Why eye drops bottle can only be used for four weeks after opening

Eye drops occupies an important position in ophthalmic drugs and are a very common type of drug. Any medicine has a validity period. The validity period of eye drops is generally 1-3 years. If the eye drops bottle is opened, the validity period of the medicine is only four weeks.

eye dropper bottle

The 1-3 year validity period marked on the eye drop bottle packaging refers to the time when the package is unopened. The "People's Republic of China Pharmacopoeia" stipulates that "ophthalmic preparations can be used for up to 4 weeks after being used", even if the drug is still within the validity period. Inside, the eye drops can only be used for up to 4 weeks after opening.

This is because once the eye drops are opened, they are easy to come into contact with microorganisms and tears during storage and use, leading to drug contamination. Under normal circumstances, each eye drop will be available after opening in the manual [Precautions] Maximum time used. Some drugs can be used for less than 4 weeks after opening, and the specific instructions shall prevail. Patients are advised to indicate the opening time on the package after opening the eye drops to avoid expiration and deterioration.

Of course, there are some special cases. If it is a small package of eye drops without preservatives, it will not have any resistance to bacteria and viruses floating in the air after opening. Each small bottle is only used for one time. Open the eye drops bottle After that, it can only be used once, and it needs to be discarded after the medication is finished.