[Decomposition of chloramphenicol in eyedrops--irritation in the eyes]

Chloramphenicol single dose eyedrops 0.5% (Nycomed Pharma) have been found to be very sensitive to exposure to light. We could detect approximately 15% decomposition after six hours of exposure to diffuse daylight. One of the decomposition products is the extremely irritant dichloroacetic acid. This may explain why some patients complain of a burning sensation in the eyes. In one of the samples of light yellow eyedrop received together with the complaints our analysis revealed 17% of the end-cleavage product p-nitrobenzaldehyde. The Norwegian Medicines Control Authority will suggest to the producers of these preparations that they market the product in special light-proof containers.