Synthesis, molecular modeling simulations and anticancer activity of some new Imidazo[2,1-b]thiazole analogues as EGFR/HER2 and DHFR inhibitors.

New imidazo[2,1-b]thiazole analogs were designed, synthesized, and biologically evaluated as anticancer agents. In vitro biological evaluation of the anticancer properties of the compounds was performed against different cancer cell lines. Compounds 23 and 39 showed remarkable broad -spectrum cytotoxic potency on most of the tested cell lines. Compounds 23 and 39 exhibited potent activity against the MCF-7 breast cancer cell line, with IC50 values of 1.81 and 4.95 µM, respectively, compared to DOX and SOR (IC50 values of 4.17 and 7.26 µM, respectively). An enzyme inhibition assay was carried out to clarify the possible mode of action of the tested compounds. Compounds 23 and 39 were identified as possible EGFR, HER-2, and DHFR inhibitors. Cell cycle arrest results indicated that compound 23 caused cell cycle arrest at the G0/G1 phase in the MCF-7 cells and at the G2/M phase in the Hep G2 cells. Compound 39 induced cell cycle arrest at the G2/M phase in Hela cells. In vivo testing of the anticancer activity of the two most promising molecules in this study was conducted, and the results indicated that they possess considerable in vivo anticancer activity in mice. Data obtained from the molecular modeling simulation study were consistent with the biological evaluation results.

Multi-targeted anti-Alzheimer's agents: Synthesis, biological evaluation, and molecular modeling study of some pyrazolopyridine hybrids.

A new series of compounds bearing a pyrazolopyridine scaffold was synthesized as integrated anti-Alzheimer's disease (AD) multi-targeted ligands. Compounds 49 and 51 showed remarkable activity as hAChE inhibitors with IC50 values of 0.17 and 0.16 µM, respectively; and proved to be active hBuChE inhibitors with IC50 values 0.17 and 0.69 µM, eight and two-fold more active than the reference compound rivastigmine, respectively. Compounds 49 and 51 showed potent GSK3ß inhibition with IC50 values of 0.21 and 0.26 µM, respectively compared to L807mts. Also, 49 and 51 showed 66.0 and 60.0% as tau protein aggregation inhibitors; and Aß1-42 self-aggregation inhibitors with 79.0 and 75.0% respectively. Furthermore, 49 and 51 could bind virtually with the PAS affecting Aß aggregation, thus preventing Aß-dependent neurotoxicity. They proved to have the ability to chelate bio-metals such as Fe2+, Cu2+, and Zn2+ preventing their oxidative damage in the brain of AD patients, in addition to their safety upon WI-38 cell line. Both compounds could virtually penetrate BBB and obeyed Lipinski's rule of five. Compounds 49 and 51 could be considered as MTDLs for AD patients and the obtained model and pattern of substitution could be used for further development of new multi-targeted anti-Alzheimer's agents.

Discovery of new pyridine heterocyclic hybrids; design, synthesis, dynamic simulations, and in vitro and in vivo breast cancer biological assays.

Pyridine is a nitrogen bearing heterocyclic scaffold that shows a wide range of biological activities. The pyridine nucleus has become an interesting target for medicinal chemistry researchers worldwide. Several pyridine derivatives exhibited good anticancer effects against diverse cell lines. Therefore, to explore new anticancer pyridine entities, novel pyridine derivatives were designed and synthesized and evaluated for their anticancer abilities in vitro and in vivo. All of the target compounds were evaluated against three different human cancer cell lines (Huh-7, A549 and MCF-7) via MTT assay. Most of the compounds exhibited significant cytotoxic activities. Compounds 3a, 3b, 5a and 5b showed superior antiproliferative activities to Taxol. Where, compound 3b showed IC50 values of 6.54, 15.54 and 6.13 µM compared to Taxol (6.68, 38.05, 12.32 µM) against Huh-7, A549 and MCF-7, respectively. Also, tubulin polymerization assay was carried out. The most potent compounds 3a, 3b, 5a and 5b could significantly inhibit tubulin polymerization with IC50 values of 15.6, 4.03, 6.06 and 12.61 µM, respectively. Compound 3b exhibited the highest tubulin polymerization inhibitory effect with an IC50 value of 4.03 µM compared to combretastatin (A-4) (1.64 µM). Molecular modeling studies of the designed compounds confirmed that most of the compounds made the essential binding interactions compared to the reference compound which assisted in the prediction of the structure requirements for the detected anticancer activity. Finally, in vivo studies showed that compound 3b could significantly inhibit breast cancer.

Hydrazinecarbonyl-thiazol-2-acetamides with pronounced apoptotic behavior: synthesis, in vitro/in vivo anti-proliferative activity and molecular modeling simulations.

A new series of N-[4-(2-substituted hydrazine-1-carbonyl)thiazole-2-yl]acetamides was synthesized and evaluated in vitro against six human cell lines as antitumor agents. Compounds 20, 21 and 22 showed remarkable inhibition to HeLa (IC50 values of 1.67, 3.81, 7.92 µM) and MCF-7 (IC50 values of 4.87, 5.81, 8.36 µM, respectively) cell growth with high selectivity indices and safety profiles. Compound 20 showed significant decreases in both tumor volume and body weight gain compared to vehicle control, in the solid tumor animal model of Ehrlich ascites carcinoma (EAC) with recovered caspase-3 immuno-expression. Flow cytometry cell analysis showed that 20 exerts anti-proliferative activity in mutant Hela and MCF-7 cell lines through arresting the cell growth at the G1/S phase producing cell death via apoptosis rather than necrosis. To explain the antitumor mode of action of the most active compounds, EGFR-TK and DHFR inhibition assays were carried out. Compound 21 conveyed dual EGFR/DHFR inhibition with IC50 0.143 (EGFR) and 0.159 (DHFR) µM. Compound 20 showed DHFR inhibition with IC50 0.262 µM. Compound 22 exhibited the best EGFR inhibitory efficacy with IC50 0.131 µM. Molecular modelling study revealed that 21 and 22 have binding interactions with EGFR amino acid residues Lys745 and Asp855. Compounds 20 and 21 showed affinity toward DHFR amino acid residues Asn64, Ser59 and Phe31. The ADMET profile and Lipinski's rule of five calculated for these compounds were acceptable. Compounds 20, 21 and 22 could be regarded as promising prototype antitumor agents for further optimization.

New quinazolinone-based derivatives as DHFR/EGFR-TK inhibitors: Synthesis, molecular modeling simulations, and anticancer activity.

New 2-mercapto-quinazolin-4-one analogs were synthesized and tested for their in vitro anticancer activity, dihydrofolate reductase (DHFR) inhibition, and epidermal growth factor tyrosine kinase (EGFR-TK) inhibition activities. Compound 24, which is characterized by a 2-benzyl-thio function, showed broad-spectrum anticancer activity with high safety profile and selectivity index. The concentrations of 24 causing 50% growth inhibition (GI50 ) and total cell growth inhibition (TGI) and its lethal concentration 50 (LC50 ) were 15.1, 52.5, and 91.2 µM, respectively, using 5-fluorouracil as a positive control. Also, it showed EGFR-TK inhibitory activity with IC50 = 13.40 nM compared to gefitinib (IC50 = 18.14 nM) and DHFR inhibitory potency with 0.30 µM compared to methotrexate (MTX; IC50 = 0.08 µM). In addition, compound 24 caused cell cycle arrest and apoptosis on COLO-205 colon cancer cells. Compounds 37, 21, and 54 showed remarkable DHFR inhibitory activity with IC50 values of 0.03, 0.08, and 0.08 µM, respectively. The inhibitory properties of these compounds are due to an electron-withdrawing group on the quinazolinone ring, except for compound 54. In a molecular modeling study, compound 24 showed the same binding mode as gefitinib as it interacted with the amino acid Lys745 via π-π interaction. Compound 37 showed a similar binding mode as MTX through the binding interaction with Lys68, Asn64 via hydrogen bond acceptor, and Phe31 via arene-arene interaction. The obtained model and substitution pattern could be used for further development.

New thiazole-based derivatives as EGFR/HER2 and DHFR inhibitors: Synthesis, molecular modeling simulations and anticancer activity.

New series of thiazole and imidazo[2,1-b]thiazole derivatives were synthesized and tested for their in vitro anticancer activity. Compounds 27, 34, 39 and 42-44 showed the best anticancer activity against the tested cancer cell lines with high safety profile and selectivity indices, especially MCF-7 breast cancer, compared to sorafenib. As an attempt to reveal their mode of cytotoxicity, EGFR, HER2 kinase and DHFR inhibition assays were performed. Compounds 39 and 43 were the most potent dual EGFR/HER2 kinase inhibitors, with IC50 values of 0.153 (EGFR), 0.108 (HER2) and 0.122 (EGFR), 0.078 (HER2) µM, respectively. 39 and 42 were the best DHFR inhibitors showing IC50 0.291 and 0.123 µM, respectively. 39 and 43 induced their cytotoxicity via cell cycle arrest at G1/S and G1 phases, respectively, and apoptosis rather than necrosis in the MCF-7 breast cancer cell line. In vivo anti-breast cancer assay of 39 and 43 showed significant tumor volume reduction with recovered caspase-3 immunoexpression. Modeling study results proved the importance of the 5-(4-substituted phenyl)-imidazo[2,1-b]thiazole moiety and the hydrazide side chain for the anticancer activity. The most potent compounds showed good drug-likeness features and could be used as prototypes for further optimization. 39 could be an example of a multi-targeting anticancer agent that acts by inhibiting EGFR/HER2 kinase, DHFR enzymes and cellular apoptosis.

Taguchi Approach for Optimization of a Green Quantitative 1H-NMR Practice for Characterization of Levetiracetam and Brivaracetam in Pharmaceuticals.

BACKGROUND: Recently, quantitative nuclear magnetic resonance (qNMR) competes with separation techniques such as high performance liquid chromatography (HPLC) and capillary electrophoresis for quantification purposes when dealing with molecules that lack a chromophore. OBJECTIVE: The advantages of the proton nuclear magnetic resonance spectroscopy as a revolutionary quantitative analysis method were exploited aimed at simple and green assessment of two racetams, namely levetiracetam (LEV) and brivaracetam (BRV), as a new family of antiepileptic medications with a unique mechanism of action. The developed technique was effectively used to determine LEV in Keppra tablets and BRV in laboratory-prepared tablets without interfering with the ordinarily suspected excipients. METHOD: A Taguchi approach was applied as a powerful and user-friendly statistical technique for optimization of the qH1NMR experimental design for both drugs. The optimum acquisition conditions were number of scans 32, pulse angle 20°, and relaxation delay of 40 s for LEV and number of scans 128, pulse angle 90°, and relaxation delay of 1 s for BRV. NMR spectra were obtained by means of phloroglucinol as an internal standard and dimethyl sulfoxide-d6 as a solvent. RESULTS: The diagnostic doublet of doublet quantitative signals at 4.3 and at 4.2 ppm were chosen to estimate LEV and BRV, respectively. The recovery of both drugs was quantified through the range of 0.1-12 mg/mL. The limits of detection were 0.013, 0.0013 and the limits of quantitation were 0.04, 0.0039 mg/mL for LEV and BRV correspondingly. CONCLUSIONS: The suggested technique was fully validated according to ICH guidelines and proved to be an eco-friendly practice by means of three different assessment tools, including the green analytical procedures index, national environmental methods index, and analytical eco-scale. qH1NMR should be considered a green alternative for quantification and quality control assessment of pharmaceuticals. HIGHLIGHTS: This research represents the first simple, quick, and green alternative method for determination of both racetams in their pharmaceuticals.

New phthalimide-based derivatives as EGFR-TK inhibitors: Synthesis, biological evaluation, and molecular modeling study.

A novel series of phthalimide derivatives was synthesized and evaluated for in vitro antitumor activity against six human cancer cell lines; HepG-2, HCT-116, MCF-7, Hep2, PC3 and Hela.The obtained results revealed that compound 32 was the most potent antitumor, while compounds 33, 22 and 24 showed strong activity against all tested cell lines. Further biological evaluation of the most active compounds was done and their in vitro EGFR-TK inhibition was tested, and the results came in accordance with the results of antitumor testing, where 32 displayed promising inhibitory activity (IC50 = 0.065 µM) compared to the standard drug erlotinib (IC50 = 0.067 µM). In addition, compounds 48, 22, 28 and 19 showed strong inhibitory activity (IC50 = 0.089, 0.093, 0.147 and 0.152 µM respectively). Cell cycle analysis was conducted and the results revealed that 32 induced cell cycle arrest on Hela and MCF-7 at G0-G1 phase and Pre-G1 phase causing cell death mainly via apoptosis. Additionally, in vivo antitumor screening revealed that 32 reduced both body weight and tumor volume in solid tumor utilizing Ehrlich ascites carcinoma (EAC) animal model. Molecular modeling study showed that 32 and 48 have the highest affinity for binding with the active site of EGFR-TK with docking score comparable to erlotinib. Compounds 32 and 48 could be used as template models for further optimization.

Thiazole-based SARS-CoV-2 protease (COV Mpro ) inhibitors: Design, synthesis, enzyme inhibition, and molecular modeling simulations.

As an attempt to contribute to the efforts of combating the pandemic virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for COVID-19, new analogs of the repurposed drug nitazoxanide which showed promising inhibitory efficacy on a viral protease enzyme were designed, synthesized and evaluated for their inhibitory activity on the main protease of the SARS-CoV-2 virus, using the COV2-3CL protease inhibition assay. The obtained results showed that the N-(substituted-thiazol-2-yl)cinnamamide analogs 19, 20, and 21 were the most active compounds with IC50 values of 22.61, 14.7, 21.99 µM, respectively, against the viral protease compared to the reference drugs, nitazoxanide, and lopinavir. Molecular modeling studies showed binding interactions of 19, 20, and 21 with hydrogen bonds to Gln189 and Glu166, arene-arene interaction between the thiazole moiety and His41, and other hydrophobic interactions between the ethene spacer moiety and Asn142. Moreover, an extra arene-arene interaction between substituted benzo[d]thiazole and His41 was observed regarding compounds 19 and 21. Surface mapping and flexible alignment proved the structural similarity between the new drug candidates and nitazoxanide. Compliance of the new compounds to Lipinski's rule of five was investigated and absorption, distribution, metabolism, excretion, and toxicology data were predicted. The newly synthesized compounds are promising template ligands for further development and optimization.

Synthesis, biological evaluation, and molecular modeling simulations of new heterocyclic hybrids as multi-targeted anti-Alzheimer's agents.

The widespread and the recognition of the multifactorial nature of Alzheimer disease (AD) increased the demands for multi-targeted directed ligands (MTDLs) to overcome possible drug-drug interactions of the combination therapy, and to acquire superior therapeutic profile than single targeted molecules. Two main scaffolds namely: pyrazolopyridine and tetrahydroacridine (THA) were used to synthesize four different series of integrated multi-targeted synthons possessing ChE (hAChE or hBuChE), Aß1-42 aggregation inhibition potency, in addition to optimum metal chelating capability. Structure modifications were performed to 9-amino function of THA core of tacrine and the pyrazolopyridine scaffolds linked to a variety of cyclic secondary amines directly or using amide spacers or ethylamine bridge or engaging THA with pyrazolopyridine to produce hybrid compounds. Different 9-amino substitutions improved the in vitro hAChE activity of 7- or 6,7-disubstituted THA derivatives. Compounds 16 and 28 proved to be multimodal anti-AD agents as they were potent hAChE inhibitors, in addition, they could bind with the amino acids of the peripheral anionic site (PAS) affecting Aß aggregation and hence Aß-dependent neurotoxicity especially compound 16 which was almost twofold more active than donepezil. Furthermore, both compounds directly inhibited Aß1-42 self-aggregation and chelated bio-metals such as Fe2+, Zn2+ and Cu2+ preventing reactive oxygen species (ROS) generation by Aß and its oxidative damage in the brain regions of AD patients. Compound 28 had superior privilege by its dual ChE activity resulting in better cognitive improvement. Compounds 16 and 28 showed acceptable relative safety upon hepG2 cell line and excellent BBB penetration with wide safety margin as their LD50 were higher than 120 mg/kg.

Nanomolar potency of imidazo[2,1-b]thiazole analogs as indoleamine 2,3-dioxygenase inhibitors.

Novel series of imidazo[2,1-b]thiazole analogs were designed, synthesized, and biologically evaluated as indoleamine 2,3-dioxygenase (IDO1) inhibitors. Imidazo[2,1-b]thiazoles 6, 7, and 8 showed inhibitory profiles against IDO1 at IC50 values of 68.48, 82.39, and 48.48 nM, respectively, compared with IDO5L at IC50 67.40 nM. Benzo[d]imidazo[2,1-b]thiazoles 17, 20, and 22 showed promising IDO1 inhibition at IC50 values of 53.58, 53.16, and 57.95 nM, respectively. Compound 7 showed a growth-inhibitory profile at GI of 39.33% against the MCF7 breast cancer cell line, while 8 proved lethal to ACHN renal cancer cells. Cells treated with compounds 17 and 22 showed a typical apoptosis pattern of DNA fragments that reflected the G0/G1, S, and G2/M phases of the cell cycle, together with a pre-G1 phase corresponding to apoptotic cells, which indicates that cell growth arrest occurred at the S phase. Molecular modeling simulations validated the potential of benzo[d]imidazo[2,1-b]thiazole analogs to chelate iron(III) within the IDO1 binding pocket and, hence, to have a better binding affinity via hydrophobic-hydrophobic interactions.

3-Methyl-imidazo[2,1-b]thiazole derivatives as a new class of antifolates: Synthesis, in vitro/in vivo bio-evaluation and molecular modeling simulations.

Inhibiting the Dihydrofolate reductase (DHFR) enzyme has been validated in multiple clinical manifestations related to bacterial infection, malaria, and multiple types of cancer. Herein, novel series of 3-methyl-imidazo[2,1-b] thiazole-based analogs were synthesized and biologically evaluated for their in vitro inhibitory profile towards DHFR. Compounds 22 and 23 exhibited potent inhibitory profile targeting DHFR (IC50 0.079 and 0.085 µM, respectively comparable to MTX IC50 0.087 µM). Compounds 22 and 23 showed promising cytotoxicity against MCF7 breast cancer cell lines inducing cell cycle arrest and apoptosis. Furthermore, Compound 23 showed its potential to reduce body weight and tumor volume significantly, using Ehrlich ascites carcinoma (EAC) solid tumor animal model of breast cancer, compared to control-treated groups. Further, molecular modeling simulations validated the potential of 22 and 23 to have high affinity binding towards Arg22 and Phe31 residues via π-π interaction and hydrogen bonding within DHFR binding pocket. Computer-assisted ADMET study suggested that the newly synthesized analogs could have high penetration to the blood brain barrier (BBB), better intestinal absorption, non-inhibitors of CYP2D6, adequate plasma protein binding and good passive oral absorption. The obtained model and pattern of substitution could be used for further development of DHFR inhibitors.

Novel 1,2,4-oxadiazole-chalcone/oxime hybrids as potential antibacterial DNA gyrase inhibitors: Design, synthesis, ADMET prediction and molecular docking study.

New antibacterial drugs are urgently needed to tackle the rapid rise in multi-drug resistant bacteria. DNA gyrase is a validated target for the development of new antibacterial drugs. Thus, in the present investigation, a novel series of 1,2,4-oxadiazole-chalcone/oxime (6a-f) and (7a-f) were synthesized and characterized by IR, NMR (1H and 13C) and elemental analyses. The title compounds were evaluated for their in-vitro antimicrobial activity by the modified agar diffusion method as well as their E. coli DNA gyrase inhibitory activity. The minimum inhibitory concentration (MIC) and the structure activity relationships (SARs) were evaluated. Among all, compounds 6a, 6c-e, 7b and 7e were the most potent and proved to possess broad spectrum activity against the tested Gram-positive and Gram-negative organisms. Additionally, compounds 6a (against S. aureus), 6c (against B. subtilis and E. hirae), 6e (against E. hirae), 6f, 7a and 7c (against E. coli) and 7d (against B. subtilis), with MIC value of 3.12 µM were two-fold more potent than the standard ciprofloxacin (MIC = 6.25 µM). Mechanistically, compounds 6c, 7c, 7e and 7b had good inhibitory activity against E. coli gyrase with IC50 values of 17.05, 13.4, 16.9, and 19.6 µM, respectively, in comparison with novobiocin (IC50 = 12.3 µM) and ciprofloxacin (IC50 = 10.5 µM). The molecular docking results at DNA gyrase active site revealed that the most potent compounds 6c and 7c have binding mode and docking scores comparable to that of ciprofloxacin and novobiocin suggesting their antibacterial activity via inhibition of DNA gyrase. Finally, the predicted parameters of Lipinski's rule of five and ADMET analysis showed that 6c and 7c had good drug-likeness and acceptable physicochemical properties. Therefore, the hybridization of the chalcone and oxadiazole moieties could be promising lead as antibacterial candidate which merit further future structural optimizations.

2-Substituted-mercapto-quinazolin-4(3H)-ones as DHFR Inhibitors.

Antifolates are a class of drugs used as antibacterial, antiparasitic, and anticancer agents. This review focuses on 2-substituted-mercapto-quinazolin-4(3H)-one analogues as dihydrofolatereductase (DHFR) inhibitors. Several research work have concluded a structural model for this class of 2-thio-quinazoline derivatives to get compounds with remarkable biological activity. The pattern and orientation of the p-system substitutions with regard to the quinazoline nucleus manipulate the activity. The application of the obtained model criteria produced compounds 18, 20 and 21, which proved to be 4-8 times more active than the reference drug methotrexate (MTX, 1).

Novel GABAA Agonist Entities: Pharmacological Investigation and Molecular Modeling Study of Thiazolo- and Thiadiazolo-[3,2-a][1,3]diazepine Analogs.

Thiazolo- and thiadiazolo-[3,2-a][1,3]diazepines and their patented derivatives, tested with diverse CNS pharmacological activities, constitute an important class of compounds for new drug development. Therefore, research efforts were continued to design, synthesize, and evaluate compounds for their ultra-short, short-acting hypnotic, anticonvulsant, and neuromuscular blocking activities. The present review provides a summary of the work accomplished by these heterocycles and their biological evaluation.

Design, synthesis and molecular modeling of novel aryl carboximidamides and 3-aryl-1,2,4-oxadiazoles derived from indomethacin as potent anti-inflammatory iNOS/PGE2 inhibitors.

The development of NSAIDs/iNOS inhibitor hybrids is a new strategy for the treatment of inflammatory diseases by suppression of the overproduction of PGE2 and NO. A novel series of aryl carboximidamides 4a-g and their cyclized 3-aryl-1,2,4-oxadiazoles 5a-g counterparts derived from indomethacin 1 were synthesized. Most of the target compounds displayed lower LPS-induced NO production IC50 in RAW 264.7 cells and potent in vitro iNOS and PGE2 inhibitory activity than indomethacin. Moreover, in carrageenan-induced rat paw oedema method, most of them exhibited higher in vivo anti-inflammatory activity than the reference drug indomethacin. Notably, 4 hrs after carrageenan injection, compound 4a proved to be the most potent anti-inflammatory agent in this study, with almost two- and eight-fold more active than the reference drugs indomethacin (1) and celecoxib, respectively. Compound 4a proved to be inhibitor to LPS-induced NO production, iNOS activity and PGE2 with IC50 of 10.70 µM, 2.31 µM, and 29 nM; respectively. Compounds 4a and 5b possessed the lowest ulcerogenic liabilities (35% and 38%, respectively) compared to 1. Histopathological analysis revealed that compounds 4a and 5b demonstrated reduced degeneration and healing of ulcers. Molecular docking studies into the catalytic binding pocket of the iNOS protein receptor (PDB ID: 1r35) showed good correlation with the obtained biological results. Parameters of Lipinski's rule of five and ADMET analysis were calculated where compound 4a had reasonable drug-likeness with acceptable physicochemical properties so it could be used as promising orally absorbed anti-inflammatory therapy and entitled to be used as future template for further investigations.

Multiobjective optimization of microemulsion- thin layer chromatography with image processing as analytical platform for determination of drugs in plasma using desirability functions.

A new platform was developed for determination of drugs in plasma without extraction or instrumental analysis just using TLC, smart phone digital camera and free image processing software. Lamotrigine, antiepileptic drug was used as model analyte. The proposed platform depends on using oil-in-water (O/W) microemulsion to isolate the drug from plasma proteins and using water-in-oil (W/O) microemulsion as mobile phase for TLC which results in complete separation between lamotrigine and plasma as viewed under UV lamp. The composition of both microemulsions was optimized using Taguchi orthogonal array and Plackett- Burman design. The optimal (O/W) microemulsion predicted composition was 0.01 mL Butyl acetate, 4 mL butanol, 0.925 gm SDS and 8.6 mL water while the (W/O) mobile phase microemulsion was 9 mL Butyl acetate, 1 mL butanol, 0.25 gm SDS, 0.25 mL water. Separation was carried out on a silica gel 60F-254 plate eluted with the (W/O) microemulsion in about 30 min development time. The images of TLC plates were processed using 4 different programs, by comparing their results it was found that "integrated density" measured by Fiji software was the most accurate response that could measure the concentration of lamotrigine in spiked plasma in the range of (20-200) ng/spot. This method was applied also for determination of lamotrigine in lamictal® tablet dosage form using the same mobile phase. The precision of the method was satisfactory; the maximum value of relative standard deviations did not exceed 1.5%. While the accuracy was proved by the low values of % error and high values of recovery.

Digitally enhanced thin layer chromatography for simultaneous determination of norfloxacin and tinidazole with the aid of Taguchi orthogonal array and desirability function approach: Greenness assessment by analytical Eco-Scale.

In this study, an eco-friendly fast simple method was developed for simultaneous determination of norfloxacin and tinidazole based on thin-layer chromatography and image-processing analysis. The binary mixture was separated using reversed phase - thin layer chromatography plates and 30% trifluoroacetic acid only as mobile phase. Mobile phase composition was optimized using Taguchi orthogonal array and Derringer's desirability function. The plates were viewed under UV lamp and photographed by iPhone camera followed by image processing with Fiji software using integrated density as the measured response. As decreasing illumination increases the sensitivity of the method, this method was applied on two different ranges for each drug. The first one was 0.6-6.0 and 0.9-9.0 µg/spot for norfloxacin and tinidazole, respectively measured on the original image with normal illumination. The second one was measured after decreasing the illumination of the captured images at 0.06-0.60 and 0.09-0.90 µg/spot for norfloxacin and tinidazole, respectively. The proposed method was successfully applied for the determination of both drugs in tablets dosage form without interference from the commonly encountered excipients. Analytical Eco-Scale was used to evaluate the greenness profile of the proposed method and it was found to be excellent green analytical method.

Antibacterial, antibiofilm and molecular modeling study of some antitumor thiazole based chalcones as a new class of DHFR inhibitors.

Some synthesized antitumor derivatives of thiazole based chalcones including thiazolo[2,3-b]quinazoline and pyrido[4,3-d]thiazolo[3,2-a]pyrimidine analogues were subjected to be tested against standard microbial strains. Compound 18 showed higher activity against both Gram-positive and Gram-negative bacteria with MIC of 1.0, 1.0, 2.0, 2.0 and 4.0 µg/ml against S. aureus, B. subtilis, M. luteus, E. coli and P. aeuroginosa respectively which is better than ampicillin and very relative to ciprofloxacin standards. Moreover, this compound shows a good anti-biofilm activity against the Gram positive bacteria. Molecular docking studies of synthesized compounds against DHFR enzyme were carried out. Interestingly, active anticancer candidates 22,38, 40 and 41 in addition to most active antimicrobial agents 15, 18 and 20 bind to DHFR with nearly the same amino acid residues as MTX especially mentioning Arg28, Arg70, Asn64 and Lys68 which support our hypothesis that these compounds could act as antitumor or antibacterial via DHFR inhibition. Flexible alignment and surface mapping techniques have further provided lipophilic distributions supporting effective binding to DHFR. ADMET calculations for compounds 15, 18 and 20 suggested that they could be good orally absorbed antibacterial agents while compound 38 could be an orally absorbed anticancer agent with diminished toxicity. The results highlight studied thiazole based chalcones as efficient leads for designing new future antibacterial drug candidates.