Chemistry

Controlled release dosage forms provide sustained therapeutics effects for prolonged period of time and improve patient compliance. In present study, controlled release co-precipitates of Metoprolol Tartrate and Losartan Potassium were prepared by solvent evaporation method using polymers such as Eudragit RL 100 and Carbopol 974PNF and controlled release tablets were directly compressed into tablets. In-vitro dissolution of controlled release co-precipitates were performed by USP Method-II (paddle method) and tablets were evaluated by USP Method-I (rotating basket method) in phosphate buffer (PH 6.8) using pharma test dissolution apparatus. The temperature was maintained constant at 37±1.0°C and the rotation speed of paddle and basket was kept constant at 100rpm. Drug release mechanisms were determined by applying Power Law kinetic model. The difference and similarity of dissolution profiles test formulations with reference standards were also determined by applying difference facto...

The aim of the current study was to formulate and evaluate glipizide controlled release matrix tablets by means of different grades of polymer Ethoceland different co-excipients in order to evaluate their effect on drug release profiles during in vitro dissolution studies. Type II diabetes mellitus is usually treated with Glipizide. Glipizide belongs to sulfonylurea group. Gastric disturbance and severe hypoglycemia has been observed after taking glipizide orally. To overcome these problems, controlled release matrices were developed using different grades of ethyl cellulose polymer with a drug-polymer ratio of 1:3by the direct compression method. The effect on drug release of partial replacement of lactose by different co-excipients, HPMC K100M, starch and CMC, were also studied. Diameter, thickness, hardness, friability, weight variations, drug contents of formulations were tested, these properties were within prescribed limits. Co-excipients and polymer containing formulations we...

The aim of the study presented is to formulate and evaluate Acarbose controlled release matrix tablets by means of different grades of polymer Ethocel and different co-excipients with the intention to see their effects on drug release profile during in vitro dissolution studies. Controlled release dosage forms is gaining rapid popularity due to its positive aspect of reduction in dosage frequency and curtailing side effects. Controlled released tablets of Acarbose were prepared by direct compression method, using Ethocel® Standard 7 Premium and Ethocel® Standard 7 FP premium polymer. The effect of co-excipients including hydroxypropyl methylcellulose (HPMC), Carboxymethyl cellulose (CMC) and starch on the drug placing 30% lactose were also examined. In-vitro studies were carried out with the help of phosphate buffer (pH 7.4) as dissolution medium. Drug release mechanism was assessed by applying various kinetic models. Similarly / dissimilarity factor f2/ f1 were applied for determin...

Hepatic injury may occur with cocaine, morphine or halothane administration. Theoretical considerations suggest that the combined administration of these agents might provoke enhanced hepatic injury. To investigate this we studied the time course (4-96 hours) of plasma isocitrate dehydrogenase activity (ICDH) in eight groups of guinea pigs (total 96) given either intra-peritoneal saline, cocaine (30 mg/Kg), morphine (100 mg/Kg) or a combination there of and then exposed to either 40% oxygen alone or with halothane 0.3% or isoflurane 0.4% for a period of 4 hours. Cocaine plus morphine (at 4, 24 and 48 hr), halothane (at 24 and 48 hr), or isoflurane (at 4hr) administration resulted in significant ICDH elevations. Cocaine sped the onset (at 4 hr) but did not enhance the hepatic injury from halothane (at 24 and 48 hr). Cocaine prolonged (at 48 hr) the hepatic injury from isoflurane. Morphine resulted in less hepatic injury than cocaine when administered with isoflurane (at 4hr). The a priori hypothesis could not be demonstrated. This study suggests that cocaine may provoke earlier hepatic injury from halothane and prolong hepatic injury from isoflurane in guinea pigs.

ABSTRACT The metal delivery mechanism of the metalloenzyme transferrin and the antitumor active interaction of the metal ions, generated by the rapid hydrolysis of bent metallocene metals (Cp2MCl2; M = Ti, V, Nb, Mo), with the transferrin enzyme have been investigated. The initial and rate determining steps of the metal delivery mechanism have been identified. Comparisons are drawn between the antitumor action of various external metal ions and the role of the weak interactions that decide the site-specific decarboxylation reaction of transferrin have been investigated. Computational results reveal that the metal delivery mechanism starts by the site-specific concerted decarboxylation of transferrin leading to the thermodynamically unstable metal-oxo product and this unstable metal-oxo product delivers the metal ion to the nucleic acid via ATP. The computed reaction barriers for the decarboxylation step nicely correlate with the antitumor activity of the bent metallocenes.

Abstract A new synthetic strategy utilizing POCl3-water for the conversion of 2′-hydroxychalcones to flavanones and flavones has been developed. The reagent efficiently promoted one-pot conversion of 2′-hydroxychalcones to flavones through flavanones involving cyclization and oxidative dehydrogenation. By changing the stoichiometery of the reagents, the reaction can be tuned to generate either flavanone or flavone. The developed protocol was found to be applicable for a variety of 2′-hydroxychalcones. GRAPHICAL ABSTRACT

Biodiesel and single cell oils obtained from oleaginous yeasts grown in industrial waste are attractive alternatives to the conventional fuels. However, there are only few articles dealing with the stability of the microbial biofuels. Hence, this study aimed at characterizing the storage time of biodiesels using Rancimat methods. The microbial oil and the biodiesel obtained from microbial oil have been characterized with storage stability due to various oxidizing and thermal damage. Here, the microbial fuels were subject to Rancimat analysis and found to have high thermal-oxidative stability of 18 and 8.78 h for biodiesel and oil, respectively. The storage stability resulting from storage conditions was extrapolated for biodiesel and oil and has been found to be 1.62 and 0.54 years, respectively. The infrared spectroscopic analysis reveals the degree of oxidation found after the induction time was reached and shows the characteristic peaks for degradation products. Gas chromatography revealed the compounds that were responsible for the stability as well as the amount of degradation products left.

Abstract Transition metal/metal ions are reported to impart very efficient co-catalytic activity to TiO2 for various photocatalytic reactions depending on the nature and oxidation state of metal ions. However, when certain metals (Mn+) having different oxidation states like Mn2+/Mn7+ or Cr3+/Cr6+ act as co-catalysts, the photocatalytic properties of Mn+-TiO2 nanocomposites may vary significantly. Different surface morphologies, electron transfer phenomena and adsorption efficacy provided by these co-catalysts will govern the Mn+-TiO2 photoactivity. In this context, this paper demonstrates the preparation and characterization of Mn2+/Mn7+-TiO2 nanocomposites for investigating the above physicochemical properties for the degradation of toxic herbicide Methyl viologen under sunlight irradiation. The optical spectra of these catalysts showed bathochromic shifts (from 355 to 572 nm) due to the presence of Mn2+ and Mn7+ ions. The higher co-catalyst stability, smaller Dmax (maximum average diameter) and mixed morphological characteristics have been illustrated by SAXS and TEM analysis with size range ∼ 25–30 and 20−35 nm for Mn2+-TiO2 and Mn7+-TiO2 nanocomposites, respectively. The adsorption-desorption studies using NH3 gas revealed that Mn7+ ions generate enhanced Lewis acidity on the co-catalyst surface compared to Mn2+ impregnations. The best fit for Freundlich adsorption isotherm (Kf = 23.44 μg/mg) was possessed by Mn7+-TiO2 than Mn2+-TiO2 and TiO2 photocatalyst confirming its higher substrate affinity and photodegradation efficiency. The Mn2+ and Mn7+ impregnations displayed 2.6 and 3.7 times higher photoactivity than bare TiO2 which has been correlated to different oxidation states and surface structural properties imparted by Mnn+ ions.

Abstract Background Nowadays, the non-steroidal drug diclofenac sodium (DCF) has emerged as hazardous pollutant due to its eco-toxic nature and its efficient elimination from wastewater is emerging as crucial problem. But, low activity, high cost and instability of the conventional photocatalysts restrain their uses. Method In this study, different anion impreganted Cu-Al layered double hydroxides (LDH) and Bi2O3 derived heterocomposites have been examined as plausible photocatalysts for degradation of DCF under visible light radiation. These composites have synthesized by simple wet impregnation methods and characterized by several methods such as XRD, HR-TEM, XPS SEM-EDX, XPS, DRS, phototuminescence(PL), BET etc. Significant Findings The BET sorption isotherms indicate that the anion loaded composites are having larger specific surface area than the pristine one. Also, upon anion impregnation the zeta potential values shift towards more negative values confirming absorption of anions. They show significantly higher (65% for carbonate and 83% for sulphate) photcatalytic activity compare to the parent hybrid (53%). Here, the anions act as efficient electron scavengers to suppress the electron-hole pair recombination. The individual photocatalytic reactions follow pseudo-first order kinetics. Due to low cost, simpler preparation, enhanced activity and recyclability the anion loaded derivatives can emerge as excellent photocatalyst for eradicating DCF.

Abstract The present work demonstrated the extraction, characterization, adsorption and photocatalytic properties of hardness causing minerals obtained from tap water distillation. The resulting white powder material is sintered at different temperature. XRD and EDS analysis revealed that powder residue consists of mainly calcium carbonate (CaCO3) having surface area 35.4 m2g−1 that decomposed to CaO after sintering at 900°C for 4h. This CaCO3 powder displayed effective adsorption and photocatalytic degradation of malachite green dye under sunlight relative to the commercial sample. The impact of different parameters like concentration of dye, amount of catalyst on adsorption and photodegradation was studied in details. The adsorption behavior follows the Freundlich adsorption isotherm and photodegradation process exhibited a higher rate constant of k = 5.1 x 10−2 min−1. Therefore, the use of this material could be a greener approach for effective removal and degradation of toxic effluent in wastewater for large-scale industrial applications.

Abstract This study presents a viable green synthesis approach to produce Ag and Cu nanoparticles (MNPs) by using carbohydrates such as glucose, fructose, sucrose, and starch as reducing agents and describes their antimicrobial activities against Escherichia coli DH5α. Optical and diffused light scattering analyses showed the Ag NPs ranged from 20 to 75 nm and the Cu NPs varied from 20 to 160 nm, which supports the differences in their absorption bands (400–434 nm for Ag and 458–641 nm for Cu). The reducing sugars interacted differently with Ag+ and Cu2+ based on their size and hydrolysis by NaOH resulting in effective stabilization of Ag0 and Cu0 and variation in the bactericidal activities of the MNPs. The antibacterial effects of the MNPs were evaluated by measuring the inhibition zones using E. coli DH5α as a test organism. No growth was observed by restreaking different parts of the clearly inhibited zones into new culture plates indicating the bactericidal efficacy of the Ag and Cu MNPs. The Ag NPs were found to be more effective in terms of the size of their inhibition zones (1.21–1.82 cm) compared with those of the Cu NPs (0.0–1.2 cm). This study provides a promising basis for the formulation of a new generation of bactericidal agents.

Photocatalytic reduction of 25 μmol 2,2'-dinitrobiphenyl in 50% aqueous iso-propanol and 50 mg P25-TiO2 under an argon atmosphere and 20 h UV light irradiation selectively produced 23.8 μmol of benzo[c]cinnoline (95%), and 2,2'-biphenyldiamine (5%) whose amount gradually increased with the irradiation time beyond 20-24 h due to further reduction of benzo[c]cinnoline.

Abstract Water colloidal solutions of iron oxide nanoparticles coated with tetramethylammonium hydroxide were synthesized by co-precipitation methods. Dimensional analyses were accomplished by transmission electron microscopy (TEM) and the crystalline features of nanoparticles were studied by means of X-ray diffraction (XRD). The iron oxide nanoparticle structure was characterized by the use of the attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman spectroscopic techniques. For the nanoparticle samples prepared at higher temperatures during synthesis, the Raman spectra demonstrated that magnetic core of iron oxide nanoparticles is composed of a mixture of magnetite (Fe3O4) and maghemite (γ-Fe2O3) phases. We believe that the oxidation of magnetite to maghemite has been occurred during the preparation protocol of nanoparticles performed at higher temperature.