Tear Cannabinoid Sampling for Fast Roadside Detection

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Solution Overview

Problem

Current methods for detecting cannabis impairment in drivers are inadequate, as they are time-consuming, unreliable, and lack standardized roadside tests that can accurately determine the presence of cannabinoids, particularly due to the hydrophobic nature of these compounds, which makes them difficult to detect in aqueous fluids like saliva and blood.

Innovation Solution

The method involves collecting and analyzing tear samples using a micropipette or capillary tube to extract cannabinoids, which are more soluble in the lipid component of tears, and employing techniques such as chromatography and spectrometry to identify the presence of cannabinoids like Delta-THC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If blood is drawn to test for THC presence, then testing accuracy is improved, but time consumption increases and ease of operation deteriorates

Engineering Contradiction:
ImproveTHC detection accuracyVSAvoidtime to obtain blood sample
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent uses saliva as an intermediary fluid to detect THC presence, avoiding the need for invasive blood draws. Saliva collection is non-invasive and can be performed immediately at the roadside, eliminating the time delay associated with obtaining court orders for blood samples while still providing reliable THC detection through analysis of cannabinoid metabolites in the oral fluid.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/invasive procedure of blood drawing with a non-invasive saliva collection method. This substitution eliminates the need for needles, syringes, and medical personnel while maintaining the ability to detect THC presence, thereby reducing time consumption and improving ease of operation.

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

2Ease of operation

If saliva is tested for cannabinoids, then ease of operation is improved, but measurement precision deteriorates due to hydrophobic nature of cannabinoids

Engineering Contradiction:
Improvesample collection easeVSAvoidcannabinoid detection reliability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the analytical parameters by using specific extraction solvents and chromatography conditions optimized for detecting hydrophobic cannabinoids in saliva. The method employs liquid-liquid extraction with organic solvents that effectively partition cannabinoids from the aqueous saliva matrix, followed by gas chromatography-mass spectrometry detection, thereby maintaining measurement precision despite the hydrophobic nature of the target compounds.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces organic extraction solvents as intermediaries to bridge the hydrophobic cannabinoids and the aqueous saliva matrix. These solvents facilitate the transfer of cannabinoids from saliva into an organic phase where they can be effectively analyzed, thereby overcoming the solubility issue while maintaining ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If tear samples are analyzed for cannabinoids, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvetesting speedVSAvoidsampling and analysis equipment
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential components needed for rapid THC detection from the complex tear fluid matrix. By focusing on specific cannabinoid metabolites and using targeted extraction methods, the method achieves rapid results while minimizing the complexity of required equipment. The extraction process isolates cannabinoids from other tear components, simplifying subsequent analysis.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Provides a fast, painless, and non-invasive means to detect cannabis impairment through tear analysis, offering reliable roadside testing with minimal training, enhancing safety and efficiency in identifying impaired drivers.

Implementation Method 1

cannabinoids, which are more soluble in the lipid component of tears

Methodology Applied
Scientific EffectLipid solubility: Solvation

Implementation Method 2

employing techniques such as chromatography and spectrometry to identify the presence of cannabinoids

Methodology Applied
Scientific EffectChromatography: Chromatography

Implementation Method 3

employing techniques such as chromatography and spectrometry to identify the presence of cannabinoids

Methodology Applied
Scientific EffectSpectrometry: Absorption Spectroscopy

Data Source

PatentEP4150351B1Method of testing tears as a biomarker for cannabinoids
Publication Date: 2026.04.15 VALENTI DENISE A
  • EP4150351B1 patent drawingFigure 1
  • EP4150351B1 patent drawingFigure 2
  • EP4150351B1 patent drawingFigure 3

AI summary

A method of obtaining and processing a tear sample from an individual, including obtaining a sample of tears from an individual by use of a flexible tapered polymer structure having opening at a distal end thereof, the opening having a diameter of less than 1 millimeter and placing the distal end of the flexible tapered polymer structure into contact with the tears adjacent the eye and applying negative pressure to the flexible tapered polymer structure. The method further includes buffering the sample of tears by addition of a buffering solution, analyzing the sample of tears to identify cannabinoids within the sample of tears; and presenting results of analysis of the sample of tears.