Testosterone and Estradiol Spray With a Washable Transfer Barrier

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Solution Overview

Problem

Current transdermal hormone formulations lack a protective barrier to prevent transfer of estradiol and testosterone to others, posing risks of side effects, and there is no FDA-approved product for treating hypoactive sexual desire disorder (HSDD) in women.

Innovation Solution

A sprayable composition containing film-forming excipients that form a washable barrier on the skin, preventing transfer of estradiol and testosterone, and includes a pump spray system for convenient application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If transdermal gel or solution formulations are used to deliver testosterone and estradiol, then the active ingredients can be delivered through the skin, but the formulations must be applied over large surface areas and lack a protective barrier to prevent transfer to others

Engineering Contradiction:
Improveamount of testosterone and estradiol deliveredVSAvoidtransfer of active ingredients to others
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies a film-forming excipient that creates a thin film on the skin surface after application. This film acts as a protective barrier that prevents transfer of testosterone and estradiol to others while allowing transdermal absorption. The film is washable with soap and water, providing both protection and ease of removal.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The formulation combines testosterone, estradiol, film-forming excipient, and penetration enhancer into a composite sprayable composition. This composite structure integrates multiple functions: drug delivery, film formation for protection, and enhanced permeation, resolving the contradiction between effective delivery and preventing transfer.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If existing transdermal formulations are used, then hormone delivery is achieved, but the application process is inconvenient requiring large surface area coverage

Engineering Contradiction:
Improveeffective dose of testosterone and estradiolVSAvoidconvenience of application
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The film-forming excipient creates a concentrated delivery system where the entire effective dose forms a small, localized film on the skin rather than requiring dispersion over a large surface area. This dramatically improves ease of application while maintaining effective hormone delivery.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If oral ingestion route is used for testosterone administration, then the medication can be easily taken, but high doses are required due to hepatic first-pass metabolism

Engineering Contradiction:
Improveease of administrationVSAvoidtestosterone dose required
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent replaces the oral ingestion route with a transdermal spray system. This substitution eliminates hepatic first-pass metabolism by delivering testosterone directly through the skin into systemic circulation, thereby reducing the required dose while maintaining ease of administration through simple spray application.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Quantity of substance

If intramuscular administration is used for testosterone, then adequate dosing is achieved, but the procedure is painful and can result in supra-physiological serum concentrations

Engineering Contradiction:
Improvetestosterone dose deliveredVSAvoidpain and supra-physiological concentrations
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces intramuscular injection with transdermal spray delivery. This substitution eliminates injection pain and the risk of supra-physiological serum concentrations by providing controlled, gradual absorption through the skin, achieving therapeutic dosing without the harmful effects of rapid intramuscular delivery.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 effectively delivers estradiol and testosterone while preventing transfer to others, offering a convenient and safe treatment for conditions related to hormone deficiencies, including HSDD, menopausal symptoms, and osteoporosis.

Implementation Method 1

The composition contains a film forming excipient, which leaves a film on the skin. This film is washable, meaning that it can be removed from the skin, e.g. with water or soap and water. This film is a barrier that prevents transference of the testosterone and/or estradiol from the spray to others

Methodology Applied
Scientific EffectFilm formation:

Implementation Method 2

The characteristics of testosterone, such as its relatively low molecular weight and moderate lipophilicity, make the transdermal route the most suitable route for the administration of testosterone

Methodology Applied
Scientific EffectTransdermal delivery: Permeation

Implementation Method 3

The composition is in a sprayable form and can be applied to the skin using a pump spray system

Methodology Applied
Scientific EffectSpray delivery: Fluid Spray

Data Source

PatentEP3817731B1Testosterone and estradiol transdermal spray
Publication Date: 2025.09.03 CELISTA PHARMACEUTICALS LLC
  • EP3817731B1 patent drawingFigure 1
  • EP3817731B1 patent drawingFigure 2
  • EP3817731B1 patent drawingFigure 3

AI summary

The invention relates to a sprayable liquid composition for transdermal delivery of testosterone and/or estradiol, and to methods of treatment using this composition.