title: Nanoparticles decorated with proteolytic enzymes, a promising strategy to overcome the mucus barrier.
abstract: The intestinal mucus gel layer represents a stumbling block for drug adsorption. This study is aimed to formulate a nanoparticulate system able to overcome this barrier by cleaving locally the glycoprotein substructures of the mucus. Mucolytic enzymes such as papain (PAP) and bromelain (BRO) were covalently conjugated to poly(acrylic acid) (PAA). Nanoparticles (NPs) were then formulated via ionic gelation method and characterized by particle size, zeta potential, enzyme content and enzymatic activity. The NPs permeation quantified by rotating tube studies was correlated with changes in the mucus gel layer structure determined by pulsed-gradient-spin-echo NMR (PGSE-NMR), small-angle neutron scattering (SANS) and spin-echo SANS (SESANS). PAP and BRO functionalized NPs had an average size in the range of 250 and 285 nm and a zeta potential that ranged between -6 and -5 mV. The enzyme content was 242 μg enzyme/mg for PAP modified NPs and 253 μg enzyme/mg for BRO modified NPs. The maintained enzymatic activity was 43% for PAP decorated NPs and 76% for BRO decorated NPs. The rotating tube technique revealed a better performance of BRO decorated NPs compared to PAA decorated NPs, with a 4.8-fold higher concentration of NPs in the inner slice of mucus. Addition of 0.5 wt% of enzyme functionalized NPs to 5 wt% intestinal mucin led to c.a. 2-fold increase in the mobility of the mucin as measured by PGSE-NMR indicative of a significant break-up of the structure of the mucin. SANS and SESANS measurements further revealed a change in structure of the intestinal mucus induced by the incorporation of the functionalized NPs mostly occurring at a length scale longer than 0.5 μm. Accordingly, BRO decorated NPs show higher potential than PAP functionalized NPs as mucus permeating drug delivery systems.
authors: Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria.
authors: Irene
authors: I
authors: Pereira de Sousa
authors: Department of Pharmaceutical, Chemical and Environmental Sciences, Faculty of Engineering and Science, University of Greenwich, Medway Campus, Chatham Maritime, UK.
authors: Beatrice
authors: B
authors: Cattoz
authors: Newcastle University, Institute for Cell and Molecular Biosciences, Newcastle upon Tyne, UK.
authors: Matthew D
authors: MD
authors: Wilcox
authors: Department of Pharmaceutical, Chemical and Environmental Sciences, Faculty of Engineering and Science, University of Greenwich, Medway Campus, Chatham Maritime, UK.
authors: Peter C
authors: PC
authors: Griffiths
authors: ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, UK.
authors: Robert
authors: R
authors: Dalgliesh
authors: ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, UK.
authors: Sarah
authors: S
authors: Rogers
authors: Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria. Electronic address: andreas.bernkop@uibk.ac.at.
authors: Andreas
authors: A
authors: Bernkop-Schnürch
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D001963:Bromelains / Q000737:chemistry / Q000378:metabolism; D018938:Caco-2 Cells; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D009077:Mucins / Q000378:metabolism; D009093:Mucus / Q000378:metabolism*; D053758:Nanoparticles; D010206:Papain / Q000737:chemistry / Q000378:metabolism; D010316:Particle Size; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000378:metabolism; D013552:Swine
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D009077:Mucins; C006903:carbopol 940; D001963:Bromelains; D010447:Peptide Hydrolases; D010206:Papain
keywords: Bromelain; Diffusion; Enzyme functionalization; Mucus permeating nanoparticles; Oral drug delivery; Papain