Pulmonary delivery is a non-invasive form of delivery that holds tremendous therapeutic promise for topical and systemic administration of several macromolecules. Oral administration of macromolecules has several limitations such as low bioavailability, degradation of drug before reaching circulation and insufficient absorption across intestinal membrane. Administration of macromolecules such as proteins, peptides and nucleic acids via inhalation offers great potential due to the avoidance of first pass metabolism, higher surface area and rapid clinical response. However, delivery of reproducible, uniform and safe doses of inhaled particles remains a major challenge for clinical translation. Recent advances in the fields of biotechnology and particle engineering led to progress in novel pulmonary drug delivery systems. Moreover, significant developments in carriers and delivery devices prevent denaturation of macromolecules and control their release within the lungs. This article reviews the advances in pulmonary drug delivery systems by focusing on the recent patents in delivery of macromolecules. Furthermore, recent patents in gene delivery to the lungs have also been discussed. List of patents included in this review is comprehensive in terms of pulmonary delivery of therapeutics. It includes inventions related to proteins and peptides, DNA therapeutics, siRNA and other genetic materials with therapeutic applications. The diseases targeted by these therapeutic molecules are varied including but not limited to different forms of cancer, respiratory diseases etc.
