A new series of thirty-one quinazolinone-chalcone hybrid molecules 13-43 were designed, synthesized, and structurally characterized by different spectroscopic techniques. All the synthesized compounds were investigated for in vitro cytotoxic activity...

We designed a new series of boronic acid-functionalized squarylium cyanine dyes (SQ-BA) with different lengths of alkyl chain residues, suitable for multiple discriminant analysis (MDA) of sialic acid (Neu5Ac) in biological samples. The SQ-BA dyes form aggregates based on hydrophobic interactions, which result in quenched fluorescence in aqueous solutions. When the boronic acid binds with saccharides, the fluorescence intensity increases as a result of dissociation to the emissive monomeric complex. We inferred that different dye aggregate structures (H-aggregates and J-aggregates) were induced depending on the alkyl chain length, so that monosaccharides would be recognized in different ways (especially, multipoint interaction with J-aggregates). A distinctive emission enhancement of SQ-BA dyes with shorter-alkyl-chains in the presence of Neu5Ac was observed (2.4-fold fluorescence enhancement; with formation constant 10(1.7) M(-1)), with no such enhancement for SQ-BA dyes with longer-alkyl-chain. In addition, various enhancement factors for other monosaccharides were observed depending on the alkyl chain length. Detailed thermodynamic and NMR studies of the SQ-BA complexes revealed the unique recognition mechanism: the dye aggregate with a shorter-alkyl-chain causes the slipped parallel structure and forms a stable 2:1 complex with Neu5Ac, as distinct from longer-alkyl-chain dyes, which form a 1:1 monomeric complex. MDA using the four SQ-BA dyes was performed for human urine samples, resulting in the successful discrimination between normal and abnormal Neu5Ac levels characteristic of disease. Thus, we successfully controlled various responses to similar monosaccharides with a novel approach that chemically modified not the boronic acid moiety itself but the length of the alkyl chain residue attached to the dye in order to generate specificity.

A N ISOCRATIC RP-HPLC method has been developed for rapid and simultaneous separation and estimation of three antidiabetics drugs, metformin, gliclazide and glimepiride in tablet dosage forms within 6 minutes. Separation was carried out on a Thermo Scientific ® BDS Hypersil C 8 column (5µm, 2.50 x 4.60 mm) using a mobile phase of MeOH : 0.025M KH 2 PO 4 adjusted to pH 3.20 using ortho-phosphoric acid (70: 30, v/v) at ambient temperature. The flow rate was 1 mL/min and UV detection was set at 235 nm. The retention time of metformin, gliclazide and glimepiride was noted to be 3.06, 4.33 and 6.00 minutes respectively, indicating a very short analysis time rather than other reported methods. Also, limits of detection were reported to be 0.05, 1.21 and 0.11 µg/mL for metformin, gliclazide and glimepiride, respectively, showing a high degree of the method sensitivity. The method was then validated according to ICH guidelines where it was found to be accurate, reproducible and robust. Finally, the method was compared statistically with reference methods indicating that there is no significant difference between them in respect of precision and accuracy.

No abstract

No abstract