Sulfadiazine Exerts Potential Anticancer Effect in HepG2 and MCF7 Cells by Inhibiting TNFα, IL1b, COX-1, COX-2, 5-LOX Gene Expression: Evidence from In Vitro and Computational Studies.

Drug repurposing is a promising approach that has the potential to revolutionize the drug discovery and development process. By leveraging existing drugs, we can bring new treatments to patients more quickly and affordably. Anti-inflammatory drugs have been shown to target multiple pathways involved in cancer development and progression. This suggests that they may be more effective in treating cancer than drugs that target a single pathway. Cell viability was measured using the MTT assay. The expression of genes related to inflammation (TNFa, IL1b, COX-1, COX-2, and 5-LOX) was measured in HepG2, MCF7, and THLE-2 cells using qPCR. The levels of TNFα, IL1b, COX-1, COX-2, and 5-LOX were also measured in these cells using an ELISA kit. An enzyme binding assay revealed that sulfadiazine expressed weaker inhibitory activity against COX-2 (IC50 = 5.27 µM) in comparison with the COX-2 selective reference inhibitor celecoxib (COX-2 IC50 = 1.94 µM). However, a more balanced inhibitory effect was revealed for sulfadiazine against the COX/LOX pathway with greater affinity towards 5-LOX (IC50 = 19.1 µM) versus COX-1 (IC50 = 18.4 µM) as compared to celecoxib (5-LOX IC50 = 16.7 µM, and COX-1 IC50 = 5.9 µM). MTT assays revealed the IC50 values of 245.69 ± 4.1 µM and 215.68 ± 3.8 µM on HepG2 and MCF7 cell lines, respectively, compared to the standard drug cisplatin (66.92 ± 1.8 µM and 46.83 ± 1.3 µM, respectively). The anti-inflammatory effect of sulfadiazine was also depicted through its effect on the levels of inflammatory markers and inflammation-related genes (TNFα, IL1b, COX-1, COX-2, 5-LOX). Molecular simulation studies revealed key binding interactions that explain the difference in the activity profiles of sulfadiazine compared to celecoxib. The results suggest that sulfadiazine exhibited balanced inhibitory activity against the 5-LOX/COX-1 enzymes compared to the selective COX-2 inhibitor, celecoxib. These findings highlight the potential of sulfadiazine as a potential anticancer agent through balanced inhibitory activity against the COX/LOX pathway and reduction in the expression of inflammatory genes.

Design, synthesis, and in-silico study of novel triarylethylene analogs with dual anti-estrogenic and serotonergic activity.

Estrogen receptor is an important target in breast cancer. Serotonin receptors (5-HT2A and 5-HT2C , in particular) were investigated for a potential role in development and progression of breast cancer. Ligands that interact with estrogenic receptors influence the emotional state of females. Thus, designing selective estrogen receptor modulator (SERM) analogs with potential serotonergic activity is a plausible approach. The dual ligands can augment cytotoxic effect of SERMs, help in both physical and emotional menopausal symptom relief, enhance cognitive function and support bone health. Herein, we report triarylethylene analogs as potential candidates for treatment of breast cancer. Compound 2e showed (ERα relative ß- galactosidase activity = 0.70), 5-HT2A (Ki = 0.97 µM), and 5-HT2C (Ki = 3.86 µM). It was more potent on both MCF-7 (GI50 = 0.27 µM) and on MDA-MB-231 (GI50 = 1.86 µM) compared to tamoxifen (TAM). Compound 4e showed 40 times higher antiproliferative activity on MCF-7 and 15 times on MDA-MBA compared to TAM. Compound 4e had higher average potency than TAM on all nine tested cell line panels. Our in-silico model revealed the binding interactions of compounds 2 and 2e in the three receptors; further structural modifications are suggested to optimize binding to the ERα, 5-HT2A , and 5-HT2C .

Novel fluorescence approach for trace quantification of levonorgestrel in breast milk based on click reaction with benzonitrofurazan azide (NBD-AZ).

Although the great importance of oral contraceptive agents in birth control, their existence in breast milk became a cause for concern, since infant exposure to these hormones is associated with many health problems. Consequentially, developing a sensitive bioanalytical method for monitoring their concentrations in breast milk is an urgent demand to examine the safety or the risk of these compounds on infants. Levonorgestrel is one of the most common contraceptive hormones under concern. Despite the high sensitivity of the fluorometric methods, detection of Levonorgestrel by them is confined because its structure does not exhibit any fluorescence. For the first time, we proposed a promising click fluorescent probe, 4-azido-7-nitrobenzoxadiazole to react with the alkyne group of Levonorgestrel, to give a highly fluorescent triazole derivative that exhibited strong signal at wavelength of 544 nm after excitation at 470 nm. Reaction parameters impacting the fluorescence were cautiously studied and optimized. The suggested approach has been successfully applied in Levonorgestrel estimation in breast milk samples with linearity of (0.4-80 ng.ml-1) and low detection limit of 0.12 ng.ml-1without interferences from any biological components and with mean % recovery of 97.84 ± 2.73. Accuracy, sensitivity, selectivity, simplicity, and low-cost makes this approach a convincing, promising, and appealing alternative over reported analytical methods for Levonorgestrel bioanalysis in different matrices.

4-Azido-7-nitrobenzoxadiazole as innovative clickable fluorescence probe for trace and selective quantification of ethinylestradiol in human plasma.

Quantification of ethinylestradiol (EE) in biological matrices is challenging as it is a very potent drug with a very low Cmax (75 pg.ml-1 ). Despite the high sensitivity of fluorometric methods, the detection of EE was confined because its structure exhibited very limited fluorescence. Therefore, it must be derivatized first using a fluorogenic agent to produce a more potent fluorescence derivative to achieve the desired ultrasensitive bioanalysis. Here, for the first time, we proposed a promising click fluorescent probe, 4-azido-7-nitrobenzoxadiazole (NBD-AZ) to react with the alkyne group of EE, with the help of copper sulphate and l-ascorbic acid to give a highly fluorescent and stable 1,2,3-triazole derivative. Density functional theory calculation revealed how the triazole formation affects the quantum yield and fluorescence of click reaction product when compared with NBD-AZ. The resulting triazole exhibited a strong signal at a wavelength of 540 nm after excitation at 470 nm. Reaction parameters impacting the intensity of fluorescence were cautiously studied and optimized. The suggested approach has shown outstanding performance, high linearity (25-300 pg.ml-1 ) and a low detection limit of 7.5 pg.ml-1 . The enhanced sensitivity and selectivity were exploited for analyzing EE in plasma using liquid-liquid extraction for samples cleaning up without interference from any biological components and with a mean % recovery of 100.13 ± 0.39. Accuracy, sensitivity, selectivity, simplicity, and cost-effectiveness make this approach a convincing, promising, and appealing alternative to the reported analytical methods for EE bioanalysis in different matrices.

Design, synthesis and antitumor evaluation of novel pyrazolo[3,4-d]pyrimidines incorporating different amino acid conjugates as potential DHFR inhibitors.

The present study aimed to investigate the antitumor effect of simultaneous inhibition of dihydrofolate reductase (DHFR) enzyme. We designed some novel pyrazolo[3,4-d]pyrimidines bearing different amino acid conjugates as efficient antifolate agents attributable to their structural similarity with methotrexate (MTX) and MTX-related antifolates. All compounds were tested to screen their enzymatic inhibition against DHFR compared with the reference drug MTX and for their in vitro antitumor cytotoxicity against six MTX-resistant cancer cell lines. The flow cytometry indicated that the most potent compound 7f arrested MCF-7 cells in the S-phase and induced apoptosis. Western blot for visualisation proved the ability of compound 7f to induce the expression of proapoptotic caspases and Bax proteins in MCF-7 breast cancer cell line beside its ability to diminish the expression of antiapoptotic Bcl-2 protein. Molecular modelling studies concluded that compound 7f displayed better binding energy than that of the normal ligand MTX. HIGHLIGHTSNew pyrazolo[3,4-d]pyrimidine derivatives 7a-m which are structurally similar to the classical methotrexate (MTX) and MTX-related antifolates were synthesised as antitumor agents.Novel N-acyl amino acid compound 7f exhibited marked DHFR inhibition activity that are parralel to both the molecular docking results and cytotoxic activity.Compound 7f could induce the expression of proapoptotic caspases and Bax proteins in MCF-7 breast cancer cell line beside its ability to diminish the expression of antiapoptotic Bcl-2 protein.All prepared compounds obey Lipinski rule of five except compound 7f.

Human dihydrofolate reductase inhibition effect of 1-Phenylpyrazolo[3,4-d]pyrimidines: Synthesis, antitumor evaluation and molecular modeling study.

A new series of pyrazolo[3,4-d]pyrimidine analogues bearing different amino acid conjugates 10a-m were synthesized with the aim to evaluate their antitumor effect through simultaneous inhibition of human dihydrofolate reductase (hDHFR). All novel compounds were tested to screen their enzyme inhibition activity against (hDHFR) beside their in vitro cytotoxicity against six human MTX resistant cancer cell lines namely, human prostate cancer (PC-3), pancreatic human cancer cell lines (BxPC-3), colorectal carcinoma (HCT-116), human hepatocellular carcinoma (HepG-2), cervical carcinoma (HeLa), and mammary gland breast cancer (MCF-7), besides normal immortalized pancreatic cell line (HPDE). Compounds 10e, 10f, 10g inhibited DHFR at considerable low (IC50 < 1 µM) in comparison to MTX (IC50 = 5.61 µM) beside their characteristic cytotoxic effects on different resistant cancer cell lines. Flow cytometry was done for the most active candidate compound 10e against MCF-7 breast cancer cell line. The results illustrated that compound 10e induced apoptosis and arrested MCF-7 cell cycle in the G1/S phase. Western blot for visualization and quantification was used to confirm the capability of compound 10e to induce the expression of proapoptotic caspases and Bax proteins in MCF-7 breast cancer cell line beside its ability to reduce the expression of antiapoptotic Bcl-2 protein. Molecular modeling studies demonstrated that compound 10e elucidated binding energy of (S= - 8.4390 Kcal/mol) that exceed that of the normal ligand MTX (S= - 8.3951Kcal/mol) in addition to several favorable binding interactions with the active site residues.

Rational Design, Synthesis and Biological Evaluation of Novel Pyrazoline-Based Antiproliferative Agents in MCF-7 Cancer Cells.

Breast cancer is a disease in which cells in the breast divide continuously without control. There are great limitations in cancer chemotherapy. Hence, it is essential to search for new cancer therapeutics. Herein, a novel series of EGFR/HER2 dual inhibitors has been designed based on the hybridization of thiazole and pyrazoline fragments. The synthesized compounds were screened for their anti-proliferative activity against MCF-7 breast cancer cell line and MCF-10 normal breast cell line. Interestingly, synthesized compounds 6e and 6k showed very potent antiproliferative activity towards MCF-7 with IC50 values of 7.21 and 8.02 µM, respectively. Furthermore, enzymatic assay was performed against EGFR and HER2 to prove the dual inhibitory action. Compounds 6e and 6k showed potent inhibitory activity for EGFR with IC50 of 0.009 and 0.051 µM, respectively, and for HER2 with IC50 of 0.013 and 0.027 µM, respectively. Additionally, compounds 6e and 6k significantly stimulated apoptotic breast cancer cell death. Compound 6e was further explored for its anticancer activity in vivo using a Xenograft model. Moreover, computational modeling studies, ADMET studies and toxicity prediction were performed to investigate their potential drug candidates.

Design, Synthesis, Anticancer Activity, and Solid Lipid Nanoparticle Formulation of Indole- and Benzimidazole-Based Compounds as Pro-Apoptotic Agents Targeting Bcl-2 Protein.

Cancer is a multifactorial disease necessitating identification of novel targets for its treatment. Inhibition of Bcl-2 for triggered pro-apoptotic signaling is considered a promising strategy for cancer treatment. Within the current work, we aimed to design and synthesize a new series of benzimidazole- and indole-based derivatives as inhibitors of Bcl-2 protein. The market pan-Bcl-2 inhibitor, obatoclax, was the lead framework compound for adopted structural modifications. The obatoclax's pyrrolylmethine linker was replaced with straight alkylamine or carboxyhydrazine methylene linkers providing the new compounds. This strategy permitted improved structural flexibility of synthesized compounds adopting favored maneuvers for better fitting at the Bcl-2 major hydrophobic pocket. Anti-cancer activity of the synthesized compounds was further investigated through MTT-cytotoxic assay, cell cycle analysis, RT-PCR, ELISA and DNA fragmentation. Cytotoxic results showed compounds 8a, 8b and 8c with promising cytotoxicity against MDA-MB-231/breast cancer cells (IC50 = 12.69 ± 0.84 to 12.83 ± 3.50 µM), while 8a and 8c depicted noticeable activities against A549/lung adenocarcinoma cells (IC50 = 23.05 ± 1.45 and 11.63 ± 2.57 µM, respectively). The signaling Bcl-2 inhibition pathway was confirmed by molecular docking where significant docking energies and interactions with key Bcl-2 pocket residues were depicted. Moreover, the top active compound, 8b, showed significant upregulated expression levels of pro-apoptotic/anti-apoptotic of genes; Bax, Bcl-2, caspase-3, -8, and -9 through RT-PCR assay. Improving the compound's pharmaceutical profile was undertaken by introducing 8b within drug-solid/lipid nanoparticle formulation prepared by hot melting homogenization technique and evaluated for encapsulation efficiency, particle size, and zeta potential. Significant improvement was seen at the compound's cytotoxic activity. In conclusion, 8b is introduced as a promising anti-cancer lead candidate that worth future fine-tuned lead optimization and development studies while exploring its potentiality through in-vivo preclinical investigation.

The Anticancer Activity for the Bumetanide-Based Analogs via Targeting the Tumor-Associated Membrane-Bound Human Carbonic Anhydrase-IX Enzyme.

The membrane-bound human carbonic anhydrase (hCA) IX is widely recognized as a marker of tumor hypoxia and a prognostic factor within several human cancers. Being undetected in most normal tissues, hCA-IX implies the pharmacotherapeutic advent of reduced off-target adverse effects. We assessed the potential anticancer activity of bumetanide-based analogues to inhibit the hCA-IX enzymatic activity and cell proliferation of two solid cancer cell lines, namely kidney carcinoma (A-498) and bladder squamous cell carcinoma (SCaBER). Bumetanide analogues efficiently inhibit the target hCA-IX in low nanomolar activity (IC50 = 4.4-23.7 nM) and have an excellent selectivity profile (SI = 14.5-804) relative to the ubiquitous hCA-II isoform. Additionally, molecular docking studies provided insights into the compounds' structure-activity relationship and preferential binding of small-sized as well as selective bulky ligands towards the hCA-IX pocket. In particular, 2,4-dihydro-1,2,4-triazole-3-thione derivative 9c displayed pronounced hCA-IX inhibitory activity and impressive antiproliferative activity on oncogenic A-498 kidney carcinoma cells and is being considered as a promising anticancer candidate. Future studies will aim to optimize this compound to fine-tune its anticancer activity as well as explore its potential through in-vivo preclinical studies.

Design and Synthesis of Imidazole and Triazole Pyrazoles as Mycobacterium Tuberculosis CYP121A1 Inhibitors.

The emergence of untreatable drug-resistant strains of Mycobacterium tuberculosis is a major public health problem worldwide, and the identification of new efficient treatments is urgently needed. Mycobacterium tuberculosis cytochrome P450 CYP121A1 is a promising drug target for the treatment of tuberculosis owing to its essential role in mycobacterial growth. Using a rational approach, which includes molecular modelling studies, three series of azole pyrazole derivatives were designed through two synthetic pathways. The synthesized compounds were biologically evaluated for their inhibitory activity towards M. tuberculosis and their protein binding affinity (K D). Series 3 biarylpyrazole imidazole derivatives were the most effective with the isobutyl (10 f) and tert-butyl (10 g) compounds displaying optimal activity (MIC 1.562 µg/mL, K D 0.22 µM (10 f) and 4.81 µM (10 g)). The spectroscopic data showed that all the synthesised compounds produced a type II red shift of the heme Soret band indicating either direct binding to heme iron or (where less extensive Soret shifts are observed) putative indirect binding via an interstitial water molecule. Evaluation of biological and physicochemical properties identified the following as requirements for activity: LogP >4, H-bond acceptors/H-bond donors 4/0, number of rotatable bonds 5-6, molecular volume >340 Å3, topological polar surface area <40 Å2.

Liquid chromatography tandem mass spectrometry for the simultaneous determination of metformin and pioglitazone in rat plasma: Application to pharmacokinetic and drug-drug interaction studies.

Failure to attain and sustain long term glycemic control is an ongoing challenge in diabetes therapy. The trend to use a combined therapy and the risk of drug-drug interaction (DDI) are elevated and thus the need for sensitive analytical methods is of great significance. Herein, a simple, robust, and sensitive reverse phase high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (ESI-MS/MS) method for simultaneous determination of metformin (MET) and pioglitazone (PGT) in rat plasma using canagliflozin (CAN) as internal standards (IS) was developed and fully validated. Prior Chromatographic separation on an Agilent Eclipse Plus C18 (4.6 × 100 mm, 3.5 µm) using gradient mobile phase system consisting of ammonium formate pH 4.5 and acetonitrile at a flow rate of 0.5 mL min-1, within a run time of 14 min, the antidiabetic drugs were extracted from rat plasma using acetonitrile-induced protein precipitation technique. Multiple reaction monitoring in positive ion mode was used for quantitation of precursor to production at m/z 130.1 → 71.0 & 60 for MET, 357.2 → 134.2 for PGT, and 462.16 → 191.1 for CAN. Method linearity was obeyed in the range of 1 to 5000 and 1 to 2500 ng mL-1 for MET and PGT, respectively. The developed method was validated in terms of accuracy, precision, selectivity, recovery, matrix effects, and stability as per US-FDA bioanalytical guidelines and successfully applied to clinical pharmacokinetic and DDI studies with a single oral administration of target compounds. The peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC) of MET was significantly influenced by the concomitant administration of PGT at equal concentration and vice versa. PGT affected the absorption and elimination rate of MET via inhibition of organic cationic transporter (OCT). Molecular modeling study revealed the significant interaction of PGT with OCT. A potential DDI in type 2 diabetic patient receiving chronic treatment with MET and PGT deserves further attention and study to improve drug therapy and prevent adverse effects.

Synthesis and biological evaluation of novel cYY analogues targeting Mycobacterium tuberculosis CYP121A1.

The rise in multidrug resistant (MDR) cases of tuberculosis (TB) has led to the need for the development of TB drugs with different mechanisms of action. The genome sequence of Mycobacterium tuberculosis (Mtb) revealed twenty different genes coding for cytochrome P450s. CYP121A1 catalyzes a CC crosslinking reaction of dicyclotyrosine (cYY) producing mycocyclosin and current research suggests that either mycocyclosin is essential or the overproduction of cYY is toxic to Mtb. A series of 1,4-dibenzyl-2-imidazol-1-yl-methylpiperazine derivatives were designed and synthesised as cYY mimics. The derivatives substituted in the 4-position of the phenyl rings with halides or alkyl group showed promising antimycobacterial activity (MIC 6.25 µg/mL), with the more lipophilic branched alkyl derivatives displaying optimal binding affinity with CYP121A1 (iPr KD = 1.6 µM; tBu KD = 1.2 µM). Computational studies revealed two possible binding modes within the CYP121A1 active site both of which would effectively block cYY from binding.

Synthesis, biological evaluation, and molecular docking investigation of benzhydrol- and indole-based dual PPAR-γ/FFAR1 agonists.

Type-2 diabetes mellitus is a progressive cluster of metabolic disorders, representing a global public health burden affecting more than 366 million people worldwide. We recently reported the discovery of three series of novel agents showing balanced activity on two metabolic receptors, peroxisome proliferator activated receptor-γ (PPAR-γ) and free fatty acid receptor 1 (FFAR1), also known as GPCR40. Our designing strategy relied on linking the thiazolidinedione head with known GPCR privilege structures. To further investigate this concept, two new scaffolds, the benzhydrol- and indole-based chemotypes, were introduced here in. Our optimization campaign resulted in three compounds; 15a, 15c, and 15d, with affinities in the low micromolar range on both targets. In vivo study of selected test compounds, revealed that 15c possesses a significant anti-hyperglycemic and anti-hyperlipidemic activities superior to rosiglitazone in fat-fed animal models. Molecular docking analysis was conducted to explain the binding modes of both series. These compounds could lead to the development of the unique antidiabetic agent acting as insulin sensitizer as well as insulin secretagogue.

Design, synthesis and 2D QSAR study of novel pyridine and quinolone hydrazone derivatives as potential antimicrobial and antitubercular agents.

The increased development of highly resistant bacterial strains and tuberculosis, constitute a serious public health threat, highlighting the urgent need of novel antibacterial agents. In this work, two novel series of nicotinic acid hydrazone derivatives (6a-r) and quinolone hydrazide derivatives (12a-l) were synthesized and evaluated as antimicrobial and antitubercular agents. The synthesized compounds were evaluated in vitro for their antibacterial, antifungal and antimycobacterial activities. Compounds 6f and 6p bearing the 3,4,5- (OCH3)3 and 2,5-(OCH3)2 benzylidene motifs were the most potent and as antibacterial, antifungal (MIC: 0.49-1.95 µg/mL) and (MIC: 0.49-0.98 µg/mL) respectively and antimycobacterial activity (MIC = 0.76 and 0.39 µg/mL) respectively. Besides, several derivatives, 6e, 6h, 6l-6o, 6q, 6r, 12a, 12b, 12e, 12h, 12k and 12l, exhibited significant antibacterial and antifungal activities with MIC values ranging from 1.95 to 7.81 µg/mL, they also displayed excellent to good activity against Mycobacterium tuberculosis with MIC range from 0.39 to 3.12 µg/mL. In addition, some of the most active compounds were tested for cytotoxic activities against human lung fibroblast normal cells (WI-38) and displayed low toxicity. Moreover, 2D-QSAR models to characterize the descriptors controlling the observed activities, were generated and validated.

Design, synthesis, and biological evaluation of novel thiazolidinediones as PPARγ/FFAR1 dual agonists.

Diabetes mellitus is a chronic metabolic disorder that affects more than 180 million people worldwide. Peroxisome proliferator activated receptors (PPARs) are a group of nuclear receptors that have been targeted by the thiazolidinedione (TZD) class of compounds for the management of type II diabetes. PPARγ is known to regulate adipogenesis and glucose metabolism. Another emerging target for the design of antidiabetic agents is the free fatty acid receptor 1 (FFAR1), previously known as GPR40. Agonists of this receptor were found to enhance insulin secretion in diabetic patients. It has been reported that some thiazolidinediones (TZDs) activate FFAR1 with micromolar potency. In this study, based on docking studies into the crystal structure of PPARγ and a homology model of FFAR1, nineteen compounds were designed, synthesized, and biologically tested for agonistic activity on both receptors. Nine compounds showed promising dual activity, with two compounds, 11a and 5b, having affinities in the low micromolar range on both targets. These molecules represent the first antidiabetic agents that could act as insulin sensitizers as well as insulin secretagogues.

1,4-Disubstituted aromatic piperazines with high 5-HT2A/D2 selectivity: Quantitative structure-selectivity investigations, docking, synthesis and biological evaluation.

Simultaneous targeting of dopamine D2 and 5-HT2A receptors for the treatment of schizophrenia is one key feature of typical and atypical antipsychotics. In most of the top-selling antipsychotic drugs like aripiprazole and risperidone, high affinity to both receptors can be attributed to the presence of 1,4-disubstituted aromatic piperazines or piperidines as primary receptor recognition elements. Taking advantage of our in-house library of phenylpiperazine-derived dopamine receptor ligands and experimental data, we established highly significant CoMFA and CoMSIA models for the prediction of 5-HT2A over D2 selectivity. Subsequently, the models were applied to identify the selective candidates 55-57 from our newly synthesized library of GPCR ligands comprising a pyrazolo[1,5-a]pyridine head group and a 1,2,3-triazole based linker unit. The test compound 57 showed subnanomolar a Ki value (0.64 nM) for 5-HT2A and more than 10- and 30-fold selectivity over the dopamine receptor isoforms D2S and D2L, respectively.

Development and validation of a sensitive UHPLC-MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics.

The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O-desmethyltramadol, dsmethyl-chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction method using ethyl acetate-diethyl-ether (1:1). Extracted samples were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 µL/min into a Hypersil-Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3-9.8 and -1.7-4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide.

Synthesis, molecular modeling, and biological evaluation of novel benzimidazole derivatives as inhibitors of hepatitis C virus RNA replication.

In this study, synthesis and docking studies of a series of new benzimidazole derivatives linked to substituted pyrimidines either through the methylenethio linkage or its bioisosteric methylene amino bridge were carried out. All the synthesized compounds were evaluated for their hepatitis C virus (HCV) RNA replication-inhibitory activity. Compounds 4d, 4f, and 4h were found to be more potent than VX-950 (IC50/90 of 4d=0.123/0.321, 4f=0.145/0.345, 4h=0.129/0.432, VX-950=0.20/0.45 µM, respectively) and 6d (IC50/90=0.116/0.452 µM) displayed activity very similar to that of the standard. Compounds 4d, 4f, 4h, and 6d were potent HCV RNA replication inhibitors and are good drug candidates for further investigations.

Synthesis and binding profile of haloperidol-based bivalent ligands targeting dopamine D(2)-like receptors.

Homodimers of dopamine D2-like receptors are suggested to be of particular importance in the pathophysiology of schizophrenia and, thus, serve as promising targets for the discovery of atypical antipsychotics. This study describes the development of a series of novel bivalent molecules with a pharmacophore derived from the dopamine receptor antagonist haloperidol. These dimers were investigated in comparison to their monomeric analogues for their D2long, D2short, D3, and D4 receptor binding and the ability to bridge two neighboring receptor protomers. Radioligand binding studies provided diagnostic insights when Hill slopes close to two for the bivalent ligand 13 incorporating 22 spacer atoms and a comparative analysis with monovalent control ligands indicated a bivalent binding mode with a simultaneous occupancy of two neighboring binding sites.

RP-HPLC/pre-column derivatization for analysis of omeprazole, tinidazole, doxycycline and clarithromycin.

A validated, reliable and accurate reversed-phase high performance liquid chromatographic method using pre-column derivatization was adopted for the simultaneous determination of two ternary mixtures containing omeprazole, tinidazole and doxycycline hyclate or clarithromycin. Separation was achieved on a C18 column, through a gradient elution system using acetonitrile-methanol-water adjusted to pH = 6.60. Drugs were detected at 277 nm over concentration ranges of 1-112, 5-125, 2.5-550 and 2.5-100 µg/mL for omeprazole, tinidazole, doxycycline hyclate and clarithromycin, respectively. This is the first method that has isolated and identified clarithromycin derivative by infrared and mass spectroscopy. This method is the first study for the simultaneous determination of omeprazole, tinidazole, doxycycline hyclate and clarithromycin in combined mixtures and pharmaceutical formulations.