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The Candida infected, embryonated hen's egg is a realistic complement for the model of the Candida infected mouse and can be used in the search for new systemically active antimycotics. This alternative method is rapid, sensitive convincing and inexpensive. The use of the embryonated hen's egg in an anti-Candida screening can reduce the use of small laboratory animals to a considerable amount. Thus, with the help of this new method pain and suffering of animals can be reduced in a part of the biologic-medical research in the sense of the animal protection law.

Out of the group of 2-amino-oxazoles 1 was found to be the most potent antiviral compound. Following p.o. or s.c. administration to rats, the 14C-labeled 1 was quickly and completely absorbed. The TRA was eliminated mainly via the kidneys and the liver with half-lives between 32 and 42 h. The acute pharmacodynamic effects of 1 were decrease of blood pressure, bradycardia, and inhibition of both gastric emptying and acid secretion. On smooth muscles spasmolytic and alpha-anti-adrenergic actions were predominant. After single administration the following MTD's were determined: 30 (mouse), 20 (rat), 10 mg/kg i.v. (pig), and 500 (mouse, rat), greater than 100 mg/kg p.o. (pig), respectively. In a subchronic toxicity study in rats, oral doses of 1 between 15 and 240 mg/kg given daily for 4 weeks were tolerated without any severe alterations related to the drug.

The preparation of the 17 beta-carbamoyl derivatives 4 and of the 17 beta-carbonic acid esters 5 from 15 beta,16 beta-epoxy-3-methoxyoestra-1,3,5(10)-triene-17 beta-ol (3a), and the subsequent opening of the 15 beta,16 beta-epoxy group resulting in 15 beta,16 alpha,17 beta-trisubstituted oestratrienes 6 are described. The influences of several substitutents in the positions 15 and 16 and of the 17 beta-hydroxy group and derivatives thereof on the uterotropic and cholesterol-lowering activities were investigated in rats after oral application. A correlation between the cholesterol-lowering and the uterotropic activity could be established. Activity dissociation was not achieved.

Disposition and excretion of the estrogen derivative STS 593 [1,3-methoxy-14 beta,15 beta-methylenestra-1,3,5(10)-triene-17 beta-ol] with antifertility activity were investigated in Beagle dogs after single and repeated administration of the tritium-labelled compound. The plasma concentration vs. time courses of total radioactivity (TRA) and of the parent drug alone were estimated in conscious animals simultaneously with the urinary and fecal excretion data. From this the basic pharmacokinetic parameters were calculated and experimentally confirmed by multiple-dosing data. STS 593 differs from estradiol with respect to its higher bioavailability after oral administration; it amounts to 34-62% depending on the administration formulation. The compound is metabolized rapidly. The accumulation factor of TRA resulting from a multiple once-a-day dose regimen of STS 593 was quantified with 3.1.