Aqueous Humor Antimicrobial Activity: In Vitro Analysis after Topical 0.5% Chloramphenicol Application.

PURPOSE: To assess aqueous humor antimicrobial activity in vitro after topical 0.5% chloramphenicol application. MATERIALS AND METHODS: This investigation included 63 eyes from 65 cataract surgery patients. The study group of 48 eyes received preoperatively four topical applications of 0.5% chloramphenicol. The control group of 15 eyes was given no topical applications. Aqueous humor samples were collected for in vitro antimicrobial analysis using Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Pasteurella multocida organisms by means of disk diffusion test. RESULTS: No inhibition halo was observed around all aqueous humor samples from all chloramphenicol-treated patients, irrespective of the sample quantity added to the paper disks, with no significant difference from aqueous humor from untreated control patients. CONCLUSIONS: Aqueous humor displayed no bactericidal effect against any of the microorganisms evaluated after topical 0.5% chloramphenicol application.

Study of alpha-lipoic acid penetration in the human aqueous after topical administration.

PURPOSE: To determine the concentration of alpha-lipoic acid in the aqueous and investigate if its topical instillation can increase quantities. METHODS: A total of 70 patients selected to undergo cataract surgery were randomly divided into two groups. Group 1 was used as a control group; for the patients in Group 2, a single instillation of alpha-lipoic acid eye drops (1%) was administered. Immediately before surgery, an aliquot of 40-120 microL of aqueous was aspirated. The individual aspirations were combined to constitute pools representing time intervals with respect to administration. The levels of alpha-lipoic acid in the aqueous were measured using gas chromatography/mass spectrometry. RESULTS: Pool 0 was created by combining the samples of aqueous obtained from the patients in Group 1, the control group; and the level of alpha-lipoic acid was 27.5 + 2.6 ng/mL. In the other pools, the time interval between the administration of the eye drops and sampling was, respectively, 23 min, 53 min, 72 min, 93 min and 114 min; and the level of alpha-lipoic acid was 33.0 + 10.8 ng/mL, 52.0 + 2.5 ng/mL, 86.7 + 2.5 ng/mL, 91.2 + 2.5 ng/mL and 80.3 + 2.5 ng/mL. CONCLUSION: Our study demonstrates the presence of alpha-lipoic acid in the aqueous and indicates that its concentration increases after it is administered in the form of eye drops, reaching maximum values after around 93 min. The concentrations that are achieved in the anterior chamber allow us to theorize the possibility of exploiting the antioxidant properties of alpha-lipoic acid.