Blood microsampling in cynomolgus monkey and evaluation of plasma PK parameters in comparison to conventional sampling.

Microsampling, a reduced volume sampling method, has successfully gained attention at the International Conference on Harmonization (ICH) level and established benefits support its use in Toxicokinetic (TK) studies. These improved sampling techniques are less invasive and in large animal species improve animal welfare (refinement). To evaluate if the plasma concentrations of drugs were influenced by the blood sampling method, the traditional method from femoral vein and microsampling from tail vein in Cynomolgus monkeys were compared.

Development and validation of bioanalytical methods for LNA-i-miR-221 quantification in human plasma and urine by LC-MS/MS.

LNA-i-miR-221, a 13-mer oligonucleotide, has proved favorable efficacy and safety profiles in the preclinical studies, leading to being approved for use in clinical trials by regulatory authorities. The objective of this study was to develop and validate LC-MS/MS methods to quantify LNA-i-miR-221 in human plasma and urine. Chromatographic separation was performed with a gradient system on HALO C18 column using hexafluoro-2-propanol/triethylamine buffer and methanol as mobile phase.

Development and validation of a highly sensitive gradient chiral separation of pramipexole in human plasma by LC-MS/MS.

Aim: Development of a high-sensitivity chiral LC-MS/MS method was required to evaluate a combination of pramipexole (S-PPX) and its enantiomer dexpramipexole (R-PPX) in a proposed clinical trial. The previously available methods suffered from low sensitivity for the (S)-enantiomer in the presence of the more abundant (R)-enantiomer. Based on the projected dosing regimen in the clinical trial, a 5000-fold improvement in sensitivity was required for the (S)-enantiomer.

Recommendations on bioanalytical method stability implications of co-administered and co-formulated drugs by Global CRO Council for Bioanalysis (GCC).

An open letter written by the Global CRO Council for Bioanalysis (GCC) describing the GCC survey results on stability data from co-administered and co-formulated drugs was sent to multiple regulatory authorities on 14 December 2011. This letter and further discussions at different GCC meetings led to subsequent recommendations on this topic of widespread interest within the bioanalytical community over the past 2 years.

Pharmacokinetics and pharmacodynamics of CHF5074 after short-term administration in healthy subjects.

CHF5074 has been shown to inhibit brain β-amyloid deposition and attenuate memory deficits in different transgenic mice models of Alzheimer disease. We evaluated the safety, pharmacokinetics, and pharmacodynamics of 3 ascending dose regimens of CHF5074 (200, 400, and 600 mg/d for 14 d) in a double-blind, placebo-controlled, parallel group study involving 48 healthy subjects. Plasma, urine, and cerebrospinal fluid (CSF) samples were collected for measuring drug and main metabolite concentrations and potential biomarkers of pharmacodynamic activity (β-amyloid1-40, β-amyloid1-42, soluble CD40 ligand, and tumor necrosis factor-α).

Conference report: the 3rd Global CRO Council for Bioanalysis at the International Reid Bioanalytical Forum.

The 3rd Global CRO Council Closed Forum was held on the 3rd and 4th July 2011 in Guildford, United Kingdom, in conjunction with the 19th International Reid Bioanalytical Forum. In attendance were 21 senior-level representatives from 19 CROs on behalf of nine European countries and, for many of the attendees, this occasion was the first time that they had participated in a GCC meeting. Therefore, this closed forum was an opportunity to increase awareness of the aim of the GCC and how it works, share information about bioanalytical regulations and audit findings from different agencies, their policies and procedures and also to discuss some topics of interest and aim to develop ideas and provide recommendations for bioanalytical practices at future GCC meetings in Europe.

A review of analytical methods for the determination of 5-fluorouracil in biological matrices.

5-Fluorouracil (5-FU) is a cytostatic agent that has been widely used in the treatment of various solid tumours for more than 20 years, and is still considered to be among the most active antineoplastic agents in advanced colorectal cancer and malignancies of the head and neck. A large number of non-chromatographic and chromatographic methods for the quantitation of 5-FU, related prodrugs and their metabolites in biological matrices have been developed in the last 30 years to support preclinical and clinical studies. However, 5-FU monitoring has not been widely used, at least not in the USA, and certainly not outside the clinical research setting, given the absence of simple, fast and inexpensive testing methods for 5-FU monitoring.

Hydrophilic interaction liquid chromatography-APCI-mass spectrometry determination of 5-fluorouracil in plasma and tissues.

A simple and fast analytical method using hydrophilic interaction liquid chromatography (HILIC) coupled with mass spectrometry was developed to analyse 5-fluorouracil (5-FU) in plasma and tissues. The HILIC system overcomes problems reported in obtaining satisfactory retention of 5-FU with other types of HPLC systems. After addition of internal standard (IS) (5-Chlorouracil (5-CU)), plasma proteins were precipitated with acetonitrile, and tissue samples homogenised with a micro-dismembrator.

Ion-suppression effects in liquid chromatography-tandem mass spectrometry due to a formulation agent, a case study in drug discovery bioanalysis.

Liquid chromatography-tandem mass spectrometry (LC/MS/MS) has become the technology of choice for bioanalysis, due to its high selectivity and high sample throughput. However, concerns have grown that this technique may be subject to errors due to "invisible" interferences, in particular ion-suppression. Investigations on ion-suppression from formulation agents have only been published to a limited extent.

Assessment of normal and tumor tissue uptake of MAG-CPT, a polymer-bound prodrug of camptothecin, in patients undergoing elective surgery for colorectal carcinoma.

Purpose: MAG-camptothecin (MAG-CPT) is the lead compound of a novel drug delivery system in which an active cytotoxic moiety, camptothecin (CPT), is covalently linked to a soluble polymeric carrier (MAG) to form an inactive prodrug. The mechanism of action of CPT remains unaltered, but the delivery system is thought to allow the carrier-bound drug to accumulate in tumor tissues and release the active CPT locally. This proof-of-concept clinical study was designed to determine whether MAG-CPT was preferentially delivered to or retained in tumor tissue compared to adjacent normal tissue or plasma, and to estimate the degree of intratissue release of CPT.

Quantitative determination of paclitaxel in human plasma using semi-automated liquid-liquid extraction in conjunction with liquid chromatography/tandem mass spectrometry.

This paper describes a high-throughput sample preparation procedure combined with LC-MS/MS analysis to measure paclitaxel in human plasma. Paclitaxel and an internal standard were extracted from plasma by a semi-automated robotic method using liquid-liquid extraction. Thereafter compounds were separated on a RP C18 column.