Abstract: The present invention relates to substituted cyclodextrin derivatives which are particularly useful intermediates for producing well-defined carboxyalkylated cyclodextrins in contrast with the poorly-defined mixtures available through prior art procedures. The present invention also relates to processes for their preparation in a limited number of steps. These well-defined carboxyalkylated cyclodextrins can be polysulfated according to procedures standard in the art and some of these polysulfates, and alkali salts thereof, have been found to exhibit biologically active properties especially for the treatment and/or prophylaxis of degenerative joint diseases (e.g. osteoarthritis) or heparin-induced thrombocytopenia, or for cartilage repair or connective tissue repair.