The present invention relates to a hyaluronic acid composition comprising a hyaluronic acid and one or more cyclodextrin molecules covalently bound to said hyaluronic acid via a bi- or polyfunctional crosslinking agent, wherein the covalent bonds between said hyaluronic acid and said crosslinking agent and between said crosslinking agent and said cyclodextrin molecules are ether bonds. The present invention relates to medical and cosmetic (non-medical) uses of such compositions further comprising a pharmaceutical or medical agent and to a method of preparing a slow release formulation.