There is not many customers concerning this point because the general nasal, throat or oral spray liquid is not UV-sensitive. Here is just a summary.
UV light refers to the light with wavelength from 10nm to 400nm. Eye can not see the UV light. The violet color we see in our living experience is because the light source generates a small part of violet visible light.
The UV light with wavelength of less than 200nm isn’t discussed normally because the air is almost “opaque” for these wavelength. The wavelength range which people discuss is from 200nm to 400nm. These range of UV is further classed as three parts including UV-C (200nm to 280nm), UV-B (280nm to 315nm), and UV-A (315nm to 400nm). The energy strength sorts from UV-C, UV-B, to UV-A. It means the ability to decompse the chemicals decreases from UV-C, UV-B, to UV-A. Therefore, the UV for chemistry reaction is UV-C. And UV-A is even used for paper money identification device and mosquito repellent lamp, although UV-A is still a minor danger.
For the UV filteration of plastic bottles, the discussed point is filtering the light with wavelength less than 400nm. Natural color PE or PP doesn’t work on filtering UV. And clear PET can filter UV-C and UV-B but can not filter UV-A. It means clear PET can filter most possibility of damaging the chemical in the bottle.
Colors can improve the filteration of UV largely. Yellow and orange can effectively suppress the transmission of UV-C already, while red or light amber can almost remove the light with wavelength even up to 500nm. I can not find the exact chart of deep amber online but it can be deduced reasonally deep amber’s filteration is not weaker than light amber’s.
The filteration of amber PET and amber glass is quite similar. Based on this graph, PET can also decrease the visible light’s strength more than glass, but it may be affected by the thickness of the testing sample. The point is not at the visible light. The point is both amber PET and amber glass can filter UV with wavelength less than 400nm high-effectively.
Another way to filter UV is add the additive chemical as UV filter in clear PET if color is not hoped to be added in this bottle. However, the additive may cause additional risk of reaction between this additive with the medicine liquid.