Aqueous Penetration of Oraland Topical Indomethacin in HumansDonald R. Sanders, MD; Bruce Goldstick, MD; Cheryl Kraff, MD;Robert Hutchins, MD; Melvin S. Bernstein; Michael A. Evans, PhD

\s=b\Aqueous humor and serum indo-methacin levels were determined follow-ing administration of the drug orally, asa topical 1% aqueous suspension andas a topical 1% oil suspension. Patientsreceiving indomethacin orally had a meanaqueous humor level below the lower limitof sensitivity of the assay, which is alsobelow the level known to inhibit prosta-glandin synthesis in vitro and a mean

serum level of 642 ng/mL. Patientsreceiving the topical 1% aqueous suspen-sion had a mean aqueous level of 198ng/mL and no detectable serum level.Patients receiving the topical 1% oil sus-pension had a mean aqueous level of 429ng/mL, which was significantly higherthan that of the aqueous suspension. Bothtopical suspensions yield levels that areable to inhibit prostaglandin synthesis.Higher aqueous levels with no detectableblood levels (and thus negligible potentialfor systemic toxic effects) make the topi-cal route of administration preferable tothe oral route.(Arch Ophthalmol 1983; 101:1614-

1616)

Tropically administered indometha--*- ein in oil or aqueous suspensionhas been shown to reduce postopera¬tive inflammation in patients whohave undergone cataract extractionwith and without intraocular lensimplantation.12 This ocular anti-

inflammatory activity implies thattherapeutic concentrations of indo¬methacin reach the inflamed tissue; toour knowledge, such an effect has notbeen demonstrated with indometha¬cin administered orally. This studywas conducted to quantitate aqueoushumor and serum indomethacin levelsin patients undergoing cataract sur¬gery who had received topical or oralindomethacin therapy preoperative-ly.

PATIENTS AND METHODS

All patients were scheduled to undergocataract surgery and consented to receiveone of the following treatment regimens.(1) Patients received 25 mg of oral indo¬

methacin four times during the 24 hoursbefore surgery, with the last dose giventwo hours preoperatively. (2) Patientsreceived indomethacin as a 1% suspensionin an aqueous pharmaceutical vehicleadministered topically. Two dosage regi¬mens were used. In the first, five doses of 1drop each were given at equally spacedintervals during the 24 hours before sur¬

gery; the last drop was given 45 minutesbefore surgery. In the second regimen, theaqueous suspension was administered asfollows: 1 drop every ten to 15 minutes forfive doses 18 hours before surgery, 1 drop12 hours before surgery, 1 drop at bedtimethe evening before surgery, then 1 drop attwo hours and 90 and 30 minutes beforesurgery. The results of the two dosageschedules using the aqueous topical prepa¬ration were combined, since preliminaryanalysis disclosed no significant differencein aqueous humor indomethacin levels. (3)Patients received indomethacin as a 1%suspension in sesame oil2 in five doses of 1drop each, as previously described for thetopical aqueous suspension. (4) Patientsreceived placebo, the identical pharmaceu¬tical vehicle as the topical indomethacinaqueous suspension but with no activeagent. Patients receiving the topical aque-

ous indomethacin suspension or placebowere part of a Food and Drug Administra¬tion-approved randomized prospectivestudy,3 those patients receiving oral indo¬methacin and topical indomethacin in ses¬ame oil were recruited after completion ofrecruitment of the prospective study.Following routine local anesthesia, sur¬

gical preparation, and draping, a partialthickness-3-mm superior limbal incisionwas made with an ultrasharp disposablerazorblade; the anterior chamber wasentered with a 25-gauge needle on a tuber¬culin syringe, and 0.1 to 0.2 mL of aqueoushumor was aspirated and immediately fro¬zen for later indomethacin assay. In asmall number of patients receiving oralindomethacin and topical aqueous suspen¬sion, a 10-mL blood specimen was simulta¬neously withdrawn from the antecubitalfossa and centrifuged at 3,000 rpm for tenminutes. The serum was then separatedand immediately frozen until analysis.

INDOMETHACIN ASSAY

The assay technique, developed inour laboratory, is a rapid and sensi¬tive high-performance liquid chroma-tography-fluorescence method suit¬able for small volume (100 /¿L) sam¬ples.4 The method consists of deacyla-tion of indomethacin by sodiumhydroxide hydrolysis to its fluores¬cent product, deschlorobenzoylindo-methacin, single extraction of an acid-buffered aqueous or serum sampleusing ethyl acetate, followed by evap¬oration of the organic phase. The sam¬ples are reconstituted with 100%methanol and injected into a high-performance liquid Chromatograph.The Chromatographie phase uses a

reversed-phase C18-bonded columnwith a solvent system of 33.3% acetyl-nitride in 0.25% acetic acid. The totaldeschlorobenzoylindomethacin (de-acylated indomethacin) content in the

Accepted for publication Nov 12, 1982.From the Departments of Ophthalmology (Drs

Sanders, Goldstick, Kraff, and Hutchins) andPharmacology (Drs Sanders and Evans and MrBernstein), Abraham Lincoln School of Medicine,University of Illinois at the Medical Center,Chicago.Reprint requests to the Department of Oph-

thalmology, University of Illinois Eye and EarInfirmary, 1855 W Taylor St, Chicago, IL 60612(Dr Sanders).

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Indomethacin Treatment AdministeredAqueous humor indomethacin concentrations in four treatment groups. Dotted line indicateslower level of sensitivity of assay procedure. Brackets enclose ± 1 SEM.

Aqueous Humor Indomethacin Concentration

Route ofAdministrationand/or Vehicle

No.of

Samples

MeanConcentration'(ng/mL)

Signlficancet

SEM Oral Aqueous Oil68 21 NSt- <.01 <.01

Oral indomethacin 49§Topical indomethacinAqueous suspension 19811Oil suspension 8 428 102

* Lower limits of sensitivity equals 50 ng/mL.tOne-way analysis of variance with Duncan's multiple range test.tNS indicates not significant at .05 level.§Value represents drug concentration two hours after last oral dose.¡[Value represents drug concentration 30 to 40 minutes after instillation of the last dosage.

extract is determined using fluoro-metric detection, with excitation at288 nm and emission at 390 nm (370nm cutoff filter). An internal stan¬dard of indole-3-propionic acid is usedfor quantitation, and the lower limitof sensitivity for indomethacin is 50ng/mL. Preliminary studies estab¬lished that no deschlorobenzoylin-domethacin was present in the sam¬

ples before alkaline hydrolysis. Fur¬ther details of the assay method aregiven elsewhere.4

RESULTSAqueous humor indomethacin con¬

centrations in the four groups testedare shown in the Table and Figure.The placebo-treated eyes and thosepatients who received indomethacinorally had a mean aqueous humorlevel at or below the lower limit ofsensitivity of the assay. There was nosignificant difference in aqueous lev¬els of indomethacin between the pla¬cebo-treated patients and the group

who received indomethacin orally.Serum levels of indomethacin in thepatients who received the oral drugwere 642 ±41 ( ± SEM) ng/mL(N = 11). Patients who received thetopical 1% aqueous suspension ofindomethacin had a mean aqueoushumor indomethacin concentration of198 ng/mL 30 to 40 minutes after theinstillation of the last dosage; thisconcentration was significantly great¬er than that in the oral-treated andplacebo-treated patients (P < .01). Noindomethacin was detected in theserum of 19 patients from this group.Patients who received the topical 1%indomethacin suspension in sesameoil had a mean aqueous humor con¬centration of 428 ng/mL, which wassignificantly higher than the othergroups (P < .01).

COMMENT

Hanna and Sharp,5 using radioac-tively labeled indomethacin, havedemonstrated good penetration of

topically applied aqueous suspensionsand oil solutions of indomethacin intothe anterior chamber of rabbits; theinitial concentration in the aqueoushumor was greater with the watersuspension. In patients, we have foundgreater penetration with an oil sus¬pension than with an aqueous phar¬maceutical vehicle, however, since thedose required to inhibit 50% ofenzyme activity (IDS0) for indometha¬cin in vitro on prostaglandin synthe-tase is 60 ng/mL,6 both topical regi¬mens yield aqueous humor concentra¬tions that are more than adequate toinhibit prostaglandin synthesis. Theaqueous suspension is certainly easierfor the patient to use and is moreamenable to large scale commercialpreparation.Conquet et al7 found that topical

administration of a 1% aqueous sus¬pension of indomethacin to rabbitsyielded 30 to 50 times higher concen¬trations in the aqueous humor than inthe blood. This is in keeping with ourhigh aqueous humor levels in patients(198 ng/mL) and no detectable levelsin the blood after topical administra¬tion.Our aqueous humor levels after top¬

ical administration of indomethacinin humans were 20 times lower thanlevels obtained when we administeredthe same preparation to rabbits (un¬published observation, August 1981).Reported levels of aqueous humorindomethacin after topical adminis¬tration in rabbits7 are also much high¬er than those we obtained inpatients.Oral administration of indometha¬

cin in rabbits yielded blood levels 90times higher than levels in the aque¬ous humor.7 This, again, is compatiblewith our findings of aqueous humorlevels below the limits of sensitivity ofour assay and high blood levels (642ng/mL).Topically administered indometha¬

cin in oil or water suspensions indosages that decrease postoperativeinflammation in patients with cata¬ract and intraocular lenses1·2 producehigh aqueous humor indomethacinlevels and nondetectable serum levels.No studies have documented the effi¬cacy of orally administered indometh¬acin on postoperative inflammation.Such an effect might not be expected,since the mean aqueous level of indo¬methacin after oral administration isbelow the ID50 for prostaglandin syn-thetase inhibition.Cystoid macular edema (CME) is a

major complication of modern cata¬ract surgery. Miyake et al8 have sug¬gested that prostaglandin synthesis,

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perhaps by the iris, results in a diffu¬sion of prostaglandins back to theretina with subsequent developmentof CME. Analysis of aqueous humorfrom cataract patients during thepostoperative period has disclosed ele¬vated levels of prostaglandin E and F.9Interrupting this pathogenic mecha¬nism with a potent prostaglandin syn-thetase inhibitor, eg, indomethacin,into the anterior segment of the eyemay reduce the incidence of CME.Topical administration of indometha¬cin in oil or aqueous medium has beenshown to decrease the angiographieincidence of CME in a number ofstudies1012 without any reported sys-

temic side effects.The effect of oral indomethacin on

the incidence of CME has been equiv¬ocal.1314 In one study,13 oral adminis¬tration of indomethacin appeared tobe effective in decreasing the inci¬dence of CME, however, 14% of thepatients who received indomethacintherapy stopped the medication spe¬cifically because of gastrointestinal orCNS side effects; an addition; 1 14%discontinued the medicatioi forunstated reasons. I. a second study,14oral administration .. f indomethacinwas ineffective in decreasing the inci¬dence of CME.Our findings combined with the

clinical findings described earlierseem to justify the use of the topicalroute of administration as comparedwith the oral route. Higher aqueouslevels, a better biological response, nodetectable blood levels, and, thus, nosystemic toxic effects, were notedwith topical administration of onefortieth of the oral dose.

This study was supported in part by core grant1P30EY01792 from the National Eye Institute,National Institutes of Health, Bethesda, Md; bythe Veterans Administration Merit Reviewgrant; and by a grant from Merck Sharp &Dohme, West Point, Pa.

References

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al: Breakdown and reestablishment of the blood\x=req-\aqueous barrier following implant surgery. ArchOphthalmol 1982;100:558-590.3. Kraff MC, Sanders DR, Jampol LM, et al:

Prophylaxis of pseudophakic cystoid macularedema with topical indomethacin. Ophthalmolo-gy 1982;89:885-890.4. Bernstein MS, Evans MA: High-perfor-

mance liquid chromatography-fluorescence anal-ysis for indomethacin and metabolites in biologi-cal fluids. J Chromatogr 1982;229:179-187.5. Hanna C, Sharp JD: Ocular absorption of

indomethacin by the rabbit. Arch Ophthalmol1972;88:196-198.6. Flower R, Gryglewski R, Hevberczynska\x=req-\

Cedro K, et al: The effect of anti-inflammatorydrugs on a cell-free prostaglandin synthesis sys-tem from dog spleen: Nature 1972;238:104-106.7. Conquet PH, Plazonnet J, LeDouarec JC:

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Prevention of cystoid macular edema after lensextraction by topical indomethacin: III. Radioim-munoassay measurement of prostaglandins inthe aqueous during and after lens extractionprocedures. Albrecht Von Graefes Arch Klin ExpOphthalmol 1978;209:83-88.10. Miyake K: Prevention of cystoid macular

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edema after lens extraction by topical indometh-acin: I. A preliminary report. Albrecht VonGraefes Arch Klin Exp Ophthalmol 1977;203:81\x=req-\88.12. Yannuzzi LA, Landau AN, Turtz AI: Inci-

dence of aphakic cystoid macular edema with theuse of topical indomethacin. Ophthalmology, inpress.13. Klein RM, Katzen HM, Yannuzzi LA: The

effect of indomethacin pretreatment on aphakiccystoid macular edema. Am J Ophthalmol 1979;87:487-489.14. Sholitan DB, Reinhart WJ, Frank KE:

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