Topical Emulsion Composition for NSAID Stability

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Solution Overview

Problem

Existing topical NSAID compositions face challenges in maintaining high drug concentration and bioavailability over time, with issues of ester formation and stability, particularly when containing ibuprofen, which affects their efficacy in treating pain and inflammation.

Innovation Solution

A novel emulsion composition with at least 7% NSAID, 15% isopropyl myristate, 25% water, and specific emulsifiers, pH adjusters, and minimal C1-C4 alcohols, ensuring less than 10% ibuprofen conversion to esters after 30 days and achieving high bioavailability with an area under the curve of at least 5000 ng*hour/mL and maximum concentration of 200 ng/mL when applied topically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high concentration of NSAID is formulated in topical composition, then bioavailability and efficacy are improved, but stability and ester formation increase

Engineering Contradiction:
ImproveNSAID concentrationVSAvoidester formation
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent uses isopropyl myristate as an intermediary substance that mediates between the NSAID and the aqueous phase. This ester solvent acts as a stabilizing intermediary that prevents direct esterification reactions while maintaining high NSAID solubility and bioavailability, thus resolving the contradiction between high drug concentration and chemical stability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameter composition by specifying minimal amounts of C1-C4 alcohols (≤5% weight) and controlling pH levels. By adjusting these chemical parameters, the formulation prevents ester formation while maintaining high NSAID concentration, thus resolving the stability contradiction

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If high amount of isopropyl myristate is used, then NSAID solubility and bioavailability are improved, but formulation complexity increases

Engineering Contradiction:
Improveisopropyl myristate contentVSAvoidformulation complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

Isopropyl myristate serves multiple functions simultaneously: it acts as a solubilizer for the NSAID, a penetration enhancer for skin absorption, and a stabilizer preventing ester formation. By using one substance with multiple functions, the patent avoids formulation complexity while achieving high bioavailability

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

3Stability of the object's composition

If minimal C1-C4 alcohols are used, then ester formation is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improveester formation controlVSAvoidalcohol content control
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent establishes predetermined concentration ranges for C1-C4 alcohols (≤5% weight) as a preventive measure. By setting these limits in advance during formulation design, the manufacturing process can follow standardized procedures without requiring excessive precision, thus balancing stability with manufacturability

Inventive Principle:
Principle #10Preliminary action

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 composition maintains high bioavailability and stability, achieving superior plasma concentrations and area under the curve compared to existing products like Ibuleve and Dolgit, with reduced ester formation, effectively treating joint, bone, and muscle pain.

Implementation Method 1

an oil continuous phase comprising at least 15%, by weight, of isopropyl myristate and from 0.1% to 5%, by weight, of one or more emulsifiers; and an aqueous phase comprising at least 25%, by weight, of water

Methodology Applied
Scientific EffectEmulsion: Emulsion

Implementation Method 2

from 0.1% to 5%, by weight, of one or more emulsifiers

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 3

an oil continuous phase comprising at least 15%, by weight, of isopropyl myristate

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentEP3720417B1Topical emulsion composition containing nonsteroidal Anti-inflammatory drug
Publication Date: 2023.11.01 KENVUE BRANDS LLC

AI summary

In one aspect, the present invention features an emulsion composition including (i) at least 3%, by weight, of a nonsteroidal anti-inflammatory drug; (ii) at least 15%, by weight, of isopropyl myristate; (iii) at least 25%, by weight, of water; and (iv) one or more emulsifiers; wherein the formulation is substantially free of C1-C4 alcohols.