Synthesis of C-6 fluoroandrogens: evaluation of ligands for tumor receptor imaging.

Seven androgens, substituted with fluorine at C-6, were prepared as potential imaging agents for androgen receptor-positive prostate tumors and were evaluated in vitro in terms of their lipophilicity and their relative binding affinities (RBA, relative to R 1881 = 100) for the androgen receptor and for sex steroid binding protein. Introduction of a fluorine atom into the C-6 position of an androgen generally decreases binding affinity to the androgen receptor, except in the two cases: 6 alpha-fluoro-19-nor-testosterone (RBA = 41.6 versus 30.6 for the unsubstituted steroid) and 6 alpha-fluorotestosterone (RBA = 8.9 versus 6.6). Receptor binding of the C-6 fluoro-androgens is also stereospecific, showing higher binding affinities for the alpha-epimers compared to the corresponding beta-epimers (4:1-15:1). Binding affinity to sex steroid binding protein is the lowest with 19-nor-testosterone, which is also the least lipophilic androgen studied. Based on the binding properties of compounds in this series, 6 alpha-fluoro-19-nor-testosterone appears to have the most promise as a tumor imaging agent.

Advantages of the scanning ion microscopy for mapping halogen corticoids in normal and transformed cells in culture.

The intra-cellular distribution of eight halogen glucocorticoids was investigated by ion microscopy in two cellular varieties of cultured non-cancer cells (fibroblast 3T3) and cancer cells (human breast tumor cells MCF-7). Two types of ion microscopy helped to determine this distribution, a direct imaging ion microscope (SMI 300) with low spatial resolution, and a scanning ion microscope (IMS4F), featuring high resolution, serving to obtain maps representing the intra-cellular distribution of the fluorine elements and drugs present in these monolayer cultured cells. The fluorine images representative of the drugs containing fluorine showed that these drugs are essentially concentrated in the cell nuclei. In these nuclei, the distribution of these drugs is different from that of heterochromatin and of the nucleolus.

Side chain modified sterols as probes into insect molting hormone metabolism. II: synthesis of monofluorocholesterols.

The hydroxylations of the cholesterol side chain at C-20, 22, and 25 are key terminal events in ecdysone biogenesis. We have prepared the C-20, C-22, C-24, and C-25 monofluorinated cholesterols as potential inhibitors of these hydroxylation events, and preliminary bioassay results in Manduca sexta are reported. The synthesis of [26(14)C]-20-fluorocholesterol is also described. Although the 20-, 22-, and 25-monofluorocholesterols do not appear to affect larval growth and development, the 24-fluoro isomer shows a moderate retardation of growth and a modest increase in mortality.

[Studies on the Pharmacology of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (diflucortolon valerate) (author's transl)]. / Untersuchungen zur Pharmakologie von 6alpha,9-Difluor-11beta-hydroxy-16-methyl-21-valeryloxy-1,40pregnadien-3,20-dion(Diflucortolonvalerianat)

The topical and systemic anti-inflammatory action of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (diflucortolone valerate, Nerisona) was studied in the rat in comparison with fluocortolone, diflucortolone and some other corticoids. In addition the effect of the compounds studied on the following parameters of corticoid activity was examined in the rat: body weight and weights of thymus, spleen and adrenals; blood sugar concentration and liver glycogen content; diuresis and Na+ and K+ elimination with the urine; the binding of diflucortolone and some diflucortolone-21-esters to the cytoplasmic corticoid receptor of the rat's thymus was also determined. In all tests diflucortolone was shown to be a corticoid with very potent topical and systemic action. Diflucortolone valerate showed the same potent anti-inflammatory action on topical application as the unesterified compound. After subcutaneous administration, however, the systemic corticoid action of the valerate was considerably inferior to that of diflucortolone on account of the kinetics of the more lipid soluble ester.

[Biotransformation of diflucortolone valerate in the skin of rat, guinea pig and man (author's transl)]. / Biotransformation von Diflucortolonvalerianat in der Haut von Ratte, Meerschweinchen und Mensch

The biotransformation of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (diflucortolone valerate, DFV, Nerisona) was examined in vitro in the skin of rat and man and in vivo in the skin of guinea pigs. In the investigations with rat skin DFV in ethanolic solution (0.1 mumol) was added and the ester hydrolysis in buffer monitored in relation to the incubation time. In the experiments with guinea pigs and with human skin DFV was applied topically in the form of a 0.1% W/O emusion employing a dose of 6 mg/cm2 skin. After the substance which had not penetrated had been recovered by means of cotton wool and adhesive film at the end of the period of exposure the portions of skin were homogenized, extracted and the extracts separated by thin-layer chromatography. DFV is hydrolysed in the skin of rats and guinea pigs with a half-life of about 30-60 min to diflucortolone 6alpha,9-difluoro-11bets,21-dihydroxy-16alpha-methyl-1,4-pregnadiene-3,20-dione) and valeric acid. In excised human skin degradation of the ester proceeds much more slowly. Even 7 h p. appl. about 80-90% DFV and only 5-15% DF were identifiable in the skin extract. Despite the estremely low absorption rate the slow hydrolysis of DFV in human skin guarantees an adequate level of active ingredient in the skin over a long period.

[Percutaneous absorption of diflucortolone valerate in guinea pigs and man (author's transl)]. / Perkutane Resorption von Diflucortolonvalerianat bei Meerschweinchen und Mensch

Percutaneous absorption of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione (difucortolone valerate, Nerisona) as dependent on the base, the concentration in the base and the condition of the skin was investigated in man and in guinea pigs. In addition the distribution of the corticoid in the stratum corneum, epidermis and corium was determined by stripping the skin and by horizontal thin-section technique. 2. In man diflucortolone valerate from all of the formulations tested (0.1 and 0.3% cream, ointment and fatty ointment) was only absorbed to a slight extent by both the intact and the stripped areas of skin on the subjects' backs. In the case of the 0.1% formulations a total of about 0.2% of the dose was absorbed within 4 h via intact skin and about 0.4% via the stripped skin. After application of the 0.3% formulations the percutaneous absorption from the ointment, fatty ointment and cream were examined separately. This revealed percutaneous absorption within 7 h of 1.7% from the ointment, 0.7% from the fatty ointment and 0.5% for the cream by combined determination through 1 intact and 1 damaged area of skin. 3. Percutaneous absorption via intact skin is slight in the case of the guinea pig also. Absorption is accelerated considerably by the removal of the stratum corneum, however, and shows a characteristic dependence on the concentration of the corticoid in the base. Whereas the corticoid from the 0.03% ointment is almost quantitatively absorbed within 7 h, absorption from the 0.5% ointment is reduced to about 30%. 4. The absolute concentrations of active ingredient in the epidermis are approximately 10(-6) mol/l and drop to approximately 10(-7) mol/l in the corium (guinea pig in vivo, man in vitro). An active ingredient flow equilibrium (inflow = outflow) is reached in the skin of the guinea pig after only 1 h.

[Pharmacokinetics and biotransformation of diflucortolone valerate in man (author's transl)]. / Pharmakokinetik und Biotransformation von Diflucortolonvalerianat beim Menschen

Two male normal subjects were each given 1 mg of 6alpha,9-difluoro-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadiene-3,20-dione1,2,4-3H (3H-diflucortolone valerate, Nerisona) by i.v. injection. The pharmacokinetics and biotransformation of the corticoid were examined by measurement of the total activity in the blood, plasma, urine and faeces and by thin-layer chromatographic analysis of the spectrum of the metabolites in plasma and urine. The compound is very rapidly degraded. No more intact ester was identifiable in the plasma 5 min after injection while, at the same time, 6alpha,9-difluoro-11beta,21-dihydroxy-16alpha-methyl-1,4-pregnadiene-3,20-dione (diflucortolone), the product of hydrolysis, was present in a concentration of 6-8 ng/ml plasma. The half-life of diflucortolone in the plasma was 4-5 h, that of the total 3H-steroids about 9 h. 80-40% of the 3H-steroids in the plasma were in unconjugated form. Besides diflucortolone and two unidentified metabolites chromatographic comparison demonstrated the presence of 6alpha,9-difluoro-21-hydroxy-16alpha-methyl-1,4-pregnadiene-3,11,20-trione (11-keto-diflucortolone) as a further metabolite in the plasma. The elimination was rapid and complete: by 24 h after injection approximately 56% of the dose had been eliminated with the urine and by 7 days after administration 98 and 93% of the dose had been recovered in urine and faeces. The ratio of elimination urine to faeces averaged 3:1. Within 48 h after the injection about 30% of the dose was eliminated in the form of unconjugated 3H-steroids, about 20% as 3H-steroid-glucuronides and about 10% as 3H-steroid-sulphates. Diflucortolone was demonstrable both in the unconjugated form and as glucuronide and 11-keto-diflucortolone as glucuronide and as sulphate. A total of 7 metabolites were characterized in the urine by means of chromatography.

[Comparative studies in man on the percutaneous absorption of diflucortolone valerate, betamethasone-17-valerate, beclomethasone dipropionate and fluocinolone acetonide]. / Vergleichende Untersuchungen am Menschen zur perkutanen Resorption von Diflucortolonvalerianat, Betamethason-17-valerianat, Beclomethasondipropionat und Fluocinolonacetonid

Percutaneous absorption of 6alpha,9-difluor-11beta-hydroxy-16alpha-methyl-21-valeryloxy-1,4-pregnadience-3,20-dione (diflucortolone valerate, DFV, Nerisona), betamethasone 17-valerate (BV), beclomethasone dipropionate (BDP) and fluocinolone acetonide (FA) by damaged skin was examined on the backs of 4 healthy males from whom the stratum corneum had been removed by "stripping". The determination of percutaneous absorption was performed on the one hand by a method employing radioactive labelled compounds (DFV, BV) and measuring the elimination with the urine and faeces and on the other hand by photometric determination (DFV, BV, BD, fa) of the corticoid remaining on the skin immediately following application and at the end of a 24-h period of exposure. Direct measurement of the radioactivity in the urine and faeces revealed that percutaneous absorption from a new W/O emulsion takes place up to 2.2+/-0.8% in the case of DFV (0.1%) and to at least 12.2+/-3.3% in the case of BV (0.12%) within 24 h. The determination of percutaneous absorption via recovery from the skin produced the following results for the 4 corticoid preparations examined: DFV (14.8+/-4.2%) and BDP (14.0+/-4.3%) approximately equal, BV (23.5+/-4.1%) a marked increase and FA (39.2+/-2.4%) the highest level of absorption. This order for percutaneous absorption appears to correlate to the frequency of systemic side effects.