Corticosteroids derivatization

New fluorimetric determination of 17-hydroxy-corticosteroids after HPLC using post-column derivatization with benzamidine. (170)... 

Early applications of thin-layer chromatography in corticosteroid analysis were mainly based on use of phenylhydrazine in sulfuric acid as a spray reagent for derivatization of the analytes (529, 530). Later applications involved use of other spray reagents including phosphoric acid in methanol, tetrazolium blue. 

Corticosteroids are used by some athletes and racing horses to enhance their performances. In order to prohibit drug doping, many sport organizations, e.g., International Olympic Committee, attempt to monitor the corticosteroids in urine of athletes. An example of earlier GC-MS method in steroid screen consists of procedures of deconjugation of glucuronide and sulfate, derivatization with MSTFA and GC-MS analysis [98], The more recent LC-MS/MS methods separate the corticosteroids by... 

LC, and analyze them with ESI-MS (either positive or negative mode) without derivatization [10, 99], Similarly, corticosteroids in racing horse urine are monitored by LC-ESI-MS/MS as well [11],... 

Katayama, M. Masuda, Y. Taniguchi, H. Determination of corticosteroids in plasma by high-performance liquid chromatography after pre-column derivatization with 2-(4-carboxyphenyl)-5,6-dime-thylbenzimidazole. J.Chromatogr., 1993, 612, 33-39... 

The gas-phase analytical techniques have been used for the analysis of urinary steroids for a long time. The determinations of urinary estrogens, progesterone metabolites, 17-ketosteroids and, to a lesser degree, corticosteroid metabolites, with packed-column GC are extensively documented in the earlier monographs on the subject [274,290]. Various sample treatments, approaches to conjugate hydrolysis, and volatile derivatives have been described. Among those steroids, aldosterone stands out as a uniquely difficult substance to derivatize and determine. 

Pentafluorobenzyl hydroxylamine has been used as a derivatization reagent in the analysis of corticosteroids including prednisolone by gas chromatography-negative ion chemical ionization mass spectrometry (NCI). The resulting... 

Chloromethyidimethylchlorosilane derivatizing corticosteroids Dimethyidiacetoxysilane dermatitis, chronic humans Potassium arsenite dermatologic agent o-Thiocresol p-Thiocresol dermatologic pharmaceuticals Sulfurated potash dermatological treatment Lactic acid dermatology... 

The selective derivatization of bifunctional compounds has been exploited very effectively for the GC and GC-MS analysis of cyclic boronates (see Chapter 7 of this volume). Somewhat analogous cyclic alkylsilylene derivatives can also be prepared. In the late 1960s, dimethylsilylene derivatives of corticosteroids were successfully prepared by Kelly and shown to be amenable to GC analysis [415, 416). Although dimethylsilylene derivatives of a wide variety of bifunctional compounds can be formed [417-420], their analytical application is limited by their tendency to polymerize and hydrolyse... 

Seki, T. Yamaguchi, Y. New fluorimetric determination of 17-hydro corticosteroids after hi -perfor-mance liquid chromatography using post-column derivatization with benzamidine. J.Chromatogr., 1984, 305, 188-193... 

The great dilemma of the GC analysis of steroids is whether to use derivatization or not. In the case of thermally unstable steroids, the answer is unequivocally yes. Steroids of this type are mainly the corticosteroids, containing the unstable a-ketol side chain. Of several possibilities, double derivatization to form the methoxime trimethylsilyl derivatives is the most widely used (see reaction [I]) ... 

It is usually carried out at ambient temperature, and for this reason it is applicable quite generally and without derivatization or hydrolysis, even in those cases where thermal instability or low volatility precludes the direct application of GC (separation and quantification of corticosteroids, conjugates, etc.). 

Five urinary corticosteroids (tetrahydrodeoxycorticosterone, tetrahydro-ll-de-oxycortisol, tetrahydrocortisol, allo-tetrahydrocortisol, tetrahydrocortisone) were isolated, derivatized with 9-anthroyl cyanide, and separated on a silica column (A = 370 run, ex 470 nm, em). A 98/293/7 (at 20 min hold 20 min) hexane/IPA gradient generated good peak shape. Standards of 10 ng injected were easily detected [721]. 

Neufeld, E. Chayen, R. Stem, N. Fluorescence derivatization of urinary corticosteroids for high-performance liquid chromatographic analysis. J. Chromatogr., B 1998, 718, TTi-111. 

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