The present invention relates to a modified L-nucleic acid, comprising a L-nucleic acid part and a non-L-nucleic acid part, whereby the L-nucleic acid part is conjugated to the non-L-nucleic acid part and the conjugation of the L-nucleic acid part with the non-L-nucleic acid past leads to a slowed elimination out of the organism, in comparison with a L-nucleic acid which only comprises the L-nucleic acid part, said L-nucleic acid part being a spiegelmer.