Ray W. Judy

Preparation of [14c]colestipol hydrochloride and its disposition in the human, dog and rat

Colestipol hydrochloride, a polymeric, ion-exchange type, hypocholesterolemic agent, acting by sequestering bile acids, was labeled with carbon-14. The disposition of the labeled material was studied in the human, dog and rat. The extent of absorption from the gastrointestinal tract, as judged by urinary excretion of radioactivity, was very small and correlated well with the contents of water-soluble and dialyzable materials in the colestipol hydrochloride. Results were consistent with the dialyzable material in the drug being the absorbable species.

Spectrophotometric Determination of Steroid Oximes

Abstract A spectrophotometric procedure for the determination of steroid oximes is described utilizing 11β-hydroxy-iia-methyl-5β-pregnane -3, 20 -dione dioxime (I) and iia-hydroxy-progesterone dioxime (II) as models. The method is based on (a) acid hydrolysis to release hydroxylamine, (b) oxidation of hydroxylamine to nitrous acid with iodine, (c) diazotization of sulfanilic acid with the nitrous acid, (d) coupling of the diazonium compound with N-(i-naphthyl)-ethylenediamine dihydrochloride, and (e) measurement of the azo dye at 550 nm. A stoichiometric yield of hydroxylamine is obtained. Analyses of I and II have given typical recoveries (mean ± S. D.) of 99.5 ± 1.1% and 97.8 + 3.5%, respectively. The method is sensitive to ≥ 0.3 × 10−5 M dioxime.

A simple apparatus for separating and trapping tritiated water from multiple biological samples

Abstract The effective use of tritiated compounds in biological systems often requires determination of the extent to which the tritium label has been removed from the compound and equilibrated with biological fluids. (1) This usually is accomplished by first determining the total tritium content of a water-containing sample and then determining either the tritiated water separated by evaporation or the tritium content of the dried sample. The former method gives a direct measure of tritiated water but involves isolating the tritiated water. In the latter method, the amount of tritium in the water is calculated as the difference between the tritium contents of the water-containing and dried samples. Although this indirect method is less accurate than the direct method, it does not require isolating the tritiated water. In both cases, it is important that very mild conditions be used for separating water from the aqueous sample in order to prevent further removal of tritium from the compound. This is accomplished conveniently by a freeze-drying procedure. Although this method is old and likely to be in common use, a convenient apparatus for processing large numbers of samples has not been described in the literature. The apparatus described in this report has been used routinely in several of our laboratories for many years to separate and collect tritiated water from biological samples, usually urine.