Application of New Analytical Techniques to Pharmacology

Abstract

Tennessee 6572Increasingly sensitive and systematic probes into the microchemistry at the receptor and cellular level in a physiological system continue to demonstrate the complexity of such an environment. The awareness that minor constituents can play a major role in mediating physiological responses has resulted in even greater demands on analytical methodology. The investigator, realizing that his" model" is no better than his methodology, seeks to isolate or measure selectively the concentration of a specific drug or hormone that is available to target tissue. The central theme of this chapter emphasizes new developments in the purification of biological samples that may contain lab ile molecules, detection of minor constituents with great specificity, and fixation of tissue to retain or more closely represent in vivo concentrations of certain heat stable drugs and hormones.Affinity chromatography, based on the biological principle of immuno chemistry, can be used as a single-step method of isolating or purifying enzymes and other macromolecules with high retention of biological activity. Applications are described for the isolation of a glucagon receptor as well as purification of acetylcholinesterase, tetrahydrofolate dehydrogenase, and various cell types. This technique also offers the possibility of selectively isolating trace quantities of a drug or specific hormone from biological fluids.Liquid chromatography holds new promise for the preliminary purification of biological samples prior to quantification by other techniques. Several new developments in high-pressure liquid chromatography permit better interaction between sample and partitioning phases resulting in faster, more efficient separa tions comparable to those obtained in gas-liquid chromatography. Examples of separating classes of benzodiazepines, coumarins, steroids, and vitamins by high pressure liquid chromatography are described as well as applications of reversed-phase and gel permeation chromatography.Multiple ion detection (MID) is described as an adjustable selective detector for biologically important molecules that are suitable for vapor phase analysis. The usefulness of this technique is demonstrated with the analysis of a complex biological sample (urinary catecholamine metabolites) that overwhelmed a flame ionization and electron capture detector, but yet was amenable to MID. Another application of MID with stable isotopes is described in the context of prostaglan din analysis. New developments in on-line data acquisition and oscilloscopic display by computer are contrasted with conventional oscillographic recording of MID data. 391Annu. Rev. Pharmacol. 1973.13:391-407. Downloaded from www.annualreviews.org Access provided by New York University -Bobst Library on 05/27/15. For personal use only.Quick links to online content Further ANNUAL REVIEWS

Gas-liquid chromatographic/mass spectrometric confirmatory assay for thiabendazole and 5-hydroxythiabendazole

“…However, a mass spectrum resulting from a single scan is of little value for quantitative purposes. The use of a mass spectrometer as a selective GLC detector is well established (Brooks and Middleditch, 1971; Jenden and Cho, 1973;Watson, 1973). Thus, Cala et al (1972), Palmer and Kolmodin-Hedman (1972), and Mirocha et al (1973) have employed GLC-MS techniques to validate other assays for pyrimethamine in chicken tissue, , -DDE in human plasma, and diethylstilbestrol in swine feedstuff, respectively.…”