Light protection info lacking in package inserts of drugs: study

A recent study in Singapore has found a lack of easily accessible detailed information on light protection in package inserts (PIs) of light-sensitive injectable drugs beyond the phrase “Protect from light.”

Only 7 percent of PIs mentioned the reason for light protection, whereas 24 percent stated the acceptable duration of exposure to light or the stages where light protection is needed.

"Regulatory authorities may consider mandating companies to provide clearer information on the stages of handling which require light protection and the appropriate light protective measures for their products,” the researchers said.

 In this study that used a descriptive design, researchers screened injectables listed in the drug formulary of a tertiary academic hospital in Singapore for light-sensitive injectables through PIs, both physical and online, for information on light protection. They also consulted references such as Micromedex, British Pharmacopoeia, US Pharmacopoeia, and Trissel’s Handbook on Injectable Drugs for verification.

Additionally, manufacturers were contacted for photostability data should the information found be insufficient. Finally, the research team performed a literature search to suggest possible light-protective measures. [Proc Singap Healthc 2025;doi:10.1177/20101058251365298]

A total of 322 injectable from the formulary were screened, of which 193 were light-sensitive. More than half (n=109, 56.5 percent) of the PIs had instructions on protective methods, while 45 (23.3 percent) stated the acceptable light exposure duration or stages requiring protection. Notably, only 13 PIs (6.74 percent) mentioned the rationale for light protection.

“Rationales and details pertaining to light protection from PIs and other sources were presented in a table, with identified discrepancies discussed,” the researchers said. “Light protective methods were subsequently suggested.”

Secondary packaging

One strategy to protect light-sensitive injectables from light is by keeping these in their secondary packaging. Manufacturers recommend this method as seen in most of the PIs (57 percent) with instructions on light protection. [https://tinyurl.com/3v79edzj]

“Indeed, this is the most commonly adopted light protective measure in the local setting,” the researchers said. “Auxiliary labels stating ‘light-sensitive’ may be placed on the secondary packaging or instructions may be stated on the bins where light-sensitive injectables are stored.”

In addition, these labels may suggest the retention of these injectables in their secondary packaging. This can work as a visual aid to alert healthcare professionals about the appropriate storage and handling.

When removing injectable drugs from their secondary packaging for reasons such as ward return or partial dispensing from original packaging, additional measures may be required, particularly when the primary packaging does not offer light protection.

Local pharmacies have different light protection measures for injectables removed from secondary packaging. The following recommendations may be considered to address this issue.

"An opaque black or brown polyethene bag may be used to block off light until the time of administration,” the researchers said. 

“Another option is the storage of light-sensitive injectables in semi-opaque low-density polyethylene (LDPE) plastic bottles,” they added.

Photostability

A drug’s behaviour under light is called photostability, and this can lead to altered drug properties, according to the researchers. [Int J Photoenergy 2016;2016:1-19] 

Such reaction is potentially driven by the change in a drug’s susceptibility to photodegradation, where a light-sensitive molecule degrades after absorbing electromagnetic radiation, such as ultraviolet and visible light. [https://ndl.ethernet.edu.et/bitstream/123456789/3007/1/37.pdf]

“Light-sensitive medications require special storage conditions as light exposure may affect their photostability,” the researchers said.