ORIGINAL RESEARCH

Distribution of 14C-Latanoprost Following a SingleIntracameral Administration Versus Repeated TopicalAdministration

Jie Shen . Rex A. Moats . Harvey A. Pollack . Michael R. Robinson .

Mayssa Attar

Received: June 26, 2020� The Author(s) 2020

ABSTRACT

Purpose: To qualitatively evaluate the ocularand periocular distribution of 14C-latanoprostfollowing a single intracameral administrationor repeated topical ocular administration inbeagle dogs and cynomolgus monkeys.Methods: In the dog study, three animalsreceived an intracameral dose of 14C-la-tanoprost bilaterally and were euthanized at 1,

2, and 4 h post dose; three control animalsreceived topical 14C-latanoprost bilaterally oncedaily for 5 days and were euthanized at 1, 4, and24 h post final dose. Sagittal 40-lm sections ofeyes with surrounding tissues were collectedand processed for autoradiography. Methods inthe monkey study were similar; two animalsreceived a unilateral intracameral dose of 14C-latanoprost.Results: After intracameral dosing in dogs,radioactivity was concentrated in the cornea,iris, ciliary body, and anterior chamber with noradioactivity detected in the eyelids or otherperiorbital tissues. After topical dosing,radioactivity was distributed in the bulbar con-junctiva, cornea, anterior chamber, iris, ciliarybody, upper and lower eyelids, and periorbitaltissues (fat/muscle). After intracameral dosingin monkeys, radioactivity was concentrated inthe anterior chamber, cornea, iris, ciliary body,and posteriorly along the uveoscleral outflowpathway; there was no radioactivity in the eye-lids or periorbital tissues aside from signal in thenasolacrimal duct, likely from reflux of 14C-la-tanoprost into the tear film.Conclusions: Intracameral delivery resulted inmore selective target tissue drug exposure.Intracameral drug delivery has potential toreduce ocular surface and periocular adverseeffects associated with topical administration ofprostaglandin analogues, such as eyelashgrowth and periorbital fat atrophy.

Digital Features This article is published with digitalfeatures to facilitate understanding of the article. Youcan access the digital features on the article’s associatedFigshare page. To view digital features for this article goto https://doi.org/10.6084/m9.figshare.12662183.

Electronic supplementary material The onlineversion of this article (https://doi.org/10.1007/s40123-020-00285-3) contains supplementary material, which isavailable to authorized users.

J. Shen (&) � M. R. Robinson � M. AttarAllergan, An AbbVie Company, Irvine, CA, USAe-mail: shen_jie@allergan.com

R. A. Moats � H. A. PollackMoats Laboratory at the Saban Research Institute,Children’s Hospital Los Angeles Research ImagingCore, Department of Radiology, Keck School ofMedicine USC, Los Angeles, CA, USA

Ophthalmol Ther

https://doi.org/10.1007/s40123-020-00285-3

Keywords: Drug delivery; Drug distribution;Eye drop; Intracameral; Prostaglandin analogue

Key Summary Points

Topical administration is the mostcommon mode of drug delivery for PGAsand other IOP-lowering medications, butpoor adherence of patients to topicalocular hypotensive regimens is endemic.

Intracameral administration may be usefulfor delivery of PGAs to target tissues forIOP lowering in patients with glaucomaand ocular hypertension.

The objective of this study was todetermine the ocular distribution of 14C-latanoprost following a singleintracameral administration or repeatedtopical ocular administration to beagledogs and cynomolgus monkeys.

The results of these studies in dogs andmonkeys demonstrate that intracameralPGA dosing delivers drug more selectivelyto intraocular target tissues comparedwith topical PGA dosing.

Intracameral PGA dosing can achievetargeted drug delivery because it bypassesthe anatomic and precorneal barriers todrug penetration encountered by topicaladministration.

Delivery of PGA by intracameral injectionmay reduce the potential for side effectsassociated with topical PGA treatment bylimiting PGA distribution to theconjunctiva, eyelids, and perioculartissues.

INTRODUCTION

Topical prostaglandin analogue (PGA) medica-tions including latanoprost, tafluprost, travo-prost, and the prostamide bimatoprost arewidely used as first-line therapy for lowering

intraocular pressure (IOP) in patients withopen-angle glaucoma (OAG) and ocular hyper-tension (OHT) [1]. These medications are welltolerated, systemically safe, and highly effica-cious in lowering IOP [1–3]. The PGAs typicallyare administered by instillation of an eye droponce daily.

Topical administration is the most commonmode of drug delivery for PGAs and other IOP-lowering medications, but poor adherence ofpatients to topical ocular hypotensive regimensis endemic [4,5]. Inconvenience, forgetfulness,difficulty in instilling eye drops, the frequencyof required dosing, medication cost, and sideeffects are commonly reported reasons forpatient nonadherence to IOP-lowering eyedrops [6–8]. Furthermore, precorneal factors(tear film, tear turnover, blinking, lacrimaldrainage, and induced lacrimation) as well asanatomical barriers (the cornea, conjunctiva,and sclera) limit the delivery of drugs appliedtopically to the eye to intraocular target tissues[9]. Drug that does not penetrate the eye has thepotential to cause ocular surface and periocularside effects, and conjunctival hyperemia, eye-lash growth, and iris, eyelid, and periocular skinpigmentation are common side effects of topi-cal PGA treatment [10]. Prostaglandin-associ-ated periorbitopathy (PAP), most likelyresulting from periorbital fat atrophy [11], isnow also recognized as a side effect of topicalPGA treatment [12]. Clinical signs of PAP asso-ciated with chronic topical PGA treatmentinclude deepening of the upper eyelid sulcus,enophthalmos, flattening of the lower eyelidbags, and inferior scleral show [13,14].

Intracameral administration of antibioticsand mydriatics is used routinely during cataractsurgery [15–17], and this route of drug admin-istration may also be useful for delivery of PGAsto target tissues for IOP lowering in patientswith glaucoma and OHT. Intracameral injectionof PGAs can potentially deliver drug to targetintraocular tissues more efficiently than topicaldosing and minimize side effects associatedwith topical PGA treatment by limiting drugexposure to the ocular surface and perioculartissues [18]. Studies in animal models haveshown that an intracameral implant deliveringbimatoprost [19–21] or another ocular

Ophthalmol Ther

hypotensive medication [22–24] including alatanoprost analogue [25] can effectively reduceIOP. The intracameral sustained-releasebimatoprost implant (DurystaTM) has demon-strated efficacy and tolerability in patients withglaucoma [26] and is now approved by the USFood and Drug Administration for the treat-ment of OAG or OHT.

Drug distribution after administration can beexpected to affect the IOP-lowering efficacy andsafety of a PGA delivered intracamerally. Theobjective of this study was to determine theocular distribution of 14C-latanoprost followinga single intracameral administration or repeatedtopical ocular administration to beagle dogsand cynomolgus monkeys.

METHODS

Animals

All animals were normal on ophthalmic exam-ination. Animals were housed under controlledconditions and received a certified canine orprimate diet and water ad libitum. The studieswere conducted at Covance Laboratories Inc(Madison, WI, USA) in accordance with theAssociation for Research in Vision and Oph-thalmology (ARVO) statement for the Use ofAnimals in Ophthalmic and Vision Research.All study procedures were performed in com-pliance with US Animal Welfare Act regulations.

Methods for Dog Study

Six male purebred treatment-naı̈ve beagle dogs(Covance Research Products, Cumberland, VAor Covance Stock Colony), ages 6–7 months,weighing 9.7–12.1 kg, were used in the study.

DrugThe test compound was 14C-latanoprost(178 mCi/mmol, 98.5% radiopurity). For intra-cameral injections, on the day of dosing, 30 lLof 14C-latanoprost was dried under a stream ofnitrogen and solubilized in 300 lL of vehiclecontaining 1% polysorbate 80, 0.75% sodiumchloride, 0.16% sodium dihydrogen phosphate

monohydrate, 0.22% disodium hydrogenphosphate anhydrous, and sterile water. Fortopical dosing, 14C-latanoprost was prepared inthe same vehicle with the addition of 0.02%benzalkonium chloride. On the first day oftopical dosing, 48.8 lL of 14C-latanoprost wasdried under a stream of nitrogen and solubilizedin 2.4 mL of vehicle containing benzalkoniumchloride. Aliquots of the solution were frozen at- 20 �C for use on the next 4 days. Drug sta-bility was demonstrated by high-performanceliquid chromatography.

Drug AdministrationAnimals were assigned to two study groups(n = 3 per group). Group 1 received a singlebilateral intracameral dose of 14C-latanoprost,and group 2 received a bilateral topical dose of14C-latanoprost once daily for 5 days. A similartopical dosing regimen of latanoprost has beenshown to achieve steady state IOP lowering inglaucomatous beagle dogs [27]. The doses oflatanoprost and radioactivity administered tothe animals in each group are shown in Table 1.

Animals in the intracameral dosing groupwere anesthetized with a regimen of oxymor-phone, glycopyrrolate, and midazolam, fol-lowed by dexmedetomidine. A topicalanesthetic was applied to the eyes, and the eyeswere then rinsed with an iodine solution fol-lowed by a saline rinse. A bilateral dose of 14C-latanoprost was administered intracamerally bya board-certified veterinary ophthalmologistusing a syringe and needle. For each adminis-tration, the eye was stabilized by grasping theconjunctiva with a fixation forceps, the needlewas tunneled through the cornea near the lim-bus and advanced several millimeters towardthe center of the anterior chamber, and a 10-lLdose was injected.

Animals in the topical dosing group receiveda topical 30-lL dose in both eyes once daily for5 days at the same time each day. The dose wasadministered onto the cornea of the eye via amicropipette. After the dose was administered,the upper and lower eyelids were held togethergently to distribute the dose across the eye.

Ophthalmol Ther

Sample CollectionAnimals were euthanized with sodium pento-barbital at designated time points after drugadministration. The three animals that receivedintracameral 14C-latanoprost were euthanizedat 1, 2, and 4 h after dosing; the three animalsthat received topical 14C-latanoprost wereeuthanized at 1, 4, and 24 h after the last dose.Following euthanasia, the animals were exsan-guinated, the head was shaved, and the eyelidson both eyes were sutured open such that thepalpebral conjunctiva were visible and outwardfacing. Left eyes were enucleated, trimmed ofexcess tissue, rinsed with saline, blotted dry,and flash-frozen in liquid nitrogen for 15–20 sbefore storage at - 20 �C. Right eyes were keptin situ following euthanasia to ensure thatperiorbital tissues would be preserved forimaging drug distribution. Right eyes with sur-rounding structures were removed and frozen ina hexane/dry ice bath for 30–120 min, blotteddry, placed on dry ice or stored at - 70 �C for atleast 12 h, stored at - 20 �C, and then wereshipped on dry ice to QPS, LLC (Newark, DE,USA) for autoradiography.

The clinical dosing regimen for latanoprosteye drops is once-daily administration, andocular samples from animals assigned to thegroup receiving 5 days of once-daily topicaladministration were collected at 1, 4, and 24 hpost final dose to cover the entire dosing inter-val. The timing of tissue sampling after intra-cameral delivery differed because aqueoushumor outflow in normal beagle dogs is esti-mated to be 4–6 lL/min [28], and with an esti-mated anterior chamber volume of 0.4–0.77 mL[28], the entire volume of aqueous humor is

expected to be turned over within 3 h. There-fore, ocular samples from animals assigned tothe intracameral dose group were collected at 1,2, and 4 h post dose.

AutoradiographyFrozen samples containing right eyes and sur-rounding structures in situ were embedded in2% carboxymethylcellulose, frozen into blocks,and sectioned on a cryomicrotome at - 20 �C.An aliquot of blood containing 14C was injectedinto each block before sectioning as a marker toaid in the alignment of sections with autora-diographs. Serial 40-lm sections were taken inthe sagittal plane at intervals of 0.5 mmthrough half of each eye (for eyes that hadreceived intracameral 14C-latanoprost adminis-tration, the half of the eye that included theinjection site). Sections were selected thatincluded the following areas/structures to beanalyzed: ciliary body, lens, anterior and pos-terior chambers, sclera, anterior and posterioruvea, iris, cornea, and bulbar and palpebralconjunctiva. The sections were collected onadhesive tape (Scotch 8210; 3M, Maplewood,MN, USA) and were air-dried in the cryomicro-tome for at least 48 h, then were mounted on acardboard backing and wrapped with a thinplastic wrap to avoid contamination of theimaging plate.

The sections and calibration standards at 10different concentrations (0.0003–5.3825 lCi/g)were then exposed to a 14C-sensitive phosphorimaging plate (Fuji Biomedical, Stamford, CT)in light-tight cassettes for 4 days at room tem-perature. Quantification was performed by

Table 1 Dog study 14C-latanoprost study groups

Study group No. ofanimals

No. oftreatedeyes

Drug delivery mode Target dose (lglatanoprost/dose)

Dosevolume(lL/dose)

Total no.of dosesper eye

Target doseradioactivity(lCi/dose)

Topical

dosing

3 6 Topical ophthalmic

drop once daily for

5 days in both eyes

1.50 30 5 0.61

Intracameral

dosing

3 6 Single intracameral

injection in both

eyes

2.45 10 1 1.0

Ophthalmol Ther

image densitometry; a standard curve was con-structed from nominal concentrations of 14C-calibration standards. Concentrations ofradioactivity were expressed as microcuries pergram (lCi/g) and converted to microgramequivalents of 14C-latanoprost per gram sample(lg equiv/g). The lower limit of quantitationwas 0.830 ng equiv/g.

Methods for Monkey Study

Two female drug-naı̈ve cynomolgus monkeys(Covance Research Products, Cumberland, VAor Covance Stock Colony), ages 3–4 years,weighing 2.7–3.4 kg, were used in the study.

Drug and Drug AdministrationFor intracameral injections, the test compoundand procedures used were similar to thosedescribed above for the dog study. A 204-lLaliquot of 14C-latanoprost was dried and solu-bilized in 2.00 mL of vehicle. Two monkeyswere anesthetized with a regimen of ketamine,glycopyrrolate, and dexmedetomidine. Afterapplication of a topical anesthetic to both eyes,the eyes were rinsed with an iodine solutionfollowed by a saline rinse, and finally, addi-tional drops of topical anesthetic were applied.A 10-lL dose of 14C-latanoprost was adminis-tered intracamerally, to the right eye only, by aboard-certified veterinary ophthalmologistusing a syringe and needle, with the same pro-cedure as described above in dogs.

Sample Collection and AutoradiographyMonkeys were euthanized with an overdose ofsodium pentobarbital and exsanguination at 0.5and 4 h post intracameral dose. Followingeuthanasia, both eyes were rinsed with saline,and the eyelids were sutured open. The headwas removed from the body with the eyesin situ and was frozen in a hexane/dry ice bathfor 15 min, then was drained, dried, placed in alabeled bag, and stored at - 70 �C for at least12 h. The head was then embedded in chilledcarboxymethylcellulose, frozen into a block,and stored at - 20 �C in preparation forautoradiographic analysis. Standards fortifiedwith 14C radioactivity were placed into the

frozen block and used for monitoring the uni-formity of section thickness.

Serial cross sections, collected up to 43 levelsusing the initial injection site as a reference,were collected on adhesive tape at 20-lmthickness using a Leica CM 3600 cryomicro-tome. Sections were dried at - 20 �C. A repre-sentative section from each level of interest wasmounted, tightly wrapped with plastic film, andexposed on a phosphor imaging screen withstandards for calibration of the imaging analysissoftware. Screens were exposed for 7 days andscanned using the Storm system (AmershamBiosciences, Sunnyvale, CA, USA). InterFocusImaging Ltd (Cambridge, England) MCIDTM

Analysis software was used to create a calibratedstandard curve and determine tissue concen-trations, which were interpolated from eachstandard curve as nanocuries per gram andconverted to lg equiv/g. The lower limit ofquantitation was 2.36 ng equiv/g.

Three-Dimensional (3D) RenderingThe autoradiography images were rendered into3D images/movies. A customized methodologywas developed by the Moats Laboratory at TheSaban Research Institute of Children’s HospitalLos Angeles to accomplish the segmentationand alignment of the autoradiography images.The pre-processed stack images were exportedto Amira Software (Thermo Fisher Scientific,Waltham, MA, USA) for 3D rendering to visu-alize the monkey images.

RESULTS

Dog Study

All animals appeared healthy after dosing. Boththe intracameral and topical ocular doses of14C-latanoprost were well tolerated with noeffects observed other than transienthyperemia.

Figure 1 shows representative sections andautoradiographs from in situ eyes of animalsthat received five daily topical doses of 14C-la-tanoprost. Radioactivity appeared to be dif-fusely distributed throughout the anteriorportion of the eye at 1, 4, and 24 h after the last

Ophthalmol Ther

dose. Radioactivity was present in the bulbarconjunctiva, cornea, anterior chamber, iris, cil-iary body, upper and lower eyelids, and perior-bital tissues (fat and muscle) after topicaladministration (Fig. 1).

Representative sections and autoradiographsfrom in situ eyes of animals that received asingle intracameral dose of 14C-latanoprost areshown in Fig. 2. Radioactivity was concentratedin ocular tissues including the cornea, iris, cil-iary body, and anterior chamber after intra-cameral dosing. There was a diminution of

signal in the anterior segment from 1 to 4 h postintracameral dose. No radioactivity was detec-ted in the eyelids or other periorbital tissuesafter intracameral dosing.

Radioactivity in anterior uvea and sclera wasdetected only sporadically on autoradiographywith both dosing routes. Distribution ofradioactivity to the posterior eye, including theretina, was negligible after both topical andintracameral dosing.

Fig. 1 Representative sections of fresh-frozen eyes in situ(right) and corresponding autoradiographs (left) frombeagle dogs that received five daily topical ophthalmicbilateral administrations of 14C-latanoprost. Eyes in situ

were collected at 1 and 4 h after the last administration.Annotations identify tissues and areas of interest

Ophthalmol Ther

Monkey Study

The 3D reconstruction of autoradiographs fromsections taken at 0.5 h post single intracameraldose showed that radioactivity was concen-trated in the anterior chamber, cornea, iris, andcilary body of the dosed eye (Fig. 3a). Radioac-tivity was also present in the uveoscleral

outflow pathway, and in larger drainage path-ways such as the superior ophthalmic vein(Fig. 3a). Some radioactivity was located in thenasolacrimal duct and nasal turbinates, andlikely resulted from reflux of some of theinjected dose into the tear film. However, noradioactivity was detected in the eyelids orother periorbital tissues. In the reconstruction

Fig. 2 Representative sections of fresh-frozen eyes in situ(right) and corresponding autoradiographs (left) frombeagle dogs that received a single bilateral intracameral

administration of 14C-latanoprost. Eyes in situ werecollected at 1, 2, and 4 h after the administration.Annotations identify tissues and areas of interest

Ophthalmol Ther

of autoradiographs from sections taken at 4 hafter the intracameral dose, radioactivity wasconcentrated in the anterior chamber of thedosed eye with less intensity compared with0.5 h. Radioactivity was absent from the eyelidsand periorbital tissues (Fig. 3b).

The full 3D reconstructions of the distribu-tion of radioactivity at 0.5 h and 4 h after theintracameral dose are shown in SupplementaryVideo 1 and Supplementary Video 2,respectively.

DISCUSSION

Autoradiography was used in this study toqualitatively evaluate the distribution and con-centration of radioactivity in dog eyes that wereadministered 14C-latanoprost by a single intra-cameral injection or daily topical instillation.After the intracameral dose, radioactivity wasconcentrated in the cornea, iris, ciliary body,bulbar conjunctiva, and anterior chamber,whereas after 5 days of topical dosing, radioac-tivity was concentrated in the cornea and

Fig. 3 Images of 3D reconstructions of the distribution ofradioactivity in cynomolgus monkeys at a 0.5 h and b 4 hafter a single intracameral administration of 14C-la-tanoprost. Phosphor imaging autoradiographs of cross

sections of the animal heads were used to develop the 3Dreconstructions. 3D 3-dimensional, arrow nasolacrimalduct, arrowhead superior ophthalmic vein, asterisk anteriorchamber

Ophthalmol Ther

bulbar conjunctiva, and was distributed morediffusely in other anterior ocular tissues.Radioactivity in the eyelids and periorbital tis-sue was detected only after topical dosing. Datain the monkey study were confirmatory with nosignal detected in the eyelids or orbit afterintracameral administration of 14C-latanoprost.

The eyes of beagle dogs are similar to humaneyes in anatomic and physiologic characteristics[28], and therefore, the beagle dog is a usefulmodel for the evaluation of ocular drug distri-bution. Drug distribution to the ciliary body isimportant for the PGA class of topical ocularhypotensive medications, because these drugsdecrease IOP by increasing uveoscleral outflow[29]. As the mechanism of action of topicalPGAs may also involve an increase in aqueousoutflow through the conventional pathway[29], distribution of drug to the anterior cham-ber adjacent to the trabecular meshwork is alsorelevant. The distribution of radioactivity seenin this study after intracameral and topicaladministration of 14C-latanoprost to dogs showsthat intracameral dosing can more selectivelydeliver PGA to target tissues for IOP lowering.Furthermore, the absence of radioactivitydetected in the eyelids and periorbital tissuesafter intracameral dosing suggests that intra-cameral administration may be associated witha reduced incidence of some side effects associ-ated with topical administration of PGAs, suchas eyelash changes and PAP.

The delivery of therapeutic agents via topicaladministration may be influenced by the use ofaccompanying procedures such as punctalocclusion or eyelid closure, which could helpincrease the concentration and duration of stayof an agent in the anterior chamber and reduceeither systemic or off-target exposure [30]. Inthe present dog study, the upper and lowereyelids of each treated eye were gently heldtogether to distribute the dose across the eyeand implement a form of eyelid closure aftertopical administration of the test compound.The marked presence of radioactivity in theeyelids and periocular tissues with these mea-sures might reinforce the finding that intra-cameral delivery yields favorable localization oftherapeutic agents compared with topicaladministration.

Although dogs are useful models for theevaluation of ocular drug distribution, theiraqueous outflow systems differ from those inhumans. In contrast, the orbital anatomy ofcynomolgus monkeys and humans is very sim-ilar [31], and the aqueous drainage apparatus incynomolgus monkeys is anatomically similar tothat in humans [32]. To confirm that intra-cameral administration has a greater targetedtissue effect, cynomolgus monkeys were alsoused. As results from a previous study showedthat drug is present in the eyelids of monkeysafter topical PGA administration [33], we deci-ded to only use intracameral administration inmonkeys for this study. The results from the 3Drendition of the autoradiography in the mon-key were very similar to the autoradiographyresults in the beagle dog. After intracameraladministration, drug exposure was mainly lim-ited to the anterior segment (the anteriorchamber, cornea, iris, and ciliary body), as wellas posterior drainage vessels, which was expec-ted as the aqueous drains through theuveoscleral pathway and episcleral veins.Importantly, there was no eyelid or orbit expo-sure. These results indicate that there is alocalized distribution of radioactivity when 14C-latanoprost is administered intracamerally.

The results of our study are consistent withthose of the recently reported drug distributionstudy of the intracameral sustained-releasebimatoprost implant in beagle dogs [18]. In thebimatoprost implant study, the maximal con-centration of bimatoprost in the iris-ciliarybody was 4 log units higher after implant (15 lgbimatoprost) administration than after 7 daysof once-daily topical administration of bimato-prost 0.03% [18]. In another study in beagledogs, the intracameral bimatoprost implant wasshown to cause selective dilation of episcleralaqueous outflow vessels [19], in contrast to thegeneralized vasodilation that causes ocular sur-face hyperemia after topical PGA administra-tion in dogs [34], consistent with the suggestionthat intracameral PGA dosing may be associatedwith reduced occurrence of ocular surface andperiocular side effects.

An advantage of the use of autoradiographyin this study is that drug distribution could beevaluated more precisely in discrete tissues

Ophthalmol Ther

compared with drug distribution studies usingisolated tissues. Radioactivity distribution intissues including the eyelids and periorbitaltissues was evaluated qualitatively. A limitationof the use of autoradiography to evaluate drugdistribution in the present study is that themolecular identity of the radioactivity presentin tissue sections (i.e., latanoprost, latanoprostacid, or other metabolite) could not bedetermined.

CONCLUSION

The results of these studies in dogs and mon-keys demonstrate that intracameral PGA dosingdelivers drug more selectively to intraoculartarget tissues compared with topical PGA dos-ing. Intracameral PGA dosing can achieve tar-geted drug delivery because it bypasses theanatomic and precorneal barriers to drug pene-tration encountered by topical administration.Delivery of PGA by intracameral injection mayreduce the potential for side effects associatedwith topical PGA treatment by limiting PGAdistribution to the conjunctiva, eyelids, andperiocular tissues.

ACKNOWLEDGEMENTS

Funding. This study was sponsored byAllergan (prior to its acquisition by AbbVie).The Rapid Service Fee was funded by AbbVieInc.

Medical Writing, Editorial, and OtherAssistance. Writing and editorial assistancewere provided to the authors by StephanieKuwahara, PhD, of AbbVie Inc., Irvine, CA, andEvidence Scientific Solutions, Inc, Philadelphia,PA, and funded by AbbVie Inc. Covance Labo-ratories (Madison, WI) conducted the monkeystudy, and also dosed animals and collectedsamples for analysis in the dog study. QPS, LLC(Newark, DE) processed the samples and per-formed the autoradiography in the dog study.

Authorship. All named authors meet theInternational Committee of Medical JournalEditors (ICMJE) criteria for authorship for thisarticle, take responsibility for the integrity ofthe work as a whole, and have given theirapproval for this version to be published. Nei-ther honoraria nor payments were made forauthorship.

Prior Presentation. This manuscript is basedon work previously presented at the Associationfor Research in Vision and Ophthalmology(ARVO) 2016 Annual Meeting (May 1–5, 2016)in Seattle, WA, USA and the American Glau-coma Society 2020 Annual Meeting (February27–March 1, 2020) in Washington, DC, USA.

Disclosure. Jie Shen, Michael R. Robinson,and Mayssa Attar are employees of AbbVie Inc.Rex A. Moats and Harvey A. Pollack declare thatthey have no conflict of interest.

Compliance with Ethics Guidelines. Animalprocedures were carried out in accordance withthe Association for Research in Vision andOphthalmology (ARVO) statement for the Useof Animals in Ophthalmic and Vision Research.All animal procedures were performed in com-pliance with US Animal Welfare Act regulations.

Data Availability. The datasets generatedduring and/or analyzed during the currentstudy are available from AbbVie Inc on reason-able request.

Open Access. This article is licensed under aCreative Commons Attribution-NonCommer-cial 4.0 International License, which permitsany non-commercial use, sharing, adaptation,distribution and reproduction in any mediumor format, as long as you give appropriate creditto the original author(s) and the source, providea link to the Creative Commons licence, andindicate if changes were made. The images orother third party material in this article areincluded in the article’s Creative Commonslicence, unless indicated otherwise in a creditline to the material. If material is not includedin the article’s Creative Commons licence andyour intended use is not permitted by statutory

Ophthalmol Ther

regulation or exceeds the permitted use, youwill need to obtain permission directly from thecopyright holder. To view a copy of this licence,visit http://creativecommons.org/licenses/by-nc/4.0/.

REFERENCES

1. Eyawo O, Nachega J, Lefebvre P, et al. Efficacy andsafety of prostaglandin analogues in patients withpredominantly primary open-angle glaucoma orocular hypertension: a meta-analysis. Clin Oph-thalmol. 2009;3:447–56.

2. Inoue K. Managing adverse effects of glaucomamedications. Clin Ophthalmol. 2014;8:903–13.

3. Aptel F, Denis P. Balancing efficacy and tolerabilityof prostaglandin analogues and prostaglandin-ti-molol fixed combinations in primary open-angleglaucoma. Curr Med Res Opin. 2011;27:1949–58.

4. Olthoff CM, Schouten JS, van de Borne BW, WebersCA. Noncompliance with ocular hypotensivetreatment in patients with glaucoma or ocularhypertension an evidence-based review. Ophthal-mology. 2005;112:953–61.

5. Yeaw J, Benner JS, Walt JG, Sian S, Smith DB.Comparing adherence and persistence across 6chronic medication classes. J Manag Care Pharm.2009;15:728–40.

6. Mansouri K, Iliev ME, Rohrer K, Shaarawy T. Com-pliance and knowledge about glaucoma in patientsat tertiary glaucoma units. Int Ophthalmol.2011;31:369–76.

7. Dreer LE, Girkin CA, Campbell L, Wood A, Gao L,Owsley C. Glaucoma medication adherence amongAfrican Americans: program development. OptomVis Sci. 2013;90:883–97.

8. Newman-Casey PA, Robin AL, Blachley T, et al. Themost common barriers to glaucoma medicationadherence: a cross-sectional survey. Ophthalmol-ogy. 2015;122:1308–16.

9. Gaudana R, Ananthula HK, Parenky A, Mitra AK.Ocular drug delivery. AAPS J. 2010;12:348–60.

10. Alm A, Grierson I, Shields MB. Side effects associ-ated with prostaglandin analog therapy. SurvOphthalmol. 2008;53(Suppl 1):S93–105.

11. Jayaprakasam A, Ghazi-Nouri S. Periorbital fatatrophy—an unfamiliar side effect of prostaglandinanalogues. Orbit. 2010;29:357–9.

12. Di Staso S, Agnifili L, Cecannecchia S, Di GregorioA, Ciancaglini M. In vivo analysis of pros-taglandins-induced ocular surface and periocularadnexa modifications in patients with glaucoma.In Vivo. 2018;32:211–20.

13. Filippopoulos T, Paula JS, Torun N, Hatton MP,Pasquale LR, Grosskreutz CL. Periorbital changesassociated with topical bimatoprost. OphthalmicPlast Reconstr Surg. 2008;24:302–7.

14. Nakakura S, Yamamoto M, Terao E, et al. Pros-taglandin-associated periorbitopathy in latanoprostusers. Clin Ophthalmol. 2015;9:51–6.

15. Bowen RC, Zhou AX, Bondalapati S, et al. Com-parative analysis of the safety and efficacy ofintracameral cefuroxime, moxifloxacin and van-comycin at the end of cataract surgery: a meta-analysis. Br J Ophthalmol. 2018;102:1268–76.

16. Vazquez-Ferreiro P, Carrera-Hueso FJ, Barreiro-Ro-driguez L, et al. Effectiveness of intracameralphenylephrine in achieving mydriasis and reducingcomplications during phacoemulsification: a sys-tematic review and meta-analysis. J Ocul PharmacolTher. 2017;33:735–42.

17. Brandsdorfer A, Patel SH, Chuck RS. The role ofperioperative nonsteroidal anti-inflammatory drugsuse in cataract surgery. Curr Opin Ophthalmol.2019;30:44–9.

18. Seal JR, Robinson MR, Burke J, Bejanian M, CooteM, Attar M. Intracameral sustained-release bimato-prost implant delivers bimatoprost to target tissueswith reduced drug exposure to off-target tissues.J Ocul Pharmacol Ther. 2019;35:50–7.

19. Lee SS, Burke J, Shen J, et al. Bimatoprost sustained-release intracameral implant reduces episcleralvenous pressure in dogs. Vet Ophthalmol. 2018;21:376–81.

20. Lee SS, Almazan A, Decker S, et al. Intraocularpressure effects and mechanism of action of topicalversus sustained-release bimatoprost. Transl Vis SciTechnol. 2019;8:15.

21. Lee SS, Dibas M, Almazan A, Robinson MR. Dose-response of intracameral bimatoprost sustained-re-lease implant and topical bimatoprost in loweringintraocular pressure. J Ocul Pharmacol Ther.2019;35:138–44.

22. Chou SF, Luo LJ, Lai JY, Ma DH. On the importanceof Bloom number of gelatin to the development of

Ophthalmol Ther

biodegradable in situ gelling copolymers for intra-cameral drug delivery. Int J Pharm. 2016;511:30–43.

23. Lai JY, Luo LJ. Chitosan-g-poly(N-isopropylacry-lamide) copolymers as delivery carriers for intra-cameral pilocarpine administration. Eur J PharmBiopharm. 2017;113:140–8.

24. Kim J, Kudisch M, da Silva NRK, et al. Long-termintraocular pressure reduction with intracameralpolycaprolactone glaucoma devices that deliver anovel anti-glaucoma agent. J Control Release.2018;269:45–51.

25. PolyActiva Pty Ltd. Enabling drug delivery frommedical devices: treatment of glaucoma. 2020.https://polyactiva.com/products/glaucoma-program/. Accessed Feb 1, 2020.

26. Lewis RA, Christie WC, Day DG, et al. Bimatoprostsustained-release implants for glaucoma therapy:6-month results from a phase I/II clinical trial. Am JOphthalmol. 2017;175:137–47.

27. Gelatt KN, MacKay EO. Effect of different doseschedules of latanoprost on intraocular pressureand pupil size in the glaucomatous Beagle. VetOphthalmol. 2001;4:283–8.

28. Ferrell Ramos M, Attar M, Stern ME, et al. Safetyevaluation of ocular drugs. In: Faqi AS, editor. Acomprehensive guide to toxicology in nonclinicaldrug development. 2nd ed. London: Academic;2016. p. 757–811.

29. Toris CB, Gabelt BT, Kaufman PL. Update on themechanism of action of topical prostaglandins forintraocular pressure reduction. Surv Ophthalmol.2008;53(Suppl 1):S107–120.

30. Flach AJ. The importance of eyelid closure andnasolacrimal occlusion following the ocular instil-lation of topical glaucoma medications, and theneed for the universal inclusion of one of thesetechniques in all patient treatments and clinicalstudies. Trans Am Ophthalmol Soc. 2008;106:138–48.

31. Gonnering RS, Dortzbach RK, Erickson KA, Kauf-man PL. The cynomolgus monkey as a model fororbital research. I. Normal anatomy. Curr Eye Res.1984;3:529–40.

32. Bouhenni RA, Dunmire J, Sewell A, Edward DP.Animal models of glaucoma. J Biomed Biotechnol.2012;2012:692609.

33. Woodward DF, Krauss AH, Chen J, et al. Pharma-cological characterization of a novel antiglaucomaagent, bimatoprost (AGN 192024). J Pharmacol ExpTher. 2003;305:772–85.

34. Chen J, Dinh T, Woodward DF, et al. Bimatoprost:mechanism of ocular surface hyperemia associatedwith topical therapy. Cardiovasc Drug Rev.2005;23:231–46.

Ophthalmol Ther