Cholesterol anchored arabinogalactan for asialoglycoprotein receptor targeting: synthesis, characterization, and proof of concept of hepatospecific delivery.

Asialoglycoprotein receptors (ASGPR) are hepatocyte bound receptors, which exhibit receptor mediated endocytosis (RME) for galactose specific moieties. Arabinogalactan (AG), a liver specific high galactose containing branched polysaccharide was hydrophobized using cholesterol (CHOL) as a lipid anchor via a two step reaction process to yield the novel polysaccharide lipid conjugated ligand (CHOL-AL-AG). CHOL-AL-AG was characterized by Fourier transform infra red (FTIR) spectroscopy, (1)H and (13)C nuclear magnetic spectroscopy (NMR), size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). Conventional liposomes (CL) and surface modified liposomes (SML) containing CHOL-AL-AG were prepared using reverse phase evaporation technique. Effect of CHOL-AL-AG concentration on particle size and zeta potential of SML was evaluated. Surface morphology of CL and SML was studied using cryo-transmission electron microscopy (cryo-TEM). In vitro binding affinity of SML and CL was evaluated using Ricinus communis agglutinin (RCA) assay. Cellular uptake of SML and CL was determined on ASGPR expressing HepG2 cell lines by confocal laser scanning microscopy technique (CLSM). FTIR spectra revealed bands at 1736 cm(-1) and 1664 cm(-1) corresponding to ester and carbamate functional groups, respectively. Signals at δ 0.5-2.5 corresponding to the cholestene ring and δ 3-5.5 corresponding to the carbohydrate backbone were observed in (1)H NMR spectrum of the product. CHOL-AL-AG possessed a mean average molecular weight of 27 KDa as determined by size exclusion chromatography. An endothermic peak at 207 °C was observed in the DSC thermogram of CHOL-AL-AG, which was not observed in thermograms of reactants and intermediate product. Synthesized CHOL-AL-AG was successfully incorporated in liposomes to yield SML. Both CL and SML possessed a mean particle size of ∼ 200 nm with polydispersity index of ∼ 0.25. The zeta potential of CLs was observed to be -17 mV whereas zeta potential of SMLs varied from -18 to -22 mV. RCA assay revealed enhanced binding of SML compared to CL confirming presence of galactose on surface of SML. CLSM studies demonstrated enhanced cellular uptake of SMLs compared to CL by HepG2 cells post 3 h administration indicating enhanced uptake by the ASGPR. Thus surface modified liposomes specific to target heptocytes demonstrate a promising approach for targeted drug delivery in liver cancer therapeutics.

Stability Indicating RP-HPLC Method for Simultaneous Determination of Simvastatin and Ezetimibe from Tablet Dosage Form.

A simple, specific and sensitive reverse phase high performance liquid chromatographic method was developed and validated for simultaneous determination of ezetimibe and simvastatin from pharmaceutical dosage forms. The method uses C18 ODS Hypersil column and isocratic elution. The mobile phase composed of acetonitrile:phosphate buffer (pH 4.5, 0.01M) in the ratio of 65:35 v/v was used at a flow rate of 1.0 ml /min. UV detector was programmed at 232 nm for first 10 min and at 238 nm for 10 to 20 min. All the validation parameters were in acceptable range. The developed method was effectively applied to quantitate amount of ezetimibe and simvastatin from tablets. The method was also applied suitably for determining the degradation products of ezetimibe and simvastatin.

Design, Synthesis and Evaluation of Novel 1-(Substituted Acetyl)-4-(10-Bromo-8-Chloro-5,6-Dihydro-11H-Benzo[5,6]Cyclohepta[1,2-B]Pyridine-11-Ylidene)piperidines as Antitumor Agents and Farnesyl Protein Transferase Inhibitors.

Eight novel 1-(substituted acetyl)-4-(10-bromo-8-chloro-5,6-dihydro-11H-benzo[5,6] cyclohepta [1,2-b] pyridine-11-ylidene)piperidines were designed by incorporating zinc binding groups to enhance activity. The designed molecules were synthesized and were evaluated for antitumor activity in vitro in five cell lines and for farnesyl protein transferase inhibition. Test compounds (6a-h) exhibited antitumor activity in most of the cell lines but were less potent than adriamycin. Compound 6e was most active with IC(50) values of <15 µM in two cell lines tested. Test compounds also exhibited potent FPT inhibitory activity and 6c was most potent with IC(50) value of <30 µM.

Synthesis and evaluation of uterine relaxant activity for a novel series of substituted p-hydroxyphenylethanolamines.

Novel racemic 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl]aminopropan-1-ol hydrochlorides (9a-h) were synthesized by condensing racemic 1-(p-hydroxyphenyl)-2-aminopropan-1-ol hydrochloride (6) with substituted aryloxymethyloxiranes (8a-h) in DMF in presence of anhydrous potassium carbonate and then reacting with dry hydrogen chloride gas. They were evaluated for uterine relaxant activity in vitro on isolated rat uterus and in vivo in pregnant rats. Their cAMP releasing potential was studied using rat uterus tissue homogenates by cAMP [3H] assay and cardiac stimulant potential was evaluated in dog. All compounds exhibited potent uterine relaxant activity in vitro and produced a significant delay in the onset of labour in pregnant rats; their cAMP releasing potential was higher than isoxsuprine hydrochloride except for 9b and 9c. Finally insignificant cardiac stimulant potential was noted for these compounds when compared to isoxsuprine hydrochloride.

Design, synthesis and in vivo anticonvulsant screening in mice of novel phenylacetamides.

A set of seven novel N-substituted 2-anilinophenylacetamides were designed by pharmacophore generation and using flexible alignment module of MOE software. The novel molecules were synthesized and screened for anticonvulsant activity in Swiss albino mice by MES and ScPTZ induced seizure tests. Test compounds were found to be potent in MES test. Compounds 12 and 14 were found to be more potent with ED(50) values 24.0 and 8.0 mg kg(-1), respectively, and their activity was comparable to standard drugs (Phenytoin, Carbamazepine). Test compounds did not show significant activity in ScPTZ test. Compounds 12 and 14 also exhibited higher protective indices (20.3 and 87.5, respectively) when assessed for neurotoxicity by rotarod test as compared to the standards.

Design, synthesis and evaluation of naphthalene-2-carboxamides as reversal agents in MDR cancer.

A novel class of molecules with structure N-[3-(4-substituted-1-piperazinyl) propyl]-6-methoxy naphthalene-2-carboxamides were designed by generating a pharmacophore for potent MDR reversal activity, using Elacridar (GF 120918) as a query molecule and using MOE software. They were synthesized by condensing 6-methoxynaphthalene-2-carboxylic acid with N-[3-(4-substituted-1-piperazinyl) propyl] amines in the presence of DCC in DMF. They were evaluated in P388 murine lymphocytic leukemia cell line (P388) in vitro using SRB assay for cytotoxicity and in adriamycin-resistant P388 murine lymphocytic leukemia cell line (P388/ADR) using MTT assay for resistant reversal activity. Test compounds were non-toxic at the doses studied (upto 80 microg/ml). They effectively reversed adriamycin resistance at the doses studied (40 and 80 microg/ml). The percentage enhancement in adriamycin activity was in the range 33.58 -90.67 (at 40 microg/ml) and 8.80-46.04 (at 80 microg/ml) and the corresponding reversal potency values were in the range 1.33-1.90 and 1.08-1.46, respectively. Test compounds 2, 3, and 5 exhibited better activity as compared to the standard resistant reversal agent (Verapamil), at same concentration.

Docking studies and development of novel 5-heteroarylamino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines as potential antimalarials.

MOE-Dock (Docking software) was used to predict the binding modes of 10 novel and potent 5-substituted amino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines (compounds I-X) as part of our antimalarial drug development programme. This was done by analyzing the interaction of these compounds with the active sites of 11 enzymes present in Plasmodium falciparum and based on this, effective binding was observed to enzyme P. falciparum glutathione reductase (PfGR). The binding scores for compounds I-X with PfGR were also congruent with their antimalarial activity. Three additional analogs were then designed and synthesized based on the above docking study and the pharmacophoric requirements for this class.

Design, synthesis and evaluation of racemic 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl]amino-1-propanol hydrochlorides as novel uterine relaxants.

Novel 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl]amino-1-propanol hydrochlorides were designed based on the pharmacophore for potent uterine relaxant activity and by utilizing the principles of structural hybridization. The designed molecules were synthesized as racemates by a novel route and were evaluated for uterine relaxant activity in vitro on isolated rat uterus and in vivo in pregnant rats. Their cAMP-releasing potential was studied using rat uterus tissue homogenates by the cAMP [(3)H] assay, and cardiac stimulant potential was evaluated on isolated guinea pig right atrium. All compounds exhibited potent uterine relaxant activity in vitro and produced a significant delay in the onset of labour in pregnant rats; their cAMP-releasing potential was slightly less, while their cardiac stimulant potential was insignificant as compared to isoxsuprine hydrochloride.

Novel fluoroquinolones: design, synthesis, and in vivo activity in mice against Mycobacterium tuberculosis H37Rv.

Novel 6,8-difluoro-1-alkyl-5-amino-1,4-dihydro-4-oxo-7-{4-substituted piperazin-1-yl}-quinoline-3-carboxylic acids, with the substituents at 4th position of piperazine being -[2(pyridine-4-carbonyl) hydrazono]propyl and -2 [(pyrazine-2-carbonyl) amino] ethyl, were synthesized and evaluated in vivo against Mycobacterium tuberculosis H(37)Rv in Swiss albino mice. Test compounds exhibited activity comparable to that of sparfloxacin (survival rate, reduction of splenomegaly and reduced tubercular lesions) at a dose of 200 mg/kg.

Design, synthesis and evaluation of 5-substituted amino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines as novel antimalarials.

Novel 5-substituted amino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines were designed based on a pharmacophore developed for potent antimalarial activity using Chem-X and MOE softwares. The designed molecules were synthesized by following a novel route and were evaluated by Rane's test for blood schizonticidal activity in mice infected by Plasmodium berghei. Based on the Mean Survival Time (MST) data, of the nine compounds evaluated, three had curative potential when compared with chloroquine.