SHORT SEQUENCE RNAS AND LIPID CONJUGATES AS NOVEL DRUG DELIVERY SYSTEMS

Manoj G. Tyagi*, William T. Raja and Kapil D. Sagar

ABSTRACT

Lipids are an integral part of the cell membrane and synthetic lipids have become increasingly important as
formulation excipients and as active ingredients per se. The present article summarizes particular features of
commonly used phospholipids and their application spectrum and elucidates current strategies to improve
bioavailability and disposition of administered microRNA or short interfering RNA (miRNA)/siRNA).
Technological strategies to achieve these effects are highly diverse and offer various possibilities of liquid, semiliquid
and solid lipid based formulations for novel nucleotide based delivery optimization. The complexity of
microRNA-mediated pathway control has burgeoned since the discovery that miRNAs are found in the
extracellular space and constitute a form of cell to cell communication. miRNAs have been found in plasma, urine,
and saliva and have recently been shown to be carried on lipoproteins. Although our understanding of the cellular
machinery responsible for the secretion of miRNA is still incomplete, there is little doubt that extracellular
miRNAs delivered as conjugates with lipids will hold tremendous potential as both diagnostic and therapeutic
agents.

Keywords: Nanoparticles, phospholipids, microRNA, drug, membrane.