Ginsenoside Rb2: A review of pharmacokinetics and pharmacological effects.

Ginsenoside Rb2 is an active protopanaxadiol-type saponin, widely existing in the stem and leave of ginseng. Rb2 has recently been the focus of studies for pharmaceutical properties. This paper provides an overview of the preclinical and clinical pharmacokinetics for Rb2, which exhibit poor absorption, rapid tissue distribution and slow excretion through urine.

Screening, simulation, and optimization design of small molecule inhibitors of the SARS-CoV-2 spike glycoprotein.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak is a public health emergency of international concern. The spike glycoprotein (S protein) of SARS-CoV-2 is a key target of antiviral drugs. Focusing on the existing S protein structure, molecular docking was used in this study to calculate the binding energy and interaction sites between 14 antiviral molecules with different structures and the SARS-CoV-2 S protein, and the potential drug candidates targeting the SARS-CoV-2 S protein were analyzed.

Structure-Based Bioisosterism Yields HIV-1 NNRTIs with Improved Drug-Resistance Profiles and Favorable Pharmacokinetic Properties.

The development of efficacious NNRTIs for AIDS therapy commonly encountered the rapid generation of drug-resistant mutations, which becomes a major impediment to effective anti-HIV treatment. Using a structure-based bioisosterism strategy, a series of piperidine-substituted thiophene[2,3-]pyrimidine derivatives were designed and synthesized. Compound yielded the greatest potency, exhibiting significantly better anti-HIV-1 activity than against all of the tested NNRTI-resistant HIV-1 strains.

Discovery and Characterization of Fluorine-Substituted Diarylpyrimidine Derivatives as Novel HIV-1 NNRTIs with Highly Improved Resistance Profiles and Low Activity for the hERG Ion Channel.

Our previous efforts have led to the development of two potent NNRTIs, K-5a2 and 25a, exhibiting effective anti-HIV-1 potency and resistance profiles compared with etravirine. However, both inhibitors suffered from potent hERG inhibition and short half-life. In this article, with K-5a2 and etravirine as leads, series of novel fluorine-substituted diarylpyrimidine derivatives were designed via molecular hybridization and bioisosterism strategies.

Stimuli-responsive charge-reversal nano drug delivery system: The promising targeted carriers for tumor therapy.

The stimuli-responsive charge-reversal nano drug delivery system (CRNDDS) for the treatment of tumors has attracted much attention as an effective drug delivery system. The charge-reversal nanocarriers are either uncharged or negatively charged under normal physiological environment; however, they acquire positive charged in tumor tissue microenvironment. The process of charge reversal from negative-to-positive results in not only quick drug release in acidic environment but also enhance the cellular uptake of drug through electrostatic absorptive endocytosis resulting in improvement of cancer therapeutic outcome.

Smart albumin-loaded Rose Bengal and doxorubicin nanoparticles for breast cancer therapy.

To synthesise HSA-RB-DOX nanoparticles, measure its characteristics and preliminarily evaluate its anti-cancer effects. Doxorubicin (DOX) and Rose Bengal (RB) were co-delivered using albumin as a carrier. HSA-RB-DOX nanoparticles were prepared by RB-induced self-assembly of albumin.

Structure-Based Optimization of N-Substituted Oseltamivir Derivatives as Potent Anti-Influenza A Virus Agents with Significantly Improved Potency against Oseltamivir-Resistant N1-H274Y Variant.

Due to the emergence of highly pathogenic and oseltamivir-resistant influenza viruses, there is an urgent need to develop new anti-influenza agents. Herein, five subseries of oseltamivir derivatives were designed and synthesized to improve their activity toward drug-resistant viral strains by further exploiting the 150-cavity in the neuraminidases (NAs). The bioassay results showed that compound 21h exhibited antiviral activities similar to or better than those of oseltamivir carboxylate (OSC) against H5N1, H5N2, H5N6, and H5N8.

Optimization of N-Substituted Oseltamivir Derivatives as Potent Inhibitors of Group-1 and -2 Influenza A Neuraminidases, Including a Drug-Resistant Variant.

On the basis of our earlier discovery of N1-selective inhibitors, the 150-cavity of influenza virus neuraminidases (NAs) could be further exploited to yield more potent oseltamivir derivatives. Among the synthesized compounds, 15b and 15c were exceptionally active against both group-1 and -2 NAs. Especially for 09N1, N2, N6, and N9 subtypes, they showed 6.

Structure-Based Optimization of Thiophene[3,2-d]pyrimidine Derivatives as Potent HIV-1 Non-nucleoside Reverse Transcriptase Inhibitors with Improved Potency against Resistance-Associated Variants.

This work follows on from our initial discovery of a series of piperidine-substituted thiophene[3,2-d]pyrimidine HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTI) ( J. Med. Chem.

Design, Synthesis, and Evaluation of Thiophene[3,2-d]pyrimidine Derivatives as HIV-1 Non-nucleoside Reverse Transcriptase Inhibitors with Significantly Improved Drug Resistance Profiles.

We designed and synthesized a series of human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitors (NNRTIs) with a piperidine-substituted thiophene[3,2-d]pyrimidine scaffold, employing a strategy of structure-based molecular hybridization and substituent decorating. Most of the synthesized compounds exhibited broad-spectrum activity with low (single-digit) nanomolar EC50 values toward a panel of wild-type (WT), single-mutant, and double-mutant HIV-1 strains. Compound 27 was the most potent; compared with ETV, its antiviral efficacy was 3-fold greater against WT, 5-7-fold greater against Y181C, Y188L, E138K, and F227L+V106A, and nearly equipotent against L100I and K103N, though somewhat weaker against K103N+Y181C.

A sensitive LC-MS/MS method to quantify methylergonovine in human plasma and its application to a pharmacokinetic study.

Methylergonovine (ME) is a semisynthetic ergot alkaloid that is used for the treatment and prophylaxis of postpartum hemorrhage. In recent years, methylergonovine has been effective in the control of refractory headaches and is likely to be employed as chemosensitizers for cancer. However, this alkaloid sometimes causes elevated blood pressure.

Synthesis and Biological Evaluation of a Series of 2-((1-substituted-1H-1,2,3-triazol-4-yl)methylthio)-6-(naphthalen-1-ylmethyl)pyrimidin-4(3H)-one As Potential HIV-1 Inhibitors.

A series of novel S-DABO derivatives with the substituted 1,2,3-triazole moiety on the C-2 side chain were synthesized using the simple and efficient CuAAC reaction, and biologically evaluated as inhibitors of HIV-1. Among them, the most active HIV-1 inhibitor was compound 4-((4-((4-(2,6-dichlorobenzyl)-5-methyl-6-oxo-1,6-dihydropyrimidin-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)benzenesulfonamide (B5b7), which exhibited similar HIV-1 inhibitory potency (EC50  = 3.22 μm) compared with 3TC (EC50  = 2.

Synthesis and Preliminary Antiviral Activities of Piperidine-substituted Purines against HIV and Influenza A/H1N1 Infections.

We have developed a series of N(2) -(1-(substituted-aryl)piperidin-4-yl)-N(6) -mesityl-9H-purine-2,6-diamine derivatives as potent antiviral agents. Preliminary biological evaluation indicated that nearly half of them possessed remarkable HIV inhibitory potencies in cellular assays. In particular, FZJ13 appeared to be the most notable one, which displayed anti-HIV-1 activity compared to 3TC.

A liquid chromatography-tandem mass spectrometric assay for the antihypertensive agent azelnidipine in human plasma with application to clinical pharmacokinetics studies.

A robust and sensitive high-performance liquid chromatographic-tandem mass spectrometric (HPLC-MS/MS) assay for the high-throughput quantification of the antihypertensive drug azelnidipine in human plasma was developed and validated following bioanalytical validation guidelines. Azelnidipine and internal standard (IS), telmisartan, were extracted from human plasma by precipitation protein and separated on a C18 column using acetonitrile-methanol-ammonium formate with 0.1% formic acid as mobile phase.

Enhanced oral absorption and therapeutic effect of acetylpuerarin based on D-α-tocopheryl polyethylene glycol 1000 succinate nanoemulsions.

Background: Acetylpuerarin (AP), because of its lower water solubility, shows poor absorption that hinders its therapeutic application. Thus, the aim of this study was to prepare nanoemulsions for AP, enhance its oral bioavailability, and thus improve the therapeutic effect.

Methods: The nanoemulsions stabilized by D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) were prepared by high-pressure homogenization and characterized in terms of particle size, drug loading, morphology, and in vitro drug release.

Conformational restriction: an effective tactic in 'follow-on'-based drug discovery.

The conformational restriction (rigidification) of a flexible ligand has often been a commonly used strategy in drug design, as it can minimize the entropic loss associated with the ligand adopting a preferred conformation for binding, which leads to enhanced potency for a given physiological target, improved selectivity for isoforms and reduced the possibility of drug metabolism. Therefore, the application of conformational restriction strategy is a core aspect of drug discovery and development that is widely practiced by medicinal chemists either deliberately or subliminally. The present review will highlight current representative examples and a brief overview on the rational design of conformationally restricted agents as well as discuss its advantages over the flexible counterparts.

Recent advances in the discovery and development of novel HIV-1 NNRTI platforms (Part II): 2009-2013 update.

The long-term usage of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) eventually leads to rapid emergence of drug-resistant viruses and severe side effect. Therefore, it is imperative to seek the additional NNRTIs with potent and broad spectrum anti-mutant activities, and excellent pharmacokinetic profiles. The discovery of etravirine, rilpivirine and other successful examples has influenced the NNRTIs design strategy profoundly.

HIV-1 NNRTIs: structural diversity, pharmacophore similarity, and implications for drug design.

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) nowadays represent very potent and most promising anti-AIDS agents that specifically target the HIV-1 reverse transcriptase (RT). However, the effectiveness of NNRTI drugs can be hampered by rapid emergence of drug-resistant viruses and severe side effects upon long-term use. Therefore, there is an urgent need to develop novel, highly potent NNRTIs with broad spectrum antiviral activity and improved pharmacokinetic properties, and more efficient strategies that facilitate and shorten the drug discovery process would be extremely beneficial.

1,2,3-thiadiazole thioacetanilides. Part 2: Synthesis and biological evaluation of a new series of 2-{[4-(3,4-dichlorophenyl)-1,2,3-thiadiazol-5-yl]sulfanyl}acetanilides as HIV-1 inhibitors.

As part of our studies to discover new HIV-1 reverse transcriptase inhibitors, a series of 3,4-dichlorophenyl substituted 1,2,3-thiadiazole thioacetanilide (TTA=[(1,2,3-thiadiazole-5-yl)sulfanyl]acetanilide) derivatives were synthesized, and in vitro anti-HIV activity was evaluated. The results revealed that nearly half of the compounds show moderate-to-good inhibitory potency against HIV-1. In particular, compound 7f is highly potent, with an EC(50) value of 0.

1,2,3-Selenadiazole thioacetanilides: synthesis and anti-HIV activity evaluation.

The development of new HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) offers the possibility of generating novel structures of increased potency. Based on the bioisosteric principle, novel series of 1,2,3-selenadiazole thioacetanilide derivatives were designed, and synthesized using an original synthetic route, structurally confirmed by spectral analysis, and evaluated for their anti-HIV activity in MT-4 cells. The results showed that only compound 7f possessed potent activity against HIV-1 replication (EC(50)=2.

Synthesis and biological evaluation of imidazole thioacetanilides as novel non-nucleoside HIV-1 reverse transcriptase inhibitors.

A series of 2-(1-aryl-1H-imidazol-2-ylthio)acetamide [imidazole thioacetanilide (ITA)] derivatives were synthesized and evaluated as potent inhibitors of human immunodeficiency virus type-1 (HIV-1). Among them, the most potent HIV-1 inhibitors were 4a5 (EC(50)=0.18microM), and 4a2 (EC(50)=0.

Synthesis and anti-HIV activity evaluation of 2-(4-(naphthalen-2-yl)-1,2,3-thiadiazol-5-ylthio)-N-acetamides as novel non-nucleoside HIV-1 reverse transcriptase inhibitors.

A series of 2-(4-(naphthalen-2-yl)-1,2,3-thiadiazol-5-ylthio)acetamide (TTA) derivatives were synthesized and evaluated as potent inhibitors of HIV-1. Among the newly disclosed TTAs, compounds 7f, 7 g and 7c were the most potent inhibitors of HIV-1 replication of the series (EC(50)=0.17+/-0.

Novel 1,2,3-thiadiazole derivatives as HIV-1 NNRTIs with improved potency: Synthesis and preliminary SAR studies.

A novel synthetic route and anti-HIV activity evaluation of a new series of 2-(4-(2,4-dibromophenyl)-1,2,3-thiadiazol-5-ylthio)acetamide (TTA) derivatives are described. Bioactivity assay indicated that most of the title compounds showed good activities against HIV-1. In particular, compound 7c displayed the most potent anti-HIV-1 activity (EC(50)=36.