Determination of retinol and retinyl esters in human plasma by high-performance liquid chromatography with automated column switching and ultraviolet detection

Inhibition of Retinoic Acid Biosynthesis by the Bisdichloroacetyldiamine WIN 18,446 Markedly Suppresses Spermatogenesis and Alters Retinoid Metabolism in Mice

“…Retinyl stearate, retinyl linoleate, and retinyl oleate were synthesized from retinol and corresponding fatty acids following a reported method (15). WIN 18,446 was obtained from Acros Organics (Geel, Belgium).…”

HPLC/UV quantitation of retinal, retinol, and retinyl esters in serum and tissues

“…The majority of measurements use the ROL/RE method and the RAL method, which use the same solvents and analytical column, allowing for seamless transition between the two analyses. Both the ROL/RE and the RAL methods have run times of 25 min, including re-equilibration, which is shorter than other methods, for which some separations take >100 min (17,18,(22)(23)(24)(25)30,31,48,51,53,55). Additionally, our limits of detection/quantification and linear working ranges have been characterized rigorously for each analyte, and the analyte concentration is determined from a standard curve spanning the physiological range of the analyte.…”

“…Schmidt et al also provide evidence of an analytically rigorous assay appropriate for tissue retinoid quantification (44), whereas other assays have only been assessed for simpler matrices, such as serum (51,52,55), and/or have not been comprehensively characterized for analytical performance (16,17,19,(22)(23)(24)(25)30,31,36,54). Simplification of the sample matrix also enhances accuracy and the lives of guard and analytical columns.…”

Methods for detecting and identifying retinoids in tissue

“…SPE coupled on-line via an automated diversion valve was originally described in 1981 by Roth et al for extraction of drugs in bio-fluids. Variants of this technique were later adapted by Kraft et al (1988), researchers at Hoffman-La Roche in Basel, and several others for the analysis of retinoids in biological samples (Wyss andBucheli, 1988b, 1992;Gundersen et al, 1997;Wyss et al, 1998;Sakhi et al, 1998;Gundersen and Blomhoff, 1999;Ulven et al, 2000Ulven et al, , 2001Hartman et al, 2001;Otto et al, 2003;Ruhl and Schweigert, 2003;Moren et al, 2005;Ruhl et al, 2005;Berggren et al, 2005). A drawback of this technique is a high degree of complexity requiring a notable level of technical expertise by the user as well as a somewhat higher initial cost compared to regular HPLC systems.…”

“…The described method allowed analysis of both polar and apolar retinoids in the same run with high recoveries. Hartman et al (2001) used a similar system with on-line SPE in combination with column switching to extract REs from plasma. High recoveries were obtained for REs by diluting plasma with 7.5 volumes of ethanol and reducing the elution strength before SPE by on-line dilution with 1% ammonium acetate buffer.…”