This review provides the reader a concise overview of
the different biological barriers that hinder the delivery of
therapeutic agents through membranes, such as intestinal mucosa,
Brain Blood Barrier (BBB), and mediators of transport such as
efflux transporters and etc., and the approaches for overcoming
such barriers. The approaches discussed in this review include:
utilizing natural occurring transporters to deliver drugs
specifically to their targets, nucleoside analogues delivery, CYPactivated
prodrugs that target drugs to the liver, modification of
passive diffusion by efflux pumps, intestinal transporters such as
PEPT1 and GLUT1, Carrier Mediated Transport (CMT) systems
for transporting nutrients, vitamins or hormones into the central
nervous system, tissue selective drug delivery, administration of
an exogenous enzyme to reach the tumor site which is followed
by systemic administration of non-toxic prodrugs (ADEPT,
GDEPT and VDEPT), enzymes involve in the bioconversion of
ester-based prodrugs for activation (hydrolysis) of prodrugs to
their active forms, brain targeted Chemical Delivery Systems
(CDS), amino acid prodrugs to improve oral bioavailability,
sustained drug delivery and intravenous drug delivery.
In addition, Receptor-Mediated Transcytosis (RMT) for
efficacious delivery of Nano particles through the intestinal
mucosa and BBB, and the prodrug chemical approach based on
intra molecularity to deliver anti-cancer drugs is discussed
