Authors:Yi Changhou, Jin Jannan, Zhang Shuyuan, Wang Ketai, Zhang Dayuan, and Zhou Maolun
An organic compound labelled by using radioastatine was conjugated to a protein.211At reacts with the diazo-compound of para-aminobenzoic acid to yield para-astatobenzoic acid, which is separated by ether extraction and high performance liquid chromatography (HPLC) and then conjugated with IgG and bovine serum albumin (BSA) via an acylation reaction. The results of the animal experiments have shown that the211At-carbon bond is stable in vivo and the conjugate contains at least 40% of the initial activity of211At. Astatine-211 labelled proteins have also been prepared by direct oxidation with hydrogen peroxide or Chloramine-T. The separation of labelled proteins by Sephadex chromatography is very effective. The structure of proteins affects the labelling results and the yield of211At-BSA labelled by oxidation with hydrogen peroxide can be increased up to 96.4%.
The intestinal microflora
has been adapted to utilize, as a source of energy, complex carbohydrates that escape hydrolysis by human digestive enzymes, for example fructo-oligosaccharides (FOS). The ability of intestinal microflora to utilize carbohydrates in complex mixtures is of particular interest, even though few data have been reported. This paper presents the results obtained using an innovative analytical approach based on instrumental HPTLC-AMD (automated multiple development) to investigate the metabolic behavior of
MB 239 as a case study. Raffinose, FOS (sucrose, 1-kestose, nystose, fructosyl-nystose), lactose, and their monomeric moieties glucose, galactose, and fructose were simultaneously present as carbon sources in the solution to be fermented by the bacterium. The method proposed has enabled quantitative monitoring of sugar concentrations during the entire time-course of the processes. The complex sugar mixtures were separated by use of acetonitrile-acetone-water mobile phases on diol layers derivatized with 4-aminobenzoic acid.
Authors:H. S. O. Chan, S. C. Ng, S. H. Seow, W. S. Sim, and T. S. A. Hor
The thermal characteristics of polyaniline (PANI), poly(o-aminobenzoic acid) (POABAC) and poly(o-aminobenzyl alcohol) (POABOL) are determined and compared by thermogravimetry (TG) and differential scanning calorimetry (DSC). The higher thermal stability of POABOL is attributed to heat-induced condensation between the polymer chains. The DSC results suggest both intra- and inter-molecular interaction in the form of hydrogen bonding due to the substituent group in POABAC and POABOL. These interactions, however, occur mainly in the doped from and is greatly reduced when the dopant is expelled from the system at higher temperatures.
The present article describes the synthesis, structural features and thermal studies of the complexes of the type [M(SB)2(H2O)2]·nH2O [where HSB=pyridine-m-carboxaldene-o-aminobenzoic acid and M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)]. The complexes have been characterized on the basis of elemental analyses, magnetic susceptibility measurements, (FTIR and electronic) spectra and thermal studies. The nature of the bonding has been discussed on the basis of infrared spectral data. Magnetic susceptibility measurements and electronic spectral data suggest a six-coordinated structure of these complexes. The complexes of Mn(II), Co(II), Ni(II), Cu(II) are paramagnetic, while Zn(II) and Cd(II) are diamagnetic in nature.
The thermal decomposition of the complexes have been studied and indicates that not only the crystallization and coordinated water are lost but also that the decomposition of the ligand from the complexes is necessary to interpret the successive mass losses. The kinetic parameters such as order of reaction (n) and the energy of activation (Ea) have been reported using Freeman–Carroll method. The entropy (S*), the pre-exponential factor (A), the enthalpy (H*) and the Gibbs free energy (G*) have been calculated.
A DSC compositional analysis of 3 model binary systems of pharmaceutical significance has been conducted. Mixtures of known
selected composition for each of the systems 3,5-dinitrobenzoic acid/benzoic acid, paracetamol/4-aminobenzoic acid and acetylsalicylic/salicylic
acid were prepared and analyzed by DSC. The respective compositions derived from applications of the van't Hoff equation were
correlated with the corresponding theoretical values and with the corresponding fusion temperatures and fusion enthalpies,
obtained from the relevant DSC profiles.
Linear correlations were found to exist between the theoretical compositions, fusion temperatures and fusion enthalpies for
each of these systems and it is apparent that with suitable calibration procedures, the DSC compositional analysis method
can be applied to determine the purity at the 90–95 mole% level. This level is of considerable interest in drug stability
studies and has real significance in purity assays of commercial pharmaceutical preparations.
Authors:S. Bojcsev, A. Almási, H. Simon, P. Perjési, and Emil Fischer
Lauterbach F, Schorn M, Sprakties G, Sund RB: Compartmentalization of intestinal conjugation reactions and conjugate transports: studies with phenols and p-aminobenzoicacid. Progr. Pharmacol. Clin. Pharmacol 7, 231–242 (1982)
Authors:Annamária Krajníková, Katarína Győryová, Jana Kovářová, Daniela Hudecová, Jana Hubáčková, Faten Nour El-Dien, and Marián Koman
scientists [ 3 – 5 ]. As a bioactive ligand in these complexes drugs (phenazone, papaverine), vitamins (nicotinamide, 2-aminobenzoicacid) or compounds with antimicrobial activity (benzoic and salicylic acid) can be used [ 6 – 9 ]. It was found that the
Authors:Giuseppina Castronuovo and Marcella Niccoli
-Rylic , M , Kumeev , RS 2010 Thermodynamics of inclusion complex formation of hydroxypropylated α- and β-cyclodextrins with aminobenzoicacids in water . J Therm Anal Calorim 101 : 15 – 23 10.1007/s10973