Dissolution enhancement of Gefitinib by solid dispersion and complexation with β-cyclodextrins: In vitro testing, cytotoxic activity, and tablet formulation

Cancer is the leading cause of mortality worldwide. In patients with metastatic non-small cell lung cancer, epidermal growth factor receptor (EGFR) is often overexpressed. Gefitinib (GEF), an inhibitor of EGFR, is approved for the treatment of patients with metastatic non-small cell lung cancer (NSCLC). However, the low solubility and dissolution of GEF limits its bioavailability. Numerous methods, including solid dispersion (SD) and complexation, have been reported to enhance the dissolution of poorly soluble drugs. In this study, GEF complexes were prepared using methyl-β-cyclodextrin (MβCD) and hydroxypropyl-β-cyclodextrin (HPβCD) in two molar ratios (1:1 and 1:2), furthermore, GEF SDs were prepared using polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and poloxamer-188(PXM) in three different ratios (1:2, 1:4 and 1:6 w/w). Dissolution studies were conducted on the prepared formulations. Dissolution results showed a 1.22-2.17-fold enhancement in drug dissolution after one hour compared to untreated GEF. Two formulations that showed higher dissolution enhancement were subsequently evaluated for in-vitro cytotoxicity and were formulated into tablets. The selected PVP-GEF (1:4 w/w) and MβCD-GEF (1:1M) formulas displayed improved cytotoxicity compared to untreated GEF. The IC50 values of the PVP-GEF and MβCD-GEF were 4.33 ± 0.66 and 4.84 ± 0.38 µM, respectively which are significantly lower (p < 0.05) than free GEF. In addition, the formulated tablets exhibited enhanced dissolution compared to pure GEF tablets. PVP-GEF SD tablets released (35.1 %±0.4) of GEF after one hour, while GEF-MβCD tablets released (42.2 % ± 0.7) after one hour. In the meantime, tablets containing pure GEF showed only 15 % ± 0.5 release at the same time. The findings of this study offer valuable insights for optimizing the dissolution and hence therapeutic capabilities of GEF while mitigating its limitations.

Bioinformatics-driven discovery of novel EGFR kinase inhibitors as anti-cancer therapeutics: In silico screening and in vitro evaluation

Epidermal growth factor receptor EGFR inhibitors are widely used as first line therapy for the treatment of non-small-cell lung cancer (NSCLC) in patients harboring EGFR mutation. However, the acquisition of a second-site mutation (T790 M) limited the efficacy and developed resistance. Therefore, discovery and development of specific drug target for this mutation is of urgent needs. In our study we used the ChemDiv diversity database for receptor-based virtual screening to secure EGFR-TK inhibitors chemotherapeutics. We identified four compounds that bind to the ATP-binding region of the EGFR-TK using AutoDock 4.0 and AutoDock Vina1.1.2 and post-docking investigations. The ligand showed hydrophobic interactions to the hydrophobic region of the binding site and engaged in hydrogen bonding with Met793. The ligands also explored π-cation interactions between the π-system of the ligand-phenyl ring and the positive amino group of Lys745. Molecular mechanics Poisson-Boltzmann surface area MM/PBSA per-residue energy decomposition analyses revealed that Val726, Leu792, Met793, Gly796, Cys797, Leu798, and Thr844 contributed the most to the binding energy. Biological evaluation of the retrieved hit compounds showed suppressing activity against EGFR auto phosphorylation and selective apoptosis-induced effects toward lung cancer cells harboring the EGFR L858R/T790M double mutation. Our work anticipated into novel and specific EGFR-TKIs and identified new compounds with therapeutic potential against lung cancer.

Design, synthesis and molecular modeling of isatin-aminobenzoic acid hybrids as antibacterial and antibiofilm agents

Number of factors, including newly emerging infectious diseases and an increase in multi-drug resistant microbial pathogens with particular relevance for Gram-positive bacteria, make the treatment of infectious diseases in hospital-based healthcare a major challenge in the medical community. 4-Aminobenzoic acid (PABA), has demonstrated a variety of biological actions particularly, antimicrobial activity. In our study we coupled this vitamin-like molecule with different isatin derivatives. We investigated the antibacterial activity of the synthesized Schiff's bases. The compounds showed high selective activity against Gram-positive bacteria and showed weak or no activity against both Gram-negative bacteria and fungi. Compound 2a showed highest activity against S. aureus and B. subtilis (MIC 0.09 mmol/L). Additionally, these substances exhibit strong anti-B. Subtilis biofilm formation. We were able to shed insight on the binding mode of these new inhibitors using in silico docking of the compounds in the binding sites of a 3D structure of B. subtilis histidine kinase/Walk. The binding free energy of the compound 2a to the catalytic domain walk, of histidine kinase enzyme of B. subtilis bacteria, was calculated using molecular mechanics/generalized born surface area scoring. The key residues for macromolecule-ligand binding were postulated. The optimized 3D protein-ligand binding modes shed light on the B. subtilis HK/Walk-ligand interactions that afford a means to assess binding affinity to design new HK/Walk inhibitor as antibacterial agents.

Design and synthesis of multi-functional small-molecule based inhibitors of amyloid-β aggregation: Molecular modeling and in vitro evaluation

Amyloid-β1-42 (Aβ42) peptide aggregate formation in the brain plays a crucial role in the onset and progression of Alzheimer's disease. According to published research, the Aβ monomer's amino acid residues KLVFF (16-20) self-associate to create antiparallel β-sheet fibrils. Small compounds can prevent self-assembly and destroy Aβ fibrils by attaching to the Aβ16-20 regions of Aβ42. To enhance biological characteristics and binding affinity to the amyloid beta peptide, β-sheet breaker small molecules can be developed and modified with various scaffolds. In the current study, a novel series of 2,3-disubstitutedbenzofuran derivatives was designed and created by fusing the benzofuran core of a known iron chelator, neuroprotective, and neurorestorative agent, like VK-28, with a motif found in the structure of a known muscarinic inhibitor and amyloid binding agent, like SKF-64346. Measurements of the binding affinity and in vitro aggregation inhibition of the Aβ42 peptide were made using the thioflavin T (ThT) test. Using AutoDock 4.2 software, molecular docking studies of the synthesized compounds were performed on the monomer and fibril structures of amyloid beta peptide. The compounds 8a-8g exhibited strong binding energy and affinity to Aβ fibrils as well as a 50%-67% reduction of the growth of Aβ aggregation. Finally, the positive traits of our recently synthesized compounds make them excellent candidates for additional in vivo testing as a "β-sheet breaking agent."

Molecular scaffold and biological activities of anti- Alzheimer agents

Alzheimer’s disease (AD) is an age-associated and neurodegenerative illness which results in progressive dementia and severe cognitive malfunctions. The pathogenesis of AD is affected by some factors such as accumulation of β-amyloid, aggregation of tau protein, cholinergic insufficiency, neuroinflammation, oxidative stress and apoptosis. Factors such as gene mutation, as well as environmental, psychical and other co-existing diseases influence the pathogenesis of AD to varying extents. While there are no available drugs for arresting AD-associated neurodegeneration, the characteristics that result from AD treatment are considered as indexes of symptomatic cure. Several medications with varied scaffolds have been used for the treatment of many cognitive syndromes, including AD. These medications act as anti-inflammatory and antioxidant agents, and as inhibitors of cholinesterase and β-secretase. Moreover, these drugs suppress the accumulation of β-amyloid and its fibril. This review is an update and compilation of various scaffolds of anti-AD medications used to ameliorate the deleterious effects of the disease, based on their pharmacologic characteristics.

Enhancement of the dissolution and in-vitro activity of a new antineoplastic agent

The cell-surface molecule CD44 plays a major role in the regulation of cancer stem cells. The CD44 inhibitor compound N'-(1-dimethylaminomethyl-2-oxoindolin-3-ylidene)-2-(benzyloxy)benzohydrazide (OYB), anticancer agent is practically insoluble in water. Hence, the solid dispersion (SD) technique was used for enhancing the dissolution of OYB. The SD of OYB was achieved using OYB:poloxamer 188 (1:7) via the fusion method. The anticancer activities of the free-OYB solution and the SD formulation (OYB-SD) were investigated in-vitro. The dissolution rate of OYB-SD (1:7) increased by two-fold compared with the untreated drug (51.52% to 100% at pH 1.2 and 8.25% to 19.15% at pH 7 buffer). In addition, OYB-SD afforded 3 folds cytotoxic effect, against LoVo cells, compared to the untreated compound (IC50 4.72 ± 0.57 µg/ml and 13.97 ± 0.90 µg/ml respectively) and against HepG2 (∼3-fold) (4.98 ± 0.368 µg/ml and 13.85 ± 1.82 µg/ml respectively) and MCF-7 (1.4-fold) cells (15.20 ± 0.20 µg/ml and 21.12 ± 0.51 µg/ml respectively), and enhanced the apoptotic potential in LoVo cells compared with free-OYB. The improved cytotoxic activity of the drug might be attributable to the enhanced dissolution of OYB.

Preparation, characterization, dissolution, and permeation of flibanserin - 2-HP-β-cyclodextrin inclusion complexes

Flibanserin (FLB), an antiserotonin drug, is used to treat women with hypoactive sexual appetite disorder. FLB shows low bioavailability (~33%) probably due to its low water solubility. The current study investigated the impact of hydroxypropyl-β-cyclodextrin (HP-β-CD) and sodium lauryl sulfate (SLS) on the dissolution and permeation of FLB. HP-β-CD-FLB inclusion complexes were prepared using physical mixing and kneading at 1:1 and 1:2 M ratios and characterized using differential scanning calorimetry, Fourier transform infrared spectroscopy, and powder X-ray diffractometry. The dissolution and permeation of the complexes through a cellophane membrane were performed in, 0.1, 0.3 and 0.5% SLS in phosphate buffer (pH 6.8). Derived from the slope of the linear phase solubility diagram, the apparent stability constant (K 1:1) was 372.54 M-1. Kneading changed the crystalline form of FLB to an amorphous appearance characterized by minimal crystalline peaks, indicating successful inclusion complex formation. In addition, the HP-β-CD-FLB inclusion complexes showed twofold increased dissolution efficiency at 6 h. The cumulative FLB amount permeated at 6 h increased from 14.1% to 21.88% and 34.56% in the presence of 0.1% and 0.3% of SLS, respectively. However, increasing SLS to 0.5% did not show an increase in FLB permeation. Therefore, the HP-β-CD-FLB inclusion complex has an improved dissolution rate compared to FLB alone. The presence of SLS in the dissolution medium increases the dissolution rate of pure FLB and its complex with HP-β-CD. kneaded 1:1 complex was formulated bioadhesive buccal tablets and showed enhanced drug release.

The capability of coenzyme Q10 to enhance heat tolerance in male rabbits: evidence from improved semen quality factor (SQF), testicular oxidative defense, and expression of testicular melatonin receptor MT1

Heat stress (HS) has a great influence on the etiology of male infertility. Coenzyme Q10 (CoQ10), known to have powerful antioxidant effects, has been reported to have such actions that are effective to treat infertility caused by HS. The aim of the present study was to investigate the antioxidative effect of CoQ10 on sperm quality, testicular antioxidant activities, and male fertility under HS. For this purpose, 18 mature male rabbits (aged 22 wk) of the Sinai Gabali breed were equally divided into 3 groups and placed at temperature-humidity index of 29 for 8 wk at a farm. The supplementation of CoQ10 at 0, 10, and 20 mg/kg of body weight was done in the first, second, and third groups, respectively. The results showed that the supplementation of CoQ10 had significant (P < 0.05) effect on semen quality factor (SQF) and testicular antioxidant activities by the supplementation of CoQ10. Moreover, a significant improvement in the concentration of testosterone, integrity of testicular DNA, and the expression of melatonin receptors was also observed, which were consistent with a significant improvement in buck fertility. The prolificacy was significantly increased (P < 0.05) in females when inseminated from bucks that were treated with CoQ10. Our results suggest that CoQ10 tends to decrease oxidative stress by enhancing testicular antioxidant activities, which are considered the most important factors for a buck's fertility. Hence, CoQ10 could be a suitable feed supplement to increase fertility, through enhancing the semen quality, in male rabbits and reducing the harmful effects of HS.

Target β-catenin/CD44/Nanog axis in colon cancer cells by certain N'-(2-oxoindolin-3-ylidene)-2-(benzyloxy)benzohydrazides

Cell surface molecule CD44 plays a major role in regulation of cancer stem cells CSCs on both phenotypic and functional level, however chemical inhibition approach of CD44 to targets CSCs is poorly studied. Herein, we report the discovery of certain N'-(2-oxoindolin-3-ylidene)-2-(benzyloxy)benzohydrazides as a novel inhibitor of CD44. Molecular docking study showed interference of the scaffold of these compounds with β-catenin/TCF-4 complex, building a direct relationship between CD44 inhibition and observed well-fitted binding domain. Compound 11a, most potent member elicits inhibition effect on TCF/LEF reporter activity conformed the involvement of Wnt pathway inhibition as a mechanism of action. Furthermore, the treatment by the mentioned compound leads to inhibition of embryonic transcriptional factor Nanog but not Sox2 or Oct-4 suggested specific targeted effect. Moreover, the cytotoxicity and cell cycle effect of this series seems to be dependent on CD44 expression.

Targeting cancer using cholesterol conjugates

Conjugation of cholesterol moiety to active compounds for either cancer treatment or diagnosis is an attractive approach. Cholesterol derivatives are widely studied as cancer diagnostic agents and as anticancer derivatives either in vitro or in vivo using animal models. In largely growing studies, anticancer agents have been chemically conjugated to cholesterol molecules, to enhance their pharmacokinetic behavior, cellular uptake, target specificity, and safety. To efficiently deliver anticancer agents to the target cells and tissues, many different cholesterol-anticancer conjugates were synthesized and characterized, and their anticancer efficiencies were tested in vitro and in vivo.

1-Aryl-3-(1H-imidazol-1-yl)propan-1-ol esters: synthesis, anti-Candida potential and molecular modeling studies

BACKGROUND

An increased incidence of fungal infections, both invasive and superficial, has been witnessed over the last two decades. Candida species seem to be the main etiology of nosocomial fungal infections worldwide with Candida albicans, which is commensal in healthy individuals, accounting for the majority of invasive Candida infections with about 30-40% of mortality.

RESULTS

New aromatic and heterocyclic esters 5a-k of 1-aryl-3-(1H-imidazol-1-yl)propan-1-ols 4a-d were successfully synthesized and evaluated for their anti-Candida potential. Compound 5a emerged as the most active congener among the newly synthesized compounds 5a-k with MIC value of 0.0833 μmol/mL as compared with fluconazole (MIC value >1.6325 μmol/mL). Additionally, molecular modeling studies were conducted on a set of anti-Candida albicans compounds.

CONCLUSION

The newly synthesized esters 5a-k showed more potent anti-Candida activities than fluconazole. Compounds 7 and 8 revealed significant anti-Candida albicans activity and were able to effectively satisfy the proposed pharmacophore geometry, using the energy accessible conformers (Econf < 20 kcal/mol).

Synthesis, and docking studies of some fused-quinazolines and quinazolines carrying biological active isatin moiety as cell-cycle inhibitors of breast cancer cell lines

3 series of novel fused heterocyclic systems, viz. triazolo[4,3-a]quinazolin-7-ones (3), 1 2 4 5-tetrazino[4,3-a]-quinazolin-8-ones (5) and Schiff's bases of isatin derivatives with 2-hydrazinoquinazolin-4-ones (7) have been synthesized. Several of them showed variable and promising in vitro antiproliferative activity against the MCF-7 cells. Compounds 3a-3c, 6, 7a-7 f showed promising activity (IC50=12.45-15.79 μM). Compound 7 f possessed notable cell cycle disrupting and apoptotic activities with enhanced selectivity against cancer cells, suggesting the potential for the development of new selective cell cycle inhibitors. In silico docking study of the compound 7 f with EGFR enzyme postulated that the designed compound might act on the same enzyme target where DJK_3021_A x-ray structure acted.

Microwave irradiation-assisted synthesis of a novel crown ether crosslinked chitosan as a chelating agent for heavy metal ions (M(+n))

Microwave irradiation was used to obtain a di-Schiff base type crosslinked chitosan dibenzocrown ether (CCdBE) via the reaction between the -NH(2) and -CHO groups in chitosan and 4,4'-diformyldibenzo-18-c-6, respectively. The structure of the synthesized compound was characterized by elemental analysis, solid state 13C-NMR and FT-IR spectra analysis. The results showed that the mass fraction of nitrogen in the CCdBE derivative was much lower than those of chitosan. The FT-IR spectra of CCdBE revealed the expected chitosan-crown ether structure, as evidenced by the presence of the characteristic C=N and Ar peaks. The adsorption properties of CCdBE for Pd2+ and Hg2+ were investigated and the results demonstrated that the adsorbent has both desirable adsorption properties with a high particular adsorption selectivity for Hg2+ when in the presence of Pb2+ as well as selectivity coefficients for metal ions of K(Hg(2+)/Pb(2+)) = 8.00 and K(Hg(2+)/Pb(2+)) = 10.62 at pH values of 4 and 6, respectively. The reusability tests for CCdBE for Pb2+ adsorption showed that complete recovery of the ion was possible with CCdBE after 10-multiple reuses while CTS had no reusability at acidic solution because of its higher dissolution. The studied features of CCdBE suggested that the material could be considered as a new adsorbent. It is envisaged that the crosslinking of CTS into CCdBE would enhance practicality and effectiveness of adsorption in ion separation and removal procedures.

Biopharmaceutical applications of nanogold

The application of nanogold in biopharmaceutical field is reviewed in this work. The properties of nanogold including nanogold surface Plasmon absorption and nanogold surface Plasmon light scattering are illustrated. The physical, chemical, biosynthesis methods of nanogold preparation are presented. Catalytic properties as well as biomedical applications are highlighted as one of the most important applications of nanogold. Biosensing, and diagnostic and therapeutic applications of gold nanoparticles are evaluated. Moreover, gold nanoparticles in drugs, biomolecules and proteins' delivery are analyzed. Gold nanoparticles for the site-directed photothermal applications are reviewed as the most fruitful research area in the future.

Pharmacophore elucidation and molecular docking studies on 5-phenyl-1-(3-pyridyl)-1h-1,2,4-triazole-3-carboxylic acid derivatives as COX-2 inhibitors

A set of 5-phenyl-1-(3-pyridyl)-1H-1,2,4-triazole-3-carboxylic acid derivatives (16–32) showing anti-inflammatory activity was analyzed using a three-dimensional qualitative structure-selectivity relationship (3D QSSR) method. The CatalystHipHop approach was used to generate a pharmacophore model for cyclooxygenase-2 (COX-2) inhibitors based on a training set of 15 active inhibitors (1–15). The degree of fitting of the test set compounds (16–32) to the generated hypothetical model revealed a qualitative measure of the more or less selective COX-2 inhibition of these compounds. The results indicate that most derivatives (16, 18, 20–25, and 30–32) are able to effectively satisfy the proposed pharmacophore geometry using energy accessible conformers (E_conf < 20 kcal/mol). In addition, the triazole derivatives (16–32) were docked into COX-1 and COX-2 X-ray structures, using the program GOLD. Based on the docking results it is suggested that several of these novel triazole derivatives are active COX inhibitors with a significant preference for COX-2. In principle, this work presents an interesting, comprehensive approach to theoretically predict the mode of action of compounds that showed anti-inflammatory activity in an in vivo model.

Rational procedure for 3D-QSAR analysis using TRNOE experiments and computational methods: application to thermolysin inhibitors

The success or failure of 3D QSAR, particularly CoMFA, is most strongly dependent, especially for flexible compounds, on the conformation of the molecule used in the analysis, and on the orientation of the molecule relative to the other molecules in 3D space (i.e., alignment). The present study suggests a rational procedure for the estimation of binding conformation that uses the transferred nuclear Overhauser effect (TRNOE) experiment in combination with conformational analysis using CAMDAS (Conformational Analyzer with Molecular Dynamics And Sampling) program that is developed in our laboratory. In the next step the TRNOE-obtained conformation can be used as a reference template in order to obtain alignment of other ligands, that have a common binding site. In this step we used the SUPERPOSE program created in our laboratory, in order to estimate the binding conformation of other compounds, and to simultaneously obtain the alignment of compounds for CoMFA. The resulting CoMFA models could be expected to closely reproduce the interaction mode with protein represented by the reported X-ray results. In order to confirm the validity of our procedure described above, we show its application in obtaining CoMFA models of thermolysin inhibitors. We obtained twenty CoMFA models, and that with the highest q2 value (q2 = 0.701) was found to provide an interaction mode very similar to that represented by the X-ray results.

Influence of micronutrients on citric acid production by Candida lipolytica (Y 1095)

FeSO4 . 7 H2O, PbSO4, CuSO4 . 5 H2O, MnSO4 . 4 H2O, ZnSO4 . 7 H2O, CoCl2 . 6 H2O, and (NH4)6Mo7O24 . 4 H2O were added to the fermentation medium to investigate their potentialities on citric acid production by Candida lipolytica (Y 1095). FeSO4 . 7 H2O and MnSO4 . 4 H2O were more suitable than the other micronutrients for citric acid production. Addition of certain amino acids to the fermentation medium completely inhibited biosynthesis of citric acid by Candida lipolytica (Y 1095). When the fermentation medium was supplied with certain vitamins, yield of citric acid was increased in the presence of thiamine, nicotinic acid, and nicotinamide. The optimum concentration of thiamine which favoured yield of citric acid was 6 mg/l.