Preservative-Free Ophthalmic Drops With Controlled Drop Volume

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Solution Overview

Problem

Existing ophthalmic formulations face challenges in providing stable, preservative-free solutions with efficient dosing and reduced drop volume variability, while ensuring patient compliance and minimizing systemic side effects.

Innovation Solution

Aqueous pharmaceutical formulations with controlled surface tension, viscosity, and pH, packaged in containers with integral bacterial protection systems, including mechanical tip-seal technology and silver ions, to ensure stability and accurate drop size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If preservatives are added to multi-dose ophthalmic containers, then microbial contamination is prevented, but preservative-related side effects and patient compliance issues occur

Engineering Contradiction:
Improvemicrobial contamination preventionVSAvoidpreservative-related side effects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes preservatives from the ophthalmic composition entirely, relying instead on the sterile barrier properties of the dropper tip and controlled dispensing system to prevent microbial contamination without exposing the eye to harmful preservative chemicals

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The dropper tip acts as an intermediary barrier that prevents microbial contamination of the preservative-free formulation. The tip's design creates a physical barrier that maintains sterility without requiring chemical preservatives in the medication itself

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If conventional dropper tips are used, then dispensing is simple, but drop size variability is high leading to imprecise dosing

Engineering Contradiction:
Improvedispensing simplicityVSAvoiddrop size accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The invention changes the geometric parameters of the dropper tip, specifically the orifice diameter (0.45-0.65mm) and tip dimensions, to control and standardize drop size. This geometric control ensures consistent drop volumes (25-35µl) while maintaining ease of dispensing operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces reliance on user technique and variable manual dispensing with a mechanically controlled tip design that inherently produces consistent drop sizes through its specific orifice geometry and structure

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

3Object-affected harmful factors

If preservative-free formulations are used, then patient compliance and safety improve, but chemical and physical stability becomes problematic

Engineering Contradiction:
Improvepreservative-related side effectsVSAvoidchemical and physical stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The invention applies local quality control by optimizing specific formulation parameters (pH 5.0-7.0, viscosity 0.5-2.0 cP, surface tension 25-35 mN/m) and using localized stabilizing excipients to maintain stability of the preservative-free formulation without requiring broad-spectrum preservatives

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If drop size is not controlled, then dispensing is flexible, but dosing accuracy and treatment effectiveness decrease

Engineering Contradiction:
Improvedispensing flexibilityVSAvoiddosing accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention establishes specific parameter ranges for the dropper tip (orifice diameter 0.45-0.65mm, tip outer diameter 2.0-3.0mm) and formulation properties (viscosity 0.5-2.0 cP, surface tension 25-35 mN/m) that together ensure consistent drop sizes while preserving dispensing flexibility

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3973954B1Preservative free pharmaceutical compositions for ophthalmic administration
Publication Date: 2026.04.22 NTC SRL

AI summary

The present invention relates to a preservative-free, aqueous solution in the form of eye drops packed in a container that ensures stability of the product, ideal eye drop volume and reduced drop volume variability and provides efficient dispensing.