Population pharmacokinetics of nevirapine in Malaysian HIV patients: a non-parametric approach.

AIMS: Nevirapine is the first non-nucleoside reverse-transcriptase inhibitor approved and is widely used in combination therapy to treat HIV-1 infection. The pharmacokinetics of nevirapine was extensively studied in various populations with a parametric approach. Hence, this study was aimed to determine population pharmacokinetic parameters in Malaysian HIV-infected patients with a non-parametric approach which allows detection of outliers or non-normal distribution contrary to the parametric approach. METHODS: Nevirapine population pharmacokinetics was modelled with Pmetrics. A total of 708 observations from 112 patients were included in the model building and validation analysis. Evaluation of the model was based on a visual inspection of observed versus predicted (population and individual) concentrations and plots weighted residual error versus concentrations. Accuracy and robustness of the model were evaluated by visual predictive check (VPC). The median parameters' estimates obtained from the final model were used to predict individual nevirapine plasma area-under-curve (AUC) in the validation dataset. The Bland-Altman plot was used to compare the AUC predicted with trapezoidal AUC. RESULTS: The median nevirapine clearance was of 2.92 L/h, the median rate of absorption was 2.55/h and the volume of distribution was 78.23 L. Nevirapine pharmacokinetics were best described by one-compartmental with first-order absorption model and a lag-time. Weighted residuals for the model selected were homogenously distributed over the concentration and time range. The developed model adequately estimated AUC. CONCLUSIONS: In conclusion, a model to describe the pharmacokinetics of nevirapine was developed. The developed model adequately describes nevirapine population pharmacokinetics in HIV-infected patients in Malaysia.

Structural Modifications of Benzimidazoles via Multi-Step Synthesis and Their Impact on Sirtuin-Inhibitory Activity.

Benzimidazole derivatives have been shown to possess sirtuin-inhibitory activity. In the continuous search for potent sirtuin inhibitors, systematic changes on the terminal benzene ring were performed on previously identified benzimidazole-based sirtuin inhibitors, to further investigate their structure-activity relationships. It was demonstrated that the sirtuin activities of these novel compounds followed the trend where meta-substituted compounds possessed markedly weaker potency than ortho- and para-substituted compounds, with the exception of halogenated substituents. Molecular docking studies were carried out to rationalize these observations. Apart from this, the methods used to synthesize the interesting compounds are also discussed.

Report: Demographic profiles and sleep quality among patients on methadone maintenance therapy (MMT) in Malaysia.

Poor sleep quality was frequently reported by opioid dependence patients during methadone maintenance therapy (MMT). The study investigated a sample of patients on MMT to investigate the severity and prevalence of sleep problems in MMT patients. We evaluated sleep quality and disturbances of 119 Malay male patients from MMT clinics in Kelantan, Malaysia between March and July 2013 using the Pittsburgh Sleep Quality Index (PSQI)-Malay version. Patients' demographic, clinical data, past drug history and methadone treatment variables were recorded. Patients averaged 37.5 years of age (SD 6.79) and their mean age of first time illicit drug use was 19.3 years (SD 4.48). Their mean age of entering MMT was 34.7 years (SD 6.92) and the mean duration in MMT was 2.8 years (SD 2.13). The mean current daily dosage of methadone was 77.8 mg (SD 39.47) and ranged from 20 to 360 mg. The mean global PSQI score was 5.6 (SD 2.79) and 43.7% patients were identified as 'poor sleepers' (global PSQI scores >5). This study confirms the poor overall sleep quality among patients on MMT. The prevalence and severity of sleep problems in MMT patients should not be underestimated.

Antimycobacterial evaluation of novel hybrid arylidene thiazolidine-2,4-diones.

A series of novel hybrid heterocycles comprising arylidene thiazolidine-2,4-dione and 1-cyclopropyl-2-(2-fluorophenyl)ethanone were synthesized. These compounds were evaluated for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv in High Throughput Screen. Most of the hybrid arylidene thiazolidine-2,4-diones displayed moderate to good activity with MIC of less than 50 µM. Compound 1m exhibited maximum potency being 5.87 fold more active at EC50 and 6.26 fold more active at EC90 than the standard drug pyrimethamine.

Synthesis and evaluation of novel benzimidazole derivatives as sirtuin inhibitors with antitumor activities.

A total of 15 novel benzimidazole derivatives were designed, synthesized and evaluated for their SIRT1 and SIRT2 inhibitory activity. All compounds showed better inhibition on SIRT2 as compared to SIRT1. Among these, compound 5j displayed the best inhibitory activity for SIRT1 (IC50=58.43µM) as well as for SIRT2 (IC50=45.12µM). Cell cytotoxicity assays also showed that compound 5j possesses good antitumor activity against two different cancer cell lines derived from breast cancer (MCF-7 and MDA-MB-468). A simple structure-activity-relationship (SAR) study of the newly synthesized benzimidazole derivatives was also discussed.

Facile, regio- and diastereoselective synthesis of spiro-pyrrolidine and pyrrolizine derivatives and evaluation of their antiproliferative activities.

A number of novel spiro-pyrrolidines/pyrrolizines derivatives were synthesized through [3+2]-cycloaddition of azomethine ylides with 3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones 2a-n. Azomethine ylides were generated in situ from the reaction of 1H-indole-2,3-dione (isatin, 3) with N-methylglycine (sarcosine), phenylglycine, or proline. All compounds (50 µM) were evaluated for their antiproliferative activity against human breast carcinoma (MDA-MB-231), leukemia lymphoblastic (CCRF-CEM), and ovarian carcinoma (SK-OV-3) cells. N-α-Phenyl substituted spiro-pyrrolidine derivatives (5a-n) showed higher antiproliferative activity in MDA-MB-231 than other cancer cell lines. Among spiro-pyrrolizines 6a-n, a number of derivatives including 6a-c and 6i-m showed a comparable activity with doxorubicin in all three cell lines. Among all compounds in three classes, 6a, 6b, and 6m, were found to be the most potent derivatives showing 64%, 87%, and 74% antiproliferative activity in MDA-MB-231, SK-OV-3, and CCRF-CEM cells, respectively. Compound 6b showed an IC50 value of 3.6 mM in CCRF-CEM cells. These data suggest the potential antiproliferative activity of spiro-pyrrolidines/pyrrolizines.

A one-pot domino synthesis and discovery of highly functionalized dihydrobenzo[b]thiophenes as AChE inhibitors.

A library of novel 5-amino-2,7-diaryl-2,3-dihydrobenzo[b]thiophene-4,6-dicarbonitriles have been synthesized regioselectively in good yields through the one-pot domino reactions of 5-aryldihydro-3(2H)-thiophenones, malononitrile and aromatic aldehydes in the presence of morpholine. This transformation presumably involves Knoevenagel condensation-Michael addition-intramolecular Thorpe-Ziegler cyclization-Tautomerization-Elimination sequence of reactions. These compounds were evaluated for their acetylcholinesterase (AChE) inhibitory activity and 5-amino-2,7-bis(4-methoxyphenyl)-2,3-dihydrobenzo[b]thiophene-4,6-dicarbonitrile was found to be the most potent against AChE with IC50 4.16 µmol/L.

A facile three-component [3+2]-cycloaddition for the regioselective synthesis of highly functionalised dispiropyrrolidines acting as antimycobacterial agents.

A series of fourteen dispiropyrrolidines were synthesized using [3+2]-cycloaddition reactions and were screened for their antimycobacterial activity against Mycobacterium tuberculosis H(37)Rv in HTS (High Throughput Screen). Most of the compounds showed moderate to good activity with MIC of less than 20 µM. Compound 4'-(4-bromophenyl)-1'-methyldispiro[acenaphthylene-1,2'-pyrrolidine-3',2″-indane]-2,1″(1H)-dione (4c) was found to be the most active with MIC of 12.50 µM.

Synthesis, characterization, and molecular docking analysis of novel benzimidazole derivatives as cholinesterase inhibitors.

Two series of novel acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors containing benzimidazole core structure were synthesized by a four-step reaction pathway starting from 4-fluoro-3-nitrobenzoic acid as the basic compound. The structure of the novel benzimidazoles was characterized and confirmed by the elemental and mass spectral analyses as well as (1)H NMR spectroscopic data. Of the 34 novel synthesized compounds, three benzimidazoles revealed AChE inhibition with IC50<10 µM. The highest inhibitory activity (IC50=5.12 µM for AChE and IC50=8.63 µM for BChE) corresponds to the compound 5IIc (ethyl 1-(3-(1H-imidazol-1-yl)propyl)-2-(4-nitrophenyl)-1H-benzo[d]imidazole-5-carboxylate). The relationship between lipophilicity and the chemical structures as well as their limited structure-activity relationship was discussed.

Ethyl 2-[4-(di-methyl-amino)-phen-yl]-1-phenyl-1H-benzimidazole-5-carboxyl-ate.

In the title compound, C24H23N3O2, the benzimidazole ring system makes dihedral angles of 7.28 (5) and 67.17 (5)°, respectively, with the planes of the benzene and phenyl rings, which in turn make a dihedral angle of 69.77 (6)°. In the crystal, mol-ecules are connected by C-H⋯N and C-H⋯O inter-actions, forming a layer parallel to the bc plane. A π-π inter-action, with a centroid-centroid distance of 3.656 (1) Å, is observed in the layer.

4'-(4-Fluoro-phen-yl)-1'-methyl-dispiro-[indane-2,2'-pyrrolidine-3',2''-indane]-1,3,1''-trione methanol hemisolvate.

The asymmetric unit of the title compound, C29H24FNO5·0.5CH3OH, contains two independent mol-ecules and a one methanol solvent mol-ecule. The methanol mol-ecule is O-H⋯O hydrogen bonded to one of the independent mol-ecules. The pyrrolidine rings in both mol-ecules adopt half-chair conformations, while the cyclo-pentane rings within the indane groups are in flattened envelope conformations, with the spiro C atoms forming the flaps. The benzene rings of the indane ring systems form a dihedral angle of 35.06 (7)° in one independent mol-ecule and 31.16 (8)° in the other. The fluoro-substituted benzene ring forms dihedral angles of 65.35 (6) and 85.87 (7)° with the indane group benzene rings in one mol-ecule, and 72.78 (8) and 77.27 (8)° in the other. In each mol-ecule, a weak intra-molecular C-H⋯O hydrogen bond forms an S(6) ring motif. In the crystal, weak C-H⋯O, C-H⋯N and C-H⋯F hydrogen bonds link the mol-ecules into a three-dimensional network.

Ethyl 2-[5-(4-fluoro-phen-yl)pyridin-3-yl]-1-[3-(2-oxopyrrolidin-1-yl)prop-yl]-1H-benzimidazole-5-carboxyl-ate.

In the title compound, C28H27FN4O3·H2O, the benzimidazole ring system is essentially planar with a maximum deviation of 0.028 (1) Å. It makes dihedral angles of 47.59 (5) and 60.31 (5)°, respectively, with the pyridine and benzene rings, which make a dihedral angle of 22.58 (6)° with each other. The pyrrolidine ring shows an envelope conformation with one of the methyl-ene C atoms as the flap. In the crystal, the components are connected into a tape along the b-axis direction through O-H⋯O and O-H⋯N hydrogen bonds and a π-π inter-action between the pyridine and benzene rings [centroid-centroid distance of 3.685 (8) Å]. The tapes are further linked into layers parallel to the ab plane by C-H⋯O and C-H⋯F inter-actions.

A regio- and stereoselective 1,3-dipolar cycloaddition for the synthesis of new-fangled dispiropyrrolothiazoles as antimycobacterial agents.

A series of dispiropyrrolothiazoles compounds were synthesized using 1,3-dipolar cycloaddition and were screened for antimycobacterial activity against Mycobacterium tuberculosis H(37)Rv and INH resistant M. tuberculosis strains. Two of them were showing good activity with MIC of less than 1 µM. Compound (5f) was found to be the most active with MIC of 0.210 and 8.312 µM respectively.

AChE inhibitor: a regio- and stereo-selective 1,3-dipolar cycloaddition for the synthesis of novel substituted 5,6-dimethoxy spiro[5.3']-oxindole-spiro-[6.3″]-2,3-dihydro-1H-inden-1″-one-7-(substituted aryl)-tetrahydro-1H-pyrrolo[1,2-c][1,3]thiazole.

Pyrrolothiazolyloxindole analogues share vital pharmacological properties, considered useful in Alzheimer's disease (AD). The aim of this study was synthesis and evaluate pyralothiazolyloxindole analogues if possess acetyl cholinesterase (AChE) inhibitory activity. The easily accessible one-pot synthesis of these compounds resulted to be significantly less difficult and expensive than that of donepezil. Several compounds possess anti-cholinesterase activity in the order of micro and sub-micromolar. Particularly, compound was the most potent inhibitors of the series against acetyl cholinesterase enzyme with IC(50) 0.11µmol/L.

Antimycobacterial activity: a facile three-component [3+2]-cycloaddition for the regioselective synthesis of highly functionalised dispiropyrrolidines.

A series of twelve dispiropyrrolidines were synthesized using [3+2]-cycloaddition reactions. The synthesized compounds were screened for their antimycobacterial activity against M. tuberculosis H(37)Rv and INH resistant M. tuberculosis strains using agar dilution method, four of them showed good activity with MIC of less than 1 µM. Compound 4'-[5-(4-fluorophenyl)pyridin-3-yl]-1'-methyldispiro[indan-2,2' pyrrolidine-3',2″-indan]-1,3,1″-trione (4b) was found to be the most active with MIC of 0.1215 and 5.121 µM, respectively.

Synthesis and biological evaluation of novel 6, 7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-yl-4-substituted phenylmethanone/ethanone derivatives.

A series of 6,7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-yl-4-substituted phenylmethanone/ethanone derivatives were synthesized and in vitro activity against mycobacterium tuberculosis (MTB) and INHR-MTB were carried out. Among the synthesized compounds, compound (4h) 6,7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-yl-4-pyridyl methanone was found to be the most active agent against MTB and INHR-MTB with a minimum inhibitory concentration of 0.22 µM.

7'-(2,5-Dimeth-oxy-phen-yl)-1',3',5',6',7',7a'-hexa-hydro-dispiro-[indan-2,5'-pyrrolo-[1,2-c][1,3]thia-zole-6',2''-indan]-1,3,1''-trione.

In the title compound, C(30)H(25)NO(5)S, all the five-membered rings are in envelope conformations with the spiro and methylene C atoms as the flap atoms. Intra-molecular C-H⋯O inter-actions stabilize the mol-ecular structure and form S(6) and S(7) ring motifs. The mean plane through the hexa-hydro-pyrrolo-[1,2-c]thia-zole ring [r.m.s deviation of 0.0393 (1) Å] makes dihedral angles of 60.92 (5), 88.33 (4) and 84.12 (4)° with the terminal benzene ring and the mean planes of the mono and di-oxo substituted indan rings, respectively. Mol-ecules are linked by inter-molecular C-H⋯O inter-actions into a three-dimensional network. In addition, C-H⋯π and π-π inter-actions [centroid-to-centroid distance = 3.4084 (8) Å] further stabilize the crystal structure.

4'-(3-Bromo-phen-yl)-1'-methyl-dispiro-[indan-2,2'-pyrrolidine-3',2''-indan]-1,3,1''-trione.

In the title compound, C(27)H(20)BrNO(3), two intra-molecular C-H⋯O hydrogen bonds both form S(6) rings. The pyrrolidine ring adopts a twisted conformation about the C-C bond bearing the indane ring systems. The other two five-membered rings within the indane systems are in shallow envelope conformations, with the spiro C atoms as the flap atoms. The mean plane of the pyrrolidine ring [maximum deviation = 0.275 (1) Å] makes dihedral angles of 65.25 (7), 78.33 (6) and 75.25 (6)° with the bromo-substituted benzene ring and the mean planes of the mono- and dioxo-substituted indane rings, respectively. In the crystal, mol-ecules are linked by C-H⋯O and C-H⋯N hydrogen bonds into a three-dimensional network. In addition, C-H⋯π inter-actions are observed.

Ethyl 2-[4-(morpholin-4-yl)phen-yl]-1-[3-(2-oxopyrrolidin-1-yl)prop-yl]-1H-1,3-benzimidazole-5-carboxyl-ate monohydrate.

The asymmetric unit of the title compound, C(27)H(32)N(4)O(4)·H(2)O, contains two independent benzimidazole-5-carboxyl-ate mol-ecules and two water mol-ecules. In both main mol-ecules, the pyrrolidine rings are in an envelope conformation with a methyl-ene C atom as the flap. The morpholine rings adopt chair conformations. Both benzimidazole rings are essentially planar, with maximum deviations of 0.008 (1) Å, and form dihedral angles of 37.65 (6) and 45.44 (6)° with the benzene rings. In one mol-ecule, an intra-molecular C-H⋯O hydrogen bond forms an S(7) ring motif. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds connect pairs of main mol-ecules and pairs of water mol-ecules into two independent centrosymmetric four-compoment aggregates. These aggregates are connect by C-H⋯O hydrogen bonds leading to the formation of a three-dimensional network, which is stabilized by C-H⋯π interactions.

Ethyl 2-(1,3-benzodioxol-5-yl)-1-[3-(1H-imidazol-1-yl)prop-yl]-1H-benzimidazole-5-carboxyl-ate.

In the title compound, C(23)H(22)N(4)O(4), the essentially planar [maximum deviation = 0.022 (1) Å] benzimidazole ring system forms dihedral angles of 86.16 (7) and 37.38 (6)°, respectively, with the imidazole and benzene rings. The dioxolane ring adopts an envelope conformation with the methyl-ene C atom at the flap. In the crystal, C-H⋯O and C-H⋯N inter-actions link the mol-ecules into a ribbon along the a axis. The crystal packing is further stabilized by weak π-π stacking inter-actions [centroid-centroid distances = 3.5954 (8) and 3.7134 (8) Å] and C-H⋯π inter-actions.