Pharmacokinetics of 10‐hydroxycamptothecin–tetrandrine liposome complexes in rat by a simple and sensitive ultra‐high performance liquid chromatography with tandem mass spectrometry

Therapeutic effects of tetrandrine in inflammatory diseases: a comprehensive review

Inflammation can be triggered by any factor. The primary pathological manifestations can be summarized as the deterioration, exudation, and proliferation of local tissues, which can cause systemic damage in severe cases. Inflammatory lesions are primarily localized but may interact with body systems to cause provocative storms, parenchymal organ lesions, vascular and central nervous system necrosis, and other pathologic responses. Tetrandrine (TET) is a bisbenzylquinoline alkaloid extracted from the traditional Chinese herbal medicine Stephania tetrandra, which has been shown to have significant efficacy in inflammatory conditions such as rheumatoid arthritis, hepatitis, nephritis, etc., through NF-κB, MAPK, ERK, and STAT3 signaling pathways. TET can regulate the body's imbalanced metabolic pathways, reverse the inflammatory process, reduce other pathological damage caused by inflammation, and prevent the vicious cycle. More importantly, TET does not disrupt body's normal immune function while clearing the body's inflammatory state. Therefore, it is necessary to pay attention to its dosage and duration during treatment to avoid unexpected side effects caused by a long half-life. In summary, TET has a promising future in treating inflammatory diseases. The author reviews current therapeutic studies of TET in inflammatory conditions to provide some ideas for subsequent anti-inflammatory studies of TET.

A separate assay of released and liposomal encapsulated eribulin in dog plasma by liquid chromatography with tandem mass spectrometry for its application to a pharmacokinetic study

Eribulin has been used as a drug for the treatment of metastatic breast cancer and liposomal formulation of eribulin (E7389-LF) is under development to achieve a wider therapeutic index. It is important to separately determine released and encapsulated drugs in a systemic circulation for liposomal drugs. In this study, a separate assay method was developed for the determination of released and total (encapsulated+released) eribulin concentrations in dog plasma by liquid chromatography with tandem mass spectrometry. The released eribulin in dog plasma was separated by ultrafiltration of plasma samples. Obtained plasma ultrafiltrate and untreated plasma samples recognized as released and total eribulin, respectively, were subjected to protein precipitation for extraction of eribulin. Eribulin was quantifiable from 0.1 ng/mL. Accuracy and precision of eribulin in both matrices were within ±15% and 15%, respectively, indicating a robust assay. Released and total eribulin concentrations in plasma were determined after intravenous administration of E7389-LF to dogs, resulting in minimal released eribulin in plasma. In conclusion, a robust method for released and total eribulin levels in dog plasma was developed and was successfully applied to a pharmacokinetic study in dogs to characterize the pharmacokinetic profiles. This article is protected by copyright. All rights reserved.

A validated HPLC-MS/MS method for determination of simmitecan and its metabolite chimmitecan in human plasma and its application to a pharmacokinetic study in Chinese patients with advanced solid tumor

Simmitecan is a new ester anticancer prodrug which can exert the antiproliferation activity through its active metabolite, chimmitecan. In the current study, a simple and reliable liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of simmitecan and chimmitecan in human plasma. Both irinotecan and 7-ethyl-10-hydroxycamptothecin were used as the internal standards. Plasma samples were protein precipitated by acetonitrile (0.2% formic acid, v/v) and processed samples were chromatographed on a Hypersil GOLD^TM C₁₈ column (100 × 4.6 mm, i.d. 3.0 μm) with acetonitrile and 10 mM ammonium acetate (0.1% formic acid, v/v) as the mobile phase. The calibration curves showed good linearity (R ≥ 0.99) over the concentration range of 1-500 ng/mL and 0.25-125 ng/mL for simmitecan and chimmitecan, respectively. Intra- and inter-run precisions (CV%) were ≤10.2% for simmitecan and ≤12.1% for chimmitecan. The accuracies were 99.4-103.5% for simmitecan and 95.4-103.5% for chimmitecan. This method was further successfully applied to a pharmacokinetic study of simmitecan in Chinese advanced solid cancer patients after administration of simmitecan hydrochloride injection.

Tailored nanodisc immobilization for one-step purification and reconstitution of cytochrome P450: A tool for membrane proteins' hard cases

A novel nanodisc-based immobilization method was developed for high-efficient purification and reconstitution of cytochrome P450 in one step. Using membrane scaffold protein containing a histidine tag, charged-nanodiscs were prepared in the form of self-assembly of lipid-protein nanoparticles. Their properties including the particle diameter and its distribution and Zeta potential were controlled well by adjusting molar ratios of phospholipids to membrane scaffold protein. At an optimum lipid-to-membrane scaffold protein molar ratio of 60:1, uniformly regular-shaped and discoidal nanodiscs with an average particle diameter of 10 nm and Zeta potential of -19 mV were obtained. They can be well fractionated by size exclusion chromatography. Charged-nanodiscs were successfully immobilized onto Ni-chelating microspheres via histidine tags with a density of 6.6 mg membrane scaffold protein/mL gel. After being packed in a column, chromatography studies demonstrated that this nanodisc-immobilized chromatographic medium had a specific binding to cytochrome P450 in rat liver microsome. Nanodiscs containing cytochrome P450 can be furthermore eluted from the column with a diameter of about 87.0 nm and height of about 8.0 nm, respectively. The purity of cytochrome P450 after purification increased 25 folds strikingly. This nanodisc-immobilized chromatography method is promising for the one-step purification and reconstitution of membrane protein.

Combination Nanotherapeutics for Dry Eye Disease Treatment in a Rabbit Model

Purpose

Anti-inflammation is essential for dry eye disease. Traditional anti-inflammation agent corticosteroids applied in dry eye disease (DED) treatment could result in high intraocular pressure, especially in long-term treatment. Thus, we have prepared a liposome loading 1-bromoheptadecafluorooctane and tetrandrine (PFOB@LIP-Tet) to treat DED via anti-inflammation that hardly affects intraocular pressure in this study, which provided another therapy strategy for dry eye disease.

Methods

We firstly detected the physicochemical properties of PFOB@LIP-Tet. Next, we tested the biosafety of synthesized liposomes for corneal epithelium. Then, we explored the accumulations and distribution of PFOB@LIP-Tet both in cellular and animal models. And then, we assessed the therapeutic effects of PFOB@LIP-Tet formulations by laboratory and clinical examinations. Last, we examined the changes in eye pressure before and after treatment.

Results

PFOB@LIP-Tet and Tet showed a characteristic absorption peak at 282 nm while PFOB@LIP did not. Large amounts of PFOB@LIP-Tet remained on the ocular surface and accumulated in the corneal epithelial cells in DED rabbits. Corneal staining scores of DED rabbits respectively treated by ATS, PFOB@LIP-ATS, Tet-ATS and PFOB@LIP-Tet-ATS for seven days were 3.7±0.5, 3.2±0.4, 1.5±0.5 and 0.5±0.5. The expressions of related cytokines were correspondingly downregulated significantly, indicating that the inflammation of DED was successfully suppressed. The intraocular pressure changes of DED rabbits before and after treatment by PFOB@LIP-Tet showed no statistical significance.

Conclusion

We successfully synthesized PFOB@LIP-Tet, and it could effectively treat dry eye disease via anti-inflammation but hardly affected the intraocular pressure.