Soft Gel Naproxen Formulation for High Drug Loading

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Solution Overview

Problem

Existing soft gel capsule formulations face challenges in achieving high concentrations of poorly soluble drugs like naproxen without increasing the capsule size, and require complex pH adjustment processes that can be corrosive and inefficient.

Innovation Solution

A formulation combining naproxen, naproxen sodium, polyethylene glycol, propylene glycol, povidone, and water, allowing for higher concentrations and adjustable pH without neutralization steps, ensuring compatibility with the capsule shell and improved bioavailability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If naproxen is formulated in traditional soft gel capsules using polyethylene glycol, then the capsule can be manufactured, but the solubility is insufficient to provide a reasonably sized capsule small enough to be comfortably administered

Engineering Contradiction:
Improvecapsule sizeVSAvoidnaproxen concentration
Core Design Contradiction:
Volume of moving objectVSQuantity of substance

Solution Approach 1:

The patent changes the chemical parameters of the solvent system by introducing a eutectic mixture of polyethylene glycol and propylene glycol, which fundamentally alters the solubility characteristics. This parameter change enables higher naproxen concentration (up to 25% w/w) in a smaller volume, resolving the contradiction between capsule size and drug concentration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite solvent system combining polyethylene glycol and propylene glycol in specific ratios to create a eutectic mixture. This composite material provides synergistic solubility enhancement that neither component achieves alone, allowing high naproxen loading in small capsule volumes

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If pH adjustment processes are used to enhance naproxen solubility, then solubility improves, but the process becomes complex and corrosive

Engineering Contradiction:
Improvenaproxen solubilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the pH adjustment step from the manufacturing process. By using the eutectic solvent system, naproxen achieves high solubility without requiring acidic or basic pH modification, thereby removing the complex and corrosive pH adjustment operations from the process

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces complex pH adjustment procedures with a simple, straightforward dissolution process using the eutectic solvent mixture. This simpler approach is more economical and avoids the need for additional chemicals and process steps

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

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 solution enables smaller, more stable, and safer capsules with enhanced bioavailability and pH adjustability, reducing manufacturing complexity and costs.

Implementation Method 1

a eutectic mixture of polyethylene glycol and propylene glycol

Methodology Applied
Scientific EffectEutectic mixture:

Implementation Method 2

The solvent systems provide for a highly concentrated solution capable of encapsulation into a small vessel

Methodology Applied
Scientific EffectSolubility enhancement: Solvation

Data Source

PatentUS12605348B2Pharmaceutical formulations of naproxen for soft gel encapsulation and combinations thereof
Publication Date: 2026.04.21 CATALENT ONTARIO LTD

AI summary

Disclosed are methods of using a naproxen fill formulation suitable for encapsulation into a soft gel dosage unit to treat inflammation and pain. Methods include administering naproxen to a subject in need thereof to treat pain and inflammation. Methods can include administering naproxen together with another medicament to a subject in need thereof to treat an additional condition such as a cough, cold, allergy, congestion, etc.