Placenta Barrier and Drug Delivery

The placenta is only a temporary, disc-shaped organ which connect mother with the fetus via the umbilical cord to the uterine wall to provide the nutrition and protection. At the current era pregnancy complications like including pre-eclampsia, fetal development restriction, premature birth, placental abruption, and late pregnancy loss makes the scientist to turn their focuses on placental barrier for the drug transport. The formation of the placenta immediately starts after the implementation of the blastocyst. The blastocyst trophoblast form multinucleated syncytiotrophoblast and proliferate to form cytotrophoblast cells. Trophoblastic composite and trophoblast intrusion contributes in the reconstructing of maternal spiral arteries within the uterine wall. The branch structure of trophoblast inside the lacunar spaces consequence in the constitution of villous trees responsiple for the exchange of nutrition and gas. Drug molecules basically pass through the placenta barrier using the passive diffusion, facilated transport and efflux, and transcytosis pathways. The passive diffusion of the drugs through the placenta depends on the nature of the drug where as Facillited transport is membrane proteins dependent. The hydrolyze adenosine triphosphate (ATP) is the key for the active transporation governed by ATP-binding cassette (ABC) protein. Endocytosis mechanism is responsible for both endogenous compound transport as well as xenobiotics such as drug-loaded nanoparticle present in placental syncytiotrophoblast. Nanotechnology approaches is the latest trend to deliver the drug to the fetus as well and to restrict the entry of the drugs to protect the fetus damage. Placenta on chip is few latest trend for the placental drug delivery. The review specifically forcus on the variors transport mechanism of the drugs through the placenta as well as the metabolism of the drugs.