Abstract: The present invention provides a drug delivery system wherein a “parachute” structure is coupled to a therapeutic compound. The “parachute” structure comprises hydrophilic branched molecules with a defined action diameter. The complex (a parachute structure coupled with a therapeutic compound) is either fixed at a cell membrane or delivered to a defined distance from the membrane within the cell. The membrane-anchoring/localizing effect of the parachute is achieved by hydrophilic structures linked with a branching unit of desired therapeutic compounds. Furthermore, the parachute structures can be connected by a spacer (e.g. &bgr;-amino acids, &ggr;-amino butyric acid, or poly-amino acids) instead of directly binding to the therapeutic compound, so that the therapeutic compounds can be localized within the cells at a defined distance from the cell membrane. A spacer containing a breaking point can determine the time span, during which the drug exhibits its therapeutic activity.

Abstract: A drug delivery system and methods are provided wherein a therapeutic/diagnostic agent or a component of the immune system is directed to particular cells in a selected organ or a specific site. Such a system can be formed by a photoselective compound generally described as V-M-P-C. V is a vector component suitable to target particular cells in a selected organ or site, where the type of the cell or antigen does not have to be specific to the desired treatment site. M is a marker component that is capable of being targeted by a therapeutic/diagnostic agent or a component of the immune system. P is a photocleavable or photosensitive bond, and C is a cap component rendering M ineffective. C is connected to M by the photocleavable or photosensitive bond. The photoselective compound is administered and marks targets of a certain kind of cell or a specific site.

Abstract: A cyclodextrin oligomer comprising two cyclodextrins connected through a spacer at the secondary side, characterized in that said spacer comprises the unit B which is a rigid and preferably hydrophilic structural element.

Abstract: A rigidly spaced, cyclodextrin dimers having a preselected breaking point within the spacer sequence so as to controllably release the active pharmaceutically active substance only after it reaches the desired treatment site is described. These preselected breaking points are stable in blood but are cleavable within cells. In preferred embodiments, the cyclodextrin-pharmaceutically active substance complex is targeted to specific sites via incorporation of specific antibodies for the targeted sites, typically by complexing a biotin-avidin system to specific antibodies which thereby targets the complex to a specific site. Once at the site as the complex is taken up into the cell the preselected break point is cleaved and the encapsulated pharmaceutically active substance becomes available for action within the targeted cell.