This invention relates to medicaments for therapeutic treatments, such as treatments for protecting sensitized nerve endings from over stimulation, and is more particularly, but not exclusively, concerned with treatment of allergies and other conditions caused by inhalation of airborne irritants. Many people suffer to a greater or lesser extent from the effects of allergies due to inhalation of airborne irritants, such as pollen or household dust.

The effects of an allergy to pollens are commonly styled "hay fever" (Allergic Rhinitis) , and can lead to sneezing, catarrh and conjunctivitis amongst other symptoms. Known methods of treatment of hay fever are not always reliable and can give rise to undesirable side effects, such as drowsiness.

It is an object of the invention to provide a medicament for treatment of such allergies and other respiratory complaints which is straightforward to use and does not have undesirable side effects.

According to one aspect of the invention there is provided a medicament comprising methylcellulose or hydroxyalkyl methylcellulose for use as an active ingredient in a therapeutic method.

According to another aspect of the present invention there is provided a medicament comprising methylcellulose or hydroxyalkyl methylcellulose for use in

the treatment by nasal administration of allergies and other conditions caused by inhalation of airborne irritants.

According to another aspect of the invention there is provided the use of methylcellulose or hydroxyalkyl methylcellulose for the preparation of a medicament for use as an active ingredient in a therapeutic method involving protecting sensitized nerve endings from over stimulation. According to a further aspect of the present invention, there is provided the use of methylcellulose or hydroxyalkyl methylcellulose for the preparation of a medicament for use in the treatment by nasal administration of allergies and other conditions caused by inhalation of airborne irritants.

The methylcellulose or hydroxyalkyl methylcellulose may be in powder, liquid or gel form, and may be in the form of hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, hydroxymethyl methylcellulose or hydroxybutyl methylcellulose.

In such an application, where the methylcellulose or hydroxyalkyl methylcellulose is in the form of a powder, it is important that the powder has effective particle sizes acceptable to the nose and preferably less than about 50 microns diameter (or about 25 microns diameter in some circumstances) . Typically at least about 90% by weight of the powder will consist of particles having effective particle diameters in the range

of about 5 to about 50 microns, and preferably in the range of about 10 to about 40 microns.

The use of hydroxypropyl methylcellulose as a thickener and suspending agent in the pharmaceutical and food industries is well known. It is also used as a tablet binder and in ophthalmic preparations (see Martindale, The Extra Pharmacopeia, 28th Edition, page 956) . However, so far as the Applicant is aware, there has been no previous suggestion to use this substance as the therapeutic component of a medicament for use in desensitizing over-sensitized nerve endings, or more specifically in the treatment by nasal administration of allergies and other conditions caused by inhalation of airborne irritants. The medicament of the invention is capable of broad application to humans or animals in the treatment of respiratory problems, including pneumoconiosis and asthma, as well as in other applications in which sensitized nerve endings are to be protected from over stimulation. In certain of these applications it may be appropriate for the medicament to be orally inhaled or swallowed, or for the medicament to be in the form of a gel.

The invention also provides a delivery system for a medicament for use as an active ingredient in a therapeutic method, the system comprising a container for the medicament, sealing means for closing off the container, and open cell foam means within the container for holding medicament in such a manner as to enable a

quantity of the medicament held within the foam means to be inhaled through the user's nose or otherwise administered to the user.

In one embodiment the container is a flexible strip having a pocket containing the foam means and having an opening to the pocket in one face, and the sealing means is a piece of adhesive tape which closes off the opening.

In another embodiment the container is a receptacle having a top and having a pad of foam means at its top so that the foam means may be charged with medicament by turning the receptacle upside down, and the sealing means is a detachable cap which closes off the top of the receptacle including the foam means. In this case the receptacle preferably has flexible walls so as to permit the receptacle to be squeezed to assist inhalation of medicament.

In order that the invention may be more fully understood, reference will now be made, by way of example, with reference to the accompanying drawing, in which:

Figure l is a schematic view of a delivery system for the medicament in accordance with the invention;

Figure 2 is a section through an alternative delivery system for the medicament in accordance with the invention.

In one form of the invention, hydroxypropyl methylcellulose powder is taken by the user in the manner

of snuff. The hydroxypropyl methylcellulose powder is produced from the cellulose fibres of cotton linters or wood pulp with hydroxypropyl substitution on the anhydroglucose unit being introduced during manufacture. An appropriate powder is that sold under the Registered Trade Mark, Methocel. Such a powder conforms to U.S.P., Food Chemicals Codex, Kosher Certification and F.D.A. regulations.

Whilst various grades of hydroxypropyl methylcellulose powder may be used, it is much preferred that a grade of powder should be used which has a nominal viscosity in a 2% aqueous solution close to that of mucus, and typically in a range of 4000 to 100000 cP at 20° C (although it is preferable that this value is greater than 6000, and most preferably greater than 8000, and/or that this value is less than 50000, and most preferably less than 30000) . The powder should also have a high hydration rate so that it will form a gel in a short period of time, typically 3 to 5 seconds, on contact with warm, damp air. A preferred grade of Methocel powder is that sold as K15M Premium which has a nominal viscosity of 15000 cP in 2% aqueous solution at 20° C.

When inhaled the powder acts as a "chemical bandage" to protect sensitized nerve endings within the nose or throat from over stimulation by inhaled irritants. It does this because the powder turns to a gel on contact with the moisture naturally present in the nasal passages. This gently protects the disturbed nerve endings long

enough for them to return to their normal sensitivity. The powder disperses after a while, and is absorbed by the body without any adverse affect. Under most conditions it should not be necessary to administer the powder more than once or twice a day.

If required the powder can be used as a carrier for carrying any suitable drug, for use in treatment of asthma, for example, to the respiratory tract, or elsewhere in the body, and for holding the drug in the required location.

Whilst the powder can be taken simply in the manner of snuff without requiring a special delivery system, it is preferred that the powder is applied and administered by a special delivery system which ensures that the correct amount of powder is taken in a particularly reliable manner.

Figure 1 shows a delivery system 1 in the form of a flexible and transparent plastics strip 2 formed by heat welding together two plastics sheets along weld lines 3, 4 and 5 so as to form a pocket 6 for a pad 7 of open cell foam containing the powder. A circular opening 8 is provided in one of the plastics sheets to provide access to the pocket 6, and this opening 8 is closed off by a piece 9 of adhesive tape (shown in broken lines) applied to one face of the strip 2 when the delivery system 1 is supplied for use.

In use of the delivery system 1 of Figure 1, the piece 9 of adhesive tape is removed so as to provide

access to the powder in the foam pad 7 by way of the opening 8 to permit the powder to be delivered to the user's nose or mouth. The strip 2 is then held by the user grasping each end of the strip 2 between the thumb and forefinger of each hand, and positioned so that the opening 8 is immediately beneath one nostril. The required amount of powder is then taken up by a gentle sniff, and the procedure is repeated for the other nostril. The delivery system 1 is then disposed of. Figure 2 shows an alternative delivery system 10 in which a quantity of powder 11 sufficient for a number of doses is held within a tubular receptacle 12 made of flexible plastics material. The receptacle 12 is formed at its top with a first screwthread 13 for receiving a detachable screwthreaded cap 14, and a second screwthread 15 for receiving a screwthreaded foam pad holder 16. The pad holder 16 comprises a screwthreaded collar 17, an open cell foam pad 18 and an apertured domed member 19. The form of the apertures in the domed member 19 is shown in the view from below of the member 19 at (a) in Figure 2. The foam pad 18 is held at its periphery between an outer circular flange 20 of the domed member 19 and an inner circular flange 21 of the collar 17. Furthermore the flange 20 of the domed member 19 is trapped in position when the collar 17 is held in screwthreaded engagement with the top of the receptacle 12.

In use of the delivery system 10, the receptacle 12 is turned upside down to charge the foam pad 18 with

powder. The receptacle 12 is then turned upright and the cap 14 is removed by unscrewing it from the receptacle 12. After the user has gently blown his nose, he then places the foam pad 18 on top of the receptacle 12 immediately below one nostril and lightly sniffs the pad 18 so as to inhale the powder, whilst squeezing the walls of the flexible receptacle 12. The procedure is then repeated for the second nostril, and the cap 14 is subsequently replaced, the receptacle 12 being stored for further use. Whilst the description of the medicament above is concerned with inhalation of the powder for treatment of airborne allergies, it should be appreciated that the medicament can also be used as a "chemical bandage" in other applications within the scope of the invention. For example, the medicament may be applied in the form of a powder or liquid to tissue during surgery so that it will form a "chemical bandage" preventing undesirable cohesion of tissue after surgery.