title: Revisiting structure-property relationship of pH-responsive polymers for drug delivery applications.
abstract: pH-responsive polymers contain ionic functional groups as pendants in their structure. The total number of charged groups on polymer chains determines the overall response of the system to changes in the external pH. This article reviews various pH-responsive polymers classified as polyacids (e.g., carboxylic acid based polymers, sulfonamides, anionic polysaccharides, and anionic polypeptides) and polybases (e.g., polyamines, pyridine and imidazole containing polymers, cationic polysaccharides, and cationic polypeptides). We correlate the pH variations in the body at the organ level (e.g., gastrointestinal tract and vaginal environment), tissue level (e.g., cancerous and inflamed tissues), and cellular level (e.g., sub-cellular organelles), with the intrinsic properties of pH-responsive polymers. This knowledge could help to select more effective ('smart') polymeric systems based on the biological target. Considering the pH differences in the body, various drug delivery systems can be designed by utilizing smart biopolymeric compounds with the required pH-sensitivity. We also review the pharmaceutical application of pH-responsive polymeric carriers including hydrogels, polymer-drug conjugates, micelles, dendrimers, and polymersomes.
authors.affiliation: Department of Biomedical Engineering, Amirkabir University of Technology, Tehran 15875-4413, Iran.
authors.forename: Salime
authors.initials: S
authors.lastname: Bazban-Shotorbani
authors.affiliation: Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, School of Dentistry, University of California, Los Angeles, CA 90095, United States; Parker H. Petit Institute for Bioengineering and Bioscience, G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States. Electronic address: Mahdi.hasani@gatech.edu.
authors.forename: Mohammad Mahdi
authors.initials: MM
authors.lastname: Hasani-Sadrabadi
authors.affiliation: Department of Biomedical Engineering, Amirkabir University of Technology, Tehran 15875-4413, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Karkhaneh
authors.affiliation: Cardiovascular Institute, Stanford University, 300 Pasteur Dr., Stanford, CA 94305, United States.
authors.forename: Vahid
authors.initials: V
authors.lastname: Serpooshan
authors.affiliation: Parker H. Petit Institute for Bioengineering and Bioscience, G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
authors.forename: Karl I
authors.initials: KI
authors.lastname: Jacob
authors.affiliation: Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, School of Dentistry, University of California, Los Angeles, CA 90095, United States. Electronic address: amoshaverinia@dentistry.ucla.edu.
authors.forename: Alireza
authors.initials: A
authors.lastname: Moshaverinia
authors.affiliation: Nanotechnology Research Center and Department of Nanotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 14155-6451, Iran; Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States. Electronic address: mmahmoudi@bwh.harvard.edu.
authors.forename: Morteza
authors.initials: M
authors.lastname: Mahmoudi
mesh_terms: D000818:Animals; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D011108:Polymers
keywords: Dendrimer; Drug delivery systems; Hydrogels; Micelle; Polymer-drug conjugate; Polymersome; pH-responsive polymers