Bachelor of Pharmacy, Mandesh Institute of Pharmaceutical Science and Research Center, Mhaswad
Nasal drug delivery has gained significant attention as a convenient, effective, and promising route for systemic drug administration. This approach is favored because of the nasal cavity’s rich blood supply, large surface area, and its ability to bypass hepatic first-pass metabolism, intestinal metabolism, and degradation in the gastrointestinal tract. The present review aims to present an overview of the naso-pulmonary drug delivery system, including its advantages and disadvantages, mechanisms of drug absorption, anatomical features of the nasal cavity and respiratory tract, factors influencing nasal absorption, various dosage forms, innovative formulations, and recent developments in nasal drug delivery technologies. The intranasal route has emerged as one of the most extensively explored areas in pharmaceutical research for the delivery of polar compounds, hormones, vaccines, proteins, and peptides. Owing to the favorable properties of the nasal mucosa for targeted delivery, various therapeutic agents can be administered intranasally to achieve local, systemic, and central nervous system (CNS) effects. Currently, naso-pulmonary drug delivery systems (NPDS) are being widely studied for direct drug transport to the brain and CNS to achieve rapid therapeutic responses.
The nasal route has been recognized as a promising method for drug administration, offering faster and more efficient absorption. This is because the nasal mucosa is more permeable to various compounds than the gastrointestinal tract, owing to the absence of pancreatic and gastric enzyme activity, the neutral pH of nasal mucus, and minimal dilution compared to gastrointestinal contents. Intranasal therapy has long been a recognized treatment method in the Ayurvedic system of Indian medicine. In recent years, many drugs have demonstrated improved systemic bioavailability when administered nasally compared to oral routes. At present, inhalation therapy is the preferred approach for managing respiratory conditions such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD). These localized treatments enable the use of smaller doses while minimizing systemic side effects. Inhalation has long been the most traditional and widely used method for delivering medications to the lungs and airways. Drugs administered through this route serve three primary purposes: prevention, treatment of local or systemic diseases, and therapeutic management. Various inhalation devices—such as nebulizers, metered-dose inhalers, dry powder inhalers, and other aerosol-based technologies—are utilized for effective drug delivery. Intranasal drug delivery is increasingly acknowledged as a practical and dependable alternative to oral and parenteral routes. For many years, nasal administration has been commonly used for symptom relief and for the prevention or treatment of various nasal disorders. In this method, drugs are introduced through the nasal cavity, allowing for both topical and systemic delivery—depending on whether the medication acts locally within the nasal passages or enters systemic circulation to produce broader therapeutic effects.
Anatomy of Nose: -
The anatomy of the nose is essential for understanding nasal drug delivery, as its structure directly affects drug deposition, absorption, and clearance. The nose can be divided into external and internal parts, and each region has specific functions relevant to drug delivery.
1.External Nose
Composed of bone and cartilage. Includes the nasal bridge, dorsum, tip, alae (sides), and nostrils (nares). Acts as the primary entry for air and inhaled drugs.
2. Internal Nose
The internal nasal cavity extends from the nostrils to the nasopharynx and is divided by the nasal septum into two chambers.
The anterior part of the nasal cavity. Lined with stratified squamous epithelium and contains hair (vibrissae) that filters large particles.
Makes up most of the nasal cavity. Lined with ciliated pseudostratified columnar epithelium with goblet cells that produce mucus. Highly vascularized, enabling rapid drug absorption. Contains turbinates/conchae (superior, middle, inferior):
Increase surface area for warming, humidifying, and filtering air. Direct airflow and affect drug deposition.
c. Olfactory Region
Located at the roof of the nasal cavity. Contains olfactory receptor neurons responsible for the sense of smell. Provides a direct pathway to the central nervous system, useful for nose-to-brain drug delivery.
3. Blood Supply
Nasal cavity is richly vascularized by branches of the internal and external carotid arteries, including:
4. Lymphatic Drainage
Lymph vessels drain into the cervical lymph nodes. Plays a role in immune response and vaccine delivery.
5. Nasal Functions Relevant to Drug Delivery
Filtration: Nasal hairs trap large particles.
Humidification and warming: Turbinates condition inhaled air.
Mucociliary clearance: Moves mucus and trapped particles to the pharynx; affects residence time of drugs.
Absorption: Rich vascularization and thin epithelial lining enhance systemic drug uptake.
If you want, I can create a labeled diagram of the nasal anatomy highlighting the regions important for drug delivery. This makes it much easier to visualize for NPDS purposes.
Chopade Pooja*, Adhav Akanksha, Shinde Reshma, Patil Shreya, Jagtap Puja, A Review: Nasopulmonary Drug Delivery System, Int. J. Sci. R. Tech., 2025, 2 (11), 404-409. https://doi.org/10.5281/zenodo.17611705
10.5281/zenodo.17611705
