Pharmacokinetics and Pharmacology of Latanoprost 0.005% without Benzalkonium Chloride Vs Latanoprost 0.005% with Benzalkonium Chloride in New Zealand White Rabbits and Beagles.

Purpose : Many intraocular pressure (IOP)-lowering medications contain benzalkonium chloride (BAK), a preservative associated with unfavorable outcomes.A formulation of latanoprost 0.005% ophthalmic without BAK is approved by the FDA and indicated for reduction of IOP in patients with open-angle glaucoma or ocular hypertension. We present two preclinical studies of latanoprost 0.005% BAK-free vs latanoprost with BAK; one examining plasma and ocular tissue pharmacokinetics (PK) in New Zealand white rabbits, and one comparing in vivo IOP-lowering efficacy in healthy beagles. Methods : In the PK study, one drop of treatment (latanoprost BAK-free or latanoprost with BAK) was instilled into both eyes of rabbits in each treatment group (n = 18). At 0.25, 0.5, 1, 4, 6, and 24 hours postdose, three rabbits per study group underwent terminal blood and tissue collection.In the IOP study, in the first dosing period, both eyes of each beagle received either 1 drop latanoprost BAK-free or latanoprost with BAK, once daily for 10 days. After a 10-day washout period, a second 10-day dosing period was conducted and latanoprost BAK-free or latanoprost with BAK were dosed in the opposite eyes, respectively. IOP measurements were taken at 1, 6, and 12 hours postdose. Results : The maximum plasma concentration for latanoprost BAK-free and latanoprost with BAK occurred 0.25 hours after administration (174.1 vs 217.2 pg/mL, respectively). Area under the concentration time curve from zero to infinity was highest in aqueous humor for latanoprost BAK-free and latanoprost with BAK (133.1 vs 119.6 hr·ng/mL, respectively) and was not estimable in vitreous humor. In beagles, once-daily administration of latanoprost BAK-free or latanoprost with BAK led to a significant reduction in IOP vs baseline ( P < .001); there was no difference between groups ( P > .05). Conclusions : Latanoprost BAK-free showed comparable activity in reducing IOP, and comparable plasma and ocular PK parameters to latanoprost with BAK.