Intracameral Sustained-Release Bimatoprost Implant Delivers Bimatoprost to Target Tissues with Reduced Drug Exposure to Off-Target Tissues.
PURPOSE
To explore the ocular distribution of bimatoprost after intracameral administration of a biodegradable sustained-release bimatoprost implant (Bimatoprost SR) versus repeated topical administration of bimatoprost 0.03% ophthalmic solution in dogs. Bimatoprost SR and topical bimatoprost 0.03% previously were shown to have similar intraocular pressure-lowering effects in humans in a phase 1/2 clinical trial.


METHODS
Twenty-four beagle dogs received either once-daily topical bimatoprost 0.03% for 7 days or a bilateral intracameral administration of Bimatoprost SR (15 μg). At predetermined time points, ocular tissues were collected and concentrations of bimatoprost and bimatoprost acid were quantified using liquid chromatography-tandem mass spectrometry.


RESULTS
Bimatoprost SR administration enhanced delivery of study drug to a site of action [iris-ciliary body (ICB)] compared with topical bimatoprost (Cmax [bimatoprost+bimatoprost acid] = 18,200 and 4.13 ng/g, respectively). However, distribution of drug to tissues associated with prostaglandin analog (PGA)-related side effects (i.e., bulbar conjunctiva, eyelid margins, and periorbital fat) was limited following Bimatoprost SR administration (Cmax [bimatoprost+bimatoprost acid] = BLQ [beneath the limit of quantitation] to 0.354 ng/g) compared with topical dosing (Cmax [bimatoprost+bimatoprost acid] = 36.6-2,110 ng/g).


CONCLUSIONS
Bimatoprost SR administration in dogs selectively delivered drug to the ICB with low or undetectable drug levels in ocular surface and extraocular tissues. Use of Bimatoprost SR for glaucoma treatment may reduce the incidence of adverse events typically associated with topical PGAs by targeting bimatoprost delivery to the key site of action of the PGA class and reducing exposure to off-target tissues.
['Seal|Jennifer R|JR|', 'Robinson|Michael R|MR|', 'Burke|James|J|', 'Bejanian|Marina|M|', 'Coote|Michael|M|', 'Attar|Mayssa|M|']
D000287:Administration, Topical D000818:Animals D000959:Antihypertensive Agents D000069580:Bimatoprost D004285:Dogs D004305:Dose-Response Relationship, Drug D005260:Female D056965:Injections, Intraocular D007429:Intraocular Pressure D009798:Ocular Hypertension D009883:Ophthalmic Solutions
bimatoprost implant eye drops ocular drug distribution pharmacokinetics preclinical