ABSTRACT
With the in-depth knowledge of the pathological and physiological characteristics of the intestinal barrier-portal vein/intestinal lymphatic vessels-systemic circulation axis, oral targeted drug delivery is frequently being renewed. With many advantages, such as high safety, convenient administration, and good patient compliance, many researchers have begun to explore targeted drug delivery from intravenous injections to oral administration. Over the past few decades, the fields of materials science and nanomedicine have produced various drug delivery platforms that hold great potential in overcoming the multiple barriers associated with oral drug delivery. However, the oral transport of particles into the systemic circulation is extremely difficult due to immune rejection and biochemical invasion in the intestine, which limits absorption and entry into the bloodstream. The feasibility of the oral delivery of targeted drugs to sites outside the gastrointestinal tract (GIT) is unknown. This article reviews the biological barriers to drug absorption, the in vivo fate and transport mechanisms of drug carriers, the theoretical basis for oral administration, and the impact of carrier structural evolution on oral administration to achieve this goal. Finally, this article reviews the characteristics of different nano-delivery systems that can enhance the bioavailability of oral therapeutics and highlights their applications in the efficient creation of oral anticancer nanomedicines.
Subject(s)
Antineoplastic Agents , Nanomedicine , Neoplasms , Humans , Nanomedicine/methods , Neoplasms/drug therapy , Neoplasms/therapy , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/chemistry , Administration, Oral , Animals , Drug Carriers/chemistry , Drug Delivery Systems/methods , Biological Availability , Nanoparticles/chemistry , Nanoparticles/administration & dosageABSTRACT
In a recent Nature elegant study, Wang et al. identified CD300ld, a novel functionally highly conserved tumor immunosuppressive receptor, highly expressed specifically on polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), as well as a key receptor in the regulation of recruitment and immunosuppressive function of PMN-MDSCs. Targeting CD300ld could remodel the tumor immune microenvironment, resulting in a broad-spectrum anti-tumor effect.