Evaluation of spontaneous contamination of ocular medications

A. Marchese, M. Bozzolasco, L. Gualco, G. C. Schito, E. A. Debbia

Research output: Contribution to journalArticlepeer-review


Background: In order to evaluate whether single-dose ophthalmic preparations in 0.5-ml containers can safely be used within 24 h after the first opening, eigth different sterile ocular medications containing timolol, jaluronic acid, diclofenac, ketotifen, pilocarpine, formocortal, formocortal-gentamycin, and tetryzoline-feniramine (Farmigea, Italy) were opened and tested for spontaneous bacterial contamination after exposure to air. Methods: Samples (10 μl) were collected from exposed ophthalmic preparations after 0, 2, 4, 8 and 24 h. Results: No viable microorganisms were detected during and at the end of the evaluation period. In order to assess whether the resident or pathogenic ocular bacterial population due to repeated handling might contaminate the medications, about 105 cells of different species (Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus pneumoniae, Streptococcus spp., Corynebacterium spp., Pseudomonas aeruginosa, Neisseria spp., Acinetobacter spp., Haemophilus influenzae, Escherichia coli and Candida albicans) were added to the containers and incubated at 37°C or at room temperature. Samples were collected and the number of viable bacteria was estimated. The antibacterial effect of the ophthalmic compounds varied depending on the species considered. Tetryzoline-feniramine, pilocarpine, ketotifen and formocortal-gentamycin exhibited a frank bactericidal activity (

Original languageEnglish
Pages (from-to)304-308
Number of pages5
Issue number4
Publication statusPublished - 2001


  • Bacterial contamination
  • Microorganisms
  • Ocular medications
  • Ophthalmic preparations
  • Spontaneous contaminations

ASJC Scopus subject areas

  • Pharmacology (medical)


Dive into the research topics of 'Evaluation of spontaneous contamination of ocular medications'. Together they form a unique fingerprint.

Cite this