WO1992019143A2

WO1992019143A2 - Method for the delivery of compositions to the ocular tissues

Info

Publication number: WO1992019143A2
Application number: PCT/US1992/003459
Authority: WO
Inventors: Harvey A. Lincoff
Original assignee: Cornell Research Foundation, Inc.
Priority date: 1991-04-26
Filing date: 1992-04-27
Publication date: 1992-11-12
Also published as: US5207660A; WO1992019143A3

Abstract

Therapeutic compositions are administered to the ocular tissues by positioning a balloon catheter having an illuminating fiberoptic stylette therein in the retrobulbar or parabulbar space of a patient. After the catheter is properly positioned, the composition is sequentially injected at predetermined intervals over a period of time. A variety of compositions can be administered including corticosteroids, antibiotics, macular degeneration alleviating compositions and inflammation alleviating compositions. Such administration of the therapeutic composition sustains appropriate levels of the composition in the ocular tissues without inducing toxic effects in unaffected tissues.

Description

- I-

METHOD FOR THE DELIVERY OF COMPOSITIONS TO THE OCULAR TISSUES

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method for delivery of compositions to the ocular tissues and, more particularly, to a method for delivering compositions to the ocular tissues in sufficient quantity without toxic effects. Description of the Related Art

The administration of compositions to the eye and optic nerve has been used in the treatment of a variety of different medical conditions. For example, medications such as corticosteroids have been used to treat multiple sclerosis, optic neuritis (inflammation of the optic nerve) and posterior uveitis (inflammation of the posteri¬ or portion of the vascular layer of the eye) .

Typically, such medications are systemically administered for penetration into the eye. The penetra- tion, however, is substantially hindered by the blood- retinal barrier. Accordingly, large doses of the medica¬ tion must be administered in order for therapeutic bene¬ fits to be obtained in the portion of the eye to be treated. Furthermore, systemic administration of medica- tions for treatment of such conditions produces numerous side effects and complications, particularly if the medications are administered over a prolonged period of time. Such side effects and complications include round¬ ing and puffiness of the face, chemosis and swelling of the eyelids, obesity, hypertension, hyperlipidemia, hyperglycemia, glycosuria, negative nitrogen balance, muscle weakness, osteoporosis, acne, hirsutism, delayed wound healing, peptic ulcers, bruising of the skin, subconjunctival and retinal hemorrhage, psychoses, in- creased susceptibility to infections, hypokalemia, hypo- chloremic alkalosis, sodium retention and edema, thrombo- e bilic phenomena, pseudotumor cerebri with papilledema, loss of libido and amenorrhea. A rapid reduction in the administration of such medications may result in acute adrenocortical insufficiency.

Retrobulbar local administration of medications has been used for the treatment of inflammation of poste- rior portions of the eye and optic nerve. Such adminis¬ tration delivers a high concentration into the surrounding tissue while minimizing the toxicity encountered in systemic administration. This retrobulbar administration, however, requires repeated injections. As a result of the necessity for repeated injections, further complications arise including retrobulbar hemorrhage, infection and penetration of the globe or optic nerve.

An indwelling catheter has been used to orbitally infuse medications. This catheter is, however, difficult to secure in place. Accordingly, glue or sutures are used therewith, the glue or sutures increasing the risk of infection encountered in using the catheter.

The Lincoff et al article, "A Fiberoptic Stylette for Localizing the Balloon Buckle", describes a fiberoptic balloon catheter for insertion into the parabulbar space.

After positioning of the balloon catheter, the balloon is expanded for compression between the eye and the bony orbit and elevation of intraocular pressure. As the eye decompresses, the indentation of the balloon increases and produces a buckle high enough to close a retinal break and cause subretinal fluid to be absorbed. The balloon is correctly placed by the illumination of a fiberoptic stylette positioned in the expanded balloon and monitoring of the catheter tip using an ophthalmoscope. While such a catheter is useful for the temporary retinal buckling procedure, the use of this balloon catheter for the delivery of medications to the ocular tissues is not recognized.

U.S. Patent No. 3,788,327 to Donowitz et al discloses a surgical implant device including a valve conduit as a means for controlling intra-ocular pressure.

The implant device drains excess fluid build-up in the anterior and posterior chambers of the eye, thus relieving the increased pressure. The valve is a one way valve allowing only the drainage of excess fluid and not the administration of a medication.

U.S. Patent No. 4,820,270 to Hardcastle et al discloses a balloon catheter for passage into a body cavity. The device has a stem portion comprising two concentric tubes being joined at one pair of ends by a flexible member covering the opening of a passage formed between the two tubes. The balloon can be inflated within the body cavity using pressurized fluid supplied thereto. In addition, the device can be used to remove or supply a fluid to the body cavity. The catheter has a central lumen which may contain, e.g. , fiberoptics for visual¬ ization of the body interior. U.S. Patent No. 4,454,151 to Waterbury discloses the use of pyrrolo pyrroles to treat ophthalmic diseases, particularly those diseases associated with inflammation. The compounds can be delivered to the eye topically in the form of an ointment, by subconjunctival injection and by retrobulbar injection. Accordingly, repeated injection of the compounds is required to achieve the desired level of the administered compound, thus increasing the possibility of further complications.

U.S. Patent No. 4,689,041 to Corday et al disclos- es a method and apparatus for the delivery of fluids via a catheter inserted into a patient's regional venous system. The catheter has an inflatable balloon on its distal end which maintains the positioning of the catheter while diagnostic agents are administered. U.S. Patent No. 3,954,110 to Hutchinson discloses a retention catheter having a balloon enclosing the distal tip and a pair of opposed drainage openings retracted from the distal tip, the openings extending through the balloon into a drainage lumen. Upon inflation of the balloon, the catheter assumes a correct position enabling drainage of a body cavity. The device is not used for the administra¬ tion of a medication. While the related art describes devices for delivering medication to the body, the related art does not achieve delivery of sufficiently high levels of a composition to the ocular tissues without producing toxic effects to other organs.

OBJECTS AND SUMMARY OF THE INVENTION An object of the present invention is to provide a method for administering a sufficient quantity of composi¬ tion to the ocular tissues. Another object of the present invention is to administer a composition to the ocular tissues without producing toxic effects on other organs.

A further object of the present invention is to administer a composition to the ocular tissues with a minimum amount of trauma.

To achieve the foregoing and other objects and to overcome the shortcomings discussed above, a method of administering compositions to the ocular tissues is provided which delivers an appropriate level of the composition without producing toxic effects on other organs. A multiple lumen balloon catheter is inserted into the retrobulbar or parabulbar space. The catheter contains a fiberoptic stylette which is illuminated for observation by an ophthalmoscope to ensure proper posi- tioning of the catheter. The balloon is expanded to retain the catheter in its proper position. The composi¬ tion is sequentially injected at predetermined intervals until a steady state at the desired therapeutic level is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to the following drawings in which like refer¬ ence numerals refer to like elements and wherein:

Figures 1A-1C illustrate an embodiment of an apparatus used for composition delivery to the ocular tissues to the ocular tissues; Figure 2 shows a graph of the hydrocortisone concentration in the ' chorioretina of a treated and un¬ treated eye;

Figure 3 shows a graph of the hydrocortisone concentration in the optic nerve of a treated and untreat¬ ed eye;

Figure 4 shows a graph of the hydrocortisone concentration in the vitreous of a treated and untreated eye; Figure 5 shows a comparative graph of the hydro¬ cortisone concentration in the serum;

Figure 6 shows a graph of hydrocortisone concen¬ tration in the chorioretina after repeated injections;

Figure 7 shows a graph of hydrocortisone concen- trations in the optic nerve after repeated injections;

Figure 8 shows a graph of hydrocortisone concen¬ tration in the vitreous after repeated injections; and

Figure 9 shows a comparative graph of hydrocorti¬ sone concentration in the serum after repeated injections. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and particularly to Figures 1A-1C thereof, a device used for the delivery of a composition to the ocular tissues is described. Apparatus 1 includes a double lumen catheter 10 having a distal end portion 11 of a blunt, soft, preferably plastic material. Distal end 11 of catheter 10 includes a balloon 12. A fluid source 26 communicates with balloon 12 via a first lumen 14, the fluid source supplying fluid to balloon 12 for expansion thereof. At least one opening 16 is provid- ed in lumen 14 to supply the fluid from fluid source 26 to balloon 12.

Catheter 10 includes a second lumen 18 through which a composition is administered to the retrobulbar or parabulbar space through openings 22. Composition source 28 supplies the composition to lumen 18 for delivery to the retrobulbar or parabulbar space.

A fiberoptic stylette 20 is provided in lumen 18. Illumination of fiberoptic stylette 20 enables observation of the distal end 11 of catheter 10 by an ophthalmoscope 30 as catheter 10 is guided to its proper position in the retrobulbar or parabulbar space. While fiberoptic sty¬ lette 20 is shown as being located in lumen 18, alterna- tively, an additional lumen can be provided in catheter 10 for receipt of fiberoptic stylette 20. In addition, any lumenal configuration can be used such as multiple concen¬ tric lumens.

The diameter of catheter 10 preferably approxi- mates 1.9 millimeters to minimize trauma during insertion. Fiberoptic stylette 20 is preferably a 20-gauge plastic fiberoptic.

Apparatus 1 is accurately positioned within the retrobulbar or parabulbar space. After proper position- ing, a therapeutic composition is supplied from composi¬ tion source 28 through lumen 18 and openings 22 into the retrobulbar or parabulbar space. Predetermined amounts of the composition are sequentially injected at predetermined intervals to obtain sufficiently high concentrations of the composition in the ocular tissues without producing toxic effects to other areas.

The following examples illustrate the enhanced effect of administering compositions to the retrobulbar or parabulbar space using apparatus 1. Experiment

Materials and Methods Thirty New Zealand Albino rabbits weighing 2.7-3.5 kg were used in this experiment. Each animal was anesthe¬ tized with an intramuscular injection of 1ml of ketamine hydrochloride (lOOmg/ml) and 1ml of xylazine hydrochloride (20mg/ml) . One drop of 1% tropicamide and 1% cyclogel were applied topically to dilate the rabbits' pupils. A pretreatment sample of blood was withdrawn. The left eye of each rabbit was anesthetized with one drop of propra- caine hydrochloride. The double lumen fiberoptic para¬ bulbar balloon catheter was placed inferotemporally between the lateral and inferior rectus muscles of the left eye through a 2 mm conjunctival incision at the limbus. The catheter was guided to be placed near the optic nerve visually via an indirect ophthalmoscope. When the balloon was within a half disc diameter from the disc, it was inflated with 0.6 ml of sterile water to secure its position. The portion of the catheter extending beyond the eye was taped to the rabbit's ear.

Twelve rabbits were used to study the concentra¬ tion of cortisol in ocular tissues following a single injection through the catheter. Fifty milligrams of hydrocortisone sodium succinate (500mg/4ml Abott Laborato¬ ries, North Chicago, Illinois) were injected through the stylette lumen of the fiberoptic balloon catheter. Post treatment blood samples were withdrawn and the animals were euthanized at 1, 2 , 3 and 4 hours after injection. Nine other rabbits were used to study the concentration of cortisol levels in ocular tissues following repeated administration of 50mg of hydrocortisone sodium succinate. The drug was injected through the balloon catheter two, four and six times at three hour intervals. Post treat- ment samples of blood were drawn and the animals were euthanised three hours after their last scheduled dose.

One rabbit was used to evaluate the ocular tissue levels produced by an intravenous injection of 50mg of hydrocortisone sodium succinate, and the eyes were enucle- ated at 30 minutes and 2 hours post injection. One rabbit was used to assess serum levels at various intervals between 10 minutes and two days after retrobulbar injec¬ tion of 50 mg hydrocortisone sodium succinate via the balloon catheter. Four other rabbits were used to study the histopathology of the catheterized eye following six injections of 50mg hydrocortisone sodium succinate at three hour intervals. One of these rabbits was prepared for electron microscopy study.

Specimen Preparation The pretreatment and post treatment blood samples were centrifuged and the serum obtained for analysis. Both eyes of each animal were enucleated. The adventitial tissue was removed, and the eye was rinsed under a stream of normal saline for twenty seconds. The eye was opened with a circumferential incision 2 mm from the limbus, and the anterior segment was removed. All of the vitreous was separated from the retina. The retina and the choroid were dissected from the scleral shell. The chorioretinal tissue sample was then weighed and placed in a glass tube with 1 ml of methylene dichloride. Similarly, the optic nerve was dissected from the sclera, weighed and placed in 1 ml of methylene dichloride. The optic nerve, chorio- retinal and vitreous samples were then homogenized with a tissue tearer for 45 seconds.

All samples were then centrifuged at 2,000 RPM for 10 minutes. The supernatant was then analyzed for corti¬ sol by radioimmunoassay capable of detecting 0.01 ug/ml with an accuracy of ±5%.

Results The concentrations of cortisol (hydrocortisone) in the optic nerve, choroid-retina and vitreous in the catheterized eyes reached their peak levels at two hours after a single injection. The ocular tissue levels subsequently declined to approximate the serum level 4 hours after the single injection. Peak cortisol levels in the catheterized eyes were 120 times greater in the choroid-retina, 80 times greater in the optic nerve, and 20 times greater in the vitreous compared to the fellow eyes. As shown in Figure 2, the average chorioretinal concentration in the treated eyes was 54.15, 349.11, 67.63 and 0.76 ug/g wet tissue after 1, 2, 3 and 4 hours respec¬ tively. These concentrations were much higher than the fellow eye (Fig. 1) .

As shown in Figure 3, the average concentration of cortisol in the treated optic nerve was 28.08, 403.61, 58.71 and 0.98 ug/ml after 1, 2, 3 and 4 hours respective¬ ly. These levels were much higher than the levels at- tained in the fellow optic nerve.

As shown in Figure 4, the average concentration of cortisol in the vitreous was 2.38, 11.48, 0.82 and 0.24 ug/ml after 1, 2, 3 and 4 hours respectively which was higher than the vitreous levels in the fellow eye.

As shown in Figure 5, the average cortisol level in the serum was 2.85, 3.09, 0.82 and 0.5 ug/ml at 1,2,3 and 4 hours respectively which was comparable to ocular tissue levels in the fellow eye.

Concentrations in the optic nerve, retina, vitre¬ ous and serum are tabulated in Table 1 below for each animal.

Table 1- Experiment 1, Part A- Bioassay of Hydrocortisone Sodium Succinate After Single Does of 50mg Given Retrobulbarly in the Left Eye via the balloon catheter.

^■Left Eye- -Right Eye-

Rabbit Serum Chorio- Optic Vitreous Chorio- Optic Vitreou No. Retina Nerve Humor Retina Nerve Humor

Time ug/ml ug/g ug/g ug/ml ug/g ug/g ug/ml

1 hr. 1 1.83 66.279 31.25 3.78 1.836 1.649 308

2 3.2 61.29 20.205 2.77 5.82 1.645 680

3 3.53 34.89 32.773 0.59 2.97 4.65 700

Avg 2.853 54.153 28.079 2.38 3.542 2.648 562

2 hr. 1 1.94 184.783 139.216 .7 1.327 4.827 494

2 3.16 380.41 387.80 13.4 3.48 7.826 508

3 3.16 482.14 683.809 14.04 1.84 4.01 402

Avg 3.086 349.11 403.608 11.48 2.215 5.554 .468

3 hr. 1 .89 45.098 86.111 .86 .474 .7097 228

2 .8 92.754 55.593 .85 1.009 1.5 332

3 .78 65.04 34.44 .76 .6745 2.368 ,64

Avg .823 67.631 58.71 .823 .719 1.529 .400

4 hr. 1 570 0.555 0.606 .358 464 588 .346

2 220 0.91 1.8 .340 125 596 .294

3 72 0.819 .522 .375 1241 305 .303

Avg 503 0.761 .976 .357 238 496 .314

The half life of cortisol in ocular tissues was calculated and the schedule for repeated injection was made every three hours with the aim of achieving a steady state in the trough level of the curve. With repeated injections, the concentration of cortisol in the choroid- retina and optic nerve achieved a steady state level as shown in Table 2 below and illustrated in Figs. 6 and 7.

Table 2- Experiment 2, Part A- Bioassay of Hydrocortisone Sodium Succinate After Repeat Administration of 50mg Given Retrobulbarly in the Left Eye via the balloon catheter at 3 h intervals.

^■-Left Eye- -Right Eye-

Rabbit Serum Chorio- Optic Vitreous Chorio- Optic Vitreo No. Retina Nerve Humor Retina Nerve Humor Injection ug/ml ug/g ug/g ug/ml ug/g ug/g ug/ml

1 1.44 159.574 445.454 5.54 1.205 1.829 .366

2 1.41 42.22 110.52 1.8 .996 .939 .864

3 0.83 70 292.92 8.84 1.387 1.792 .370

Avg 1.226 90.598 282.964 5.39 1.196 1.52 .533

1 1.73 48.83 231.578 4.2 1.094 2.227 1.44

2 0.5 80.292 519.355 12 0.391 1.147 0.24

3 1.06 229.911 543.75 24.4 1.452 3.448 0.38

Avg 1.09 119.68 431.558 13.533 0.979 2.274 .686

1 1.87 229.76 .140.64 33.3 2.13 2.524 .96

2 0.85 52.72 250.33 15.92 2.207 2.69 .816

3 0.73 96.977 674 17.88 1.009 7.44 .502

Avg 1.15 126.486 354.99 22.366 1.782 4.218 .759

The levels in the vitreous continued to rise as shown in Figure 8.

Intravenous injection of 50mg of hydrocortisone sodium succinate produced ocular tissue levels comparable to that of the fellow eyes of the rabbits treated with the parabulbar balloon catheter. As illustrated in Figure 9, peak serum levels of cortisol after intravenous injection were 8 times greater than the peak serum levels after hydrocortisone administration via the parabulbar balloon catheter.

In the above described experiment, the administra¬ tion of compounds to the ocular tissues achieves a higher concentration of the composition in the intended area without adversely affecting other body tissues and organs. Apparatus 1 enables administration of the composition over an extended period of time so that the level of the composition can be sustained. Furthermore, the patient is not exposed to the hazardous effects and complications associated with repeated retrobulbar injections such as perforation of the globe, intraocular injection, optic nerve meninges injection with resulting central nervous system complications and injection into the choroidal or retinal vasculature. Since distal end 11 of catheter 10 is formed as a blunt, soft plastic material, puncture and hemorrhage is inhibited.

Because catheter 10 is positioned adjacent the intended area and the amount of the composition adminis¬ tered by source 28 is readily determined, the dose of composition administered can be accurately titrated according to the patient's clinical response.

While the above-described experiment involved the administration of corticosteroid material, it is readily apparent that various compositions can be administered using apparatus l. For example, an antibiotic such as clindamycin can be administered to treat ocular lesions such as toxoplasma choroiditis. Other antibiotics such as vancomycin, garamycin, tetracycline and sulfonamides can be administered to treat bacterial endophthalmitis. Compositions can be introduced directly beneath the macula to alleviate the progression of age related macular degeneration. For example, a tissue plasminogen activator can be infused to dissolve the subretinal hemorrhage associated with degenerative maculopathy.

While this invention has been described in con¬ junction with a specific embodiment thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiment of the invention as set forth herein is intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.

Claims

WHAT IS CLAIMED IS:

1. A method for administering a composition to the ocular tissues, comprising: positioning a catheter in the retrobulbar space; and sequentially injecting through the catheter a predetermined amount of the composition at predetermined intervals.

2. The method according to claim 1, wherein said catheter includes an illuminating fiberoptic stylette and said positioning includes guiding said catheter into the retrobulbar space by observing said catheter using an ophthalmoscope.

3. The method according to claim 1, wherein said catheter is a balloon catheter and said positioning includes expanding the balloon to maintain the position of the catheter in the retrobulbar space.

4. The method according to claim 1, wherein the composition is a corticosteroid.

5. The method according to claim 1, wherein the composition is an antibiotic.

6. The method according to claim 1, wherein the composition alleviates macular degeneration.

7. The method according to claim 1, wherein the composition alleviates inflammation.

8. A method for administering a composition to the ocular tissues, comprising: positioning a catheter in the parabulbar space; and sequentially injecting through the catheter a predetermined amount of the composition at predetermined intervals.

9. The method according to claim 8, wherein said catheter includes an illuminating fiberoptic stylette and said positioning includes guiding said catheter into the parabulbar space by observing said catheter using an ophthalmoscope.

10. The method according to claim 8, wherein said catheter is a balloon catheter and said positioning includes expanding the balloon to maintain the position of the catheter in the parabulbar space.

11. The method according to claim 8, wherein the composition is a corticosteroid.

12. The method according to claim 8, wherein the composition is an antibiotic.

13. The method according to claim 8, wherein the composition alleviates macular degeneration.

14. The method according to claim 8, wherein the composition alleviates inflammation.