NCs, was well aligned with characteristic nanoparticle attributes including size distribution, polydispersity, and zeta potential. Further, ALN + OA@NCs showed enhanced efficacy in comparison to OA@NCs suggesting the cytotoxic roles of ALN towards cancer cells, followed by augmentation ROS generation (40.81%), mitochondrial membrane depolarization (57.20%), and induction of apoptosis (40.43%). We found that ALN + OA@NCs facilitated inhibiting osteoclastogenesis and bone resorption followed by inhibited osteolysis. In vivo activity of ALN + OA@NCs in the 4 T1 cell-induced tibia model rendered a reduced bone loss in the treated mice followed by restoring bone morphometric markers which were further corroborated bone-targeting effects of ALN + OA@NCs to reduce RANKL-stimulated osteoclastogenesis. Further, In vivo intravenous pharmacokinetics showed the improved therapeutic profile of the ALN + OA@NCs in comparison to the free drug, prolonging the levels of the drug in the systemic compartment by reducing the clearance culminating the higher accumulation at the tumor site. Our finding proposed that ALN + OA@NCs can effectively target and treat breast cancer metastasis to bone and its associated complications.

Synthesis, Pharmacokinetic Profile, Anticancer Activity and Toxicity of the New Amides of Betulonic Acid-In Silico and In Vitro Study.

Betulonic acid (B(O)A) is a pentacyclic lupane-type triterpenoid that widely exists in plants. There are scientific reports indicating anticancer activity of B(O)A, as well as the amides and esters of this triterpenoid. In the first step of the study, the synthesis of novel amide derivatives of B(O)A containing an acetylenic moiety was developed. Subsequently, the medium-soluble compounds (EB171 and EB173) and the parent compound, i.e., B(O)A, were investigated for potential cytotoxic activity against breast cancer (MCF-7 and MDA-MB-231) and melanoma (C32, COLO 829 and A375) cell lines, as well as normal human fibroblasts. Screening analysis using the WST-1 test was applied. Moreover, the lipophilicity and ADME parameters of the obtained derivatives were determined using experimental and in silico methods. The toxicity assay using zebrafish embryos and larvae was also performed. The study showed that the compound EB171 exhibited a significant cytotoxic effect on cancer cell lines: MCF-7, A-375 and COLO 829, while it did not affect the survival of normal cells. Moreover, studies on embryos and larvae showed no toxicity of EB171 in an animal model. Compared to EB171, the compound EB173 had a weaker effect on all tested cancer cell lines and produced less desirable effects against normal cells. The results of the WST-1 assay obtained for B(O)A revealed its strong cytotoxic activity on the examined cancer cell lines, but also on normal cells. In conclusion, this article describes new derivatives of betulonic acid-from synthesis to biological properties. The results allowed to indicate a promising direction for the functionalization of B(O)A to obtain derivatives with selective anticancer activity and low toxicity.

The novel nanocomplexes containing deoxycholic acid-grafted chitosan and oleanolic acid displays the hepatoprotective effect against CCl4-induced liver injury in vivo.

Chemical liver injury threatens seriously human health, along with the shortage of efficiency and low-toxicity drugs. Herein, the novel oral nanocomplexes composed of deoxycholic acid-grafted chitosan and oleanolic acid were constructed to reverse the CCl4-induced acute liver damage in mice. Results indicated core-shell nanocomplexes, maintained by the hydrophobic interaction between deoxycholic acid and oleanolic acid, could be dissociated in the intestine. Notably, the nanocomplexes possessed superior hepatoprotective effect in vivo, possibly due to the synergistic effect between grafted chitosan and oleanolic acid. Mechanism investigations suggested that nanocomplexes reversed CCl4-induced liver injury through improving hepatic antioxidant capacity via NrF2/Keap1 pathway and regulating inflammation response via NF-κB signaling pathway. The novel oral nanocomplexes represent an effective strategy for chemical liver injury therapy.

Metabolite profiling of Shuganzhi tablets in rats and pharmacokinetics study of four bioactive compounds with liquid chromatography combined with electrospray ionization tandem mass spectrometry.

Shuganzhi Tablets (SGZT) is developed on the basis of a clinical empirical formula as a hospital preparation for the treatment of fatty liver. In this study, a rapid and highly sensitive LC-MS/MS method was established and validated for simultaneous determination of ginsenoside Re, ginsenoside Rg1, notoginsenoside R1, naringin, specnuezhenide, emodin, polydatin, hesperidin and saikosaponin A in rat plasma. Multiple reaction monitoring mode played an important role in simultaneous quantitative analysis of multiple components. The analytes were separated by the action of an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 µm) in five minutes. The validated LC-MS/MS method was successfully applied to the pharmacokinetic analysis of hesperidin, emodin, polydatin and naringin of SGZT in rat plasma after administration. A UHPLC system couple with a quadrupole combined with time of flight mass spectrometer was used for qualitatively analyzing of the composition of SGZT and its metabolites in serum, urine, bile and feces of rats. The results showed that a total of 65 components were detected in rat biological samples, including 10 prototype components and 55 metabolites. It was speculated that the ingredients of SGZT experienced mainly the following reactions in rats: phase I reaction such as hydrolysis, oxidation, hydroxylation, carboxylation and dehydroxylation and phase Ⅱ reaction such as glucuronidation and sulfation. These results provide useful information for the further study of its active ingredients.

Development and Evaluation of Oleanolic Acid Dosage Forms and Its Derivatives.

Oleanolic acid is a pentacyclic triterpenoid compound that exists widely in medicinal herbs and other plants. Because of the extensive pharmacological activity, oleanolic acid has attracted more and more attention. However, the structural characteristics of oleanolic acid prevent it from being directly made into new drugs, which limits the application of oleanolic acid. Through the application of modern preparation techniques and methods, different oleanolic acid dosage forms and derivatives have been designed and synthesized. These techniques can improve the water solubility and bioavailability of oleanolic acid and lay a foundation for the new drug development. In this review, the recent progress in understanding the oleanolic acid dosage forms and its derivatives are discussed. Furthermore, these products were evaluated comprehensively from the perspective of characterization and pharmacokinetics, and this work may provide ideas and references for the development of oleanolic acid preparations.

Co-delivery of doxorubicin and oleanolic acid by triple-sensitive nanocomposite based on chitosan for effective promoting tumor apoptosis.

Nanocomposites as "stevedores" for co-delivery of multidrugs hold great promise in addressing the drawbacks of traditional cancer chemotherapy. In this work, our strategy presents a new avenue for the stepwise release of two co-delivered agents into the tumor cells. The hybrid nanocomposite consists of a pH-responsive chitosan (CS), a thermosensitive poly(N-vinylcaprolactam) (PNVCL) and a functionalized cell-penetrating peptide (H6R6). Doxorubicin (DOX) and oleanolic acid (OA) are loaded into the nanocomposite (H6R6-CS-g-PNVCL). The system displayed a suitable size (∼190 nm), a high DOX loading (13.2 %) and OA loading efficiency (7.3 %). The tumor microenvironment triggered the nanocomposite to be selectively retained in tumor cells, then releasing the drugs. Both in vitro and in vivo studies showed a significant enhancement in antitumor activity of the co-delivered system in comparison to mono-delivery. This approach which relies on redox, pH and temperature effects utilizing co-delivery nanosystems may be beneficial for future applications in cancer chemotherapy.

Pharmacokinetics of maslinic and oleanolic acids from olive oil - Effects on endothelial function in healthy adults. A randomized, controlled, dose-response study.

To date, pharmacokinetics of maslinic (MA) and oleanolic (OA) acids, at normal dietary intakes in humans, have not been evaluated, and data concerning their bioactive effects are scarce. We assessed MA and OA pharmacokinetics after ingestion of olive oils (OOs) with high and low triterpenic acid contents, and specifically the effect of triterpenes on endothelial function. We performed a double-blind, dose-response, randomized, cross-over nutritional intervention in healthy adults, and observed that MA and OA increased in biological fluids in a dose-dependent manner. MA bioavailability was greater than that of OA, and consumption of pentacyclic triterpenes was associated with improved endothelial function. To the best of our knowledge, this is the first time MA pharmacokinetics, and effects on endothelial function in vivo, have been reported in humans.

Hyaluronic acid-coated nanostructured lipid carriers for loading multiple traditional Chinese medicine components for liver cancer treatment.

This study aimed to develop hyaluronic acid (HA)-coated nanostructured lipid carriers (NLC) loaded simultaneously with oleanolic acid (OA), ursolic acid (UA) and Ginsenoside Rg3 (Rg3), prepared by electrostatic attraction for delivering OA, UA and Rg3 (OUR), termed HA-OUR-NLC, to tumors over expressing cluster determinant 44(CD44). The dialysis method was used to assess the in vitro release of OUR. Parameters such as pharmacokinetics, biodistribution, fluorescence in vivo endo-microscopy (FIVE), optical in vivo imaging (OIVI) data, and in vivo antitumor effects were evaluated. The results showed a total drug loading rate of 8.76±0.95% for the optimized HA-OUR-NLC; total encapsulation efficiency was 45.67±1.14%; particle size was 165.15±3.84%; polydispersity index was 0.227±0.01; zeta potential was -22.87±0.97 mV. Drug release followed the Higuchi kinetics. Pharmacokinetics and tissue distribution, as well as antitumor effects were evaluated in nude mice in vivo. HA-OUR-NLC were better tolerated, with increased antitumor activity compared with 5-Fu. In in vivo optical imaging, we use 1,1'-dioctadecyl-3,3,3',3'-tetramethy(DiR) as a fluorescent dye to label the NLC. The DiR-OUR-NLC group showed bright systemic signals, while the tumor site was weak. The present findings indicated that HA-OUR-NLC accumulated in the tumor site, prolonging OUR duration in the circulation and enhancing tumoral concentrations. Therefore, NLC prepared by electrostatic attraction constitute a good system for delivering OUR to tumors.

Preparation and evaluation of a novel solid dispersion using leucine as carrier.

OBJECTIVE: The aim of this study was to develop a novel formulation of oleanolic acid (OA) solid dispersion (SD), using leucine (Leu) as the carrier to improve OA oral bioavailability. METHODS: The OA-Leu SD was prepared by solvent evaporation and was evaluated in vitro using differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, flowability, hygroscopicity and dissolution test. The stability of the SD was evaluated using accelerated testing. In vivo pharmacokinetic tests were performed in male Sprague Dawley rats using a liquid chromatography tandem-mass spectrometry bioanalytical method. KEY FINDINGS: OA-Leu SD was successfully prepared, and OA was mostly in an amorphous state. More than 80% of OA could dissolve in OA-Leu SD in 20 min, while only 13.4% of free OA dissolved. The powder flow of OA-Leu SD was clearly improved compared with free OA and its moisture absorption was 3.4%. The accelerated testing further demonstrated that SD could maintain OA in an amorphous state at 40 °C for 6 months. OA-Leu SD showed higher relative oral bioavailability (189.7%) than free OA in rats. CONCLUSIONS: Using Leu as a carrier produced a SD with good flowability, low hygroscopicity and high bioavailability.

Analysis of five active ingredients of Er-Zhi-Wan, a traditional Chinese medicine water-honeyed pill, using the biopharmaceutics classification system.

Er-Zhi-Wan (EZW) is a traditional Chinese medicine with many clinical applications and used as a health product in East Asia. Five active ingredients (salidroside, specnuezhenide, nuezhenoside, luteolin, and oleanolic acid) were screened out from EZW to develop an in vitro rapid evaluation method for the classification of in vivo drug absorption behavior by biopharmaceutics classification system (BCS). Ultra-performance liquid chromatography was used for quantitative analysis. Solubility and permeability were assayed by equilibrium solubility and multiple models: everted rat intestinal sac model, cultured Caco-2 cells, octanol-water partition coefficient (LogP) method. The BCS properties of drugs were predicted using software applications, and the correlations of measured and predicted values of factors affecting oral drug absorption were calculated. The results were verified by measuring the absolute bioavailability of the active ingredients. Salidroside, specnuezhenide, and nuezhenoside were classified as BCS class III drugs, and luteolin was classified as a BCS class III/I drug because of the difference in LogP and intestinal permeability. Oleanolic acid was classified as a BCS class II/IV drug in acidic media and BCS class I/III drug in other media. Overall, EZW may be classified as a BCS class III drug, and permeability was identified as the primary factor limiting absorption. The results provide a novel method for the evaluation of the in vivo absorption of oral traditional Chinese medicines.

Inhibitory Effects of Ginsenoside Ro on the Growth of B16F10 Melanoma via Its Metabolites.

Ginsenoside Ro (Ro), a major saponin derived and isolated from Panax ginseng C.A. Meyer, exerts multiple biological activities. However, the anti-tumour efficacy of Ro remains unclear because of its poor in vitro effects. In this study, we confirmed that Ro has no anti-tumour activity in vitro. We explored the anti-tumour activity of Ro in vivo in B16F10 tumour-bearing mice. The results revealed that Ro considerably suppressed tumour growth with no significant side effects on immune organs and body weight. Zingibroside R1, chikusetsusaponin IVa, and calenduloside E, three metabolites of Ro, were detected in the plasma of Ro-treated tumour-bearing mice and showed excellent anti-tumour effects as well as anti-angiogenic activity. The results suggest that the metabolites play important roles in the anti-tumour efficacy of Ro in vivo. Additionally, the haemolysis test demonstrated that Ro has good biocompatibility. Taken together, the findings of this study demonstrate that Ro markedly suppresses the tumour growth of B16F10-transplanted tumours in vivo, and its anti-tumour effects are based on the biological activity of its metabolites. The anti-tumour efficacy of these metabolites is due, at least in part, to its anti-angiogenic activity.

Effects of Animal Strain, Dose, and Cotreatment with Saikosaponin b2 on the Pharmacokinetics of Saikosaponin a in Rats.

BACKGROUND AND OBJECTIVES: Radix Bupleuri (RB, Chaihu in Chinese) has been used as a traditional medicine for more than 2000 years in China, Japan, Korea, and other Asian countries. Saikosaponin a (SSa), the most abundant saikosaponin in RB, exhibits various pharmacological activities, including anti-inflammatory, antitumor, antiviral, immunoregulatory, neuromodulatory, and hepatoprotective activities. A comprehensive study of the pharmacokinetic characteristics of SSa is needed to gain a detailed understanding of its pharmacodynamic mechanism. METHODS: Here, we determined the effects of rat strain (Sprague Dawley and Wistar), oral dose, and cotreatment with saikosaponin b2 (SSb2) on the pharmacokinetics of SSa by measuring SSa in plasma via LC-MS/MS. RESULTS: The results showed that the absorption of SSa in Wistar rats was statistically superior to its absorption in Sprague Dawley rats based on pharmacokinetic parameters such as the area under the concentration-time curve (AUC0-t) and the peak concentration (Cmax). Pharmacokinetic studies of different doses of SSa in Wistar rats revealed that the systemic exposure of SSa, based on AUC values, increased disproportionately with dose, indicating that SSa exhibits non-dose-proportional pharmacokinetics. In addition, our studies showed that SSb2, a characteristic component of vinegar-baked Radix Bupleuri (VBRB), inhibits the absorption of SSa in rats. CONCLUSIONS: The pharmacokinetic data for SSa obtained in this study will play an important role in attempts to better understand the fate of SSa in rats and to explore how these saikosaponins are likely to exert their pharmacological effects in vivo. In addition, further research is needed to elucidate the interactions of saikosaponins with metabolic enzymes and transporters in order to account for the phenomena observed in this study.

Biopharmaceutics classification and intestinal absorption of chikusetsusaponin IVa.

The objective of this study was to investigate the absorption behavior of chikusetsusaponin IVa (CHS-IVa) in the rat intestine using single-pass intestinal perfusion (SPIP) and to classify CHS-IVa into the biopharmaceutics classification system (BCS). The equilibrium solubility of CHS-IVa was determined by the shaker method. The absorption mechanism of CHS-IVa in the intestine was studied by comparing the Peff of different concentrations of CHS-IVa. The intestinal site dependence of CHS-IVa absorption was studied by comparing the Peff of the same concentration of CHS-IVa in different intestinal segments. The relationship between CHS-IVa and intestinal efflux protein was studied by perfusion with an efflux protein inhibitor. The permeability of CHS-IVa was investigated by comparing the Peff of CHS-IVa and the reported value. The solubility of CHS-IVa over the pH range 1.0-7.5 was 14.4 ± 0.29 to 16.9 ± 0.34 mg/ml. The Peff of CHS-IVa in the duodenum was 1.76 × 10-3 to 2.00 × 10-3  cm/min. The Peff of CHS-IVa in the jejunum was 1.26 × 10-3 to 1.39 × 10-3  cm/min. The Peff of CHS-IVa in the ileum was 1.25 × 10-3 to 1.31 × 10-3  cm/min. The Peff of CHS-IVa in the colon was 1.02 × 10-3 to 1.08 × 10-3  cm/min. There was no statistical difference of the Peff in the four segments at different CHS-IVa concentrations. The Peff of CHS-IVa (0.07, 0.7 and 7.0 mg/ml) were all notably smaller than the reported Peff (3.00 × 10-3  cm/min) in the jejunum. The Peff of CHS-IVa was not influenced by verapamil (P-gp inhibitor), indomethacin (MRP inhibitor) and pantoprazole (BCRP inhibitor). CHS-IVa was classified as high solubility, low permeability and BCS III. The main absorptive tracts were the upper intestinal tracts and the rank order of intestinal permeability was duodenum > jejunum ≈ ileum > colon. The transport mechanism of CHS-IVa in all intestinal segments might be primarily passive transport. CHS-IVa was not a substrate of P-gp, MRP and BCRP.

Pharmacokinetics and oral bioavailability studies of three saikogenins in rats using a validated UFLC-MS/MS method.

Radix Bupleuri (RB) has been widely used in Traditional Chinese Medicine with a long history. Saikosaponins (SSs), the major constituents of RB, are assumed to be transformed into saikogenins (SGs) by human intestinal microflora prior to absorption and then exert pharmacological effects. There have been detailed reports on the deglycosylation of SSs in the gastrointestinal tract. But to date, there is very limited research addressing the further absorption, distribution, metabolism, and excretion of these deglycosylated derivatives in vivo. In this study, a rapid UFLC-MS/MS method was established and fully validated for simultaneously determining four SGs (SGF, SGA, SGD, and SGG) in rat plasma. The developed method was successfully applied to the pharmacokinetics of three SGs (SGF, SGD, and SGG) in rats after oral and intravenous administrations. Finally, the absolute bioavailabilities were calculated at 0.71% for SGF and 0.66% for SGD. However, the oral bioavailability of SGG was not obtained due to the extremely poor absorption in rats.

Effects of Bardoxolone Methyl on Magnesium in Patients with Type 2 Diabetes Mellitus and Chronic Kidney Disease.

BACKGROUND: Treatment with bardoxolone methyl (Bard) in a multinational phase 3 trial, Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON), resulted in increases in estimated glomerular filtration rate with concurrent reductions in serum magnesium. We analyzed data from several trials to characterize reductions in magnesium with Bard. METHODS: BEACON randomized patients (n = 2,185) with type 2 diabetes (T2DM) and stage 4 chronic kidney disease (CKD) 1:1 to receive Bard (20 mg) or placebo once daily. In a separate open-label study, magnesium levels from 24-hour urine and sublingual epithelial cell samples were analyzed in patients with stage 3b-4 CKD and T2DM administered 20 mg Bard for 56 consecutive days. RESULTS: BEACON patients randomized to Bard experienced significant reductions in serum magnesium from baseline relative to patients randomized to placebo (-0.17 mEq/L, 95% CI -0.18 to -0.60 mEq/L; p < 0.001). A separate study showed intracellular and urinary magnesium levels were unchanged with Bard treatment. CONCLUSIONS: Bard treatment results in significant decreases in serum magnesium that are not associated with changes in intracellular and urinary magnesium levels, indicating that magnesium decreases are not due to renal magnesium wasting or total body magnesium depletion. Importantly, the decreases in serum magnesium with Bard are not associated with adverse effects on QT interval.

A rapid and sensitive UHPLC-MS/MS method for the determination of celosin A in rat plasma with application to pharmacokinetic study.

Celosin A (CA), a natural compound isolated from Celosia argentea L., has been shown significant hepatoprotective effect on AHNP-induced liver injury. This study described a rapid and sensitive ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay for determination of CA in rat plasma. Methanol-mediated precipitation was used for sample pretreatment. Chromatographic separation was achieved on a T3 column with gradient elution using water and acetonitrile as mobile phase. Determination was obtained using an electrospray ionization source in negative selected reaction monitoring mode at the transitions of m/z 793.3 → m/z 661.2 and m/z 955.6 → m/z 793.2 for CA and IS, respectively. The assay was linear over the concentration range 0.25-2500 ng/mL (r > 0.995) with a lowest limit of quantification (LLOQ) of 0.25 ng/mL. The intra- and inter-day precisions (RSD) were 1.65-9.84 and 2.46-13.49%, respectively, while accuracy (RR) ranged from 96.21 to 99.45%, respectively. The recovery ranged from 95.09 to 102.22% and the matrix effect from 98.29 to 100.13%. The analyte was stable under the tested storage conditions. The method has been successfully applied to a preclinical pharmacokinetic study in rats after a single intravenous (2 mg/kg) or oral (50 mg/kg) administration. The oral bioavailability of CA was ~1.94%; in addition, there was no difference between male and female rats. This is the first time of the use of an UHPLC-MS/MS method for determination of CA concentration in rat plasma and for evaluation of its pharmacokinetic behavior.

Intestinal absorption mechanisms of araloside A in situ single-pass intestinal perfusion and in vitro Caco-2 cell model.

Araloside A is a triterpenoid saponin,which exhibits a broad spectrum of pharmacological activities, such as stimulating fibrinolysis, preventing coagulant, inhibiting renin, and decreasing blood pressure. Our previous report found that the compound exhibits a poor absolute bioavailability. However the underlying mechanisms of its absorption have not been investigated in the small intestine or in a Caco-2 cell model. In this study, the absorption mechanisms of araloside A were investigated in a Caco-2 cell monolayer and in a single-pass intestinal perfusion in situ model with Sprague-Dawley rats. The effects of basic parameters, such as compound concentration, time, temperature, paracellular pathway, different intestinal segments were analyzed, and the susceptibility of araloside A absorption process to treatment with various inhibitors, such as the P-gp inhibitor verapamil, the multidrug resistance protein2 inhibitors (MRP2) MK571 and indomethacin, the breast cancer resistance protein (BCRP) inhibitors Ko143 and reserpine, and endocytosis inhibitor chlorpromazine were assessed. It can be found that the mechanisms of intestinal absorption of araloside A may involve multiple transport pathways, such as passive diffusion, the paracellular pathway, as well as the participation of efflux transporters.