June E. Goodrich

Accuracy of Published Medical Reference Citations

Among 2, 195 reference citations, published during 1975 in ten major US medical journals, 634 (29%) were found to be erroneous on direct checking of the original source. The percentage of error within individual journals ranged from 14 to 50 per cent. Such a high error rate would seem to seriously diminish the usefulness of published reference lists and, possibly, raise questions about the accuracy of other portions of the literature also.

Liquid ion exchangers in paper chromatography of steroidal glucosiduronic acids, glucosiduronic esters and free steroids : Influence of concentration of exchanger and counterion

The chromatographic mobility of steroidal glucosiduronic acids on paper in chloroform-formamide increases as the concentration of ion exchanger in the chloroform phase increases; mobility decreases as the concentration of counterion in formamide increases. Mobility of glucosiduronic esters and of hydroxylated free steroids increases with an increase in concentration of exchanger; small changes in concentration of counterion in the stationary phase do not alter the migration of these nonionizable compounds. Data are presented which suggest that partition of the glucosiduronic acids between the two phases occurs predominantly by an ion-exchange process and that hydrogen bonding plays a secondary role. Partition of the glucosiduronic esters and hydroxylated free steroids appears to occur primarily by a hydrogen-bonding process.

Liquid ion exchangers in reversed-phase systems for chromatography of steroidal glucosiduronic acids.

Steroidal glucosiduronic acids were chromatographed on paper by the reversed-phase technique using five different liquid ion exchangers as stationary phase and aqueous KCl as mobile phase. The relationship of mobility of the acids (Rm) to both the amount of exchanger on the paper and the concentration of KCl in the mobile phase is discussed: the relationships may be expressed as Rm=n.log [exchanger] + const. and RM=-N.LOG [KCl] + const., respectively. Migration of the acids in the presence of different exchangers is correlated by use of the equation Rm (exchanger Y)=a.Rm (exchanger X) + b. The lack of appreciable correlation between migration of the acids in a reversed-phase system and a corresponding straight-phase system is discussed and expressed by means of regression equations. The correlation coefficients and standard errors of estimate from these equations provide useful indices for selecting two solvent systems that are to be used sequentially to obtain maximal resolution of a group of compounds. deltaRm values obtained for various functional groups with reversed-phase and straight-phase techniques are compared.

Liquid ion exchangers in paper chromatography of steroidal glucosiduronic acids : Influence of different exchangers on the mobility in chloroform-formamide and correlation of chromatographci data

A group of 25 steroidal glucosiduronic acids was chromatographed on paper chloroform-formamide in the presence of several different liquid ion exchangers. Chromatograms were run also in three Bush-type systems. RF values were converted into RM values and the data were correlated by use of a series of regression equations of the type RM(Y) = a-RM(X) + b, in which X designates a standard system to which each other system (Y) is compared. The ratio of the slope a to the correlation coefficient r (i.e., a/r) is a measure of the resolving power of system Y relative to the standard system; intercept b, in association with slope a, is an indication of the polarity of system Y relative to X. The correlation coefficient r and the standard error of estimate sy-x are indications of whether solvent systems Y and X have very similar or relatively different resolving properties for a group of solutes. The regression equations are useful for correlating chromatographic data obtained from a group of compounds in several solvent systems. Properties of the chromatography systems are discussed and the relative importance of ion exchange and hydrogen bonding with the various solvent systems is pointed out. Delta RMg and delta RMr values are given for functional groups at several locations in the conjugates for ten of the chromatography systems.

C-3 glucosiduronates of metabolites of adrenal steroids

On treatment with methyl 2,3,4-tri-O-acetyl-1-bromo-1-deoxy-alpha-D-glucuronate and silver carbonate, tetrahydrocortisone 21-acetate gave the corresponding 3-glucosiduronate triacetyl methyl ester. This product was converted into the 20-semicarbazone which, by treatment with alkali to hydrolyze the ester functions and acid to hydrolyze the semicarbazone moiety, gave tetrahydrocortisone 3-glucosiduronic acid. The acid was converted into the crystalline barium salt and into the methyl ester. An analogous series of reactions was carried out on tetrahydrocortexolone 21-acetate. Treatment of the 20-semicarbazone of tetrahydrocortisone 3-glucosiduronic acid with potassium borohydride reduced the 11-oxo function to an 11 beta hydroxyl group; acid-catalyzed removal of the semicarbazone group produced tetrahydrocortisol 3-glucosiduronic acid which also was obtained as the barium salt and the methyl ester.

Liquid ion exchangers for chromatography of steroidal glucosiduronic acids and other polar compounds.

Abstract Many of the solvent systems which are commonly used to chromatograph corticosteroids can be used to chromatograph the corresponding glucosiduronic acids if the mobile phase is made about 0.1 M with tetraheptylammonium chloride and the stationary phase is made about 0.1 M with potassium chloride. The rates of movement of the glucosiduronates relative to one another are different in the various solvent systems which are described.

Chromatographic mobilities and partition coefficients of synthetic corticosteroid glucosiduronates

Abstract Analytical data are presented on the free acids, the methyl esters, the methyl ester triacetates and the methyl ester triacetate semicarbazones of C-21 glucosiduronic acid conjugates of six adrenal hormones. Chromatographie mobilities of all of these compounds in three or more solvent systems are given. The stability of the steroidal glucosiduronic acids in alkali, their hydrolysis by β-glucuronidase and their partition coefficients in several solvent systems are also given.

Interference of Phenaglycodol in Determination of Urinary 17-Ketogenic Steroids and 17-Ketosteroids

Abstract The mechanism by which phenaglycodol causes increased values for urinary 17-ketogenic steroids and 17-ketosteroids has been investigated. On treatment with sodium bismuthate, phenaglycodol yields p-chloroacetophenone; this substance produces a typical blue color in the Zimmermann reaction for 17-ketosteroids. Thus, the presence of phenaglycodol in urine increases the value found for 17-ketogenic steroids. During the acid-catalyzed hydrolysis of conjugated 17-ketosteroids, phenaglycodol undergoes a pinacol rearrangement to form a ketone which gives color when treated with the Zimmermann reagent. The mixture from the Zimmermann reaction, when chromatographed on paper, shows the presence of a pigment which is derived from the ketone. The reaction product of a urinary extract with the Zimmermann reagent contains this pigment if the person whose urine is being tested is ingesting phenaglycodol. Addition of the normal daily dose of phenaglycodol (1,200 mg.) to a 24-hour sample of urine increased the 17-ketogenic steroid value from 4 to 154 mg. and the 17-ketosteroid value from 18 to 30 mg.

Use of anionic liquid ion exchangers in the chromatography of steroidal glucosidoronic acids

Small amounts of various anionic liquid ion exchangers (e.g., tetraheptylammonium chloride) greatly increase the solubility of steroidal glucosiduronic acids in nonpolar solvents. This property of liquid ion exchangers has been utilized to devise a series of chromatography systems which are particularly useful for the separation and identification of steroidal glucosiduronic acids. A typical chromatography system consists of 0.02–0.2 N tetraheptylammonium chloride in the nonpolar phase and 0.02–0.4 N potassium chloride in the polar phase; the chromatograms are run in the conventional manner. The liquid ion exchangers can be used with systems B4 of Bush, NE-10 of Eberlein, formamide/chloroform of Zaffaroni and so forth to chromatograph conjugates such as cortisone-21-glucosiduronic acid, cortisol-21-glucosiduronic acid, and related conjugates. A chromatogram can be run either with the polar phase adsorbed on the supporting medium or by a reversed-phase technique. When a particular liquid ion exchanger (e.g., tetraheptylammonium chloride) is employed with a series of chromatography systems (B4, formamide/chloroform, NE-10, etc.) the rate of migration of the conjugates relative to one another changes from system to system. Conversely, when a particular chromatography solvent system (e.g., formamide/chloroform) is used with a series of liquid ion exchangers (secondary amine hydrochlorides, tertiary amine hydrochlorides and quaternary ammonium chlorides) the rate of migration of the conjugates relative to one another is determined by the particular liquid ion exchanger used. Migration of the conjugates relative to one another is dependent also on which particular liquid ion exchanger is employed when reversed-phase chromatography is performed. In general, a linear relationship between RM and log [liquid ion exchanger] in the mobile phase is obtained if the [Cl−] in the stationary phase is kept constant; for monoglucosiduronic acids the slope of the line approaches −1. When the concentration of liquid ion exchanger in the mobile phase is held constant and [Cl−] is varied there is a linear relationship between RM and log (1/[Cl−]); the slope approaches +1. With the liquid ion exchanger in the mobile phase, the ΔRMg values for 11β-OH in pairs of compounds usually have not been in good agreement. The same is true for ΔRMg values of 11=O and 17α-OH and for ΔRMr (11=O → 11β-OH). Nevertheless the ΔRMr values of steroidal glucosidunoic acids have differed greatly among various solvent combinations containing liquid ion exchangers. A limited number of chromatograms of steroidal glucosiduronic acid methyl esters have been run in solvent systems containing liquid ion exchangers. The exchangers cause a large increase in mobility of the esters, but the [Cl−] in the stationary phase has a negligible effect on RM. Secondary and tertiary amine hydrochlorides have a much larger effect on RM than do the free secondary and tertiary amines. In reversed-phase chromatography (using tetraheptylammonium chloride adsorbed on paper), there is a linear relationship between RM and [Cl−] in the mobile phase; for a steroidal monoglucosiduronic acid the slope is about −0.85 and for a diglucosiduronic acid the slope is approximately −1.65. When [cl−] in the mobile phase is held constant and the concentration of liquid ion exchanger is varied there is a linear relationship between RM and log [liquid ion exchanger]. For both a monoglucosiduronic acid and a diglucosiduronic acid the slope is about 1.0. ΔRMg and ΔRMr values were determined for a series of steroidal glucosiduronic acids using a quaternary, a tertiary, a secondary and a primary amine hydrochloride as liquid ion exchanger and with the ion exchanger adsorbed on the paper and aqueous as were those for 11 = O and 17α-OH. Also, values for ΔRMr (11 = O → 11β-OH) were in good agreement. In addition, ΔRMr (11 = O → 11β-OH) is positive, a finding that was unexpected since an 11β-OH group usually is more polar than an 11 = O group. ΔRMg (11β-OH) and ΔRMg (11 = O) values were negative. The averages of ΔRMg (17α-OH) values were 0.26, 0.14, 0.02 and −0.35, respectively, when a quaternary, a tertiary, a secondary and a primary amine salt were employed as ion exchangers. Thus, with the quaternary and tertiary amine salts as ion exchangers the 17α-OH group actually promotes retention of the steroidal glucosiduronic acids by the non-aqueous phase.

Chemical synthesis of glucuronidated metabolites of cortisol

During in vivo metabolism the addition of six atoms of hydrogen to cortisone at the appropriate location and configuration can lead to formation of either 3 alpha,17,20 alpha,21-tetrahydroxy 5 beta-pregnan-11-one (cortolone) or 3 alpha,17,20 beta,21-tetrahydroxy-5 beta-pregnan-11-one (beta-cortolone). Likewise, metabolic reduction of cortisol can lead to formation of either 5 alpha-pregnane-3 alpha,11 beta,17,20 alpha,21-pentol (cortol) or the 20 beta isomer (beta-cortol). This paper describes the chemical syntheses of the C-3 beta-D-glucosiduronates of cortolone, beta-cortolone, cortol and beta-cortol-conjugates which are normal excretory products of man. The foregoing conjugates are characterized as free acids (or salts), as methyl esters and as polyacetate methyl esters.