the present invention relates to the delivery of drug , peptide and protein pharmaceuticals using a biotin - mediated uptake system . more particularly the invention relates to the amplification of active substance delivery with the biotin uptake system using a biotin - active substance - polymer conjugate or a biotin - nanoparticle conjugate . the invention also relates to processes for preparing the conjugates , pharmaceutical and diagnostic compositions containing same and methods of diagnosis and treatment involving the conjugates .