title: Study of alpha-lipoic acid penetration in the human aqueous after topical administration.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Ophthalmology, University of Perugia, Perugia, Italy. carlocagini@hotmail.com
authors.forename: Carlo
authors.initials: C
authors.lastname: Cagini
authors.forename: Arianna
authors.initials: A
authors.lastname: Leontiadis
authors.forename: Maria A
authors.initials: MA
authors.lastname: Ricci
authors.forename: Anna
authors.initials: A
authors.lastname: Bartolini
authors.forename: Annalisa
authors.initials: A
authors.lastname: Dragoni
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Pellegrino
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000378:metabolism*; D002138:Calibration; D003315:Cornea / Q000378:metabolism; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008063:Thioctic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D000975:Antioxidants; D009883:Ophthalmic Solutions; D008063:Thioctic Acid