Hypotonic Mucus-Penetrating Nanoparticle Formulations
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Solution Overview
Problem
The challenge lies in delivering therapeutics effectively to mucosal surfaces, particularly due to the barrier posed by the protective mucus layer, which limits the retention and distribution of drugs and nanoparticles, especially in highly viscoelastic and adhesive environments like the respiratory, gastrointestinal, and female reproductive tracts, leading to poor efficacy and rapid clearance.
Innovation Solution
A hypotonic formulation comprising mucus-penetrating nanoparticles with a PEG or block copolymer coating that enhances diffusion through mucus, maintaining a surface density between 0.05 to 100 chains per nm² and a ζ-potential between 10 mV and -10 mV, allowing for rapid transport to epithelial surfaces, thereby overcoming the mucus barrier and achieving uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional particulate drug delivery systems are used, then they can be administered to mucosal surfaces, but they are trapped by the mucus layer and fail to achieve uniform distribution
Solution Approach 1:
The patent modifies the surface properties of nanoparticles by coating them with PEG and adjusting their size to 100-200 nm, changing their physical parameters to enable mucus penetration. This resolves the contradiction by transforming conventional particles that are trapped into modified particles that can distribute uniformly through the mucus layer while maintaining reliable drug delivery to epithelial surfaces.
Solution Approach 2:
The patent creates composite nanoparticles consisting of a core material (for drug loading) coated with PEG chains. This composite structure combines the drug delivery capability of the core with the mucus-penetration ability of the PEG coating, enabling both reliable delivery and uniform distribution that conventional single-material particles cannot achieve.
2Duration of action of moving object
If mucoadhesive particles are used to increase residence time, then they adhere to mucus, but they are immobilized and cannot spread over the mucosal surface
Solution Approach 1:
The patent changes the surface characteristics of particles by coating with PEG, which alters their interaction with mucus from adhesive to non-adhesive. This enables particles to move freely across the mucosal surface while the hypotonic formulation ensures prolonged residence time through osmotic retention, resolving the contradiction between mobility and residence time.
3Productivity
If hypertonic formulations are used, then they can deliver drugs to mucosal surfaces, but they cause fluid secretion and rapid clearance
Solution Approach 1:
The patent inverts the conventional approach by using hypotonic formulations instead of hypertonic ones. The hypotonic formulation creates osmotic retention that prevents fluid secretion and formulation leakage, while still enabling effective drug delivery to mucosal surfaces. This resolves the contradiction by reversing the tonicity approach to simultaneously achieve delivery efficiency and retention.
4Speed
If PEG coating is applied to nanoparticles, then they can penetrate mucus rapidly, but the surface density must be precisely controlled to avoid aggregation
Solution Approach 1:
The patent establishes specific parameter ranges for PEG surface density (0.05 to 100 chains per nm²) and nanoparticle size (100-200 nm) that optimize both mucus penetration rate and colloidal stability. By defining these precise parameters, the patent resolves the contradiction between achieving rapid penetration and preventing aggregation through proper surface density control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hypotonic formulation significantly enhances the delivery and retention of therapeutic agents to mucosal surfaces, including deep recesses, improving treatment efficacy and minimizing toxicity, with minimal risk of epithelial damage, as demonstrated by increased surface coverage and prolonged residence time.
Implementation Method 1
Dense surface coats of low molecular weight polyethylene glycol (PEG) allow nanoparticles to rapidly penetrate through highly viscoelastic human and animal mucus secretions. The hydrophilic and bioinert PEG coating effectively minimizes adhesive interactions between nanoparticles and mucus constituents.
Implementation Method 2
Osmosis can be used to cause rapid penetration of mucus-penetrating particles into deep recesses in highly-folded mucosal tissues.
Data Source
Figure 1A~1D
Figure 1E~1G
Figure 1H~2A
AI summary
Hypotonic formulations were evaluated for delivering water-soluble drugs and for drug delivery with muco-inert (that is, non-adhesive) mucus-penetrating nanoparticles (MPP). Hypotonic formulations markedly increased the rate at which drugs and MPP reached the epithelial surface, including deep into the vaginal folds. Minimally hypotonic formulations, preferably ranging from 20-220 mOsm/kg, provided rapid and uniform delivery of MPP to the entire vaginal surface, with minimal risk of epithelial toxicity. Data also show that there is a higher osmolality in the colon, such that vehicles with an osmolality above that of blood plasma (generally considered isotonic at ~300 mOsm/kg), still lead to improvements in distribution in the colon due to rapid, osmotically-induced fluid absorption. The range for improved colon distribution with a hypotonic vehicle in the colon is ~20 mOsm/kg-450 mOsm/kg.