Discovery of a novel water-soluble, rapid-release triptolide prodrug with improved drug-like properties and high efficacy in human acute myeloid leukemia.

In this work, a series of water-soluble triptolide prodrugs were synthesized, and their triptolide release rate, pharmacokinetic characteristics and anti-tumor effect were measured. We found that inserting glycolic acid as a linker between triptolide and the cyclic amino acid accelerated the release of triptolide from prodrugs into the plasma while preserving its safety. Among them, prodrug TP-P1 was significantly better than Minnelide (the only water-soluble triptolide prodrug in clinical trials) in terms of release rate in plasma and synthetic yield. In mouse models of human acute myeloid leukemia (AML), TP-P1 was effective in reducing xenograft tumors at dose levels as low as 25 µg/kg, and eliminating tumors at dose 100 µg/kg. Furthermore, TP-P1 could significantly enhance the efficacy of FLT3 inhibitors in the treatment of AML. These experimental results showed the potential of TP-P1 as water-soluble prodrugs of triptolide.

Acupoint nanocomposite hydrogel for simulation of acupuncture and targeted delivery of triptolide against rheumatoid arthritis.

BACKGROUND: Attenuating inflammatory response and relieving pain are two therapeutic therapeutical goals for rheumatoid arthritis (RA). Anti-inflammatory and analgesic drugs are often associated with many adverse effects due to nonspecific distribution. New drug delivery systems with practical targeting ability and other complementary strategies urgently need to be explored. To achieve this goal, an acupoint drug delivery system that can target deliver anti-inflammatory drugs and simulate acupuncture in relieving pain was constructed, which can co-deliver triptolide (TP) and 2-chloro-N (6)-cyclopentyl adenosine (CCPA). RESULTS: We have successfully demonstrated that acupoint nanocomposite hydrogel composed of TP-Human serum album nanoparticles (TP@HSA NPs) and CCPA could effectively treat RA. The result shows that CCPA-Gel can enhance analgesic effects specifically at the acupoint, while the mechanical and thermal pain threshold was 4.9 and 1.6 times compared with non-acupoint, respectively, and the nanocomposite gel further enhanced. Otherwise, the combination of acupoint and nanocomposite hydrogel exerted synergetic improvement of inflammation, bone erosion, and reduction of systemic toxicity. Furthermore, it could regulate inflammatory factors and restore the balance of Th17/Treg cells, which provided a novel and effective treatment strategy for RA. Interestingly, acupoint administration could improve the accumulation of the designed nanomedicine in arthritic paws (13.5% higher than those in non-acupoint at 48 h), which may explain the better therapeutic efficiency and low toxicity. CONCLUSION: This novel therapeutic approach-acupoint nanocomposite hydrogel, builds a bridge between acupuncture and drugs which sheds light on the combination of traditional and modern medicine.

Prodrug polymeric micelles integrating cancer-associated fibroblasts deactivation and synergistic chemotherapy for gastric cancer.

BACKGROUND: The prognosis of patients with advanced gastric cancer (GC) remains unsatisfactory owing to distant metastasis and resistance to concurrent systemic therapy. Cancer-associated fibroblasts (CAFs), as essential participators in the tumor microenvironment (TME), play a vital role in tumor progression. Thus, CAFs-targeting therapy is appealing for remodeling TME and sensitizing GC to conventional systemic therapy. METHODS: Amphiphilic SN38 prodrug polymeric micelles (PSN38) and encapsulated the hydrophobic esterase-responsive prodrug of Triptolide (TPL), triptolide-naphthalene sulfonamide (TPL-nsa), were synthesized to form PSN38@TPL-nsa nanoparticles. Then, CAFs were isolated from fresh GC tissues and immortalized. TPL at low dose concentration was used to investigate its effect on CAFs and CAFs-induced GC cells proliferation and migration. The synergistic mechanism and antitumor efficiency of SN38 and TPL co-delivery nanoparticle were investigated both in vitro and in vivo. RESULTS: Fibroblast activation protein (FAP), a marker of CAFs, was highly expressed in GC tissues and indicated poorer prognosis. TPL significantly reduced CAFs activity and inhibited CAFs-induced proliferation, migration and chemotherapy resistance of GC cells. In addition, TPL sensitized GC cells to SN38 treatment through attenuated NF-κB activation in both CAFs and GC cells. PSN38@TPL-nsa treatment reduced the expression of collagen, FAP, and α-smooth muscle actin (α-SMA) in tumors. Potent inhibition of primary tumor growth and vigorous anti-metastasis effect were observed after systemic administration of PSN38@TPL-nsa to CAFs-rich peritoneal disseminated tumor and patient-derived xenograft (PDX) model of GC. CONCLUSION: TPL suppressed CAFs activity and CAFs-induced cell proliferation, migration and chemotherapy resistance to SN38 of GC. CAFs-targeted TPL and SN38 co-delivery nanoparticles exhibited potent efficacy of antitumor and reshaping TME, which was a promising strategy to treat advanced GC.

Sorafenib and triptolide loaded cancer cell-platelet hybrid membrane-camouflaged liquid crystalline lipid nanoparticles for the treatment of hepatocellular carcinoma.

In addition to early detection, early diagnosis, and early surgery, it is of great significance to use new strategies for the treatment of hepatocellular carcinoma (HCC). Studies showed that the combination of sorafenib (SFN) and triptolide (TPL) could reduce the clinical dose of SFN and maintain good anti-HCC effect. But the solubility of SFN and TPL in water is low and both drugs have certain toxicity. Therefore, we constructed a biomimetic nanosystem based on cancer cell-platelet (PLT) hybrid membrane camouflage to co-deliver SFN and TPL taking advantage of PLT membrane with long circulation functions and tumor cell membrane with homologous targeting. The biomimetic nanosystem, SFN and TPL loaded cancer cell-PLT hybrid membrane-camouflaged liquid crystalline lipid nanoparticles ((SFN + TPL)@CPLCNPs), could simultaneously load SFN and TPL at the molar ratio of SFN to TPL close to 10:1. (SFN + TPL)@CPLCNPs achieved long circulation function and tumor targeting at the same time, promoting tumor cell apoptosis, inhibiting tumor growth, and achieving a better "synergy and attenuation effect", which provided new ideas for the treatment of HCC.

Transdermal delivery of triptolide-phospholipid complex to treat rheumatoid arthritis.

The aim of this study was to develop and evaluate a triptolide phospholipid complex (TPCX) for the treatment of rheumatoid arthritis (RA) by transdermal delivery. TPCX was prepared and characterized by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR) analysis, transmission electron microscope (TEM), and scanning electron microscope (SEM). The solubility of TPCX was determined. Then, a TPCX cream was prepared to evaluate its percutaneous permeability and the antiarthritis effect. The transdermal permeability was determined using the Franz method, and a microdialysis system was used for skin pharmacokinetic study. A rat model of RA was prepared to evaluate the pharmacological effects. TPCX increased the solubility of triptolide in water, and the percutaneous permeability of TPCX cream was greatly enhanced compared with triptolide cream. The skin pharmacokinetic study indicated that TPCX cream has a longer biological half-life (t1/2) and mean residence time (MRT), but it has a shorter Tmax than that of triptolide cream in vivo. The area under the curve (AUC0-t)/AUC0-∞) and the peak concentration (Cmax) of TPCX cream were obviously higher than those of triptolide cream. The TPCX-loaded cream alleviated paw swelling and slowed down the progression of arthritis by inhibiting the inflammatory response by down regulating the TNF-α, IL-1ß, and IL-6 levels, thus exhibiting excellent antiarthritic effects. In summary, the prepared TPCX effectively increases the hydrophilicity of triptolide, which is good for its percutaneous absorption and enhances its effect on RA rats. TPCX can be a good candidate for the transdermal delivery to treat RA.

Multiple-Coated PLGA Nanoparticles Loading Triptolide Attenuate Injury of a Cellular Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease, which is associated with extracellular deposition of amyloid-ß proteins (Aß). It has been reported that triptolide (TP), an immunosuppressive and anti-inflammatory agent extracted from a Chinese herb Tripterygium wilfordii, shows potential neuroprotective effects pertinent to AD. However, the clinical use of TP for AD could be hampered due to its high toxicity, instability, poor water solubility, and nonspecific biodistribution after administration. In this paper, we reported a kind of multiple-coated PLGA nanoparticle with the entrapment of TP and surface coated by chitosan hydrochloride, Tween-80, PEG20000, and borneol/mentholum eutectic mixture (MC-PLGA-TP-NP) as a novel nasal brain targeting preparation for the first time. The obtained MC-PLGA-TP-NP was 147.5 ± 20.7 nm with PDI of 0.263 ± 0.075, zeta potential of 14.62 ± 2.47 mV, and the entrapment efficiency and loading efficiency of 93.14% ± 4.75% and 1.17 ± 0.08%, respectively. In comparison of TP, MC-PLGA-TP-NP showed sustained-release profile and better transcellular permeability to Caco-2 cells in vitro. In addition, our data showed that MC-PLGA-TP-NP remarkably reduced the cytotoxicity, attenuated the oxidative stress, and inhibited the increase of the intracellular Ca2+ influx in differentiated PC12 cells induced by Aß 1-42. Therefore, it can be concluded that MC-PLGA-TP-NP is a promising preparation of TP, which exerts a better neuroprotective activity in the AD cellular model.

UPLC-MS/MS method for the simultaneous quantification of pravastatin, fexofenadine, rosuvastatin, and methotrexate in a hepatic uptake model and its application to the possible drug-drug interaction study of triptolide.

A rapid and specific UPLC-MS/MS method with a total run time of 3.5 min was developed for the determination of pravastatin, fexofenadine, rosuvastatin, and methotrexate in rat primary hepatocytes. After protein precipitation with 70% acetonitrile (containing 30% H2 O), these four analytes were separated under gradient conditions with a mobile phase consisting of 0.03% acetic acid (v/v) and methanol at a flow rate of 0.50 mL/min. The linearity, recovery, matrix effect, accuracy, precision, and stability of the method were well validated. We evaluated drug-drug interactions based on these four compounds in freshly suspended hepatocytes. The hepatic uptake of pravastatin, fexofenadine, rosuvastatin, and methotrexate at 4°C was significantly lower than that at 37°C, and the hepatocytes were saturable with increased substrate concentration and culture time, suggesting that the rat primary hepatocyte model was successfully established. Triptolide showed a significant inhibitory effect on the hepatic uptake of these four compounds. In conclusion, this method was successfully employed for the quantification of pravastatin, fexofenadine, rosuvastatin, and methotrexate and was used to verify the rat primary hepatocyte model for Oatp1, Oatp2, Oatp4, and Oat2 transporter studies. Then, we applied this model to explore the effect of triptolide on these four transporters.

Triptolide and atorvastatin synergistically promote hepatotoxicity in cultured hepatocytes and female Sprague-Dawley rats by inhibiting pregnane X receptor-mediated transcriptional activation of CYP3A4.

Triptolide (TP), an active component of Tripterygium wilfordii Hook. F, has been widely used in China for treating autoimmune and inflammatory diseases, and has also been validated by modern science and developed as a candidate anti-cancer treatment. However, liver toxicity of TP has seriously hindered its use and development, the clinical features and primary toxicological mechanism have been unclear. Considering the major target regulation mechanism of TP is the suppression of global transcription regulated by RNAPII, which is closed related with the detoxification of drugs. This paper tries to verify the synergistic liver injury and its mechanism of TP when co-administered with CYP3A4 substrate drug. The experiments showed that TP dose-dependently blocked transcriptional activation of CYP3A4 in both hPXR and hPXR-CYP3A4 reporter cell lines, lowered the mRNA and protein expression of PXR target genes such as CYP3A1, CYP2B1, and MDR1, and inhibited the functional activity of CYP3A in a time- and concentration-dependent manner in sandwich-cultured rat hepatocytes (SCRH) and female Sprague-Dawley (f-SD) rats. Furthermore, TP combined with atorvastatin (ATR), the substrate of CYP3A4, synergistically enhanced hepatotoxicity in cultured HepG2 and SCRH cells (CI is 0.38 and 0.29, respectively), as well as in f-SD rats, with higher exposure levels of both drugs. These results clearly indicate that TP inhibits PXR-mediated transcriptional activation of CYP3A4, leading to a blockade on the detoxification of itself and ATR, thereby greatly promoting liver injury. This study may implies the key cause of TP related liver injury and provides experimental data for the rational use of TP in a clinical scenario.

Effects of Multiple Doses of Dichloroacetate on GSTZ1 Expression and Activity in Liver and Extrahepatic Tissues of Young and Adult Rats.

Glutathione transferase zeta 1 (GSTZ1), expressed in liver and several extrahepatic tissues, catalyzes dechlorination of dichloroacetate (DCA) to glyoxylate. DCA inactivates GSTZ1, leading to autoinhibition of its metabolism. DCA is an investigational drug for treating several congenital and acquired disorders of mitochondrial energy metabolism, including cancer. The main adverse effect of DCA, reversible peripheral neuropathy, is more common in adults treated long-term than in children, who metabolize DCA more quickly after multiple doses. One dose of DCA to Sprague Dawley rats reduced GSTZ1 expression and activity more in liver than in extrahepatic tissues; however, the effects of multiple doses of DCA that mimic its therapeutic use have not been studied. Here, we examined the expression and activity of GSTZ1 in cytosol and mitochondria of liver, kidney, heart, and brain 24 hours after completion of 8-day oral dosing of 100 mg/kg per day sodium DCA to juvenile and adult Sprague Dawley rats. Activity was measured with DCA and with 1,2-epoxy-3-(4-nitrophenoxy)propane (EPNPP), reported to be a GSTZ1-selective substrate. In DCA-treated rats, liver retained higher expression and activity of GSTZ1 with DCA than other tissues, irrespective of rodent age. DCA-treated juvenile rats retained more GSTZ1 activity with DCA than adults. Consistent with this finding, there was less measurable DCA in tissues of juvenile than adult rats. DCA-treated rats retained activity with EPNPP, despite losing over 98% of GSTZ1 protein. These data provide insight into the differences between children and adults in DCA elimination under a therapeutic regimen and confirm that the liver contributes more to DCA metabolism than other tissues. SIGNIFICANCE STATEMENT: Dichloroacetate (DCA) is one of few drugs exhibiting higher clearance from children than adults, after repeated doses, for reasons that are unclear. We hypothesized that juveniles retain more glutathione transferase zeta 1 (GSTZ1) than adults in tissues after multiple DCA doses and found this was the case for liver and kidney, with rat as a model to assess GSTZ1 protein expression and activity with DCA. Although 1,2-epoxy-3-(4-nitrophenoxy)propane was reported to be a selective GSTZ1 substrate, its activity was not reduced in concert with GSTZ1 protein.

Triptolide-nanoliposome-APRPG, a novel sustained-release drug delivery system targeting vascular endothelial cells, enhances the inhibitory effects of triptolide on laser-induced choroidal neovascularization.

PURPOSE: To investigate whether triptolide-nanoliposome-APRPG (TP-nanolip-APRPG), a novel sustained-release nano-drug delivery system that targets vascular endothelial cells, could enhance the inhibition of triptolide (TP) on laser-induced choroidal neovascularization (CNV). METHODS: TP was encapsulated with or without APRPG (Ala-Pro-Arg-Pro-Gly) peptide-modified nanoliposomes. CNV was induced by laser photocoagulation in C57BL/6J mice. One microliter of 10 µg free TP monomer, TP-nanolip containing 10 µg TP, TP-nanolip-APRPG containing 10 µg TP, or an identical volume of PBS was intravitreally injected in mice immediately after laser photocoagulation. Seven days after laser photocoagulation, CNV volumes were calculated in each group. Infiltration of M2 macrophages as well as protein levels of vascular endothelial growth factor (VEGF) and inflammatory factors including ICAM-1 and MCP-1 in the RPE-choroid complex were determined. In vitro assays for cell proliferation, migration, and tube formation were also performed. RESULTS: TP-nanolip-APRPG was successfully synthesized and exhibited good TP delivery and enhanced the cellular uptake of TP in vitro. In vitro studies showed that TP-nanolip-APRPG was a better inhibitor of cell proliferation (31.34 ±â€¯3.89 % vs 41.25 ±â€¯4.67 % vs 53.55 ±â€¯5.76 %), migration (62.60 ±â€¯8.88 vs 104.60 ±â€¯13.32 vs 147.00 ±â€¯13.15), and tube formation (681.26 ±â€¯108.15 vs 926.75 ±â€¯54.01 vs 1189.84 ±â€¯157.14) than TP-nanolip or free TP (all P < 0.05). Intravitreal injections of free TP (77588.10±7719.28 µm3), TP-nanolip (64628.23 ±â€¯5857.96 µm3), and TP-nanolip-APRPG (50880.34 ±â€¯6606.56 µm3) inhibited the development of CNV compared with the PBS control group (120338.07 ±â€¯17428.90 µm3) (P < 0.01, n=6). TP-nanolip-APRPG and TP-nanolip significantly down-regulated the protein levels of VEGF (152.76±19.55 vs 182.24±19.98 vs 208.55±21.93 pg/mg total protein) and inflammatory factors including ICAM-1 (61.69±3.49 vs 72.04±3.49 vs 81.92±4.09 ng/mg total protein) and MCP-1 (40.14±3.50 vs 50.75±4.18 vs 60.27±5.23 pg/mg total protein) compared with the free TP monomer group (all P < 0.05, n=8), which paralleled the decreased infiltration of M2 macrophages in the CNV lesions. Moreover, no influence on retinal morphology and function was observed before or after treatment in each group (P > 0.05, n=6). CONCLUSIONS: TP-nanolip-APRPG, a novel sustained-release drug delivery system targeting endothelial cells of CNV lesions, could enhance TP inhibition of the development of CNV without toxicity in the retina, suggesting therapeutic potential for CNV-related diseases in future clinical practice.

Human phase I in vitro liver metabolism of two bisphenolic diglycidyl ethers BADGE and BFDGE.

Root canal sealers are commonly used to endodontically treat teeth with periapical infections. Some root canal sealers based on epoxy resin contain bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE). The presence of these chemicals is of concern due to the close contact to the blood stream at the apex and the long setting times of up to 24 h. These chemicals, or any of their degradation products or metabolites, can then exert their toxic effects before being excreted. This study aimed to identify the phase I in vitro biotransformation products of BADGE and BFDGE using human liver microsomes. During incubation with microsomal fractions, the epoxides were rapidly hydrolysed in a NADPH independent manner resulting in the formation of BADGE.2H2O and BFDGE.2H2O. Further, oxidative reactions, such as hydroxylation and carboxylation, generated other BADGE metabolites, such as BADGE.2H2O-OH and BADGE.H2O.COOH, respectively. For BFDGE, further oxidation of BFDGE.2H2O led to the newly reported carboxylic acid, BFDGE.H2O.COOH. In total, three specific metabolites have been identified which can serve in future human biomonitoring studies of BADGE and BFDGE.

Circadian clock regulates hepatotoxicity of Tripterygium wilfordii through modulation of metabolism.

OBJECTIVES: We aimed to determine the diurnal rhythm of Tripterygium wilfordii (TW) hepatotoxicity and to investigate a potential role of metabolism and pharmacokinetics in generating chronotoxicity. METHODS: Hepatotoxicity was determined based on assessment of liver injury after dosing mice with TW at different circadian time points. Circadian clock control of metabolism, pharmacokinetics and hepatotoxicity was investigated using Clock-deficient (Clock-/- ) mice. KEY FINDINGS: Hepatotoxicity of TW displayed a significant circadian rhythm (the highest level of toxicity was observed at ZT2 and the lowest level at ZT14). Pharmacokinetic experiments showed that oral gavage of TW at ZT2 generated higher plasma concentrations (and systemic exposure) of triptolide (a toxic constituent) compared with ZT14 dosing. This was accompanied by reduced formation of triptolide metabolites at ZT2. Loss of Clock gene sensitized mice to TW-induced hepatotoxicity and abolished the time-dependency of toxicity that was well correlated with altered metabolism and pharmacokinetics of triptolide. Loss of Clock gene also decreased Cyp3a11 expression in mouse liver and blunted its diurnal rhythm. CONCLUSIONS: Tripterygium wilfordii chronotoxicity was associated with diurnal variations in triptolide pharmacokinetics and circadian expression of hepatic Cyp3a11 regulated by circadian clock. Our findings may have implications for improving TW treatment outcome with a chronotherapeutic approach.

Influence of astragaloside IV on pharmacokinetics of triptolide in rats and its potential mechanism.

Context: It is common to combine two or more drugs in clinics in China. Triptolide (TP) has been used primarily for the treatment of inflammatory and autoimmune diseases. Astragaloside IV (AS-IV) has been applied with many other drugs, due to its various pharmacological effects. AS-IV and TP can be used together for the treatment of diseases in clinics in China.Objective: This study investigates the effects of astragaloside IV (AS-IV) on the pharmacokinetics of TP in rats and its potential mechanism.Materials and methods: The pharmacokinetics of orally administered triptolide (2 mg/kg) with or without AS-IV pre-treatment (100 mg/kg/day for 7 d) were investigated. Additionally, the effects of AS-IV on the transport of triptolide were investigated using the Caco-2 cell transwell model.Results: The results indicated that when the rats were pre-treated with AS-IV, the Cmax of triptolide decreased from 418.78 ± 29.36 to 351.31 ± 38.88 ng/mL, and the AUC0-t decreased from 358.83 ± 19.56 to 252.23 ± 15.75 µg/h/L. The Caco-2 cell transwell experiments indicated that AS-IV could increase the efflux ratio of TP from 2.37 to 2.91 through inducing the activity of P-gp.Discussion and conclusions: In conclusion, AS-IV could decrease the system exposure of triptolide when they are co-administered, and it might work through decreasing the absorption of triptolide by inducing the activity of P-gp.

Synchronous measuring of triptolide changes in rat brain and blood and its application to a comparative pharmacokinetic study in normal and Alzheimer's disease rats.

Triptolide, a major active ingredient of Tripterygium wilfordii Hook F, provides anti-inflammatory and neuroprotective activities. In this study, a microwave-assisted stable isotope labeling derivatization-magnetic dispersive solid phase extraction (MA-SILD-MDSPE) combined with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method has been developed for the determination of the triptolide in rat microdialysates. A pair of SILD reagents (d0-/d3-3-N-methyl-2'-carboxyl Rhodamine 6G, d0-/d3-MCR6G) were used to label triptolide in real samples and standards under mild conditions. The introduction of SILD reagents enhanced the sensitivity of MS/MS detection and ensured accurate quantification. A novel molecularly imprinted polymer coating with d0-MCR6G labeled triptolide as template was firstly synthesized by precipitation polymerization method, and used to selectively extract the labeled triptolides from complex matrices. The purified d0-/d3-MCR6G-triptolides were determined by UHPLC-MS/MS analysis. Using the proposed method, a good linearity (R2>0.995), low limits of detection (LOD, 0.45-0.50 pg/mL) and quantification (LOQ, 3.0 pg/mL) were achieved. The intra- and inter-day precision and accuracy were within the acceptable ranges. No significant matrix effect was observed. The derivatization efficiency was more than 96 %. The validated method was successfully applied to a comparative pharmacokinetic study of triptolide synchronously in brain and blood of normal and Alzheimer's disease rats by in vivo microdialysis sampling technique.

Dihydromyricetin affect the pharmacokinetics of triptolide in rats.

1. Dihydromyricetin (DMY) has anti-tumor and hepatoprotective activities and inhibits the activity of CYP enzymes and P-gp. In this research, we explored the effect of DMY on the pharmacokinetics of triptolide (TP), an anti-tumor Chinese medicine that is mainly metabolized by CYP enzymes and is the substrate of P-gp.2. Rats were administrated TP (1.2 mg/kg) with and without DMY in different dosage regimens, then a sensitive and reliable LC-MS/MS method was developed and applied to assess the pharmacokinetics of TP. The blood samples for TP were collected from each rat up to 120 min after administration of TP.3. When co-administrated with single dose of DMY (100 mg/kg), the AUC, Cmax and T1/2 of TP were significantly enhanced by 98, 83 and 66%, respectively. The T1/2 of TP was significantly prolonged from 23.6 ± 6.4 to 70.5 ± 12.5 min with 14-doses pretreatment of DMY (500 mg/kg), conversely, the Cmax was decreased by 30% and the AUC was enhanced by 24%.4. These results hinted that administration of DMY with TP did alter the pharmacokinetics of TP, and provided the theoretical pharmacokinetic basis to study on the protective effects of DMY against acute liver injury caused by TP.

Combination of metronomic administration and target delivery strategies to improve the anti-angiogenic and anti-tumor effects of triptolide.

The metronomic administration of a low-dose cytotoxic agent with no prolonged drug-free breaks is an anti-angiogenic cancer treatment method. The use of nano-formulations in this manner enhances anti-tumor efficacy and reduces toxicity by inhibiting angiogenic activity, reduces adverse effects, and changes the biodistribution of TP in the body, steering TP away from potentially endangering healthy tissues. The present study uses liposomes and Asn-Gly-Arg (NGR) peptide conjugated aminopeptidase N(APN)-targeted liposomes for triptolide (TP), as a model for the investigation of targeted metronomic administration and subsequent effects on the toxicity profile and efficacy of the chemotherapeutic agent. Metronomic NGR-PEG-TP-LPs have been found to have enhanced anti-tumor activity, a phenomenon that is attributed to an increase in angiogenic inhibition properties. In vitro experiments demonstrate that the viability, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) are obviously suppressed in comparison with that of other treatment groups. In vivo experiments also demonstrate that the anti-tumor efficacy of targeted metronomic administration is superior to that of liposome-administered treatments given at maximum tolerated dose (MTD) schemes, as is evidenced by markedly decreased tumor volume, vessel density, and the volume of circulating endothelial progenitor cells (CEPCs) in serum. Moreover, we observed that the metronomic administration of NGR-PEG-TP-LPs could elevate thrombospondin-1 (TSP-1) expression in tumors, a finding that is consistent with the promotion of TSP-1 secretion specifically from HUVECs. Additionally, metronomic NGR-PEG-TP-LPs have minimal drug-associated toxicity (weight loss, hepatotoxicity and nephrotoxicity in mice). Our research demonstrates the significance of targeted metronomic administration using liposomes for anti-angiogenic cancer therapy.

[Establishment of skin and joint micro-dialysis sampling method of triptolide in vivo by HPLC-MS/MS].

To detect the concentration of triptolide in skin and joint after percutaneous administration,an HPLC-MS/MS method and skin and joint micro-dialysis( MD) method of triptolide were established in this study. The separation was achieved on triple quadrupole( AB QTRAP4500) and phenomenex-C18( 4. 6 mm×150 mm,5 µm,luna) column with acetonitrile-water with 0. 1% formic acid( 65 ∶35) as the mobile phase at a flow rate of 0. 7 m L·min-1. An electrospray ionization( ESI) source was applied and operated in the positive multiple reaction monitoring( MRM) mode. The fragment ion for triptolide was m/z 361. 1→145. 0. The effects of different perfusion [Ringer's,PBS( p H 7. 4),30% ethanol saline]drug concentrations and flow rates on the recovery rate,as well as the relationship between the recovery rate and the loss rate were determined by incremental( dialysis) and reduction( retrodialysis) methods.The reduction method was applied in the in vivo study to investigate and determine the stability of the probe recovery rate in 10 h. The results of HPLC-MS/MS detection method conformed to the requirements of biological samples. The perfusion fluid was 30% ethanol saline. The recovery rate of skin and joint probes in vitro of triptolide increased within the flow rate of 0. 5-2. 5 µL·min-1. In order to increase the timeliness of data and the accuracy,the flow rate was determined to be 1 µL·min-1,and the sample interval was determined to be 0. 5 h. The recovery rate of triptolide in skin and joint probes in vitro and the loss rate were stable and equal despite of change of triptolide concentration within 10-200 µg·L-1. This indicated that the effect of drug concentration on the MD probe recovery rate was small,and the recovery rate could be replaced by the loss rate. The loss rate in vivo using MD method was measured at 10 h,indicating that the transfer rate of triptolide was stable within 10 h. The established method of triptolide in MD and HPLC-MS/MS can be applied to investigate the kinetic in skin and joint after percutaneous administration of triptolide.

Kidney-targeted triptolide-encapsulated mesoscale nanoparticles for high-efficiency treatment of kidney injury.

Bad water solubility and undesired toxicity of triptolide (TP) still restrict its clinical applications in renal diseases. In this work, well-defined, monodispersed, and uniform-sized TP-encapsulated mesoscale nanoparticles (TP-MNPs) were fabricated through a nanoprecipitation method, which possesses special kidney-targeting capacity, slow-release property, and high-efficiency treatment for renal ischaemia-reperfusion injury (IRI). The TP-MNPs had good cytocompatibility in wide TP concentration (0-500 ng ml-1) and time ranges (6-24 h). Ex vivo organ fluorescence imaging and pharmacokinetic analysis suggested that TP-MNPs possessed excellent kidney-targeting capability with long retention time (7 days). The TP-MNPs with a very low dose of TP (0.01 mg kg-1) could effectively protect the kidney against IRI, while 0.01 mg kg-1 TP was completely ineffective. After treatment with TP-MNPs, the serum creatine, blood urea nitrogen, expression of C3 complement, and phospho-extracellular signal-regulated kinase of renal IRI mice were estimated to be 5.9-, 2.0-, 5.4-, and 2.8-fold lower than those of the mice treated with TP, respectively. Compared with TP, the TP-MNPs exhibited ignorable hepatotoxicity, reproductive toxicity, and immunotoxicity, such as lower alanine aminotransferase (0.5 fold) and aspartate aminotransferase (0.2 fold), and a higher ratio of CD4+/CD8+ (2.2 fold). Thus, the monodispersed and uniform-sized TP-MNPs with special kidney-targeting and slow-release property may pave an avenue for designing a new therapeutic strategy for renal diseases.

Effects of puerarin on the pharmacokinetics of triptolide in rats.

Context: Puerarin and triptolide are sometimes used together for the treatment of disease in Chinese clinics; however, the drug-drug interaction between puerarin and triptolide is still unknown. Objective: This study investigates the effects of puerarin on the pharmacokinetics of triptolide in rats and clarifies its main mechanism. Materials and methods: The pharmacokinetic profiles of oral administration of triptolide (1 mg/kg) in Sprague-Dawley rats with (test group, n = 6) or without pretreatment (control group, n = 6) with puerarin (100 mg/kg/day for seven days) were investigated. The effects of puerarin on the transport and metabolic stability of triptolide were also investigated using Caco-2 cell transwell model and rat liver microsomes. Results: The results showed that puerarin could significantly increase the peak plasma concentration (from 187.25 ± 15.36 to 219.67 ± 21.52 ng/mL), and decrease its oral clearance (from 4.92 ± 0.35 to 62.46 ± 3.75 ± 0.19 L/h/kg). The Caco-2 cell transwell experiments indicated that puerarin could decrease the efflux ratio of triptolide from 2.70 to 1.33, and the intrinsic clearance rate of triptolide was decreased by the pretreatment with puerarin (38.8 ± 4.7 vs. 32.9 ± 6.5 µL/min/mg protein). Discussion and conclusions: Puerarin could significantly change the pharmacokinetic profiles of triptolide in rats, and it might exert these effects through increasing the absorption of triptolide by inhibiting the activity of P-gp, or through inhibiting the metabolism of triptolide in rat liver. The results also showed that the dose of triptolide should be decreased when these drugs were co-administered.

Quantitative in vitro-to-in vivo extrapolation (QIVIVE) of estrogenic and anti-androgenic potencies of BPA and BADGE analogues.

The goal of the present study was to obtain an in vivo relevant prioritization method for the endocrine potencies of different polycarbonate monomers, by combining in vitro bioassay data with physiologically based kinetic (PBK) modelling. PBK models were developed for a selection of monomers, including bisphenol A (BPA), two bisphenol F (BPF) isomers and four different bisphenol A diglycidyl ethers (BADGEs), using in vitro input data. With these models, the plasma concentrations of the compounds were simulated, providing means to estimate the dose levels at which the in vitro endocrine effect concentrations are reached. The results revealed that, whereas the in vitro relative potencies of different BADGEs (predominantly anti-androgenic effects) can be up to fourfold higher than BPA, the estimated in vivo potencies based on the oral equivalent doses are one to two orders of magnitude lower than BPA because of fast detoxification of the BADGEs. In contrast, the relative potencies of 2,2-BPF and 4,4-BPF increase when accounting for the in vivo availability. 4,4-BPF is estimated to be fivefold more potent than BPA in humans in vivo in inducing estrogenic effects and both 2,2-BPF and 4,4-BPF are estimated to be, respectively, 7 and 11-fold more potent in inducing anti-androgenic effects. These relative potencies were considered to be first-tier estimates, particularly given that the potential influence of intestinal metabolism on the in vivo availability was not accounted for. Overall, it can be concluded that both 2,2-BPF and 4,4-BPF are priority compounds.