Polymeric nanotherapeutics acting at special regions of body
Tivadar Feczkó
Abstract
Nanoparticulate drug delivery systems provide a vast number of potential nanomedicines. Biocompatible synthetic and natural polymers are especially promising materials for nanoparticle (NP) preparation. Biodegradable polymeric NPs may improve the drug stability, availability and activity of insoluble active agents. Their size can be tunable and they might protect the drug from degradation. Due to their benefits, they can decrease dose frequency, thus, reduce side effects. They are especially useful in non-invasive drug delivery routes, such as nasal, oral, ocular and pulmonary. Polymeric NPs can be efficient carriers of biomolecules due to their low toxicity and immunogenicity, sufficient mechanical strength, biocompatibility and biodegradability. The aim of this work is to discuss polymeric nanotherapeutics considering the method of their delivery. From the point of view of the administration route, the gastrointestinal tract plays a predominantly important role as the most convenient and thus most favourable way of dosage. In stomach targeting the mucoadhesive polymers such as chitosan derivatives are promising nanocarriers, while to target the small intestine non-mucoadhesive but mucus-penetrating functionalization e.g. with polyethylene glycol can be an effective strategy. The parenteral route is essential in the case of some diseases because of its rapid action and enhanced bioavailability. To cross the blood brain barrier, the polymeric nanocarriers are generally coated with surfactants or apolipoproteins. Besides the intravenously administered polymer NPs, the nasal and inhalable nanotherapeutics must also face the problem of internalization by macrophages; thus, to evade them, mucoadhesive polymers are preferably used. The efficacy of ocular drug administration is eliminated by the superficial and internal barriers of the eye. Transdermal drug delivery by nanomedicines offers a possibility to improve skin penetration of hydrophobic, hydrophilic drugs and macromolecules. It has got high patient acceptance; furthermore, it bypasses the first-pass metabolism in the liver.