High-performance liquid chromatographic determination of diclofenac in human plasma after solid-phase extraction.

A novel high-performance liquid chromatographic (HPLC) method for the quantification of diclofenac in human plasma was set up. Samples, added with ibuprofen (used as internal standard) were purified by solid-phase extraction using Abselut Nexus cartridges (Varian) not requiring pre-conditioning. Drugs of interest were eluted directly into the autosampler vials and injected.

Quantification of gentamicin in Mueller-Hinton agar by high-performance liquid chromatography.

The aim of this study was to optimise a method for gentamicin determination in an agar matrix and to investigate if and how agar composition can affect the gentamicin diffusion kinetics during the agar diffusion tests for antibiotics sensitivity. Gentamicin was separated by RP-HPLC and detected at 365 nm after pre-column derivatization with 1-fluoro-2,4-dinitrobenzene. Recovery (> or = 79%), linearity (r2 > or = 0.

Evaluation of ceftazidime concentration released in agar from an E test strip.

The aim of this study was to evaluate, using high-performance liquid chromatography, the concentration of ceftazidime in agar released from an E test strip, sampling at the edge of the strip at different points (1, 2, 4, 8, 16, 32, 64, and 128 microg/ml) at 6, 15, and 24 h after its deposition on uninoculated plates. From 6 to 24 h, the ceftazidime concentration in agar increased at the graduations 1, 2, and 4 microg/ml (+140, +82, and +58%, respectively), remained fairly constant at 8 microg/ml (-1.9%), and decreased at 16, 32, 64, and 128 microg/ml (-25, -44, -36, and -58%, respectively).

Processing and release of human proinsulin-cleavage products into culture media by different engineered non-endocrine cells: a specific assessment by capillary electrophoresis.

The aim of this study was to compare the metabolic pathway to mature insulin through the intermediate forms (32-33 split, 65-66 split, des31,32 and des64,65) in human or murine cells engineered for the release of wild-type human proinsulin and in a genetically mutated one, in the search for a new approach for an insulin-dependent diabetes mellitus cure by gene therapy. Primary human fibroblasts, myoblasts and stabilized cell lines (HepG2 and NIH3T3) were transduced either with a retroviral vector coding for wild-type proinsulin or for a genetically mutated one, carrying cleavage sites sensitive to furin. The pattern of all the proinsulin cleavage products released into the cell culture supernatants was analyzed by capillary electrophoresis.

Multi-step purification strategy for RANTES wild-type and mutated analogues expressed in a baculovirus system.

RANTES (regulated on activation, normal T cell expressed and secreted), a C-C chemokine, is one of the major HIV-suppressive factors produced by CD8+ T cells. Wild-type RANTES and genetically modified analogues were expressed in a baculovirus system and purified from cell culture supernatants employing a multi-step strategy based on affinity and RP-HPLC. Quantification and purity control of the final proteins were carried out by capillary electrophoresis using the synthetic or the recombinant wild-type RANTES as a reference.