Abstract
Aims: The aim of this work is to “predict” the remaining shelf-life of chloramphenicol
(CH) eye drops, commercially marketed, using the theoretical “Longland–Rowbotham model,””
followed by confirmation of findings by practical means. Materials and Methods: The methods used for the evaluation of CH-eye drops included the assay of the active
ingredient, sterility testing, and minimum inhibitory concentration (MIC) determination
using official methods during 6 months stability study at variable temperatures (4,
25°C). Furthermore, a 3-month accelerated stability study was carried out. Statistical
analysis tests included Student's t-test and analysis of variance. Results: The prediction model indicated that in pessimistic conditions, the remaining shelf
life was reduced to a merely 1 month following production (this is versus the 2 years
expiration date given by manufacturer). However, the samples analyzed throughout a
6-month stability study revealed that storing CH solution at 4°C or 25°C does not
produce any statistical difference regarding drug content, MIC, or sterility. Accelerated
stability studies for 3 months period showed that only after 2 months from storage
at 55°C the drug will start to degrade and a statistical difference could be observed.
Conclusion: Storing CH-eye drops at room temperature for up to 6 months appears to have no effect
on the stability of this antibiotic.
Key-words:
Accelerated conditions - chloramphenicol - eye drops - stability study - sterility
