Glucocorticoids-based prodrug design:Current strategies and research progress

Attributing to their broad pharmacological effects encompassing anti-inflammation,antitoxin,and immunosuppression,glucocorticoids(GCs)are extensively utilized in the clinic for the treatment of diverse diseases such as lupus erythematosus,nephritis,arthritis,ulcerative colitis,asthma,keratitis,macular edema,and leukemia.However,longterm use often causes undesirable side effects,including metabolic disorders-induced Cushing's syndrome(buffalo back,full moon face,hyperglycemia,etc.),osteoporosis,aggravated infection,psychosis,glaucoma,and cataract.These notorious side effects seriously compromise patients'quality of life,especially in patients with chronic diseases.Therefore,glucocorticoid-based advanced drug delivery systems for reducing adverse effects have received extensive attention.Among them,prodrugs have the advantages of low investment,low risk,and high success rate,making them a promising strategy.In this review,we propose the strategies for the design and summarize current research progress of glucocorticoid-based prodrugs in recent decades,including polymer-based prodrugs,dendrimer-based prodrugs,antibody-drug conjugates,peptide-drug conjugates,carbohydrate-based prodrugs,aliphatic acid-based prodrugs and so on.Besides,we also raise issues that need to be focused on during the development of glucocorticoid-based prodrugs.This review is expected to be helpful for the research and development of novel GCs and prodrugs.

Computer-assisted anti-AIDS drug development: cyclophilin B against the HIV-1 subtype A V3 loop

Aim: The objects of this study originated from the experimental observations, whereby the HIV -1 gp120 V3 loop is a high-affinity ligand for immunophilins, and consisted in generating the structural complex of cyclophilin (Cyc) B belonging to immunophilins family with the virus subtype A V3 loop (SA-V3 loop) as well as in specifying the Cyc B segment forming the binding site for V3 synthetic copy of which, on the assumption of keeping the 3D peptide structure in the free state, may present a forwardlooking basic structure for anti-AIDS drug development. Methods: To reach the objects of view, molecular docking of the HIV-1 SA-V3 loop structure determined previously with the X-ray conformation of Cyc B was put into practice by Hex 4.5 program (http://www.loria.fr/~ritchied/ hex/) and the immunophilin stretch responsible for binding to V3 (Cyc B peptide) was identified followed by examination of its 3D structure and dynamic behavior in the unbound status. To design the Cyc B peptide, the X-ray conformation for the identical site of the native protein was involved in the calculations as a starting model to find its best energy structural variant. The search for this most preferable structure was carried out by consecutive use of the molecular mechanics and simulated annealing methods. The molecular dynamics computations were implemented for the Cyc B peptide by the GROMACS computer package (http:// www.gromacs.org/). Results: The overmolecular structure of Cyc B with V3 was built by computer modeling tools and the immunophilinderived peptide able to mask effectively the structurally invariant V3 segments embracing the functionally crucial amino acids of the HIV-1 gp120 envelope protein was constructed and analyzed. Conclusions: Starting from the joint analysis of the results derived with those of the literature, the generated peptide was suggested to offer a promising basic structure for making a reality of the protein engineering projects aimed at developing the anti-AIDS drugs able to stop the HIV’s spread.

Application of Computer-Aided Drug Design to Traditional Chinese Medicine

Computer-aided drug design (CADD) is an interdisciplinary subject, playing a pivotal role during new drug research and development, especially the discovery and optimization of lead compounds. Traditional Chinese Medicine (TCM) modernization is the only way of TCM development and also an effective approach to the development of new drugs and the discovery of potential drug targets (PDTs). Discovery and validation of PTDs has become the “bottle-neck” restricted new drug research and development and is urgently solved. Innovative drug research is of great significance and bright prospects. This paper mainly discusses the “druggability” and specificity of PTDs, the “druglikeness” of drug candidates, the methods and technologies of the discovery and validation of PTDs and their application. It is very important to achieve the invention and innovation strategy “from gene to drug”. In virtue of modern high-new technology, especially CADD, combined with TCM theory, research and develop TCM and initiate an innovating way fitting our country progress. This paper mainly discusses CADD and their application to drug research, especially TCM modernization.

Formulation of self-nanoemulsifying drug delivery systems containing monoacyl phosphatidylcholine and Kolliphor^(■) RH40 using experimental design

The development of self-nanoemulsifying drug delivery systems(SNEDDS) to enhance the oral bioavailability of lipophilic drugs is usually based on traditional one-factor-at-a-time approaches. These approaches may be inadequate to analyse the effect of each excipient and their potential interactions on the emulsion droplet size formed when dispersing the SNEDDS in an aqueous environment. The current study investigates the emulsion droplet sizes formed from SNEDDS containing different levels of the natural surfactant monoacyl phosphatidylcholine to reduce the concentration of the synthetic surfactant polyoxyl 40 hydrogenated castor oil(Kolliphor ~? RH40). Monoacyl phosphatidylcholine was used in the form of Lipoid S LPC 80(LPC, containing approximately 80% monoacyl phosphatidylcholine, 13% phosphatidylcholine and 4% concomitant components). The investigated SNEDDS comprised of long-chain or medium-chain glycerides(40% to 75%), Kolliphor ~? RH40(5% to 55%), LPC(0 to 40%) and ethanol(0 to 10%). D-optimal design, multiple linear regression, and partial least square regression were used to screen different SNEDDS within the investigated excipient ranges and to analyse the effect of each excipient on the resulting droplet size of the dispersed SNEDDS measured by dynamic light scattering. All investigated formulations formed nano-emulsions with droplet sizes from about 20 to 200 nm. The use of mediumchain glycerides was more likely to result in smaller and more monodisperse droplet sizes compared to the use of long-chain glycerides. Kolliphor~? RH40 exhibited the most significant effect on reducing the emulsion droplet sizes. Increasing LPC concentration increased the emulsion droplet sizes, possibly because of the reduction of Kolliphor~? RH40 concentration. A higher concentration of ethanol resulted in an insignificant reduction of the emulsion droplet size. The study provides different ternary diagrams of SNEDDS containing LPC and Kolliphor ~? RH40 as a reference for formulation developers.

Organs-on-a-Chip: A Future of Rational Drug-Design

Many recent advances in biomedical research are related to the combination of biology and microengineering. Microfluidic devices, such as organ-on-a-chip systems, integrate with living cells to allow for the detailed in vitro study of human physiology and pathophysiology. With the poor translation from animal models to human models, the organ-on-a-chip technology has become a promising substitute for animal testing, and their small scale enables precise control of culture conditions and high-throughput experiments, which would not be an economically sound model on a macroscopic level. These devices are becoming more and more common in research centers, clinics, and hospitals, and are contributing to more accurate studies and therapies, making them a staple technology for future drug design.

Insights into the structural biology of G-protein coupled receptors impacts drug design for central nervous system neurodegenerative processes

In the last few years, there have been important new insights into the structural biology of G-protein coupled receptors. It is now known that allosteric binding sites are involved in the affinity and selec- tivity of ligands for G-protein coupled receptors, and that signaling by these receptors involves both G-protein dependent and independent pathways. The present review outlines the physiological and pharmacological implications of this perspective for the design of new drugs to treat disorders of the central nervous system. Specifically, new possibilities are explored in relation to allosteric and or- thosteric binding sites on dopamine receptors for the treatment of Parkinson＇s disease, and on muscarinic receptors for Alzheimer＇s disease. Future research can seek to identify ligands that can bind to more than one site on the same receptor, or simultaneously bind to two receptors and form a dimer. For example, the design of bivalent drugs that can reach homo/hetero-dimers of D2 dopa- mine receptor holds promise as a relevant therapeutic strategy for Parkinson＇s disease. Regarding the treatment of Alzheimer＇s disease, the design of dualsteric ligands for mono-oligomeric mus- carinic receptors could increase therapeutic effectiveness by generating potent compounds that could activate more than one signaling pathway.

Deep Learning in Medical Imaging and Drug Design

Over the last decade,deep learning(DL)methods have been extremely successful and widely used in almost every domain.Researchers are now focusing on the convergence of medical imaging and drug design using deep learning to revolutionize medical diagnostic and improvement in the monitoring from response to therapy.DL a new machine learning paradigm that focuses on learning with deep hierarchical models of data.Medical imaging has transformed healthcare science,it was thought of as a diagnostic tool for disease,but now it is also used in drug design.Advances in medical imaging technology have enabled scientists to detect events at the cellular level.The role of medical imaging in drug design includes identification of likely responders,detection,diagnosis,evaluation,therapy monitoring,and follow-up.A qualitative medical image is transformed into a quantitative biomarker or surrogate endpoint useful in drug design decision-making.For this,a parameter needs to be identified that characterizes the disease baseline and its subsequent response to treatment.The result is a quantifiable improvement in healthcare quality in most therapeutic areas,resulting in improvements in quality and life duration.This paper provides an overview of recent studies on applying the deep learning method in medical imaging and drug design.We briefly discuss the fields related to the history of deep learning,medical imaging,and drug design.

Comparative and Computer Assisted Drug Designing of Fatty Acids Isolated from Flowers, Leaves, Stem Bark, Root Bark and Nuts of Semecarpus anacardium L. f. （Anacardiaceae）

Objectives： Computational study will help us in reducing the experimental work. The process of drug discovery involves the designing of molecules with appropriate pharmacophores with the help of various soft wares. The purpose of this paper is to study the probable binding modes of fatty acids on fatty acids after enzymatic hydrolysis of the FAAH （fatty acid amide hydrolase） in different extracts of flowers, leaves, stem bark, root bark and nuts of Semecarpus anacardiurn L. f. by using molecular modeling study and computer assisted drug designing. Nuts yielded 20 fatty acids including saturated, ω-3 unsaturated, ω-6 unsaturated, ω-7 unsaturated and ω-9 unsaturated fatty acids. Based on IR, IH NMR, 13C NMR, MS （mass） spectrometry, GC analysis, the structural elucidation of these isolated fatty acids was established. Methods： A dataset comprising of 20 fatty acids were drawn in ChemDraw and converted into 3D-molecules with all possible tautomers and chiral centers. The minimization of molecules was carried out using PRCG （Polak-Ribiere Conjugate Gradient） method with maximum of 5000 iterations. The minimized compounds were used for protein preparation. The crystal structure of human FAAH （PDB ID： 3K84） is prepared and selected for the docking studies of 20 fatty acids using Schr6dinger docking program module.. Conclusions： In this study, we carried out the molecular docking studies in order to understand the probable binding mode of 20 fatty acids in FAAH from which we identified key active site residues for FAAH, thereby it can be used to design the novel compounds for FAAH targets.

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.

In vitro and in vivo evaluation of gastroretentive floating drug delivery system of ofloxacin

This study aimed to develop hydrophilicmatrix based controlled release gastroretentive drug delivery system of ofloxacin and conducting its in vitro and in vivo evaluations.Effervescent floating gastroretentive drug delivery system of ofloxacin was prepared utilizing Boxe Behnken statistical design with 3 factors,3 levels and 15 experimental trials.Formulation optimization was done by setting targets on selected responses.In vivo studies were carried out for the optimized formulation with 12 healthy human volunteers and obtained pharmacokinetic parameters were compared with themarketed once daily formulation,“Zanocin OD”.Optimized formulation showed satisfactory controlled in vitro drug release for more than 12 h with excellent buoyancy properties(floating lag time<1 min,floating duration>16 h).Optimized and marketed formulations were found to have similar in vitro release profile(f2¼79.22)and also were found to be bioequivalent.Serum ofloxacin concentration was well maintained above its reported minimum inhibitory concentrations for most of the pathogens for sufficiently longer duration.Cmax and AUC values of optimized formulation were found to be significantly higher than of marketed product despite their bioequivalence.Bettertherapeutic effect can be expected since ofloxacin exhibits concentration dependent killing.Hence,gastroretention can be a promising approach to enhance bioavailability of ofloxacin with narrow absorption window in upper GIT.

Modern drug discovery for inflammatory bowel disease: The role of computational methods

Inflammatory bowel diseases(IBDs)comprising ulcerative colitis,Crohn’s disease and microscopic colitis are characterized by chronic inflammation of the gastrointestinal tract.IBD has spread around the world and is becoming more prevalent at an alarming rate in developing countries whose societies have become more westernized.Cell therapy,intestinal microecology,apheresis therapy,exosome therapy and small molecules are emerging therapeutic options for IBD.Currently,it is thought that low-molecular-mass substances with good oral bio-availability and the ability to permeate the cell membrane to regulate the action of elements of the inflammatory signaling pathway are effective therapeutic options for the treatment of IBD.Several small molecule inhibitors are being developed as a promising alternative for IBD therapy.The use of highly efficient and time-saving techniques,such as computational methods,is still a viable option for the development of these small molecule drugs.The computeraided(in silico)discovery approach is one drug development technique that has mostly proven efficacy.Computational approaches when combined with traditional drug development methodology dramatically boost the likelihood of drug discovery in a sustainable and cost-effective manner.This review focuses on the modern drug discovery approaches for the design of novel IBD drugs with an emphasis on the role of computational methods.Some computational approaches to IBD genomic studies,target identification,and virtual screening for the discovery of new drugs and in the repurposing of existing drugs are discussed.

Power Analysis and Sample Size Determination for Crossover Trials with Application to Bioequivalence Assessment of Topical Ophthalmic Drugs Using Serial Sampling Pharmacokinetic Data

Objective To develop methods for determining a suitable sample size for bioequivalence assessment of generic topical ophthalmic drugs using crossover design with serial sampling schemes.Methods The power functions of the Fieller-type confidence interval and the asymptotic confidence interval in crossover designs with serial-sampling data are here derived.Simulation studies were conducted to evaluate the derived power functions.Results Simulation studies show that two power functions can provide precise power estimates when normality assumptions are satisfied and yield conservative estimates of power in cases when data are log-normally distributed.The intra-correlation showed a positive correlation with the power of the bioequivalence test.When the expected ratio of the AUCs was less than or equal to 1, the power of the Fieller-type confidence interval was larger than the asymptotic confidence interval.If the expected ratio of the AUCs was larger than 1, the asymptotic confidence interval had greater power.Sample size can be calculated through numerical iteration with the derived power functions.Conclusion The Fieller-type power function and the asymptotic power function can be used to determine sample sizes of crossover trials for bioequivalence assessment of topical ophthalmic drugs.

One and the same androgen for all?towards designer androgens

The introduction of designer oestrogens as a treatment modality in hormone replacement in women has invited toconsider the concept of compounds with selective androgenic effects for male hormone replacement therapy. The fullspectrum of the actions of testosterone may not be necessary of even undesired for certain indications for testosteronetreatment. To define for what indications certain androgenic properties are desired and undesired more insight in basicandrogen (patho)physiology is required. There is convincing evidence that aromatization of androgenic compounds tooestrogens might be an advantage for maintenance of bone mass and it might also mitigate negative effects of androgenson biochemical parameters of cardiovascular risks; the potentially negative effects of oestrogens on prostate pathology inageing men needs further elucidation. While the role of dihydro-testosterone (DHT) for the male sexual differentiationand for pubertal sexual maturation is evident, its role in mature and ageing males seems less significant or may even beharmful. It is, however, of note that a negative effect of DHT on prostate pathophysiology is certainly not proven.For male contraception a progestational agent with strong androgenic properties might be an asset. For most of theandrogenic actions the critical levels of androgens are not well established. The latter is relevant since the large amountof androgen molecules required for its biological actions (as compared to oestrogens)is an impediment in androgenreplacement modalities. There may be room for more biopotent androgens since delivery of large amounts of androgenmolecules to the circulation poses problems for treatment modalities.

Biodegradable polymer stents vs second generation drug eluting stents:A meta-analysis and systematic review of randomized controlled trials

AIM: To evaluate the premise, that biodegradable polymer drug eluting stents(BD-DES) could improve clinical outcomes compared to second generation permanent polymer drug eluting stents(PP-DES), we pooled the data from all the available randomized control trials(RCT) comparing the clinical performance of both these stents.METHODS: A systematic literature search of Pub Med, Cochrane, Google scholar databases, EMBASE, MEDLINE and SCOPUS was performed during time period of January 2001 to April 2015 for RCT and comparing safety and efficacy of BD-DES vs second generation PP-DES. The primary outcomes of interest were definite stent thrombosis, target lesion revascularization, myocardial infarction, cardiac deaths and total deaths during the study period. RESULTS: A total of 11 RCT's with a total of 12644 patients were included in the meta-analysis, with 6598 patients in BD-DES vs 6046 patients in second generation PP-DES. The mean follow up period was 16 mo. Pooled analysis showed non-inferiority of BD-DES, comparing events of stent thrombosis(OR = 1.42, 95%CI: 0.79-2.52, P = 0.24), target lesion revascularization(OR = 0.99, 95%CI: 0.84-1.17, P = 0.92), myocardial infarction(OR = 1.06, 95%CI: 0.86-1.29, P = 0.92), cardiac deaths(OR = 1.07, 95%CI 0.82-1.41, P = 0.94) and total deaths(OR = 0.96, 95%CI: 0.80-1.17, P = 0.71).CONCLUSION: BD-DES, when compared to second generation PP-DES, showed no significant advantage and the outcomes were comparable between both the groups.

Applications and prospects of cryo-EM in drug discovery

Drug discovery is a crucial part of human healthcare and has dramatically benefited human lifespan and life quality in recent centuries, however, it is usually time-and effort-consuming. Structural biology has been demonstrated as a powerful tool to accelerate drug development. Among different techniques, cryo-electron microscopy(cryo-EM) is emerging as the mainstream of structure determination of biomacromolecules in the past decade and has received increasing attention from the pharmaceutical industry. Although cryo-EM still has limitations in resolution, speed and throughput, a growing number of innovative drugs are being developed with the help of cryo-EM. Here, we aim to provide an overview of how cryo-EM techniques are applied to facilitate drug discovery. The development and typical workflow of cryo-EM technique will be briefly introduced, followed by its specific applications in structure-based drug design, fragment-based drug discovery, proteolysis targeting chimeras, antibody drug development and drug repurposing. Besides cryo-EM, drug discovery innovation usually involves other state-of-the-art techniques such as artificial intelligence(AI), which is increasingly active in diverse areas. The combination of cryo-EM and AI provides an opportunity to minimize limitations of cryo-EM such as automation, throughput and interpretation of mediumresolution maps, and tends to be the new direction of future development of cryo-EM. The rapid development of cryo-EM will make it as an indispensable part of modern drug discovery.

Utilization of kinase inhibitors as novel therapeutic drug targets:A review

Kinase inhibitors are a significant and continuously developing division of target therapeutics.The drug discovery and improvement efforts have examined numerous attempts to target the signaling pathway of kinases.The Kinase inhibitors have been heralded as a game-changer in cancer treatment.For developing kinase inhibitors as a treatment for various non-malignant disorders like auto-immune diseases,is currently undergoing extensive research.It may be beneficial to investigate whether cell-specific kinase inhibitor administration enhances therapeutic efficacy and decreases adverse effects.The goal of the current review is to gain insight into the role of kinase inhibitors in facilitating effective target drug delivery for the treatment of various anti-inflammatory,auto-immune,and anticancer disorders.The aim of this review is also to shed light on drug discovery approaches for kinase inhibitors,their mode of action,and delivery approaches.The variation in the binding of kinases bestows different target approaches in drug design,which can be employed for designing the targeted molecules.Several target sites have been studied,exceeding the design of drugs for various diseases like cancer,Alzheimer’s,rheumatoid arthritis,etc.Diverse delivery approaches have also been studied for the targeted application of kinase inhibitors.

Design,synthesis,and evaluation of fluoroquinolone derivatives as microRNA-21 small-molecule inhibitors

MicroRNA-21(miRNA-21)is highly expressed in various tumors.Small-molecule inhibition of miRNA-21 is considered to be an attractive novel cancer therapeutic strategy.In this study,fluoroquinolone derivatives A1eA43 were synthesized and used as miRNA-21 inhibitors.Compound A36 showed the most potent inhibitory activity and specificity for miRNA-21 in a dual-luciferase reporter assay in HeLa cells.Compound A36 significantly reduced the expression of mature miRNA-21 and increased the protein expression of miRNA-21 target genes,including programmed cell death protein 4(PDCD4)and phosphatase and tensin homology deleted on chromosome ten(PTEN),at 10 μM in HeLa cells.The Cell Counting Kit-8 assay(CCK-8)was used to evaluate the antiproliferative activity of A36;the results showed that the IC_(50) value range of A36 against six tumor cell lines was between 1.76 and 13.0 μM.Meanwhile,A36 did not display cytotoxicity in BEAS-2B cells(lung epithelial cells from a healthy human donor).Furthermore,A36 significantly induced apoptosis,arrested cells at the G_(0)/G_(1) phase,and inhibited cell-colony formation in HeLa cells.In addition,mRNA deep sequencing showed that treatment with A36 could generate 171 dysregulated mRNAs in HeLa cells,while the expression of miRNA-21 target gene dual-specificity phosphatase 5(DUSP5)was significantly upregulated at both the mRNA and protein levels.Collectively,these findings demonstrated that A36 is a novel miRNA-21 inhibitor.

Intelligent Drug Delivery System Using UML Diagrams Analysis

A novel intelligent drug delivery system potential for the more effective therapy of the diabetics was proposed, and the composition of system was analyzed. Based on the design of micro-electro-mechanical systems (MEMS), an iterative modeling process was introduced. Unified modeling language (UML) was em-ployed to describe the function requirement, and different diagrams were built up to explore the static model, the dynamic model and the employment model. The mapping analysis of different diagrams can simply verify the consistency and completeness of the system model.

Drug-DNA Interaction: A Theoretical Study of the Stability of CP-DNA Binding with Thionine

The recent study on binding of small molecules to double stranded DNA suggested that the intercalation of a tricyclic heteroaromatic molecule, thionine, with natural DNA provided thermal stabilization to the complex. In the present study, we reported theoretical analysis of thionine binding with Clostridium perfringenes DNA duplex (CP-DNA) by using an amended Zimm and Bragg theory, to explain the melting behaviour and heat capacity of CP-DNA with and without thionine binding. The experimental models of Paul et al. (2010) have been used for the study. The sharpness of transition has been examined in terms of half width and sensitivity parameter (?H/σ). The results of theoretical approach suggested that the various parameters such as transition profile, sharpness of the transition, heat capacity curve and half widths are in good agreement with the experimental measurements for binding of thionine. Therefore, the proposed theoretical analysis may be useful in order to understand interaction of small molecules to DNA that may be applied in the process of drug development and for designing more potential DNA binding therapeutic molecules.