Role of Drug Repurposing in Cancer Treatment and Liposomal Approach of Drug Targeting

Cancer is the leading cause of death, and incidences are increasing significantly and patients suffering from it desperately need a complete cure from it. The science of using an already-invented drug that has been approved by the FDA for a new application is known as “drug repurposing.” Currently, scientists are drawn to drug repositioning science in order to investigate existing drugs for newer therapeutic uses and cancer treatment. Because of their unique ability to target cancer cells, recently repurposed drugs and the liposomal approach are effective in the treatment of cancer. Liposomes are nanovesicles that are drastically flexible, rapidly penetrate deeper layers of cells, and enhance intracellular uptake. More importantly, liposomes are biocompatible, biodegradable; entrap both hydrophobic and hydrophilic drugs. This chapter summarizes various approaches to drug repurposing, as well as drug repurposing methods, advantages and limitations of drug repurposing, and a liposomal approach to using repurposed drugs in cancer targeting. This chapter also summarizes liposomal structure, drug loading, and the mechanism of liposomes in targeted cancer treatment. The lipid-based liposomal approach is emerging as a powerful technique for improving drug solubility, bioavailability, reducing side effects, and improving the therapeutic efficacy of repurposed drugs for cancer treatment

Studies on phosphine free Pd-salen complexes as effective catalysts for aqueous Suzuki reaction

565-572 Palladium complexes of the salen ligands, N,N'-bis(salicylidene)-ethylenediamine and N,N'-bis(salicylidene)-1,2-phenylenediamine have been explored for their catalytic activity in a phosphine-free aqueous Suzuki reaction. The various reaction parameters have been systematically optimized with respect to various solvents, bases, temperatures and Pd concentrations. The studies conclude that 1:1 DMF to water solvent ratio, Na2CO3 as base and 0.5 mol% of palladium at 90°C is apt for Suzuki reactions. Rapid transformation of substituted aryl iodides and aryl bromides into corresponding biaryls has been observed with excellent yield ranging from 70-86%, under optimized conditions. </smarttagtype

Heck reaction over palladium supported on nickel ferrite as an efficient and inexpensive catalyst

1549-1554The palladium supported on nickel ferrite found to be highly active catalyst for the Heck olefination of aryl iodides and activated aryl bromides providing an excellent yield in an aerobic condition, in shorter reaction time

Liquid phase oxidation of amines to azoxy compounds over ETS-10 molecular sieves

A convenient method for the oxidation of aryl amines to azoxybenzenes with H<SUB>2</SUB>O<SUB>2</SUB> or tertiary butyl hydroperoxide over the titanosilicate ETS-10 is reported. Over ETS-10, aniline is transformed into azoxybenzene in greater than 97% yield with H<SUB>2</SUB>O<SUB>2</SUB> as the oxidant. Substituted anilines are also transformed in good yields. Yield and H<SUB>2</SUB>O<SUB>2</SUB> efficiency depend largely on experimental parameters such as catalyst concentration, H<SUB>2</SUB>O<SUB>2</SUB>: substrate mole ratio and the nature of the solvent

Molecular modeling studies on zeolite catalysts for shape-selective electrophilic substitution: I acylation of 2-methoxynaphthalene

The diffusion characteristics of acylated 2-methoxynaphthalene inside large pore zeolites were investigated. The interaction of the three isomers with fully siliceous zeolite lattices was studied by energy-minimization calculations. The favorable adsorption sites and the orientation of the acylated products of 2-methoxynaphthalene were analyzed in detail. Three large pore zeolites having 12 m channels were selected: (i) mordenite with an elliptical 1-d channel, (ii) zeolite-L with a circular channel and 2-d cages, and (iii) zeolite-β with circular 3-d channel systems. It was observed that the shape selectivity properties of the zeolites could be profitably used to produce 2-acyl-6-methoxynaphthalene. In the case of mordenite, the diffusion of all three isomers is facile, whereas in the case of zeolite-L, the diffusion of 1-acyl-7-methoxynaphthalene is more facile than 2-acyl-6-methoxynaphthalene and 1-acyl-2-methoxynaphthalene. In the case of zeolite-β, the energy barrier for the diffusion of 2-acyl-6-methoxynaphthalene is significantly smaller than those of the other two isomers. Thus zeolite-β is predicted to be a suitable catalyst for the shape-selective acylation of 2-methoxynaphthalene to 2-acyl-6-methoxynaphthalene

Molecular modeling studies on zeolite catalysts for shape-selective electrophilic substitution: formation of xylenes

Energy minimization methodology has been used to study the interaction of isomers of xylene with ZSM-5, mordenite and MCM-22 zeolites. Adsorption sites and the mechanism of diffusion of the reactant molecules in the alkylation of toluene and xylene isomers inside these zeolites were studied. When molecules diffuse through 10-member and 12-member ring channels, they pass through favorable and unfavorable adsorption sites. ZSM-5 shows significant selectivity for p-xylene over the o- and m-xylenes. In large pore mordenite, the difference between favorable and unfavorable adsorption sites is not significant for xylene isomers. In the case of MCM-22, there are significant energy barriers, and the diffusivity is not high in spite of the presence of large cages. Results of this study emphasize the importance of the shape and the size of molecules as well as the pore dimensions and architecture of zeolites in effectively controlling molecular diffusion characteristics. The diffusion characteristics of the molecules inside a zeolite are sensitive to its pore architecture. The results offer the reasons based on molecular level interactions, for the experimentally observed shape selectivities in the above three zeolites

Efficient liquid phase acylation of alcohols over basic ETS-10 molecular sieves

Acylation of alcohols with acetic acid can be carried out efficiently in the liquid phase over microporous titanosilicate ETS-10-type catalysts. The reaction was studied over ETS-10 exchanged with, Li, Na, K, Rb, Cs, Ba and H ions. Activity for acylation of primary alcohols depends on the exchanged alkali ion and increases in the order Li &lt; Na &lt; K &lt; Ba ~H ~Rb ~Cs-ETS-10. These molecular sieves are also suitable for the acylation of secondary alcohols and esterification with long chain carboxylic acids. Liquid phase acylation of alcohols over basic ETS-10 molecular sieves

Influence of cation exchange on M-Pt-ETS-10 molecular sieve: correlation between ab initio results, catalytic activity, and physicochemical investigations

The electronic property of Pt supported on cation-exchanged Pt-M-ETS-10 [where M = Li, Na, K, Rb, Cs, Mg(OH), Ca(OH), Sr(OH), and Ba(OH) ions] depends on the location of Pt and the nature of the exchanged metal ion. Electronic changes on the Pt cluster are highly influenced when it is near TiO6 rather than SiO4 units. The benzene selectivity in the transformation of n-hexane over Pt-M-ETS-10 molecular sieves is found to correlate with the basicity of the exchanged cations and the average electron density of Pt. The relationship between electron density on Pt and the amount of CO2 adsorbed (from TPD) and the frequency of the &#957;3 band of CO2 adsorbed in FTIR is established. We report here the results of ab initio Hartree-Fock calculations on model clusters representing the Pt (active) site, molecular sieve with cations, Pt-M-molecular sieve, benzene, and H2S adsorbed over Pt-molecular sieve. Generally, the charge density on Pt decreases in the order Cs &gt; Rb &gt; K &gt; Ba(OH) &gt; Na &gt; Sr(OH) &gt; Ca(OH) &gt; Li &gt; Mg(OH) and indicates that the electron transfer is from the support to the Pt. Catalytic activity of Pt-M-ETS-10 corroborates well and explains the experimentally observed higher activity as compared to commercial Pt-Al2O3 catalyst. The larger benzene yield in the case of Pt supported over basic zeolites could be attributed to the ease of desorption of benzene, and it is supported by a decreasing binding energy of benzene from Li to Cs and Mg(OH) to Ba(OH) in Pt-M-ETS-10. The electron density on Pt decreases drastically in the presence of sulfur, in the order Cs &lt; Rb &lt; K &lt; Na &lt; Li and Ba(OH) &lt; Sr(OH) &lt; Ca(OH) &lt; Mg(OH)