This invention relates to the use of a cyclic compound of formula (I), wherein A, B independently in each occurrence is alkane-i,j-diyl having k carbon atoms, i and independently j being less than or equal k and k being selected from 1 to 10, wherein said alkane-i,j-diyl (i) may comprise one or more double bonds； (ii) is optionally substituted； and/or (iii) comprises a cycle, wherein the total number of cycles being cyclic sugars in said compound is selected from 0 to 4 and is less than p (n+m)； X,Y independently in each occurrence is a biocompatible functional group comprising at least one oxygen atom or two sulphur atoms； n, m independently of each other are selected from 0 to 20； p is selected from 1 to 10； n+m is equal or greater than 1； and p.(n+m) is selected from 3 to 30； wherein said compound is capable of forming a complex with a protonated primary and/or protonated secondary amino group and/or a protonated guanidinium group for the manufacture of a pharmaceutical or diagnostic composition further comprising a pharmaceutically or diagnostically active agent, said active agent comprising one or more protonated primary and/or protonated secondary amino groups and/or a protonated guanidinium groups, wherein (a) transmembrane and/or transmucosal delivery； (b) solubility in non-aqueous solvents； and/or (c) stability of said active agent are improved.
