Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Northern Chile is characterized by water scarcity. The Lluta River, located in the XV region of Arica and Parinacota, is the one of the main rivers in northern Chile. The elevated levels of metals and metaloids in the river reduce the agricultural productivity and variety of species can be cultivated within the valley, which are of great importance for the consumption of the inhabitants of the area. Heavy metals in river bottoms may cause various effects on the water quality, as such the capacity to accumulate metals; levels of toxicity and metal stabilization in sediments have often been considered a pollution index of a territory. In this work the concentrations of Al, Cu, Fe, Mn, Mo, Pb and Zn from the pseudo-total and labile fraction of Lluta river sediments were studied. Samples from 10 sites along the river were collected. The sediments were characterized determining: pH, electrical conductivity, organic carbon (OC), organic total carbon (OTC), available phosphorus and boron. Heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS). For the metals analyzed in the pseudo-total fraction, the highest concentrations found were: Al in the site 10, (17061 mg kg-1) and Fe on site 6, (29898 mg kg-1). For the labile fraction, highest concentrations of metals were: Al in site 6 (1079 mg kg-1), Fe in site 9, (275 mg kg -1) and Mn in site 9 (1578 mg kg-1). Using the Risk assessment code (RAC), the site 6 presents the greatest risk with high values of Cu, Mn, Pb and Zn, followed by site 1 with high values of Mn, Cu and Zn, and site 9 with high values of Mn, Cu and Pb. On the other hand, the MacDonald PEC (probable effect concentration) and TEC (threshold effect concentration) toxicity criteria, showed that the sites 4 and 6 have levels above the TEC for Cu, Fe, Pb and Zn, and levels above the PEC at six sites for Mn.

An efficient and reusable molybdenum-based catalyst has been prepared by tethering dioxomolybdenumacetylacetonate complex, MoO2(acac)2, via post-synthesis modification of zeolite beta. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) and inductively coupled plasma (ICP). The catalyst exhibited very high activity for the selective oxidation of sulfides to sulfones at room temperature. The catalyst can be recycled and reused four times without significant loss of activity.

The present paper reports study of dielectric & physicochemical properties like dielectric constant, viscosity, density and refractive index for the binary mixtures of Nitromethane (NM) and Dimethylsulphoxide (DMSO) over the entire concentration range were measured at 293.15K. The experimental data further used to determine the Bruggeman factor, and excess properties viz. excess density, excess viscosity, and excess refractive index. The values of excess properties further fitted with Redlich–Kister equation. Excess properties were used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures.

Tirofiban hydrochloride was subjected to the degradation under conditions of hydrolysis (acidic and alkaline degradation), oxidative, thermal and photolytic degradation as prescribed by ICH. A simple and precise liquid chromatographic method has been developed and validated for the simultaneous determination of tirofiban hydrochloride monohydrate (TIR) and its synthetic starting material; tyrosine (TRS). All the chromatographic separations were achieved on Zorbax SB C18, 250 mm×4.6 mm i.d., 5μm column at a flow rate of 1 mL min−1. Isocratic elution based on 0.1 M phosphate buffer (pH 3) - acetonitrile (70:30, v/v) with UV detection at 227 nm was applied. For the stability study separation of TIR from its degradation products was achieved using 0.1 M phosphate buffer (pH 3) - acetonitrile (72:28, v/v) with UV detection at 210 nm. Method validation parameters namely, linearity, accuracy and precision were found to be acceptable over the concentration ranges of 10-250 μg mL-1 for TIR and 1-70 μg mL-1 for TRS. The minimum detection limits were 1.76 μg mL-1 for TIR and 0.13 μg mL-1 for TRS. The optimized method was validated and proved to be specific, robust and accurate for the quality control of the cited drug in drug substance and drug product.

The two-component reaction of 1,2-phenylenediamine derivatives and trichloroacetyl isocyanate proceeded smoothly and cleanly at room temperature and N-(1H-benzimidazol-2-yl) acetamide derivatives afforded in excellent yields and no side reactions were observed. The structures of the products were confirmed by IR, 1H NMR, 13C NMR, and elemental analysis.Also, in this investigation, the structural, electronic properties, IR, 13C and 1H NMR parameters of synthesized molecules were computed in gas in the M062X/6-311G(d,p) level of theory. 1H and 13C NMR chemical shifts were evaluated by employing of the gauge-invariant atomic orbital (GIAO) method. NBO analysis was exploited to examining of the atomic charges and their second order stabilization energy within these molecules.

An efficient and greener synthesis of a series of dihydropyrimidone (DHPMs)/ dihydropyrimithione (DHPMTs) derivatives were accomplished via three component one pot condensation between quinoline aldehyde (2-hydroxy-4-formyl quinoline/2-formyl-4-methoxy quinoline) , β – keto ester (ethyl acetoacetate / methyl acetoacetate) and urea/ thiourea using nickel(II) exchanged zeolite [Ni(II)Y] (NiNPs). The NiNPs were characterized by Infrared spectroscopy, Powder X ray diffraction patterns, Electronic microscopy studies- Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). After the course of the reaction, the NiNPs were recovered and reused without any apparent loss of activity. The newly synthesized compounds were screened for antimicrobial activity against two human bacterial pathogens, the Gram-positive Methicillin resistant Staphylococcus aureus (MRSA) and the Gram-negative Pseudomonas aeruginosa (MTCC 201) and a human yeast pathogen, Fluconazole resistant Candida albicans (FRCA). The synthesised compounds were also evaluated for their antioxidant activity and the compounds show significant scavenging activity compared to aspartic acid.

In the present study a series of novel benzoxazepine (5a-h) derivatives were synthesized by the thermal cyclization reaction of various pyrazole-chalcones (3a-h) with 2-aminophenol, by conventional heating and microwave irradiation (180 W) in solvent-free conditions in short reaction times (9–12 min), giving high yields of products (80–88%). The homogeneity of all the newly synthesized compounds has been checked by TLC. Their IR, NMR, ESI-mass spectral data and elemental analysis are in accord with the assigned structure. The title compounds were evaluated for their antibacterial activity against Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, and Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli. Compounds 3c, 3h, 5b, 5c, 5g and 5h were found to show good antibacterial activity when compared with that of standard drug Ampicillin. Furthermore, the same library of compounds were evaluated for antifungal activity against Aspergillus nigerzeae, Penicillium italicum and Fusarium oxysporum using Grieseofulvin as standard drug. The results of the above studies show that the compounds 3b, 3c, 3e, 3h, 5a, 5c, 5g and 5h showed good antifungal activity against all the tested organisms.

This work describes a simple photometric determination of iodine concentrations in urine using a dispersive liquid-liquid microextraction method. After digestion of the urine samples with ammonium persulfate, iodide was oxidized with nitrous acid to ICl2− anion at concentrated hydrochloric acid, then Rhodamine B is added and the ion-pair formed was extracted into a mixture of toluene (extracting phase) and ethanol (dispersive solvent) and measured spectrophotometrically. By means of this sensitive method, iodine concentrations can be determined in very small amount of urine specimens (250 μL). The calibration curve showed good linearity within the range of 100-900 μg.L-1 (R2 = 0.985), and the limit of detection for urine was 33.3 μg.L-1. The mean recovery of urine were 95.9-101.2 % with RSD of 2.6-6.6 %. The accuracy and precision of the method was evaluated by comparing to the standard Kolthoff-Sandell method. This suggested method affords a number of advantages, such as being simple, rapid, and inexpensive, with low organic solvent consumption, and is remarkably free from interference effects, rendering it an efficient method for the determination of iodine in urine samples in any routine clinical laboratory.

A series of 2,2’-(5-hydroxydihydropyrimidine-1,3(2H,4H)-diyl)bis-(methylene)-disubstitutedphenols was synthesized by using a Mannich-type reaction between 1,3-diaminopropan-2-ol, paraformaldehyde and substituted phenols. These previously unreported compounds were separated from the reaction mixture by column chromatography (CC) in highly pure form with a 29%-91% yield. The effect of intramolecular hydrogen bonding on the conformation of 5-hydroxyhexahydropyrimidines has been studied. Our results show that the presence of hydroxyl groups can strongly influence the stereoelectronic relationships in the six-membered heterocyclic ring.

The oral route is most popular route for the administration of therapeutic agents because of the low cost of therapy and ease of administration lead to high levels of patient compliance. The most popular oral solid dosage forms are tablets and capsules. Many patients find it difficult to swallow tablets and hard gelatin capsules particularly pediatric and geriatric patients and do not take their medicines as prescribed. The objective of this research was to prepare fast dissolving oral thin film (FDOTF) containing Montelukast sodium is indicated for the prophylaxis and chronic treatment of asthma to enhance convenience and compliance to the elderly and pediatric patients for better therapeutic efficacy. The present investigation was undertaken with the objective of formulating of the montelukast sodium fast dissolving oral thin films allowing fast reproducible drug dissolution in oral cavity thus bypassing first pass metabolism. The film were prepared by using polymers such as hydroxypropyl methyl cellulose (HPMC) and Maltodextrin, plasticizer such as PEG 400, by a solvent casting method. They were evaluated for physical characteristics such as thickness, uniformity of weight, folding endurance, drug content, surface ph, percentage elongation and tensile strength, drug polymers compatibility by FTIR study, scanning electron microscopy and in vitro drug release. The formulations were subjected to disintegration, in-vitro drug release test. The in vitro disintegration time of the optimized batch F4 was found to be 20 sec. The optimized batch was found to be stable for 1 month under specified stability conditions.