Background: The kidney is a critical organ serving several essential regulatory functions,
and any disorder in its physiological function can lead to serious problems. In past decades,
renal disease is increasingly recognized as a major worldwide public health problem. Unfortunately,
the therapeutic index of clinically available drugs for renal disease is limited. Kidneytargeted
drug delivery system, which has the ability to get to the target cells and can be subsequently
internalized, is a promising method to increase renal efficacy and reduce extra-renal toxicity.
Conclusion: Due to their targeting ability and high degree of safety, Low molecular weight proteins
(LMWC) and peptides based kidney-targeted drug delivery systems raise lots of concerns for
increasing renal effectiveness and reducing extra-renal toxicity. In general, the accumulation of
drug-carrier conjugation in the kidney is associated with its size and charge. After accumulation,
the drug need to quantitatively release from the carrier and regenerate the parent drug. Furthermore,
the linkage between the drug and carrier can significantly influence the in vivo efficacy of the drug,
it is important to employ a proper linkage to achieve a suitable balance between the drug stability in
the circulation and intrarenal release rate. Now, most of developed drug-carrier conjugations are
tested in vitro or in vivo, but not available in the clinical use. Although much future work remains
to do, the prospects are exciting, and the success may be just around the corner.