title: Challenges and Future Prospects for the Delivery of Biologics: Oral Mucosal, Pulmonary, and Transdermal Routes.
abstract: Biologic products are large molecules such as proteins, peptides, nucleic acids, etc., which have already produced many new drugs for clinical use in the last decades. Due to the inherent challenges faced by biologics after oral administration (e.g., acidic stomach pH, digestive enzymes, and limited permeation through the gastrointestinal tract), several alternative routes of administration have been investigated to enable sufficient drug absorption into systemic circulation. This review describes the buccal, sublingual, pulmonary, and transdermal routes of administration for biologics with relevant details of the respective barriers. While all these routes avoid transit through the gastrointestinal tract, each has its own strengths and weaknesses that may be optimal for specific classes of compounds. Buccal and sublingual delivery enable rapid drug uptake through a relatively permeable barrier but are limited by small epithelial surface area, stratified epithelia, and the practical complexities of maintaining a drug delivery system in the mouth. Pulmonary delivery accesses the highly permeable and large surface area of the alveolar epithelium but must overcome the complexities of safe and effective delivery to the alveoli deep in the lung. Transdermal delivery offers convenient access to the body for extended-release delivery via the skin surface but requires the use of novel devices and formulations to overcome the skin's formidable stratum corneum barrier. New technologies and strategies advanced to overcome these challenges are reviewed, and critical views in future developments of each route are given.
authors.affiliation: Department of Pharmaceutical Science and Technology, School of Chemical and Pharmaceutical Sciences, University of Chile, 8380494, Santiago, Chile. jomorales@ciq.uchile.cl.|Advanced Center for Chronic Diseases (ACCDiS), 8380494, Santiago, Chile. jomorales@ciq.uchile.cl.
authors.forename: Javier O
authors.initials: JO
authors.lastname: Morales
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas, 78712, USA.
authors.forename: Kristin R
authors.initials: KR
authors.lastname: Fathe
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas, 78712, USA.
authors.forename: Ashlee
authors.initials: A
authors.lastname: Brunaugh
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas, 78712, USA.
authors.forename: Silvia
authors.initials: S
authors.lastname: Ferrati
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA.
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Pharmaceutical Science and Technology, School of Chemical and Pharmaceutical Sciences, University of Chile, 8380494, Santiago, Chile.|Public Health Institute of Chile, 7780050, Santiago, Chile.
authors.forename: Miguel
authors.initials: M
authors.lastname: Montenegro-Nicolini
authors.affiliation: Chemical & Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran.
authors.forename: Zeynab
authors.initials: Z
authors.lastname: Mousavikhamene
authors.affiliation: College of Pharmacy, University of New Mexico, Albuquerque, New Mexico, 87131, USA. jmcconville@unm.edu.
authors.forename: Jason T
authors.initials: JT
authors.lastname: McConville
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA. prausnitz@gatech.edu.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Prausnitz
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas, 78712, USA. hugh.smyth@austin.utexas.edu.
authors.forename: Hugh D C
authors.initials: HDC
authors.lastname: Smyth
mesh_terms: D001688:Biological Products / Q000008:administration & dosage*; D004333:Drug Administration Routes; D006801:Humans
chemical_list: D001688:Biological Products
keywords: biologics; buccal; inhalation; microenvironment; mucosal; pulmonary; skin; sublingual; transdermal