Positively Charged Liposomes for Ocular Drug Delivery
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Solution Overview
Problem
Delivering lutein and zeaxanthin to the eye, particularly the macula, is challenging due to their large molecular weight and lipophilic nature, making it difficult to achieve sufficient concentrations with minimal side effects using existing methods, and iontophoresis requires a novel, stable, positively charged form to facilitate transcleral or transcorneal transport.
Innovation Solution
Formulating positively charged liposome vesicles using hydrogenated phosphatidylcholine and cationic excipients like octadecylamine to create a structure that can carry and transport lutein/zeaxanthin across cornea and sclera cells, enhancing their delivery through iontophoresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lutein/zeaxanthin are delivered through oral supplementation via systemic circulation, then lutein can reach the macula through xanthophyll-binding protein, but only a small percentage of lutein actually reaches the macula due to eye barrier limits
Solution Approach 1:
The patent uses positively charged liposomes as intermediary carriers to transport lutein/zeaxanthin across ocular barriers. The liposomes facilitate transcleral and transcorneal transport by interacting with the negatively charged ocular tissues, thereby mediating the delivery process and overcoming the barrier limitations that prevent sufficient lutein accumulation in the macula through oral supplementation.
Solution Approach 2:
The patent changes the physical and chemical parameters of lutein/zeaxanthin by encapsulating them in positively charged liposomes. This transformation from neutral lipophilic molecules to charged liposomal complexes enables active transport across ocular barriers through iontophoresis, fundamentally altering the delivery mechanism and significantly improving the quantity of lutein reaching the macula.
2Quantity of substance
If intra-vitreous injections are used to deliver lutein/zeaxanthin to the macula, then direct in-situ delivery is achieved, but the method is too invasive and results in poor patient acceptance
Solution Approach 1:
The patent replaces the mechanical injection system (intra-vitreous injection) with an electrical field-based transport system (iontophoresis). Instead of mechanically injecting lutein directly into the vitreous, the invention uses electrical current to drive positively charged liposomes containing lutein across the cornea and sclera, thereby achieving high concentration delivery without invasive surgery and significantly improving patient acceptance.
3Adaptability or versatility
If neutral lipophilic molecules like lutein are used for iontophoresis, then the intrinsic staining effect can be exploited for in-situ delivery, but the lipophilic nature and large molecular weight make transcleral or transcorneal transport nearly impossible
Solution Approach 1:
The patent changes the electrical charge parameter of lutein/zeaxanthin by incorporating them into positively charged liposomes. This parameter change from neutral to positively charged enables the molecules to respond to electrical fields and undergo iontophoretic transport across ocular barriers, while preserving the intrinsic staining effect for in-situ delivery and visualization.
Solution Approach 2:
The patent creates a composite material system where lutein/zeaxanthin are encapsulated within liposomal structures. This composite approach combines the lipophilic carotenoids with amphiphilic lipids to form stable, positively charged vesicles that can carry the lipophilic molecules while enabling their transport across hydrophilic ocular barriers through iontophoresis.
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 positively charged liposomal formulation enables effective delivery of lutein/zeaxanthin to ocular tissues, potentially delaying age-related macular degeneration progression and providing neuroprotective effects with improved patient acceptance and reduced invasiveness compared to traditional methods.
Implementation Method 1
Iontophoresis is a technology that uses controlled low-level electrical energy to transport ionized drugs through a biological membrane
Data Source
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AI summary
A method of producing positively charged liposome vesicles for use as carriers of lipophilic molecules. A mixture of hydrogenated phospholipids, a cationic excipient and a lipophilic molecule are dissolved in a solvent to form a composition. The composition is dried to remove the solvent. The dried composition is hydrated to form liposome vesicles and optionally the liposome vesicles are homogenized to form smaller vesicles. The vesicles are useful for delivery lipophilic molecules, such as, but limited to, lutein and zeaxanthin, to ocular tissues using iontophoresis.