Levels of bimatoprost acid in the aqueous humour after bimatoprost treatment of patients with cataract.
OBJECTIVE
To determine the aqueous humour concentration of the acid hydrolysis products of bimatoprost and latanoprost after a single topical dose of bimatoprost 0.03% or latanoprost 0.005% in humans.


METHODS
Randomised, controlled, double-masked, prospective study. 48 eyes of 48 patients scheduled for routine cataract surgery were randomised in an 8:2:2 ratio to treatment with a single 30 mul drop of bimatoprost 0.03%, latanoprost 0.005% or placebo at 1, 3, 6 or 12 h before the scheduled cataract surgery. Aqueous humour samples were withdrawn at the beginning of the surgical procedure and analysed using high-performance liquid chromatography-tandem mass spectrometry.


RESULTS
Bimatoprost acid (17-phenyl trinor prostaglandin F2alpha) was detected in aqueous samples at a mean concentration of 5.0 nM at hour 1, 6.7 nM at hour 3 and 1.9 nM at hour 6 after bimatoprost treatment. After latanoprost treatment, the mean concentration of latanoprost acid (13,14-dihydro-17-phenyl trinor prostaglandin F2alpha) in aqueous samples was 29.1 nM at hour 1, 41.3 nM at hour 3 and 2.5 nM at hour 6. Acid metabolites were below the limit of quantitation in all samples taken 12 h after dosing and in all samples from placebo-treated patients. None of the samples from latanoprost-treated patients contained quantifiable levels of non-metabolised latanoprost. Non-metabolised bimatoprost was detected in aqueous samples at a mean concentration of 6.6 nM at hour 1 and 2.4 nM at hour 3 after bimatoprost treatment.


CONCLUSIONS
Low levels of bimatoprost acid were detected in aqueous humour samples from patients with cataract treated with a single dose of bimatoprost. Latanoprost acid concentrations in samples from patients treated with latanoprost were at least sixfold higher. These results suggest that bimatoprost acid in the aqueous humour does not sufficiently account for the ocular hypotensive efficacy of bimatoprost.
Cantor
Louis B
LB
Glaucoma Services, Department of Ophthalmology, Indiana University Medical Center, Indianapolis, IN 46202, USA. lcantor@iupui.edu
Hoop
Joni
J
Wudunn
Darrell
D
Yung
Chi-Wah
CW
Catoira
Yara
Y
Valluri
Shailaja
S
Cortes
Arnold
A
Acheampong
Andrew
A
Woodward
David F
DF
Wheeler
Larry A
LA
D000577:Amides / Q000378:metabolism*; D000959:Antihypertensive Agents / Q000378:metabolism*; D001082:Aqueous Humor / Q000378:metabolism*; D000069580:Bimatoprost; D002386:Cataract / Q000378:metabolism*; D002387:Cataract Extraction; D003008:Cloprostenol / Q000031:analogs & derivatives* / Q000378:metabolism; D004311:Double-Blind Method; D006801:Humans; D008055:Lipids; D011446:Prospective Studies
D000577:Amides; D000959:Antihypertensive Agents; D008055:Lipids; D003008:Cloprostenol; D000069580:Bimatoprost