A novel delivery system for drugs, and especially macromolecules such as proteins or oligonucleotides through biological membranes is provided, and specifically delivery of siRNA. The delivery system comprises conjugation of the macromolecule drug to a moiety that enables effective passage through the membranes. Respectively, novel compounds and pharmaceutical compositions are provided, utilizing said delivery system. In one aspect of the invention, the compounds may be utilized in medical practice, for example, in delivery of siRNA or antisense oligonucleotides across biological membranes for the treatment of medical disorders.

Compounds having the formula

##STR00001##

or solvates of the compounds can be used as intermediates in the preparation of the synthetic steroids, Etonogestrel and Desogestrel, as well as other pharmaceutically active agents.

A process for the preparation of 11-methylene steroids from di-keto steroids involves selective olefination of the ketone at position 11 of the di-keto steroids. The resulting 11-methylene steroid products can be used as intermediates in the preparation of the synthetic steroids, Etonogestrel and Desogestrel, as well as other pharmaceutically active agents.

The invention relates to a process for the preparation of 11-methylene steroids through selective olefination of the ketone at position 11. The resulting products are useful intermediates in the preparation of several pharmaceutically active agents, such as Etonogestrel and Desogestrel.

A novel delivery system for drugs, and especially macromolecules such as proteins or oligonucleotides through biological membranes is provided, and specifically delivery of siRNA. The delivery system comprises conjugation of the macromolecule drug to a moiety that enables effective passage through the membranes. Respectively, novel compounds and pharmaceutical compositions are provided, utilizing said delivery system. In one aspect of the invention, the compounds may be utilized in medical practice, for example, in delivery of siRNA or antisense oligonucleotides across biological membranes for the treatment of medical disorders.

A novel delivery system for drugs, and especially macromolecules such as proteins or oligonucleotides through biological membranes is provided, and specifically delivery of siRNA. The delivery system comprises conjugation of the macromolecule drug to a moiety that enables effective passage through the membranes. Respectively, novel compounds and pharmaceutical compositions are provided, utilizing said delivery system. In one aspect of the invention, the compounds may be utilized in medical practice, for example, in delivery of siRNA or antisense oligonucleotides across biological membranes for the treatment of medical disorders.

The invention relates to a process for obtaining Estetrol or a salt or solvate thereof, the process comprising: a) reacting a compound of formula (IV) or a salt or solvate thereof, wherein R.sup.1 is a hydroxyl protecting group selected from a silyl ether, an ether, an ester, a carbamate and a carbonate, and R.sup.2 is a hydroxyl protecting group selected from an ether, with an oxidizing agent selected from OsO.sub.4 or a source of osmium tetroxide to produce Estetrol or a compound of formula (II) or a salt or solvate thereof wherein R.sup.1 is as defined previously; and b) if a compound of formula (II) is obtained in step a), deprotecting said compound to produce Estetrol. ##STR00001##

A novel delivery system for drugs, and especially macromolecules such as proteins or oligonucleotides through biological membranes is provided, and specifically delivery of siRNA The delivery system comprises conjugation of the macromolecule drug to a moiety that enables effective passage through the membranes. Respectively, novel compounds and pharmaceutical compositions are provided, utilizing said delivery system. In one aspect of the invention, the compounds may be utilized in medical practice, for example, in delivery of siRNA or antisense oligonucleotides across biological membranes for the treatment of medical disorders.

Compounds having the formula ##STR00001##
or solvates of the compounds can be used as intermediates in the preparation of the synthetic steroids, Etonogestrel and Desogestrel, as well as other pharmaceutically active agents.

A novel delivery system for drugs, and especially macromolecules such as proteins or oligonucleotides through biological membranes is provided, and specifically delivery of siRNA. The delivery system comprises conjugation of the macromolecule drug to a moiety that enables effective passage through the membranes. Respectively, novel compounds and pharmaceutical compositions are provided, utilizing said delivery system. In one aspect of the invention, the compounds may be utilized in medical practice, for example, in delivery of siRNA or antisense oligonucleotides across biological membranes for the treatment of medical disorders.