Quantitative determination of the dopamine agonist lisuride in plasma using high-performance liquid chromatography with fluorescence detection.

An HPLC method for the determination of lisuride hydrogen maleate in plasma is described. After addition of ergotamine tartrate as internal standard, plasma is extracted with diethyl ether. Following evaporation of the solvent and redissolving in methanol the extract is injected on a silica HPLC column and lisuride is monitored by fluorescence detection using an excitation wavelength of 322 nm and an emission wavelength of 405 nm. The method is sufficiently accurate and precise with a detection limit of 20 pg/ml lisuride in plasma. The usefulness of the method is demonstrated by measurements of lisuride levels after oral intake of a 0.6 mg dose of the drug by a healthy male volunteer, showing a peak level of 1266 pg/ml, 45 min after intake.

The determination of delta-5-androstenediol and its sulphate in serum and urine by gas chromatography-mass spectrometry.

OBJECTIVES: We developed an assay for delta-5-androstenediol (adiol) and delta-5-androstenediol-3-sulphate (adiol-3S) in serum and adiol and total adiol sulphate (adiol-S) in urine. DESIGN: An analytical procedure using HPLC and gas chromatography-mass spectrometry was devised and tested for its reliability. MEASUREMENTS: After addition of deuterated androstenediol as internal standard, serum and urine samples were extracted. Steroid sulphates were hydrolysed. The extracts and hydrolysates were purified on HPLC, adiol was derivatized using heptafluorobutyric anhydride and finally quantified by gas chromatography-mass spectrometry. RESULTS: The assay is accurate and reproducible. The coefficient of variation (CV) for the determination of adiol in serum samples is 4% (intra-assay) and 9% (interassay) and for urine samples 3 and 8% respectively. The intra-assay CV for the adiol-3S analyses is 5% for serum and 2% for urine samples while the interassay CV values for adiol-3S are 10% for serum and 7% for urine samples. The recovery of adiol and adiol-3S from serum and urine samples is 97%. CONCLUSIONS: The developed assay meets the analytical demands needed for clinical applications.

Delta-5-androstenediol and its sulphate in serum and urine of normal adults and patients with endocrine diseases.

OBJECTIVES: We evaluated the role of delta-5-androstenediol (adiol) and its sulphates in health and endocrine diseases. DESIGN: Serum and urine samples from healthy adult men and pre and post-menopausal women were analysed by gas chromatography-mass spectrometry to establish reference values. In patients who were either evaluated or treated for endocrine diseases, sequential serum samples were collected and analysed. PATIENTS: Reference values were obtained from 24 healthy male, 23 premenopausal and 30 post-menopausal female volunteers. Adiol and delta-5-androstenediol-3-sulphate (adiol-3S) concentrations were determined in combination with other relevant steroids in patients with either pituitary (n = 5), adrenal (n = 2) or gonadal dysfunction (n = 1), or testicular carcinoma (n = 19). MEASUREMENTS: After addition of deuterated adiol as internal standard, serum and urine samples were extracted. Steroid sulphates were hydrolysed. The extracts and hydrolysates were purified on HPLC, adiol was derivatized and finally quantified by gas chromatography-mass spectrometry. RESULTS: The calculated reference ranges for adiol and adiol-3S concentrations in serum are respectively: in men 1.78-7.24 and 123-579 nmol/l, in premenopausal women 0.65-6.93 and 21.2-298 nmol/l and in post-menopausal women 0.29-2.90 and 6.1-184 nmol/l. Urinary values varied considerably. In the population with endocrine abnormalities serum adiol and adiol-3S concentrations were compared with other relevant steroids. CONCLUSIONS: The wide concentration range of adiol and adiol-3S in urine makes analysis of these steroids in urine of little clinical value. Serum concentrations of adiol and adiol-3S are higher in men than in women. Premenopausal values are higher than post-menopausal. Adiol and adiol-3S in serum are significantly correlated in pre and post-menopausal women, r = 0.51 and r = 0.69 respectively, but not in men. In endocrine patients the serum concentrations of adiol show an ACTH or LH dependency in women; adiol correlates with cortisol, dehydroepiandrosterone or androstenedione and, in males, additionally with testosterone. However, in several situations adiol correlates with none of these steroids. Although adiol secretion can be stimulated by ACTH and LH, the level of serum adiol is also determined by other factors. Finally, in adrenal carcinoma serum adiol and adiol-3S may be used as tumour markers.

Determination of megestrol acetate and cyproterone acetate in serum of patients with advanced breast cancer by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method with ultraviolet detection of megestrol acetate and cyproterone acetate in human sera is described. The proposed assay is linear up to 1400 ng/ml (r = 0.999) and has a detection limit of 5 ng/ml. Recoveries of both compounds in spiked sera were ca. 95%; inter-assay coefficients of variation were 4.0 and 3.1% and intra-assay values were 1.3 and 1.4%, respectively. For validation of the method we also developed a gas chromatographic-mass spectrometric method for both steroids. The results obtained by the two methods showed good correlation: for megestrol acetate r = 0.98, n = 31, p less than 0.0001, and for cyproterone acetate r = 0.94, n = 0, p less than 0.0001. Large inter-individual differences in the serum concentrations of both substances were found in groups of patients with metastatic breast cancer receiving the same oral load of either steroid.