Determination of D-penicillamine in serum by fluorescence derivatization and liquid column chromatography.

A simple and fast method for the determination of D-penicillamine in serum is described. The analysis is based o a fluorescence derivatization of the sulfhydryl group combined with a reversed-phase liquid chromatograhic separation and fluorescence detection. Before derivatization the serum proteins are precipitated with ethanol and removed by centrifugation. As derivatizing agent 5-dimethylaminonaphthaline-1-sulfonylaziridine is used which reacts selectively with thiols under defined reaction conditions. The detection limit is in the pmol range; 50-300 ng of D-penicillamine can be determined with a relative standard deviation of 7-8%. Thus the method permits a simple determination of D-penicillamine in serum at therapeutic levels.

[Serum levels od D-thyroxine in euthyroidism and hypothyroidism (author's transl)]. / Serumspiegel von D-Thyroxin bei Euthyreose und Hypothyreose.

Serum levels of D-thyroxine (D-T4) and L-thyroxine (L-T4) were determined by use of a newly developed method for the stereospecific determination of these isomers in 8 patients with diffuse non-toxic goiter and 2 hypothyroid patients following administration of increasing doses of D-thyroxine. During the 3-day observation period a significant decrease of serum-TSH takes place. D-T4 levels are highest 4 hours after administration of the tablets and approach basal values within 24 hours in euthyroid as well as hypothyroid patients. Serum half life of D-T4 was 5.7 hours on the average in the euthyroid group and was markedly prolonged in hypothyroidism. L-T4 levels show no significant changes. Since the D-T4 preparation used, contained only very little amounts of the L-isomer, it may be assumed that D-T4 exerts a direct suppressive effect on the pituitary TSH secretion, as evidenced by the observed significant decrease in basal and TRH-stimulated TSH serum levels.

Separation of enantiomeric iodinated thyronines by liquid chromatography of diastereomers.

A method for the separation of D,L-triiodothyronine and D,L-tetraiodothyronine optical isomers is described. The iodinated thyronines are coupled with L-leucine and the resulting diastereomers are separated by reversed-phase liquid chromatography. The derivatives are detected in the UV region at 230 nm. The technique can be used for the determination of the optical purity of thyroid hormones. It is possible to determine 0.2% of the L-isomer in D-tetraiodothyronine with a relative standard deviation of 8%. One complete analysis takes about 2 h. The results are in good agreement with those of an enzymatic method.