Core-Shell Drug Delivery for Skin Permeability
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Solution Overview
Problem
Hydrophilic drugs with a molecular weight of 400 or more face difficulty in permeating through the skin, leading to early depletion and short-lasting efficacy in external preparations, limiting their use in both systemic and local action applications.
Innovation Solution
A core-shell structure is developed, where a hydrophilic drug with a molecular weight of 400 or more is used as the core, coated with a surfactant in the shell, specifically with an alkyl or alkenyl group of 10 to 20 carbon atoms, and a mass ratio of 1:5 to 1:20, enhancing skin permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a hydrophilic drug with molecular weight of 400 or more is used in an external preparation, then the drug provides sustained efficacy, but the drug difficulty permeates through skin
Solution Approach 1:
The patent introduces a surfactant as an intermediary substance that forms a core-shell structure with the hydrophilic drug. The surfactant acts as a mediator between the hydrophilic drug and the skin barrier, facilitating permeation while maintaining the drug's sustained release properties. The core-shell structure allows the drug to penetrate skin effectively without compromising its duration of action.
Solution Approach 2:
The patent creates a composite core-shell structure combining hydrophilic drug (core) and surfactant (shell). This composite material leverages the permeation-enhancing properties of the surfactant shell while maintaining the sustained efficacy of the hydrophilic drug core, resolving the contradiction between permeability and duration of action.
2Object-affected harmful factors
If a hydrophilic drug with low molecular weight is used, then the drug permeates through skin easily, but the drug is depleted early and efficacy does not last
Solution Approach 1:
The patent embeds the hydrophilic drug within a surfactant-forming core-shell structure, creating a nested configuration where the drug core is surrounded by the surfactant shell. This nesting protects the drug from early depletion while maintaining permeability, allowing sustained release over time.
Solution Approach 2:
The patent changes the physical-chemical parameters of the drug delivery system by forming a core-shell structure with specific surfactant-to-drug ratios (1:5 to 1:20 mass ratio). This parameter change enables the system to achieve both good skin permeability and sustained duration of efficacy simultaneously.
3Object-affected harmful factors
If a surfactant with long alkyl chain is used in the core-shell structure, then the skin permeability is enhanced, but the formulation complexity increases
Solution Approach 1:
The patent optimizes the surfactant structure by specifying alkyl chain lengths (C10-C20) and HLB values (1-10), transforming the formulation development into a controlled parameter optimization process. This systematic approach enhances skin permeability while managing formulation complexity through defined specifications.
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 core-shell structure significantly increases skin permeability, allowing for sustained release and prolonged efficacy of hydrophilic drugs, making them suitable for both systemic and local action type external preparations.
Implementation Method 1
a core-shell structure, including: a core portion containing a hydrophilic drug having a molecular weight of 400 or more; and a shell portion containing a surfactant
Implementation Method 2
the core-shell structure having this structure has ability to release a large amount of the hydrophilic drug to be transdermally permeable when applied to skin
Implementation Method 3
the surfactant has an alkyl group or an alkenyl group having 10 to 20 carbon atoms
Data Source
AI summary
The present invention provides a core-shell structure having high skin permeability. The core-shell structure includes a core portion containing a hydrophilic drug having a molecular weight of 400 or more; and a shell portion containing a surfactant, and the core portion is a solid, the hydrophilic drug has a water-octanol partition coefficient of −3 or more and 6 or less, the surfactant has an alkyl group or an alkenyl group having 10 to 20 carbon atoms, and a mass ratio between the hydrophilic drug and the surfactant (hydrophilic drug:surfactant) is 1:5 to 1:20.