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J C Pearce

Publications and source records attributed to J C Pearce.

10 recordsLinked to original sources
PubMed1989

Analysis of 2-cyano-1-methyl-3-[4-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl phenyl]guanidine in dog plasma by liquid-solid extraction and reversed-phase high-performance liquid chromatography.

A method for the determination of 2-cyano-1-methyl-3-[4-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin- 3- yl)phenyl]guanidine (SK&F94836, 1) in plasma is presented. The method involves liquid-solid extraction of the drug by C18 cassettes, with subsequent elution by an AASP LC module for determination by HPLC with UV detection. The assay is rapid, precise, accurate, and specific. The between-day CV values over the concentration range 50-500 ng/mL are 4% or less; this rises to 8% at 25 ng/mL. The corresponding between-day bias is less than 1% over the same range of concentrations. The limit of quantification is 25 ng/mL and the assay can be used for measuring 1 in samples from preclinical studies following either oral or intravenous administration of the compound.

Administration, Oral↗
PubMed1988

Laboratory Information Management Systems--part I. Concepts.

The purpose of this analytical survey is to give a summary of some of the main design features that can be incorporated into a Laboratory Information Management System (LIMS), in the context of the total automation of the laboratory. Additionally it will give potential purchasers of such systems some essential background knowledge and a summary of our experiences. The survey is presented in two parts: the first covers the features and the possible concepts that could be used in a LIMS system. This is followed in the second part by an outline of the stages of acquisition, validation and benefits of such a system. Together the two articles provide the information required to aid the design and installation of a LIMS. This first section deals with the possible features that a laboratory could include when contemplating the installation of such a system: the basic tools that are required for a LIMS, the database and the computer equipment are discussed. This is followed by the interfacing of analytical instruments and central versus distributed processor philosophy. The various screen formats available and the use of bar codes as a means of identifying samples and for rapid data entry into the computer system are discussed.

Journal Article↗
PubMed1988

Laboratory Information Management Systems--part II. Implementation.

In this, the second of two articles on Laboratory Information Management Systems (LIMS), the stages of the acquisition of a system are discussed. First, the laboratory automation strategy is developed leading to the writing of the requirements specification sent to prospective suppliers. The next step, in conjunction with the chosen supplier, is to write the functional and systems specifications from which the LIMS will be tailored. Once installed the LIMS must be validated and in the event of hardware or software changes, should undergo partial or full re-validation. The education and training of users, and operational considerations are presented before concluding with possible developments of LIMS in the future.

Journal Article↗
PubMed1988

The analysis of SK&F 94120, a novel inotropic agent, and its four metabolites by isolation on C18 AASP cassettes followed by high-performance liquid chromatography.

A selective and specific assay for SK&F 94120 [5-(4-acetamidophenyl)pyrazin-2(1H)-one] and its four metabolites in plasma has been developed. The method incorporates a single liquid-solid extraction step using C18 Analytichem Automated Sample Processor (AASP) cassettes. This is followed by successive elutions of the solid phase with two mobile phases of increasing acetonitrile content, by an AASP liquid chromatography module. A mobile phase containing 10% acetonitrile elutes a glucuronide metabolite from the cartridge which is then chromatographed and quantified intact. A second mobile phase, containing 20% acetonitrile, is then used to elute the unchanged drug and the three other metabolites from the same cartridge. The assay shows good accuracy and precision (less than 10% for all analytes) and is able to determine SK&F 94120 and its metabolites in plasma at concentrations between 0.05 and 1.00 mg l(-1).

Journal Article↗
PubMed1987

Analysis of drugs from biological fluids using disposable solid phase columns.

The traditional liquid-liquid extraction method for the removal of drug from biological matrix is being superseded by solid phase extraction. This involves the selection of an appropriate sorbent (normal-phase, reversed-phase, ion-exchange etc.), but once this has been achieved the method is quick and simple to operate. Most sample handling losses are avoided so recovery of drug is high and it is easily automated. Disposable columns have several advantages. Samples of 0.05-2.0 ml can be analysed routinely. Several wash stages can be included in a method to provide a specific extraction prior to a quick analysis by high-performance liquid chromatography (HPLC), radioimmunoassay, UV etc. A potential problem is that retention of the drug may involve more than one mechanism. Elution of drug may therefore require a stronger eluting solvent than analytical HPLC systems using the same stationary phase.

Antihypertensive Agents↗
PubMed1986

Analysis of 5-(4-acetamidophenyl)pyrazin-2(1H)-one (SK&F 94120) in plasma with an Analytichem automated sample processor liquid chromatography module.

A selective and specific assay for 5-(4-acetamidophenyl)pyrazin-2(1H)-one (SK&F 94120), a novel inotropic agent, has been developed. The method incorporates a liquid-solid extraction step with a C18 Analytichem automated sample processor (AASP) cassette, which consists of ten miniature extraction columns. The cassette is then loaded into the AASP auto injector, ready for automated liquid chromatography with UV detection. The AASP consists of a high-pressure sealing chamber which encapsulates each column. The high-performance liquid chromatographic mobile phase is directed through the chamber, and the analytes are eluted onto the analytical column for subsequent separation and measurement. The assay is sufficiently accurate and precise to determine SK&F 94120 at concentrations as low as 0.5 mg/l. The mean coefficient of variation for the concentration range 0.5-10.0 mg/l was 2% with a bias of +/- 1%. The assay has been used for pharmacokinetic and bioavailability studies in several species, including rat, dog, and cynomolgus monkey.

Animals↗
PubMed1986

Liquid-solid sample preparation in drug analysis.

This article compares liquid-solid extraction (LSE) with the more conventional liquid-liquid extraction (LLE) for the preparation of biological samples for assay. The commercially available manual LSE methods, Sep-Pak and Bond Elut, as well as the automated instruments Prep and Analytichem Automated Sample Processor (AASP), are reviewed. Using examples from the literature and the authors' own experiences a practical guide is given to the advantages and disadvantages of LSE.

Journal Article↗