A method of ultra flow liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was developed to elucidate the impurity of linezolid tablets. Linezolid was subjected to forced degradation under hydrolytic (acid, base and neutral), oxidative, photolytic and thermal. The structure identification of the degradation products and the fragmentation patterns for the related impurities were analyzed. A total of four degradation impurities were characterized, impurity 1 is (S)-1-amino-3-((3-fluoro-4-morpholinophenyl)amino)propan-2-ol, impurity 2 is (S)-4-(4-(5-(acetamidomethyl)-2-oxo-oxazolidin-3-yl)-2-fluorophenyl)morpholine 4-oxide, impurity 3 is (S)-5-(aminomethyl)-3-(3-fluoro-4-morpholinophenyl)oxazolidin-2-one, impurity 4 is (R)-N-(3-((3-fluoro-4-morpholinophenyl)amino)-2-hydroxypropyl)acetamide. Acid degradation induced impurity 3 and impurity 4, base degradation induced impurity 1 and impurity 4, oxidation degradation induced impurity 2, hydrolysis degradation induced impurity 4. The study also determined calibration factor using impurity references, and the calibration factors were found to be 1.3, 1.4, 0.9 and 1.1, respectively. The toxicity of the degradation impurities was predicted by web-based prediction system. The results from this study provide an important reference in quality control and evaluation of linezolid.

Over the past four decades, monoclonal antibodies (MAbs) have evolved from bioscience research tools to powerful biopharmaceutical MAbs products for multiple diseases treatment. More than 50 therapeutic MAbs have been approved by FDA, widely used in cancer, autoimmune diseases and other diseases in current market. This article reviews the current progress of MAbs development technology, key molecules for cancer-targeted therapy and immunotherapy, and emphasizes the importance of MAbs for disease diagnosis and treatment.

Drug transporters play vital roles in absorption, distribution and excretion of drugs. Understanding the transport activity can improve the effectiveness and safety of drugs and guide clinical rational use of drugs. Metformin is a first-line drug in the treatment of type 2 diabetes mellitus, of which the pharmacokinetics involves several transporters. The changes in expression and function of these transporters affect directly the pharmacokinetics/pharmacodynamics of metformin. This paper reviews the research progress of pharmacokinetics of metformin based on transporters, and these transporters are organic cation transporters (OCTs), multidrug and toxin extrusion proteins (MATE), plasma membrane monoamine transporter protein (PMAT), serotonin reuptake transporter (SERT), thiamine transporter 2 (THTR-2), and carnitine/organic cation 1 (OCTN1).

IG-105, N-(2, 6-dimethoxypyridine-3-yl)-9-methylcarbazole-3-sulfonamide, a novel antimicrotubule agent, showed potent anticancer activity in a variety of human tumor cells in vitro and in vivo. In order to characterize the metabolism and the possible drug-drug interaction of IG-105, we carried out a series of experiments. Drug metabolizing enzymes involved in IG-105 metabolism were investigated by using pooled human liver microsomes (HLMs) and recombinant cytochrome P450 isoforms (rP450s) respectively. The possible metabolites were analyzed by liquid chromatography-orbitrap-mass spectrometry (LC-Orbitrap-MS). The inhibitory effect of IG-105 on main P450 enzymes was also evaluated. The results showed that IG-105 can be metabolized by a series of rP450s, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP3A5, with the major contribution enzymes being CYP1A2, CYP2B6, CYP2C19, and CYP3A. Three metabolites (M1-M3) were identified and demethylation was the major phase I metabolic reaction for IG-105. IG-105 moderately inhibited CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A enzyme activities with IC₅₀ values of 6.42, 23.64, 0.39, 1.4, and 3.14 μmol·L^-1, respectively. Since the biotransformation of IG-105 involves multiple enzymatic pathways, the compound is less likely to be a victim of a concomitantly used medicine which inhibits activity of one of the CYPs. However, as IG-105 showed medium to strong inhibition on CYP1A2, CYP2D6, CYP3A, and CYP2C19, caution is particularly needed when IG-105 is co-administrated with other anticancer drugs which are mainly metabolized by the above enzymes.

The Hedgehog signaling pathway plays a key role in mammalian embryogenesis, while it is quiescent in adult tissues. The aberrant activation of Hedgehog signaling pathway has been linked to multiple types of malignant tumors, which makes it an attractive target for cancer therapy in recent years. Up to now, two Hedgehog inhibitors (vismodegib and sonidegib) have been proved by FDA for the treatment of tumors. However, drug resistance and severe adverse reactions represent the problems in their clinical application. Novel inhibitors targeting Smo, such as taladegib, NVP-LEQ506, MRT-92, and downstream or upstream of Smo receptor such as Shh ligand and Gli have been developed to overcome the drug resistance and adverse reactions. The current Hedgehog inhibitors are used for treatment of basal cell carcinoma only, while many ongoing clinical trials are conducted to investigate the antitumor effect of Hedgehog inhibitors in other malignancies. Here we reviewed the research progress of the new anticancer drugs targeting the Hedgehog signaling pathway and their prospect in variety of cancers therapy.

This study aims to prepare lipid bilayer-coated calcium phosphate core-shell nanoparticles (LCAPNs), which can dissolve in an acidic environment to improve the tumor cell toxicity of antitumor drug. Paclitaxel (PTX) loaded lipid coated calcium phosphate nanoparticles (PTX-LCAPNs) were prepared by thin-film dispersion method. The morphology, particle size and in vitro release behavior were characterized. Meanwhile, the intracellular uptake, intracellular dissolution, cell toxicity of PTX-LCAPNs and intracellular accumulation of PTX were evaluated in human HCC cell line (Huh-7). The results suggested that the mean diameter of the spherical LCAPNs was 124.73±6.41 nm. The PTX-LCAPNs demonstrated little drug leakage in simulated normal physiological conditions, while a rapid release was observed in simulated intracellular condition in vitro. Moreover, the PTX-LCAPNs achieved 1.7 fold improvement in the intracellular PTX concentration leading to 5-fold reduction in half maximal inhibitory concentration (IC₅₀) values of PTX compared with calcium phosphate nanoparticles loaded with PTX (PTX-CAPNs), demonstrating a stronger cancer cell lethality.

Cathepsin K (CTSK) is considered a critical pharmaceutical target in the treatment of osteoporosis. CTSK exerts proteolytic activities against regulatory proteins besides its collagenase function, which may account for some of the adverse reactions when blocked by active site-directed inhibitors. Exosite inhibitors that can discriminate between the therapeutic collagenase and other biological activities of CTSK specifically inhibit the collagenase activity of CTSK without interfering with the other proteolytic activities of the protease. Active recombinant CTSK was expressed in Pichia pastoris, and purified by n-butyl sepharose and SP sepharose column chromatography. Herba Ecliptae is a common traditional Chinese medicine in the treatment of bone diseases. Collagenase assay and benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin (Z-FR-MCA) substrate assay based on CTSK are applied to verify the exosite inhibitors. n-Butanol extract of Herba Ecliptae are the most active fraction and eclalbasaponin Ⅸ isolated from n-butanol fraction is the potential exosite inhibitor of CTSK.

Annexin is a protein of evolutionarily conserved polygene family that binds to cell membrane phosphatidylserine (PS). PS is closely related to many diseases with a potential as a new drug target. Annexin has a good value in drug discovery and new drug development. Annexin A4 is a member of the annexins family. Annexin A4 involves in a number of cellular functions, such as exocytosis and coagulation. These functions are related to binding of annexin to acidic phospholipids. However, the detail function(s) of annexin A4 has not been fully uncovered. Production of annexin A4 in large quantity is prerequisite for indepth investigation of the structure-function relationship of annexin A4. Human annexin A4 was originally purified from the natural resource at a low yield due to the complex procedure. In the present study, annexin A4 was expressed in a prokaryotic system with a high yield of soluble protein. The plasmid pET28a-annexin A4-EGFP was constructed for the expression. Recombinant annexin A4-EGFP was purified using two methods. Affinity chromatography approach gave a protein yield at purity of 80%. While, the membrane absorption method produced the protein with the purity over 90%. Flow cytometric analysis showed that the annexin A4-EGFP fusion protein could recognize and bind to the apoptotic cells with an affinity PS at 79.58±11.68 nmol·L^-1, which is at the same order of magnitude as A5-EGFP. We successfully achieved the efficient expression of annexin A4-EGFP in prokaryotic system, and provided an easy and convenient method for purifying a large amount of annexin A4-EGFP with a high purity. This study has laid a solid foundation for our study of the function of annexin A4 in the future.

Studies have shown that acetylcholinesterase inhibitors donepezil and galantamine have effects of reducing neuronal damage caused by glucose deprivation and reducing the cerebral infarction volume of cerebral ischemic animals, but their effects may not be entirely dependent on its inhibition of cholinesterase activity. In order to study the effects of donepezil and galantamine on neuronal injury of cerebral ischemia, the rat neuron-astrocyte co-culture model was successfully established in this study. In this model, we studied the effects of donepezil and galantamine on neuron apoptosis induced by oxygen-glucose deprivation/reoxygenation (OGD/R) and investigated the mechanism. The results showed that donepezil and galantamine significantly reduced the neuron apoptosis, and promoted the synthesis and secretion of BDNF and NGF in astrocytes in the co-culture system. Donepezil and galantamine activated the PI3K/Akt pathway and ERK pathway, and promoted the phosphorylation of the nuclear transcription factor CREB. These results suggest that donepezil and galantamine exhibit protective effects on neuronal damage induced by OGD/R. The mechanism may be related to activation of PI3K/Akt pathway and ERK pathway in astrocytes and promote phosphorylation of CREB, which lead to the synthesis and secretion of BDNF and NGF from astrocytes.

Mitochondrion is an important organelle in cells and plays a crucial role in tumor development. Therefore, improvement of the targeting ability of anticancer drugs to mitochondria will increase the treatment efficacy for tumor and reduce the side effect on normal tissues. Here, research progresses in mitochondrial targeting have been reviewed in three aspects for tumors treatment: the potential, permeability and translocase of mitochondrial membrane. The review provides a reference for the development of mitochondria targeted therapeutic systems.