Quantification of 3-bromopyruvate in rat plasma by HPLC-MS/MS employing precolumn derivatization and the application to a pharmacokinetics study.

A simple high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed for the determination of 3-bromopyruvate (3-BrPA) in rat plasma for the first time. The analytes were separated on a C18 column (100 × 2.1 mm, 1.7 µm) and a triple-quadrupole mass spectrometry equipped with an electrospray ionization source was applied for detection. 3-BrPA was extracted from rat plasma with protein precipitation, and then derivatized with 4-nitro-1,2-phenylenediamine to obtain the mass signal because 3-BrPA could not be detected in mass spectrometry. The method was fully validated according to the US Food and Drug Administration guidance. The method was linear over the concentration range 0.5-1,000.0 ng/ml for 3-BrPA. The precision and accuracy, extraction recovery, and matrix effect were within acceptable limits. The method was then applied to support a pharmacokinetic study after 3-BrPA and 3-BrPA-l-Val-l-Ile (a dipeptide prodrug of 3-BrPA, 3-BrPA-l-Valine-l-isoleucine) had been administered to the Sprague-Dawley rats, respectively.

Exploration of a ternary deep eutectic solvent for the efficient extraction of plantamajoside, acteoside, quercetin and kaempferol from Plantago asiatica L.

INTRODUCTION: In the present study, ternary deep eutectic solvent-based ultrasound-assisted extraction was developed for the efficient extraction of plantamajoside, acteoside, quercetin and kaempferol from Plantago asiatica L. METHODOLOGY: Six kinds of choline chloride-based ternary deep eutectic solvents (TDESs) were prepared as potential extraction solutions. In order to obtain optimal extraction efficiency, a series of extraction conditions were investigated by single-factor test and orthogonal test. RESULTS: The extraction efficiency of choline chloride/lactic acid/ethylene glycol (ChCl-LA-EG) was much higher than that of other TDESs. ChCl-LA-EG-11 synthesised with choline chloride, lactic acid and ethylene glycol (1:4:2) was considered to have a higher extraction efficiency. The optimal ultrasound-assisted extraction conditions were as follows: water content in ChCl-LA-EG-11, 50%; extraction temperature, 70°C; ratio of solid/liquid, 20 mg/mL; ultrasonic power, 60 W; extraction time, 35 min; pH of the solution, 8. Under the optimal extraction conditions, the extraction efficiencies of plantamajoside, acteoside, quercetin and kaempferol were 3.83 ± 0.41, 4.23 ± 0.45, 0.56 ± 0.15 and 0.19 ± 0.08 mg/g, respectively. The extraction efficiency of the total target components was 9.21 ± 0.63 mg/g, which was much higher than that of conventional solvents (water, methanol, ethanol, 50% methanol, 50% ethanol). The target components were isolated efficiently from the TDES solution by an AB-8 macroporous resin column with a recovery rate of 95.6%. CONCLUSION: This study demonstrated that TDESs possessed excellent physical and chemical properties and had enormous potential for active component extraction of traditional Chinese medicinal materials.

Bifunctional and Unusual Amino Acid ß- or γ-Ester Prodrugs of Nucleoside Analogues for Improved Affinity to ATB0,+ and Enhanced Metabolic Stability: An Application to Floxuridine.

Floxuridine (FUdR, 5-fluoro-2-deoxyuridine) was widely used in patients with tumor. But the poor activity and severe side effects have been observed in the clinic, which resulted from increased degradation cleavage of FUdR to 5-FU by thymidine phosphorylase and reduced transporter-mediated entry into cells. In this study, we have synthesized a series of l-aspartic acid ß-esters and l-glutamic acid γ-esters of FUdR to improve the metabolic stability of FUdR and target FUdR to cancer cells via amino acid transporter ATB0,+ which was exclusively up-regulated in some cancerous tissue. The uptake mechanism, stability, in vitro/in vivo antiproliferation action, pharmacokinetics, and tissue distribution were studied. The combined results showed the unusual 5'-ß-l-Asp-FUdR possessed a better tumor inhibition rate and a better metabolic stability than FUdR through a ATB0,+-mediated prodrug approach. The present study provided the first proof-of-concept of exploiting ATB0,+ for tumor-selective delivery of nucleoside analogues in the form of prodrug.

PEPT1-mediated prodrug strategy for oral delivery of peramivir.

Peramivir was a novel and highly potent neuraminidase (NA) inhibitor for the treatment of influenza A and B. However, it exhibited a very low oral bioavailability (only 3%) due to the high polarity (log P of -1.4) and the low membrane permeability across the intestine. To utilize the PEPT1-mediated prodrug strategy to improve the oral absorption and develop the oral alternative, seven amino acid ester prodrugs and seven amino acid amide prodrugs have been synthesized. The permeability of these prodrugs across Caco-2 cells were screened. Peramivr-(CH2)2-l-Val and Peramivir-l-Ile were of the highest permeability in ester prodrugs and amide prodrugs, respectively, and then they were selected for further studies. Glycylsarcosine (gly-sar) uptake by Caco-2 could be inbihited by Peramivir-(CH2)2-l-Val and Peramivir-l-Ile in a concentration-dependent manner, and the IC50 was 1.34 ±â€¯0.31 mM and 1.78 ±â€¯0.48 mM, respectively. The direct uptake of Peramivir-(CH2)2-l-Val and Peramivir-l-Ile in MDCK-PEPT1 cells were significantly higher than in MDCK mock cells, and could be markedly inhibited by gly-sar. The uptake of Peramivir-(CH2)2-l-Val and Peramivir-l-Ile (0.01 to 50 mM) in MDCK-hPEPT1 cells conformed to Michaelis-Menten Equation. The oral bioavailability of peramivir was 65.3% and 37.3% after the oral administration of Peramivir-(CH2)2-l-Val and Peramivir-l-Ile to rats, respectively. The oral absorption and bioactivation of Peramivir-(CH2)2-l-Val was rapid and extensive, and no Peramivir-(CH2)2-l-Val was found in plasma. Because the amide bond was relatively stable, Peramivir-l-Ile could not be totally converted to the parent drug in vivo. Peramivir-(CH2)2-l-Val with good oral profiles and rapid bioactivation might be a promising prodrug for the further clinic development. The present study also corroborated the idea that the PEPT1-mediated prodrug approach has enormous promise for improving the oral absorption of poorly absorbed drug.

[The influence of suoquan capsule on the mRNA expression of CYP11B2 in deficiency of the kidney and diuresis rats].

OBJECTIVE: To explore the mechanism of nourishing kidney and reducing urine effect of suoquan capsule by discussing the adjusting action on ALD synthase. METHODS: Built the model of deficiency of the kidney and diuresis by adenine,inspectd the contents of Cort, ALD in blood and the mRNA expression of CYP11B2 with ELISA and RT-PCR technology of the mice. RESULTS: Compared with model group, Suoquan capsule could remarkedly increase the contents of Cort, ALD in blood and the mRNA expression of CYP1 1 B2 of model rats. CONCLUSIONS: Suoquan capsule can increase the contents of Cort, ALD in blood and the mRNA expression of CYP11B2 in deficiency of the kidney and diuresis rats. Promote the combining of ALD by adjusting the ALD synthase may be the mechanism of nourishing the kidney and reducing urine of Souquan capsule from ALD synthase approach.