Roflumilast Aerosol Foam Composition for Stable Skin Delivery
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Solution Overview
Problem
Existing aerosol foam formulations for pharmaceutical applications face challenges in stability, consistency, and environmental impact, particularly with hydrocarbon and compressed-gas propellants, leading to incomplete delivery and instability of the foam structure, which affects the efficacy and patient compliance.
Innovation Solution
A roflumilast aerosol foam composition using a blend of alkyl phosphate surfactants and a propane/isobutane/butane propellant blend, ensuring stable, aesthetically pleasing, and consistent foam delivery without alcohol or propylene glycol, with a foam half-life of over 60 seconds, suitable for treating scalp and facial dermatoses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydrocarbon or compressed-gas propellants are used in aerosol foam formulations, then the foam can be generated and dispensed, but the foam structure becomes unstable and delivery is incomplete
Solution Approach 1:
The patent changes the chemical composition parameters of the foam formulation by incorporating specific surfactants (alkyl phosphates, alkyl polyglucosides, or their blends) and controlling the ratio of propellant to formulation (1:4 to 1:2). This parameter optimization stabilizes the foam structure and ensures complete delivery while maintaining ease of dispensing.
Solution Approach 2:
The patent uses composite surfactant systems combining multiple components (alkyl phosphates, alkyl polyglucosides, and optional co-surfactants) to create a stable foam formulation. This composite approach enhances foam stability and delivery completeness while preserving the ease of operation provided by the propellant system.
2Ease of operation
If conventional foam formulations are used, then foam can be applied to skin, but they cause irritation and allergic reactions
Solution Approach 1:
The patent modifies the chemical composition by selecting specific surfactants with lower irritancy profiles and controlling pH within a neutral to slightly acidic range (pH 3-7). This parameter adjustment maintains foam applicability to skin while significantly reducing irritation and allergic reaction potential.
Solution Approach 2:
The patent employs biodegradable surfactants such as alkyl polyglucosides derived from renewable resources, which are gentler on skin and environmentally friendly. These surfactants provide the necessary foam functionality without the harmful effects of conventional alternatives.
3Object-generated harmful factors
If propellant-free generation method is used, then environmental impact is reduced, but foam stability and structure are compromised
Solution Approach 1:
The patent optimizes the formulation composition parameters by incorporating specific stabilizing surfactants and controlling the propellant-to-formulation ratio (1:4 to 1:2). This allows the use of environmentally friendly propellants while maintaining foam stability and structure through enhanced surfactant stabilization.
Solution Approach 2:
The patent employs composite surfactant systems that provide both environmental compatibility and foam stability. The combination of alkyl phosphates, alkyl polyglucosides, and optional co-surfactants creates a stable foam structure that works with eco-friendly propellants, resolving the contradiction between environmental impact and foam stability.
4Area of stationary object
If foam foam is applied to hair-covered areas, then treatment coverage is improved, but rubbing is required which increases irritation
Solution Approach 1:
The patent modifies the foam's rheological parameters by adjusting surfactant concentration and formulation composition to achieve low shear sensitivity. This allows the foam to be applied to hair-covered areas without requiring significant rubbing, thereby maintaining treatment coverage while minimizing irritation.
Solution Approach 2:
The patent uses gentle, biodegradable surfactants that enable foam application without aggressive rubbing. The foam formulation is designed to penetrate and cover hair-covered areas effectively while being mild enough to avoid irritation, eliminating the need for forceful application.
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 provides stable, non-irritating, and effective delivery of roflumilast with consistent dosing, maintaining foam structure until application, reducing environmental impact, and enhancing patient compliance.
Implementation Method 1
the liquid propellant volatilizes producing a semi-solid foam product that is expanded with gas phase propellant
Implementation Method 2
an oil in water emulsion aerosol foam composition having an alkyl phosphate anionic surfactant or blend of alkyl phosphate surfactants as the emulsifier
Implementation Method 3
the surfactants concentrate at the interface between the propellant/oil phase and the aqueous phase to form a thin film referred to as the 'lamella'
Implementation Method 4
When an aerosol foam formulation is discharged from the container, the liquid propellant volatilizes producing a semi-solid foam product that is expanded with gas phase propellant
Data Source
AI summary
The present invention is directed to an aerosol foam composition comprising roflumilast, an emulsifier blend containing cetearyl alcohol, dicetyl phosphate, and ceteareth-10 phosphate and a hydrocarbon propellant. The aerosol foam composition is preferably an oil in water emulsion. The propellant is a mixture of liquefied hydrocarbon gases preferably a propane/isobutane/butane blend. The hydrocarbon propellant results in an aerosol foam which is stable, has consistent physical properties, excellent aesthetics, and no discernable degradation after long term or accelerated storage conditions.