Skin Ointment Composition for Stable Aniline Derivative Absorption

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Solution Overview

Problem

Existing external preparations for treating HPV warts and condyloma acuminatum using N-[5-fluoro-2-(1-piperidinyl)phenyl]-4-pyridinethioamide suffer from poor solubility, stability, and transdermal absorbability, leading to insufficient skin penetration and potential irritation.

Innovation Solution

A combination of an aniline derivative, such as N-[5-fluoro-2-(1-piperidinyl)phenyl]-4-pyridinethioamide, with specific absorption enhancers like monohydric higher alcohols (16-20 carbon atoms) or synthetic squalane, formulated as an oleaginous ointment to enhance stability and transdermal absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If N-[5-fluoro-2-(1-piperidinyl)phenyl]-4-pyridinethioamide is used as an active ingredient in external preparations, then antiviral activity against HPV is achieved, but solubility and stability are poor

Engineering Contradiction:

Improveantiviral activityVSAvoidsolubility and stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces a special vehicle composition containing cyclodextrin derivatives as intermediary substances to solve the solubility and stability problems of the thioamide derivative. The cyclodextrin forms inclusion complexes with the active ingredient, improving its solubility in the vehicle while maintaining stability. This mediator approach allows the active ingredient to be delivered effectively without direct contact with incompatible excipients.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite preparation system combining the thioamide derivative with cyclodextrin derivatives and specific vehicle components. This composite formulation leverages the host-guest complexation capability of cyclodextrins to encapsulate the active ingredient, providing both solubility enhancement and stability protection while maintaining antiviral activity.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the thioamide derivative is formulated as an external preparation, then antiviral effects are achieved, but transdermal absorbability is insufficient

Engineering Contradiction:

Improveantiviral effectsVSAvoidtransdermal absorbability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent modifies the physical and chemical parameters of the formulation by incorporating cyclodextrin derivatives that change the solubility characteristics and molecular environment of the active ingredient. This parameter change in the vehicle composition enables better penetration through the stratum corneum while maintaining the antiviral efficacy of the thioamide derivative.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If organic solvents are used to improve solubility, then dissolution is enhanced, but skin irritation increases

Engineering Contradiction:

ImprovedissolutionVSAvoidskin irritation

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potential harm of poor solubility into a benefit by using cyclodextrin derivatives to create soluble inclusion complexes. Instead of using harmful organic solvents to achieve dissolution, the cyclodextrin provides a benign aqueous-based solution that enhances solubility without causing skin irritation, effectively turning the solubility problem into a formulation advantage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The cyclodextrin derivative acts as an intermediary substance that mediates between the hydrophobic active ingredient and the aqueous vehicle system, enabling dissolution without requiring irritating organic solvents. The cyclodextrin's hydrophilic exterior allows aqueous compatibility while its hydrophobic cavity accommodates the active ingredient.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 provides high principal agent stability and transdermal absorbability with low skin irritation, effectively treating DNA viral diseases like HPV warts and condyloma acuminatum.

Implementation Method 1

a combination of components of external preparations for the skin that can maintain the principal agent stability and has good transdermal absorbability by using an aniline derivative together with specific absorption enhancers

Methodology Applied

Scientific EffectTransdermal absorption enhancement: Permeation

Implementation Method 2

The external preparation for skin of the present invention includes... a compound selected from the group consisting of an aniline derivative... further comprising a monohydric higher alcohol having 16 to 20 carbon atoms or synthetic squalane

Methodology Applied

Scientific EffectChemical stability:

Data Source

PatentUS20250339420A1Aniline-derivative-containing external preparation for skin

Publication Date: 2025.11.06 IWAKI SEIYAKU

AI summary

The purpose of the present invention is to provide an external preparation for skin containing an aniline derivative as a principal agent and having high principal agent stability and high transdermal absorbability. The present invention provides an external preparation for skin comprising, as an active ingredient, a compound selected from the group consisting of an aniline derivative represented by the following formula (I): [Wherein W represents S or O], a pharmacologically acceptable salt thereof, and a hydrate of the same, and further comprising a monohydric higher alcohol having 16 to 20 carbon atoms or synthetic squalane.