The Effect of Enantiomer Elution Order on the Determination of Minor Enantiomeric Impurity in Ketoprofen and Enantiomeric Purity Evaluation of Commercially Available Dexketoprofen Formulations

In a recent study, opposite enantiomer elution order was observed for ketoprofen enantiomers on two amylose-phenylcarbamate-based chiral columns with the same chemical composition of the chiral selector but in one case with coated while in the other with an immobilized chiral selector. In the present study, the influence of this uncommon effect on method validation parameters for the determination of minor enantiomeric impurity in dexketoprofen was studied. The validated methods with two alternative elution orders for enantiomers were applied for the evaluation of enantiomeric impurity in six marketed dexketoprofen formulations from various vendors. In most of these formulations except one the content of enantiomeric impurity exceeded 0.1% (w/w).

Isolation and Antimicrobial Activities of Lactic Acid Bacteria Originated From Indonesian Local Goat’s Colostrum

The objectives of this study were to isolate lactic acid bacteria (LAB) from Indonesian local goat colostrum and to characterize their suitable properties for bacteriocin production. LAB was isolated from goat colostrum. The characterization of LAB was carried out based on the shape, colony dispersal, and catalase test. For antimicrobial activity, LAB was tested by a well diffusion method followed by an antimicrobial activity test against pathogenic bacteria B. cereus, E.coli, S. aureus and S. thypimurium. A total of 8 strains of LAB were successfully isolated from goat colostrum and coded CT1 to CT8. All the isolates were rod-shaped, single or paired colonies, negative catalase, and glucose fermenting LAB. The isolates consist of four L. casei, two L. brevis or L. plantarum, one L. rhamnosus, and one, L. paracasei. CT3 isolate has 84% similarity with L. plantarum and 14.3% with L. brevis 1while CT8 isolate is 71% similar to L. brevis 1 and 28.9% to L. plantarum. Purity evaluation showed that CT3 and CT8 were L. plantarum. Well difusion test showed that all LAB strains possess very solid resistances, with diameters over 17 mm, against B. cereus, E.coli, S. aureus and S. thypimurium. The average inhibitory resistance against B. Cereus, E.coli, S.aureus and S.typhimurium was was 17.68 mm, 19.38, 19.30 and 19.03 mm, respectively. LAB isolated from Indonesian local goat colostrum are potential candidates for bacteriocin-producing bacteria.

Structural and spectroscopic investigations on the quenching free luminescence of europium oxalate nanocrystals

The structural features leading to the intense quenching free luminescence exhibited by europium oxalate nanocrystals, poly[[hexaaquatri-μ2-oxalato-dieuropium] 4.34-hydrate], {[Eu2(C2O4)3(H2O)6]·4.34H2O} n , is the focal point of this report. Europium oxalate nanocrystals were synthesized by a simple microwave-assisted co-precipitation method. Powder X-ray diffraction analysis revealed the monoclinic structure of the nanocrystals and the phase purity. The morphology and particle size were examined by transmission electron microscopy (TEM) analysis. Luminescence measurements on a series of samples of La2–x Eu x (C2O4)3·10H2O, with x varying in the range 0.1 to 2, established the quenching free nature exhibited by the europium oxalate nanocrystals. A single-crystal structure analysis was carried out and the quenching free luminescence is explained on the basis of the crystal structure. A detailed photoluminescence characterization was carried out using excitation and emission studies, decay analysis, and CIE coordinate and colour purity evaluation. The various spectroscopic parameters were evaluated by Judd–Ofelt theoretical analysis and the results are discussed on the basis of the crystal structure analysis.