The sunlight irradiation system for phototoxicity testing delivers high-efficiency phototoxicity testing and contributes to advancements in safety research.
The first sunlight irradiation system for phototoxicity testing was adopted by a government testing agency. The test results were highly rated and the system was subsequently adopted by the safety research divisions at a large number of pharmaceutical manufacturers.
The sunlight irradiation system for phototoxicity testing is a system which delivers stable irradiation of cells with ultraviolet radiation that is as close as possible to natural sunlight.
As a result, it is ideally suited for phototoxicity testing and ROS assays (chemical photoreactivity tests) not only at pharmaceutical manufacturers, but also at cosmetics manufacturers and food product manufacturers, and in other safety research.
■SXL-3000V2 that was used in verification testing to create the OECD495 phototoxicity testing guideline■
There are many cases when substances test negative at conventional animal testing, but then produce positive results at phototoxicity tests using cells (in vitro testing). This has called into question the validity of previous cell toxicity tests.
As a replacement for previous phototoxicity tests, this guideline contain a method which does not use cells and instead exposes a chemical solution to light that contains ultraviolet radiation, and detects any reactive oxygen.
The OECD Test Guideline (issued June 2019) includes the Seric sunlight irradiation system which was used in the process of establishing procedures for phototoxicity test methods.
※The previous 2500V2 has been re-released as the 3000V2 featuring improved optical output stability.
The 3000V2 sunlight irradiation system was improved over the 2500V2 to increase optical output stability, however there is no change to the performance of the output light.
Therefore the spectral distribution and other light performance of the 3000V2 are the same as those of the 2500V2.
The Seric sunlight irradiation system for phototoxicity testing incorporates the artificial solar lighting design concepts that we have developed over the past 20 years.
It is a system that delivers stable irradiation of cells with ultraviolet radiation that is as close as possible to natural sunlight.
■Sunlight irradiation system for phototoxicity testing SXL-3000V2
【Type】 Downward irradiating type
【Input power】 3φ200V 50/60Hz
【Input current】 15A
【Lamp used】 3000W xenon lamp
【Effective irradiated surface】 350×350mm
【UV-A irradiance】 2.5 mW/cm2 or more (315 – 400 nm)
【Irradiance adjustment range】 100 – 50% (stepless)
【Spatial unevenness】 ±15% or less (target value)
【Control type】 Manual
【Cooling type】 Forced air cooling
【Service temperature range】 0～30℃
【Service humidity range】 10～90％
Main unit 1700(H)×600(W)×648(D)（mm）
Power supply unit 400(H)×250(W)×500(D)（mm）
【Weight】 Main unit 90㎏ / Power supply unit 27㎏
【Option】 UV intensity meter（Light receiver and display, Topcon product）
※3000V2 is the successor model to the 2500V2 and features improved light stability.
The spectral distribution is the same as the 2500V2.
■Are you experiencing concerns or issues such as these?■
- We want to introduce a light source system for photogenotoxicity testing and cell phototoxicity testing.
- We want to introduce a light source system for chemical reactivity testing (ROS assays).
- We want to conduct phototoxicity testing and ROS assays, however we do not know what light source we should use.
- We have introduced a system for phototoxicity testing, however the results have not been what we expected.
- The performance and ease-of-use of the system we currently use is poor.
- Because the system we use was produced overseas, there are concerns about support and maintenance.
- We are considering alternative test methods to animal testing.
The 3000V2 will deliver the solution to these concerns.
■Reason why the sunlight irradiation system for phototoxicity testing is able to “resolve customer concerns”■
■Accurately reproduces natural sunlight that is as close as possible to the real thing!
The spectral distribution and test wavelength range have been made as close to sunlight as possible.
■Irradiance of UV-A contained in the light is 2.5 mW/cm2 or more!
Irradiance of 2.5 mW/cm2 or more is possible within the spectral distribution range of 315 – 400 nm.
■Almost complete elimination of heating caused by IR radiation!
The light produced by the xenon lamp contains radiation in the IR range, however a catathermic filter (IR cut filter) removes the IR radiation.
■Irradiance and irradiation distance can be freely adjusted as needed!
A knob can be used for continuous adjustment of irradiance within the range of 100 – 50%. The irradiation distance can also be set as necessary!
■High-efficiency phototoxicity testing with superior light stability and spatial unevenness!
A broad effective irradiated area can be obtained with superior light stability and good spatial unevenness.
■Made-to-order systems are available!
Options can be used to produce systems that match the customer’s requested specifications.
■Buy with confidence because this system is officially certified!
Seric provided the light source that was used when creating the guideline, and was listed in the OECD495 guideline following extensive verification testing.
Director of the Cell Toxicity Research Laboratory in the Hatano Research Institute of the Food and Drug Safety Center
Introduced product model: SXL-2500V1
Application: Photogenotoxicity testing
■Reason for introduction
I was not here when the laboratory began considering the introduction of this system, so I do not know the detailed background. However I heard that when research funding became available, the laboratory thought that it should consider a Japanese-made light source system because it previously had only test data using a light source system that was made overseas. The laboratory reached out to Seric, which they had worked with before.
The German light source system that we had been using before had some troublesome issues. For example, we had to do business directly with Germany in order to purchase lamps or calibrate the UV intensity meter. The largest problem was that there was quite large fluctuation in the UV measurement value even when measured in the same location.
Although the cause-and-effect relationship between UV value fluctuation and the test results is not known, there were sometimes results where the effects of the light source were thought to be large, and there were problems with stability of the test results.
As a result of the above, it was decided to buy the Seric light source system, which had demonstrated stable UV intensity during study tests.
■How did it perform after it was introduced?
It was easy to use and did not have the flaws that the German light source system did.
The particularly superior points include the following.
(1) The light source is stable.
(2) Adjusting the light intensity is easy. (Turning the knob to adjust the intensity does not change the unevenness within the irradiated area, and the high points and low points change by the same ratio.)
(3) A cumulative operation time meter is included, making it easy to determine the service time and timing for lamp replacement.
Seric was helpful in that they listened carefully to what we wanted, and conducted the study in line with our requests. Except for the price factor, I would recommend this system to any company that asked.
However there are some points that are not quite satisfactory. For example, the price is not inexpensive. The UV-A and UV-B ratios change as the system is used. The amount of light on the same flat surface is not as uniform as we had hoped. Except for these points, the company is technically solid and sufficiently reliable.
■【FAQ】Frequently asked questions about the sunlight irradiation system for phototoxicity testing■
【Q】What sort of system is the SXL-3000V2?
【A】This system is an irradiation system that accurately reproduces natural sunlight and is as close as possible to the real thing. The irradiance of the UV-A contained in the light emitted by this system is 2.5 mW/cm2 or more, and the infrared radiation that causes heating is nearly eliminated.
【Q】What kinds of applications is the SXL-3000V2 used for?
【A】It is used in phototoxicity tests of pharmaceuticals, cosmetics, food products, and chemicals.
【Q】What kind of tests are phototoxicity tests?
【A】Phototoxicity tests are tests that are performed to check the safety of pharmaceuticals, cosmetics, food products, and chemicals that are known from light absorbance measurement tests to absorb light in the ultraviolet range, or of substances that generated a positive result at cell phototoxicity tests.
【Q】What are the differences between the 2500V2 that is listed in OECD Guideline No. 495 and the successor model 3000V2?
【A】The 3000V2 is a successor model that delivers higher optical output stability compared to the 2500V2. The spectral distribution and other performance are identical to the 2500V2.
【Q】Can the irradiance and irradiation distance be controlled?
【A】Irradiance can be continuously adjusted in the range of 100 – 50% using the knob. The irradiation distance can be set as needed by changing the stage.
【Q】Can the sunlight irradiation system for phototoxicity testing remain illuminated continually? How long is the lamp lifetime?
【A】Continuous illumination is possible until the lamp lifetime is reached. When illuminated continuously, the average lamp lifetime is approximately 1,500 hours.
【Q】Does the sunlight irradiation system for phototoxicity testing require maintenance?
【A】Performance can be maintained by regular user inspections. When necessary, our company can provide inspection and maintenance services for a fee.
【Q】How much does the sunlight irradiation system for phototoxicity testing cost?
【A】We will present an estimate for a system that meets your requirements. It is also possible to decide specifications to meet the customer’s budget. Please contact the Sales Division of our company for details.
■Spectrum of the sunlight irradiation system for phototoxicity testing■
＜Spectral distribution of all wavelengths＞
＜Spectral distribution of the UV area＞