Transdermal Gel Using Amorphous COX-2 Inhibitor Coating

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Solution Overview

Problem

Transdermal delivery of COX-2 inhibitors, such as celecoxib, faces challenges due to low solubility, high melting point, and low penetration potential in existing topical formulations, requiring improvements in skin penetration, stability, and manufacturability while maintaining acceptable organoleptic properties.

Innovation Solution

A transdermal gel composition incorporating a selective COX-2 inhibitor in solid particulate form coated with a volatile siloxane agent, combined with solubilizers like Brij-58 and Kolliphor P407, penetration enhancers like menthol, and a gel forming agent like Carbopol 980, which maintains stability and enhances skin penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If COX-2 inhibitors are used in topical formulations, then anti-inflammatory and pain-relieving effects are achieved, but skin penetration is insufficient due to low solubility and high melting point

Engineering Contradiction:
Improvetherapeutic effectivenessVSAvoidlow skin penetration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the COX-2 inhibitor from crystalline to amorphous form, which increases solubility and skin penetration while maintaining therapeutic effectiveness. The amorphous form has higher energy state and better solubility characteristics compared to crystalline form.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite gel formulation combining the amorphous COX-2 inhibitor with specific excipients including carbopol (gel base), ethanol (penetration enhancer), and water. This composite system addresses the penetration issue while maintaining the drug's therapeutic properties.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If penetration enhancers and solubilizers are added to improve skin penetration, then delivery effectiveness increases, but formulation complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveskin penetration potentialVSAvoidformulation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses ethanol which serves multiple functions simultaneously: it acts as a penetration enhancer to improve drug delivery, as a solubilizer to dissolve the amorphous COX-2 inhibitor, and as a preservative. This multi-functionality reduces the number of separate ingredients needed and simplifies the overall formulation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The amorphous form of the COX-2 inhibitor acts as an intermediary state that bridges the gap between poor water solubility of crystalline form and the need for effective skin penetration. This intermediate amorphous state enables better interaction with penetration enhancers while maintaining stability in the gel matrix.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If microemulsion gel systems are used to improve penetration, then skin delivery is enhanced, but thermal instability and high stickiness occur

Engineering Contradiction:
Improveskin penetrationVSAvoidthermal stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent changes the gel base from microemulsion type to carbopol-based hydrogel, which has better thermal stability. The carbopol gel matrix provides a stable structure that does not undergo phase separation or instability at elevated temperatures, while still allowing effective drug penetration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a simple carbopol gel system that is easier to manufacture and more stable than complex microemulsion systems. The formulation prioritizes stability and ease of manufacture over the most advanced delivery technology, using well-established, reliable ingredients.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If COX-2 inhibitors are administered orally, then systemic therapeutic effects are achieved, but gastrointestinal side effects occur

Engineering Contradiction:
Improvetherapeutic effectivenessVSAvoidgastrointestinal side effects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the therapeutic COX-2 inhibitory activity from the oral administration route and delivers it topically through the skin. This removes the drug from contact with the gastrointestinal tract, eliminating GI side effects while preserving the anti-inflammatory and pain-relieving therapeutic effects through local and systemic absorption.

Inventive Principle:
Principle #2Taking out (Extraction)

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 formulation achieves effective skin penetration and stability, preventing side effects associated with oral administration, while being suitable for industrial-scale production and maintaining desirable organoleptic characteristics.

Implementation Method 1

the selective COX-2 inhibitor is coated with the volatile siloxane agent, or characterized in that the selective COX-2 inhibitor is dissolved in the composition and wherein the penetration enhancer is coated with the volatile siloxane agent

Methodology Applied
Scientific EffectCoating: Coatings

Implementation Method 2

a gel forming agent, a precipitating agent to bring about a pH of 5,5 -7,5 for the gel forming agent swollen in water

Methodology Applied
Scientific EffectGel formation: Gel

Implementation Method 3

There is a need for the formulation to have good physical-chemical stability, especially in the cold, and microbiological stability. In case of low-solubility active ingredient, such as celecoxib, the formulation should also improve the solubility of the active ingredient

Methodology Applied
Scientific EffectSolubilization: Solvation

Implementation Method 4

The delivery of COX-2 inhibitors, especially topically, has many challenges, as these compounds have a very low solubility, high melting point, and low penetration potential in known topical formulations

Methodology Applied
Scientific EffectPermeation enhancement: Permeation

Data Source

PatentEP2879664B1Transdermal formulation containing cox inhibitors
Publication Date: 2020.10.07 EGIS GYOGYSZERGYAR NYILVANOSAN MUKODO RESZVENY TARSASAG

AI summary

Disclosed are gel compositions suitable for the topical administration of an active compound having poor solubility and skin penetration, for example, of a COX-2 inhibitor compounds, processes of preparation thereof and methods of use thereof for the treatment of indications treatable by the active compound