On-line multidimensional liquid chromatography and capillary electrophoresis systems for peptides and proteins.

Peptides and proteins are gaining increasing attention in biosciences and, consequently, in analysis. This overview highlights the different approaches to couple on-line various separation techniques for the determination of proteins and peptides. The first section discusses the liquid chromatography (LC)-LC coupling, the second one reviews the on-line LC-capillary electrophoresis (CE) coupled systems and the third section summarizes the strategies for on-line CE-CE.

On-line coupling of size-exclusion chromatography and capillary zone electrophoresis via a reversed-phase C18 trapping column for the determination of peptides in biological samples.

Since biologically active peptides usually exhibit their effects in low concentrations, the development of sensitive analytical methods has become a challenge. In this paper, a multidimensional system is presented, consisting of a size-exclusion chromatographic (SEC) separation followed by a trapping procedure on a 4 mm x 3 mm ID reversed-phase C18 (RP18) column with subsequent elution of the trapped fraction and separation by capillary zone electrophoresis (CZE). The system has been tested with mixtures of six enkephalins and albumin, mimicking biological matrices such as plasma and cerebrospinal fluid.

On-line coupling of size exclusion and capillary zone electrophoresis via a reversed-phase C18 trapping column for the analysis of structurally related enkephalins in cerebrospinal fluid.

On-line coupled analytical techniques can be advantageous in the assay of smaller peptides in complex biological matrices such as plasma, cerebrospinal fluid (CSF) and tissues. The present study shows the feasibility of a recently developed system, consisting of a size-exclusion chromatographic (SEC) separation followed by a trapping procedure on an RP18 microcolumn with subsequent elution of the trapped fraction and separation by capillary zone electrophoresis (CZE) for the quantification of structural-related peptides in biological matrices, as demonstrated for a number of enkephalins in CSF. After SEC separation of the enkephalins from large proteins present in CSF a heart-cut of 200 nuL, containing the enkephalin peak, is taken, concentrated on the RP18 microcolumn and, after elution of the enkephalins with 80% acetonitrile, a fraction of the eluate is electrokinetically injected into the CZE system, where stacking and separation is achieved.

Development of a LC method for pharmaceutical quality control of the antimetastatic ruthenium complex NAMI-A.

Imidazolium trans-tetrachloro(dimethylsulfoxide)imidazoleruthenium(III) (NAMI-A) is a novel ruthenium complex with selective activity against metastases currently in Phase I clinical trials in the Netherlands. Pharmaceutical quality control of NAMI-A drug substance and lyophilized product warranted the development of an assay for determination and quantification of NAMI-A and degradation products. A high performance liquid chromatography (HPLC) method was developed, consisting of a C18 column with 0.

A kinetic study of the chemical stability of the antimetastatic ruthenium complex NAMI-A.

NAMI-A is a novel ruthenium complex with selective activity against cancer metastases currently in Phase I clinical trials in The Netherlands. The chemical stability of this new agent was investigated utilizing a stability-indicating reversed-phase high performance liquid chromatographic assay with ultraviolet detection and ultraviolet/visible light spectrophotometry. The degradation kinetics of NAMI-A were studied as a function of pH, buffer composition, and temperature.

On-line coupling of SEC and RP-LC for the determination of structurally related enkephalins in cerebrospinal fluid.

On-line coupled analytical techniques can be advantageous in the assay of smaller peptides in complex biological matrices such as plasma, cerebro-spinal fluid (CSF) and tissues. The present study shows the feasibility of the recently reported on-line coupled size exclusion chromatography (SEC) and reversed phase liquid chromatography (RP-LC) separation system for the quantitation of structural related peptides in biological matrices, as demonstrated for a number of enkephalins in CSF. The degradation of the peptides, caused by endogenous peptidases in the matrix, could sufficiently be inhibited with imipramine HCL to allow an assay with satisfactory linearity and intraday (0.

Photostability profiles of the experimental antimetastatic ruthenium complex NAMI-A.

NAMI-A is a novel ruthenium complex with selective activity against metastases currently in Phase I clinical trials in The Netherlands. The photostability of this new agent in solid state and in solution has been investigated utilizing a stability-indicating reversed-phase high performance liquid chromatographic (HPLC) assay and ultraviolet/visible (UV/VIS) light spectrophotometry. In solid state, NAMI-A proved to be photostable.