Simultaneous spectrophotometric determination of chlordiazepoxide and clidinium using multivariate calibration techniques.

Three multivariate modelling approaches including partial least squares regression (PLS), genetic algorithm-partial least squares regression (GA-PLS), and principal components-artificial neural network (PC-ANN) analysis were investigated for their application to the simultaneous determination of chlordiazepoxide and clidinium levels in pharmaceuticals. A set of synthetic mixtures of drugs in ethanol and 0.1 M HCL was made, and the prediction abilities of the aforementioned methods were examined using RSE% (relative standard error of the prediction).

Intracellularly grown gold nanoparticles as potential surface-enhanced Raman scattering probes.

Gold nanoparticles grown within the intracellular confines of living cells are introduced as potential surface-enhanced Raman scattering (SERS) substrates for confocal Raman spectrometry. Electron microscopy and a silver-enhanced reflectance laser scanning confocal microscopic approach were used to visualize the size, shape, and distribution of intracellularly grown gold nanoparticles (IGAuN) as small as 1 nm. Passive uptake as the conventional approach for delivering nanoparticles inside cells faces the insurmountable challenge of escaping the endosomal/lysosomal pathway.

DNA as an enzyme. The effect of imidazole derivatives as cofactors and metal ions as activators or inhibitors.

Objective: A highly sensitive spectrofluorometric method using dichlorofluorescin (LDCF) was employed to study the rate of electron transfer reaction in presence of DNA and some imidazole derivatives.

Results: In our experiments, DNA possessed a unique enzyme like catalytic function in oxidative conversion of nonfluorescent LDCF to fluorescent dichlorofluorescein (DCF). The rate enhancement was associated with the turn over constant: k(p) = 10 s(-1) for DNA and cinnamoyl imidazole as a cofactor.