IE52986B1

IE52986B1 - Eye-lorion composition containing chondroitin sulphate a

Info

Publication number: IE52986B1
Application number: IE814/82A
Authority: IE
Original assignee: Pos Lab
Priority date: 1981-04-09
Filing date: 1982-04-06
Publication date: 1988-04-27
Also published as: ATE6588T1; IE820814L; FR2503563A1; GR76048B; DE3260063D1; EP0063973B2; FR2503563B1; ES511132A0; EP0063973B1; ES8503922A1; EP0063973A1

Abstract

1. Eye-lotion for the treatment of dry-eye diseases, characterized by the fact that it contains as active component the disodic salt of chondroitine sulfate A.

Description

The present invention relates to the field of eye-lotion compositions intended for the treatment of eye disorders. It relates very particularly to a novel eye-lotion suitable for replacing an abnormal or insufficient lachrymal secretion.

It is known that the lachrymal fluid which permanently bathes the cornea, the conjunctiva and the conjuctival pockets plays an important role in defence against infections and participates in the physiology of the cornea in respect of the movement of water and the transportation of oxygen. The normal lachrymal secretion, composed of a base secretion produced by the appropriate glands and a reflex secretion caused by sensor stimulation, must be capable of perfectly transmitting the light rays of the visible spectrum, and plays a major role in ensuring the perfection of the air-cornea refractive combination.

Dryness disorders of the eye, characterised by a lack of tears, or by ineffectiveness of the tears such as, for example, the Gougerot-Sjogren syndrome and the Stevens-Johnson syndrome - can frequently cause severe corneal complications, with recurrent ulcers and/ or cicatrization and adhesion between the eyelids and the eyeball, which sometimes result in blindness.

It has already been proposed to use, for the treatment of such eye disorders, medicaments which can contain various active ingredients such as, for example, synthetic anti-malarial drugs, bromohexine or anetholetrithione given orally, polyvinyl alcohol, cellulose derivatives or acetylcysteine administered locally, etc.

However, these drugs have not proved satisfactory. The products administered orally have had to be abandoned because of their toxicity. On the other hand, the compositions having a local action do not sufficiently replace the lacking constituents of the lachrymal film and do not have the desired surface tension when employed at adequate doses.

It has now been found that the abovementioned disadvantages can be overcome and that a novel eye-lotion can be placed at the disposal of patients, which is highly efficient, well-tolerated and non-toxic, and with which hypolachrymal disorders due to insufficiency of the basic lachrymal secretions can be treated, in particular in dry keratoconjunctivitis, burning eyes, geriatric chronic watering of the eyes, eye irritation due to wearing contact lenses, and other disorders such as, for example, the Gougerot-Sjorgren syndrcms, the Riley-Day syndrcme, the StevensJohnson disease and pemphigus.

According to the invention, there is provided an evelotion composition which contains, as the active constituent, the disodium salt of chondroitin sulphate A.

It is known that chondroitin sulphate is a high viscosity mucopolysaccharide which exists in an endogenous form in the blood and urine of mammals and has pharmacological and therapeutic properties often similar to those of heparin. In practice, there are several forms of chondroitin sulphates, namely the salts of type A (or atheroitin), of type B (or beta-heparin) and of type C 2986 (Merck Index 9th edition, 1976).

In the pharmaceutical compositions disclosed hitherto and employing chondroitin as the active principle, it is always mixtures of sulphates, and especially of the abovementioned types A and C, which are employed.

Such is the case, for example, with drugs having a hypolipaemic action, known under the trademarks Arteparon and Eleparon, or with products, also presented in the form of capsules, which have been proposed for bone demineralisation conditions (trademark Structum).

Contrary to this prior art, the invention employs the pure type A chondroitin sulphate, a chemical product known per se, which is in the form of a hygroscopic, tasteless and odourless, white powder which is soluble in water and insoluble in alcohol, acetone and chloroform, and which has a mean molecular weight of between 25,000 and 50,000. Moreover, the therapeutic indications discovered for this product by the Applicant Company as well as the forms of presentation, (eye-lotion in place of capsules) and the administration routes are entirely different from those hitherto proposed for the abovementioned salt mixtures.

In addition to the abovementioned active constituent, the eye-lotion compositions according to the invention contain various agents which essentially play the role of, for example preservatives, buffers, or isotonic agents, in a manner known per se. Amongst the products acting as buffers there may in particular be mentioned monopotassium phosphate and/or dipotassium phosphate, sodium chloride and complexing agents such as, for example, ethylenediamineLptr.Mcr'lJc acid. The preservatives can consist of nontoxic mercury salts such as, for example, phenylmercuric acetate or borate, thimerosal, chlorhexidine gluconate or chlofbutol.

The isotonic agent can also be chosen from amongst the products which are well-known for this purpose; for example, boric acid is particularly suitable in the present case. Of course, as with other eye-lotions, the compositions are diluted with distilled water.

The amounts of the disodium salt of chondroitin sulphate A employed in the eye-lotions according to the invention can vary within rather wide limits and are generally between 10 and 100 g/litre of eye-lotion.

However, they are advantageously kept within the range of to 40 g/litre. The proportions of the abovementioned additional adjuvants are obviously not critical and depend on the type of product used. An example of a composition will be given in the course of the description which follows.

The numerous stability studies carried out by the Applicant Company have shown that after a period of more than 36 months, the active principle has preserved its strength unchanged and that,moreover,there has been no interaction between it and the plastic (for example polyethylene) receptacles used for storage of the eye-lotions based on chondroitin sulphate A.

Series of experiments and observations carried out with eye-lotion compositions according to the invention in the fields of toxicology, pharmacology, pharmacokinetics and biodisposability have given extremely Interesting results.

In respect of toxicity, experiments on the oral and intraperitoneal administration to mice and to rats have shown a complete absence of acute toxicity and a 50% lethal dose, LD 50, markedly greater than the maximum administered doses; the eye irritation index for rabbits is zero, and no sub-acute toxicity is found in rats; experiments on dogs have shown zero fatality and entirely normal behaviour (in respect of growth and digestion, and with no lesion whatsoever found in all the examinations carried out); no teratogenic effect has been found in experiments on rabbits and it has been, possible to conclude that the substance is extremely well tolerated by the human eye.

In the pharmacological field, the results of experiments on rabbits have been highly significant and have shown that, after simulation of dry eyes and treatment with the eye-lotion, excellent moistening of the dry eye was achieved. Experiments on cattle have permitted the conclusion that there is very little penetration of the eye-lotion into the eye, and the integrity of the cornea is preserved. A study of the biodisposability of the chondroitin sulphate A molecule, after oral administration to rabbits, has not produced any evidence of oral absorption of the substance; the absence of biodisposability is probably due to the very high molecular weight of the active principle employed in the invention; in no case has it been possible to detect any systemic toxicity.

Finally, the series of numerous clinical studies carried out on patients in various hospitals by clinical experts in ophthalmology have shown the high efficiency of the drug, markedly greater than that of reference eyelotions, including physiological serum containing 0.9% of NaCl, which is known to be the best tear substitute.

The invention will be better understood from a detailed description of the experiments and observations carried out, with reference to a non-limiting embodiment of an eye-lotion composition according to the invention.

Embodiment The eye-lotion employed for the series of experiments had the following composition by weight: Disodium salt of chondroitin sulphate A ....... 3 g Anhydrous dipotassium phosphate ............... 0.25 g Anhydrous monopotassium phosphate ............. 0.113 g Boric acid .................................... 1.2 g Phenylmercuric borate .........................^.0.0033 g Purified water, sufficient to make up to ...... 100 ml The disodium salt of the active principle had a purity of at least 95% and a mean molecular weight of the order of 30,000. a) Tests on the harmlessness of the eye-lotion.

The observations were made for 2 weeks after oral injection, through a stomach tube, of 100 mg of active principle/kg, into 12 New Zealand albino rabbits of mean weight 3 kg and of 280 mg of active principle/kg into 24 rats of mean weight 210 g.

No fatality whatsoever was found, nor any abnormality in respect of the behaviour of the animals or the condition of the gastro-intestinal tract after autopsy, b) Investigation of the 50% lethal dose (LD 50) in mice and rats.

The studies were carried out simultaneously on, firstly, batches of 50 male mice and 50 female mice and, secondly, a batch of 100 rats comprising equal numbers of males and females. After 8 days’ acclimatisation, the eye-lotion was injected intraperitoneally and continuous clinical examinations were carried out for the first six hours and thens at regular intervals,for the 13 days following the injection.

The injection of 0.5 ml of eye-lotion corresponded essentially to the peritoneal injection of 3.13, 4.70, 7.10, 10.65 or 16.0 g/kg of the active principle.

The LD 50 found was of the order of 12.8 g/kg for male mice, with the limits of 9.7 and 16.9 g/kg and of 13.0 g/kg for female mice, with the limits of 8.7 to 19.4 g/kg.

Because the mean posology of the eye-lotion is 1 to 2 drops per eye, namely 1.5 to 3 mg of active principle, it will be seen, by comparison with the LD 50 doses, that the eye-lotion according to the invention does not exhibit any toxicity whatsoever.

The results were of the same type in the case of rats, the mean LD 50 being 8.10 g/kg for the male rats and 8,30 g/kg for the female rats.

In experiments corresponding to an oral administration of the active principle to mice and a subcutaneous administration to rats, it was possible to conclude that, in the first-mentioned case, the LD 50 was markedly greater than the maximum dose administered (namely>22 g/kg), whilst in the second case the LD 50 was greater than lOg/kg. c) Sub-acute toxicity.

Experiments were carried out on 6 albino rabbits divided equally between the two sexes, by instilling the abovementioned eye-lotion into the out-turned lower eyelid of the right eye, with the left eye serving for comparison in the case of each rabbit. The animals were given 4 drops 4 times daily at intervals of 2 hours.

The treatment was carried out for 30 days, on 6 days per week. The eyes were examined each week, in the following sequence: conjunctiva, iris, cornea. It was found that the eye irritation index (E.I.I.) was zero; the product thus had zero irritancy.

Other series of experiments were carried out orally on rats, 100 mg/kg of the active principle being administered orally on 7 days per week for 8 weeks. Examinations carried out regularly on the animals permitted the conclusion that the clinical condition was unchanged, growth was normal, and there was no sign of blood intoxication nor any change in the appearance and weight of the viscera. This permitted the conclusion that the active principle according to the invention had zero toxicity. d) Chronic toxicity.

Experiments were carried out on a series of 22 Beagle dogs, divided into three groups: The first group (8 dogs) was given 60 mg/kg/day IQ of the disodium salt of chondroitin sulphate A, as a single oral dose, on 6 days per week.

The second group (8 dogs) was given 200 mg/kg/ day of the same active principle under the same conditions as above.

The third group (6 dogs) served as a comparison batch.

Throughout the duration of the treatment, the appearance and behaviour of the animals were observed.

After 3 months' treatment, the dogs were sacrificed and a complete haematological examination and an analytical study of the various organs (liver, kidney, spleen, heart, lungs, stomach, intestine, adrenal gland, pancreas, eye, etc.) were then carried out.

It vzas found that fatality was zero for all groups of animals (whether treated or not). The behaviour of the animals was normal, with increase of weight and without digestive disorders. Haematological examinations did not show any significant change due to the treatment. Moreover, anatomopathological, macroscopic and histological tests did not reveal any lesion whatsoever.

It was thus possible to conclude, in the light of these results, that the active principle of the eye25 lotion according to the invention could be administered to man at doses of 1 g/day in the course of clinical tests, this dose being substantially greater than that recommended for daily administration of the actual eyelotion composition to man. e) Foetal toxicity.

Experiments were carried out on batches of 60 rabbits and 60 rats (separated as to sex), with doses of active principle in the form of capsules of 0.250 g.

After having sacrificed half the female animals on the 28th day of gestation, it was not possible to find evidence of any teratogenic effect of the active principle according to the invention. f) Local toleration.

Evaluation of this toxicological aspect was effected by measuring the physiological parameters such as the potential difference existing between the epithelial face and the endothelial face of the cornea or the thickness of this cornea. On contact with toxic products, a thickening of the cornea and a drop in the potential difference across the cornea are in fact found.

The experiments, which were carried out on the eye-lotion of the abovementioned example, on the excipient alone (without active principle) of this eye-lotion and on known products such as tetracaine, benoxinate and a quaternary ammonium compound, have shown that the latter products were toxic to the cornea whilst no toxicity whatsoever of the eye-lotion according to the invention was detectable in vitro even after a 6 hour experiment.

This permitted the conclusion that the eye-lotion according to the invention could be administered chronically to man without causing lesion of the epithelial structures of the cornea. g) Pharmacodynamic study of the eye-lotion.

This study was intended to make it possible to simulate dry eyes in rabbits and treat these dry eyes effectively, the study being by means of a quantitative examination of the tears followed by a study of the stability of the lachrymal film.

For this purpose, the SCHIRMER test, well known for man, was used, and was applied to series of 6 albino rabbits weighing about 3 kg. First, experimental hypolachrymia was induced by instillation of an eye-lotion based on betoxycaine (a local anaesthetic). Thereafter the behaviour of the eye-lotion according to the invention was studied in respect of this desiccation.

The experiments were carried out in three stages: quantitative study of the lachrymal film in an animal with normal eyes; the same study on the animal with normal eyes, but anaesthetised, and a study on the anaesthetised animal, treated with the eye-lotion according to the invention.

On comparing, by statistical calculations, the values obtained, expressed in mm of filterpaper strip which was moistened (normal eye/dry eye), it proved possible to find a very significant difference between the two series of values compared, because the desiccation of the eye was of the order of 45%.

On subsequently carrying out series of comparisons for the results of tests comparing treated eye/dry eye and normal eye/dry eye, it was possible to demonstrate a manifest moistening of the dry eyes by the eye-lotion according to the invention, and a regain of at least 80% of the normal moistness of the eye.

Xn a second stage, the stability of the lachrymal film was studied, using the LEMP test (Arch.Ophtalm. Chicago 89 (1973) pages 103 and 105) on rabbits; this test measures the time of formation of dry zones after instillation of fluorescein into the eye. If the time required for the film to break is less than 15 seconds, the film is considered to be unstable, whilst it is held to be stable if this time is between 15 and 25 seconds. By statistical analysis of the very large number of data obtained, it was possible to obtain highly significant results which always showed an improvement in the moistening of the eye achieved by the eye-lotion according to the invention and manifesting itself in a lachrymal film which takes longer to break in the case of the treated eye, as well as good regain of the moistening of the eye.

These experiments permitted the conclusion that it was possible to test the drug in human medicine, for indications of hypolachrymia due to insufficiency of lachrymal secretions. h) Pharmacokinetics and disposability in vitro.

Studies were carried out to establish whether the active principle of the eye-lotion according to the invention could pass through the cornea.

For this purpose, work was carried out, with a suitable apparatus, on cattle corneas, kept alive by perfusion and located in a thermostatted tank. The eye-lotion according to the invention was administered to the epithelial face of the cornea and after a period allowed for perfusion the amount of active principle which had been able to pass through the cornea and which was therefore on the endothelial side was determined.

Throughout the perfusion, the absence of damage to the cornea was checked by a device for measuring the potential difference produced by the cornea, and by measurement of the thickness of the cornea with the aid of a lamp and slit. The experiments were carried out systematically, on the one hand on the eye-lotion of the invention, having the abovementioned composition and, on the other hand, by way of comparison, on only the excipient of this composition.

In spite of the particularly favourable conditions for the passage of chondroitin sulphate A, it was impossible to detect this product in the perfused fluid, whilst substances known to pass through the cornea easily, for example procaine and pilocarpine, gave cumulative amounts, after passage through the cornea, of, respectively, 100 micrograms and 200 micrograms.

Other series of experiments, on oral biodisposability in rabbits, carried out by the technique of deter25 mination of total mucopolysaccharides (endogenous amount + administered chondroitin sulphate A) and by measurement of the pharmacological activity (clarification of the plasma by administration of heparin), permitted the conclusion that the active principle according to the invention was not absorbed and hence no systemic toxicity whatsoever needed to be feared in the case of the eye-lotion based on this active principle. i) Clinical studies on human subjects.

Clinical studies carried out on numerous patients in series of different health care centres were made by comparing the action of an eye-lotion according to the abovementioned example of the invention with a conventional eye-lotion well known as a replacement for tears (physiological serum containing 0.9% of sodium chloride). In all cases, the use posology was 1 to 2 drops in each eye of the patient, 4 to 5 times per day for defined periods of time (up to several months). At each consultation with the patients, series of known tests were carried out in order to determine the amount of the tears, the nature of the tears, tne stability of the lachrymal film and the local and general toleration.

It does not seem essential to give here the detailed analytical results taking into account the parameters of sex, age and duration of treatment (on average 7 to 24 weeks) of different groups of patients. Hence, only the overall statistical results for a series of patients will be reproduced in Table 1 below.

TABLE 1 results treatments very good good noderate zero poor total Eye-loticn according to the invention 25 60 13 12 2 112 Reference eyeloticn 0 24 44 28 13 109 (1) (1) Certain experiments were stopped because of non-tolerance.

These results clearly show the marked superiority of the eye-lotion according to the invention in the two series of treatments being compared, because the proportion of very good and good results with this eye-lotion is significantly higher than with the comparison eye-lotion, in spite of the fact that the latter is well known for its effect on dry eyes.

It should moreover be mentioned that the eye disorders treated with the eye-lotion according to the invention were of diverse types, in particular including lachrymal dryness, dry kerato-eonjunctivitis, conjunctival irritation, burning eyes, geriatric chronic watering of the eyes, Gougerot-Sjogren syndrome, Riley-Day syndrome, chronic progressive polyarthritis and Stevens-Johnson disease.

Claims

1. An eye-lotion intended for the treatment of eye dryness disorders, which contains the disodium salt of chondroitin sulphate A as the active principle.

2. An eye-lotion according to Claim 1, which contains, as excipient, at least one buffer, one preservative and one isotonic agent, the whole being dissolved in purified water.

3. An eye-lotion according to Claim 2, wherein the buffer consists of a mixture of dipotassium phosphate and monopotassium phosphate.

4. An eye-lotion according to either of Claims 2 or 3, wherein the preservative consists of phenylmercuric borate.

5. An eye-lotion according to any one of Claims 2 to 4, wherein the isotonic agent is boric acid.

6. An aqueous eye-lotion composition according to any one of Claims I to 5, which comprises: Disodium salt of chondroitin sulphate A ....... 3 g Anhydrous dipotassium phosphate ............... 0.25 g Anhydrous monopotassium phosphate ............. 0.113 g Boric acid .................................... 1.2 g Phenylmercuric borate .......................^0.0033 g Purified water, sufficient to make up to ...... 100 ml

7. An eye-lotion according to any one of Claims 1 to 6 for use in the treatment of hypolachrymia due to insufficiency of basic lachrymal secretions, employing a posology of 1 to 2 drops in each affected eye several times per day for a period of 1 to 12 months.

8. An eye-lotion according to Claim 1, substantially as hereinbefore described and exemplified.