Two-Step Photodynamic Therapy Light Exposure for Lower Pain
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Solution Overview
Problem
Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) derivatives causes significant pain and has a high recurrence rate, particularly when treating facial and scalp lesions, limiting its acceptance and efficacy.
Innovation Solution
A two-step light exposure method is employed, first using sunlight or artificial sunlight for 30 minutes to 5 hours, followed by a narrower wavelength exposure matching the photosensitizer's absorbance spectrum, preferably at 635 nm, to reduce pain and recurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PDT uses high-power light sources with narrow wavelength spectrum matching photosensitizer absorbance maximum, then therapeutic efficacy is improved, but pain and side effects significantly increase
Solution Approach 1:
The patent divides the single high-power light exposure into two separate light exposure steps with different wavelength spectra. The first step uses a broad spectrum (400-700 nm) to activate multiple photosensitizer absorbance maxima, while the second step uses a narrow spectrum targeting the primary absorbance maximum. This segmentation allows each step to contribute differently to therapy, reducing peak intensity-related pain while maintaining cumulative therapeutic efficacy.
Solution Approach 2:
The patent changes the wavelength spectrum parameter between two treatment steps. The first exposure uses a broad wavelength range (400-700 nm) to activate photosensitizer at multiple absorbance peaks, while the second exposure uses a narrow wavelength range centered on the primary absorbance maximum. This parameter change enables differentiation between therapeutic activation and pain-inducing high-intensity exposure.
2Object-affected harmful factors
If daylight PDT uses broad spectrum sunlight for extended exposure, then pain is reduced, but recurrence rate significantly increases
Solution Approach 1:
The patent segments the broad-spectrum daylight exposure into a controlled two-step protocol. The first step uses controlled broad-spectrum exposure (400-700 nm) for a defined duration, and the second step adds targeted narrow-spectrum exposure. This segmentation provides the pain-reducing benefit of broad-spectrum activation while ensuring sufficient cumulative dose at the therapeutic wavelength to prevent recurrence.
Solution Approach 2:
The patent ensures continuous photosensitizer activation across two complementary exposure steps. The broad-spectrum first exposure activates photosensitizer at multiple wavelengths, and the narrow-spectrum second exposure continues activation at the primary absorbance maximum, ensuring continuous therapeutic action without interruption or insufficient dosing that would lead to recurrence.
3Loss of time
If single high-power light exposure is used to match photosensitizer absorbance maximum, then treatment time is reduced, but pain and patient discomfort increase
Solution Approach 1:
The patent segments treatment into two exposure steps where the first broad-spectrum exposure can occur relatively quickly to activate photosensitizer at multiple peaks, and the second narrow-spectrum exposure completes the therapeutic activation. This segmentation distributes the total treatment time across two less intensive exposures rather than one high-intensity exposure, reducing peak discomfort while maintaining efficiency.
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
Significantly reduces pain and recurrence rates in PDT treatments, maintaining therapeutic efficacy while improving patient comfort and treatment acceptance.
Implementation Method 1
exposure of at least said area of the skin to light of a wavelength spectrum comprising only one maximum in the absorbance spectrum of said photosensitizer
Data Source
AI summary
The present invention relates to a composition comprising a photosensitizer use in prevention or treatment of dermatological disease in a patient, wherein the composition is used in the following order of steps:(a) topical application or subcutaneous injection of said composition to an area of the skin of said patient,(b) exposure of at least said area of the skin to light with a wavelength spectrum similar or identical to sun light for a duration of 30 min to 5 hours, and(c) exposure of at least said area of the skin to light of a wavelength spectrum comprising only one maximum in the absorbance spectrum of said photosensitizeras well as to methods of treating dermatological disease using the outlined steps and kits of parts comprising such compositions and light sources suitable to apply the respectively indicated light.