Inhaled nano- and microparticles for drug delivery

Abstract

The 21st century has seen a paradigm shift to inhaled therapy, for both systemic and local drug delivery, due to the lung's favourable properties of a large surface area and high permeability. Pulmonary drug delivery possesses many advantages, including non-invasive route of administration, low metabolic activity, control environment for systemic absorption and avoids first bypass metabolism. However, because the lung is one of the major ports of entry, it has multiple clearance mechanisms, which prevent foreign particles from entering the body. Although these clearance mechanisms maintain the sterility of the lung, clearance mechanisms can also act as barriers to the therapeutic effectiveness of inhaled drugs. This effectiveness is also influenced by the deposition site and delivered dose. Particulate-based drug delivery systems have emerged as an innovative and promising alternative to conventional inhaled drugs to circumvent pulmonary clearance mechanisms and provide enhanced therapeutic efficiency and controlled drug release. The principle of multiple pulmonary clearance mechanisms is reviewed, including mucociliary, alveolar macrophages, absorptive, and metabolic degradation. This review also discusses the current approaches and formulations developed to achieve optimal pulmonary drug delivery systems.

Polymer-drug conjugates as inhalable drug delivery systems: A review

“…The pulmonary route possesses several distinct advantages over conventional oral or injectable routes of administration, including lower enzymatic activity in the lungs than that found in the gut, the avoidance of first-pass metabolism as well as the thin alveolar membrane, high surface area for absorption and extensive vasculature that can facilitate the rapid systemic absorption of drugs after inhaled administration [10,11]. However, despite the potential for very rapid drug absorption from the lungs for relatively low molecular weight materials (several thousand Da max), the tight intercellular junctions between alveolar cells…”

Synthetic Polymer-Based Nanoparticles: Intelligent Drug Delivery Systems

“…As a result, the inhaled drugs exhibit low bioavailability in the lungs. It is well known that the particulate-based DDSs could solve the problem with drug bioavailability providing (i) drug protection from enzymatic degradation, (ii) evade pulmonary clearance, (iii) target drug delivery to the desired site at the lungs, (iv) controlled drug release, (v) reduce dose frequency, (vi) maximize the therapeutic efficiency and (vii) minimize side effects [89].…”

“…Furthermore, several factors, such as aerodynamic diameters, shape and surface properties of these polymer carriers can be tailored and optimized to obtain a particulate-based DDS with high therapeutic efficiency. In an extensive review, El-Sherbiny et al [89] have presented the factors influencing pulmonary drug deposition and bioavailability as well as the significance of particulatebased pulmonary drug delivery.…”

Mucoadhesive Solid Lipid Microparticles for Controlled Release of a Corticosteroid in the Chronic Obstructive Pulmonary Disease Treatment

“…Lung drug delivery is an important field of research in the treatment of chronic inflammatory pulmonary diseases, including asthma and chronic obstructive pulmonary disease (COPD) [1,2]. The latter is a chronic inflammatory disease characterized by airflow limitation, excessive production of mucus and progressive decline of lung function.…”