Controlled release of insecticide carbaryl from crosslinked carboxymethylcellulose beads

WOS: 000222548100011Copper-carboxymethylcellulose (CuCMC) beads containing carbaryl were prepared by the ionotropic crosslinking of sodium carboxymethylcellulose (NaCMC) with copper ions. The beads were characterized by carbaryl encapsulation efficiency, bead diameter, equilibrium swelling degree and carbaryl release kinetics. The spherical nature and surface morphology of the beads were confirmed by scanning electron microscopy (SEM). The effects of the bead preparation conditions such as percent of NaCMC, carbaryl:sodium carboxymethylcellulose (car:NaCMC) ratio, crosslinker concentration and kaolin addition as a filler on carbaryl release were studied. The release results indicated that carbaryl. release from the beads increases with increase in the percentage composition of NaCMC, car:NaCMC ratio, and kaolin addition, but decreases with increase of crosslinker concentration. The equilibrium swelling degree of the beads were also in agreement with the release results. The carbaryl release experiments indicated that the transport deviates from Fickian to non-Fickian mechanism with an increase in car:NaCMC ratio

Separation characteristics of acetic acid-water mixtures by pervaporation using poly(vinyl alcohol) membranes modified with malic acid

WOS: 000229655000012The pervaporation separation of acetic acid-water mixture was carried out using poly(vinyl alcohol) (PVA) membranes modified using malic acid (MA). The effects of PVA/MA ratio, membrane thickness, operating temperature, feed concentration on the transmembrane permeation rate and separation factor were investigated. Optimum PVA/MA ratio was determined as 85/15 (v/v) for 20 wt.% acetic acid mixtures at 40 degrees C. The influence of membrane thickness on the separation factor and the permeation rate was studied in the range of 50-100 mu m at constant acetic acid concentration. It was observed that separation factor was independent of membrane thickness below a limit value of 70 mu m and permeation rate was found to be inversely proportional to the membrane thickness. The prepared membranes were also tested to separate various compositions of acetic acid-water mixtures with 20-90 wt.% acetic acid content at 40 degrees C. Typically, separation factor of 670 and total permeation rate of 4.8 x 10(-2) kg/m(2) h was obtained for 90 wt.% acetic acid concentration in the feed. Arrhenius-type relation and activation energy of 41 kJ/mol was also found for acetic acid-water mixtures. (c) 2005 Elsevier B.V. All rights reserved

Permeation and separation characteristics of acetic acid/water mixtures through poly(vinyl alcohol-g-itaconic acid) membranes by pervaporation, evapomeation, and temperature-difference evapomeation

WOS: 000223020200042In this study, itaconic acid (IA) was grafted onto poly(vinyl alcohol) (PVA) with cerium(IV) ammonium nitrate as an initiator at 45degreesC. The grafted PVA was characterized with Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. IA-grafted PVA membranes were prepared with a casting method, and the permeation and separation characteristics of acetic acid/water mixtures were investigated with pervaporation (PV), evapomeation (EV) and temperature-difference evapomeation (TDEV) methods. The effects of the feed composition, operating temperature, and temperature of the membrane surroundings on the permeation rate and separation factor for the acetic acid/water mixtures were studied. The permeation rates in EV were lower than those in PV, whereas the separation factors were higher. With the TDEV method, the permeation rates decreased and the separation factors increased as the temperature of the membrane surroundings decreased. The prepared membranes were also tested in PV, EV, and TDEV to separate the various compositions of the acetic acid/water mixtures (20-90 wt % acetic acid) at 40degreesC. The highest separation factor, 686, was obtained in TDEV with a 90 wt % acetic acid concentration in the feed. The activation energies of permeation in PV and EV were calculated to be 8.5 and 10.2 kcal/mol, respectively, for a 20 wt % acetic acid solution. (C) 2004 Wiley Periodicals, Inc

Phosphorus-nitrogen compounds. Part VI. Aminolysis of octachlorocyclotetraphosphazatetraene and the crystal structure of 2-trans-6-bis(n-propylamino)-2,4,4,6,8,8-hexakis-tert-butylaminocyclo-2 lambda(5), 4 lambda(5), 6 lambda(5), 8 lambda(5)-tetraphosphazatetraene

Hokelek, Tuncer/0000-0002-8602-4382WOS: 000186239600017The reactions of 2-trans-6-N4P4(NBPrn)(2)CI6 (2), which was obtained from N4P4Cl8 (1) and n-propylamine, with pyrrolidine and t-butylamine in different solvents have been studied. Compound (2) gave two different products, namely monocyclic (3 and 5) and bicyclic (4 and 6) phosphazenes. Compounds (2-6) have been characterized by elemental analysis, IR, H-1-, C-13-, P-31 NMR, HETCOR and MS and the structure of compound (5) has been examined crystallographically. The bicyclic phosphazene (6) is the first exciting example of bicyclic phosphazenes containing chlorine atoms, in the literature. The formation mechanisms of bicyclic phosphazenes are re-considered by taking into account the synthesis of compound (6), which contains three stereogenic phosphorus atoms. Compound (5) crystallizes in the monocyclic space group P2(1) In with a = 13.974(2), b = 17.836(5), and c = 18.683(4) Angstrom, beta = 98.50(1)degrees, V = 4605.4(2) Angstrom(3), Z = 4 and D-x = 1.051 g cm(-3). It consists of a non-centrosymmetric, nonplanar phosphazene ring in a saddle conformation, with two n-propylamino (in 2-trans-6 positions) and six bulky t-butylamino side groups. The bulky substituents are instrumental in determining the molecular geometry. (C) 2003 Elsevier B.V. All rights reserved

Novel amoxicillin nanoparticles formulated as sustained release delivery system for poultry use

Amoxicillin is used in the treatment and prevention of a wide range of diseases in poultry breeding. However, its short half-life and low bioavailability restrict its clinical application in these species. Entrapment of drugs into polymeric nanoparticles (nps) presents a means to improve gastrointestinal absorption and oral bioavailability of drugs. This study was aimed to overcome limitation of amoxicillin use in poultry breeding. Amoxicillin was loaded into sodium alginate-polyvinyl alcohol (NaAlg-PVA) blend nps, and characterization of the prepared nps was performed. For pharmacokinetic study, commercial male broilers were used and comparative pharmacokinetics of free and nanoparticle form of amoxicillin were investigated. Twenty-one broilers were divided into three groups. All groups received 10mg/kg drug. Blood samples were collected, and drug plasma concentrations were determined by HPLC. The results demonstrated that the particle size, zeta potential, encapsulation efficiency, and loading capacity of the nps were 513.96 +/- 19.46nm, -45.36 +/- 1.35mV, 43.66 +/- 3.30, and 12.06 +/- 0.83%, respectively. In vitro drug release exhibited a biphasic pattern with an initial burst release of 18% within 2hr followed by a sustained release over 22hr. The pharmacokinetic results showed that amoxicillin nps have higher bioavailability and longer plasma half-life (p<.01) than free amoxicillin. These results indicate that amoxicillin nano formulation is suitable for oral administration in broilers

Phosphorus-nitrogen compounds. spiro- and crypta-phosphazene derivatives: synthesis and spectral investigations. Structure of butane-N,N '-bis(1,4-oxybenzyl)-spiro(propane-1,3-diamino) tetrachlorocyclo-2 lambda(5), 4 lambda(5), 6 lambda(5),-triphosphazatriene. Part VII

Hokelek, Tuncer/0000-0002-8602-4382; Asmafiliz, Nuran/0000-0002-9335-4101WOS: 000222521900015The condensation reactions between trimer, N3P3Cl6, and diamines, 2 and 4 and {1-{N-[1-(2-hydroxynaphthylmethyl)aminomethylidene]}-2(1H)-naphthalenone, 3, yielded the new spiro-cyclic- (5 and 8) and the novel spiro-phosphazene (7) derivatives, respectively. The fully substituted phosphazene (6) was also obtained from the reaction of 5 with the excess of pyrrolidine. Compounds (4-8) have been characterized by elemental analyses, FTIR, H-1-, C-13-, P-31-NMR, HETCOR, COSY and MS. The structure of crypta-phosphazene, 8, has been examined crystallographically. Compound 8 is the first example of the crypta-phosphazene derivatives. The P-31-NMR spectra of compounds 7 and 8 indicate that, both of the compounds have anisochronism because of the stereogenic centers. The pyramidal geometry of two spiro-cyclic nitrogen atoms in compound 8, gives rise to stereogenic property. The sums of the bond angles around N-4 and N-5 nitrogens are 350.6(2) and 349.6(3)degrees, respectively. Compound 8 crystallizes in the triclinic space group P (1) over bar with a = 8.798(3), b = 10.498(3) and c = 15.689(4) Angstrom; alpha = 91.35(2), beta = 103.39(4) and gamma = 102.88(4)degrees; V = 1369.9(7) Angstrom(3), Z = 2 and D-x = 1.491 g cm(-3). It consists of a non-centrosymmetric, non-planar phosphazene ring with a bulky dibenzo-diazacrown etheric side group. (C) 2004 Elsevier B.V. All rights reserved

Novel amoxicillin nanoparticles formulated as sustained release delivery system for poultry use

Bakirel, Tulay/0000-0001-5805-2178;WOS: 000437133600013PubMed: 29604071Amoxicillin is used in the treatment and prevention of a wide range of diseases in poultry breeding. However, its short half-life and low bioavailability restrict its clinical application in these species. Entrapment of drugs into polymeric nanoparticles (nps) presents a means to improve gastrointestinal absorption and oral bioavailability of drugs. This study was aimed to overcome limitation of amoxicillin use in poultry breeding. Amoxicillin was loaded into sodium alginate-polyvinyl alcohol (NaAlg-PVA) blend nps, and characterization of the prepared nps was performed. For pharmacokinetic study, commercial male broilers were used and comparative pharmacokinetics of free and nanoparticle form of amoxicillin were investigated. Twenty-one broilers were divided into three groups. All groups received 10mg/kg drug. Blood samples were collected, and drug plasma concentrations were determined by HPLC. The results demonstrated that the particle size, zeta potential, encapsulation efficiency, and loading capacity of the nps were 513.96 +/- 19.46nm, -45.36 +/- 1.35mV, 43.66 +/- 3.30, and 12.06 +/- 0.83%, respectively. In vitro drug release exhibited a biphasic pattern with an initial burst release of 18% within 2hr followed by a sustained release over 22hr. The pharmacokinetic results showed that amoxicillin nps have higher bioavailability and longer plasma half-life (p<.01) than free amoxicillin. These results indicate that amoxicillin nano formulation is suitable for oral administration in broilers.Scientific Research Projects Coordination Unit of Istanbul UniversityIstanbul University [44188]Scientific Research Projects Coordination Unit of Istanbul University, Grant/Award Number: 4418

Stereogenic Centers upon the Addition of Chiral Solvating Agents

The reactions of hexachlorocyclotriphosphazatriene, N3P3Cl6, with N/O-donor-type N-alkyl (or aryl)-o-hydroxybenzylamines (la-le) produce mono- (2a-2e), di- (3a-3d), and tri- (4a and 4b) spirocyclic phosphazenes. The tetrapyrrolidino monospirocyclic phosphazenes (2f-2i) are prepared from the reactions of partly substituted compounds (2a-2d) with excess pyrrolidine. The dispirodipyrrolidinophosphazenes (3e-3h) and trispirophosphazenes (3i-3k) are obtained from the reactions of trans-dispirophosphazenes with excess pyrrolidine and sodium (3-amino-1-propanoxide), respectively. Compounds 3a-3d have cis and trans geometric isomers. Only the trans isomers of these compounds are isolated. Compounds 3a-3h have two stereogenic P atoms. They are expected to be in cis (meso) and trans (racemic) geometric isomers. In the trans trispiro compounds (3i-3k), there are three stereogenic P atoms. They are expected to be in racemic mixtures. The stereogenic properties of 3a-3k are confirmed by P-31 NMR spectroscopy upon the addition of the chiral solvating agent; (S)-(+)-2,2,2-trifluoro-1-(9'-anthryl)ethanol. The molecular structures of 3i-3k, 4a, and 4b look similar to a propeller, where the chemical environment of one P atom is different from that of others. Additionally, 4a and 4b are also expected to exist as cis-trans-trans and cis-cis-cis geometric isomers, but both of them are found to be in cis-trans-trans geometries. The solid-state structures of 2a, 2e, 2f, 3e, and 31 are determined by X-ray crystallography. The compounds 2f-2i, 3e-3i, and 3k are screened for antibacterial activity against Gram-positive and Gram-negative bacteria and for antifungal activity against yeast strains. These compounds (except 3f) have shown a strong affinity against most of the bacteria. Minimum inhibitory concentrations (MIC) are determined for 2f-2i, 3e-3i, and 3k. DNA binding and the nature of interaction with pUC18 plasmid DNA are studied. The compounds 2f-2i, 3e-3i, and 3k induce changes on the DNA mobility. The prevention of BamHI and HindIII digestion (except 2g) with compounds indicates that the compounds bind with nucleotides in DNA