The present invention is a composition for spray delivery to the nasal mucosa of l-deamino-8-D-arginine-vasopressin (desmopressin) .

Desmopressin, 1-(3-mercaptopropionic acid) -8-D-arginine- vasopressin (hereinafter also abbreviated as "DDAVP") is an analog of the neurohypophyseal peptide vasopressin. DDAVP is indicated in the management of a variety of medical conditions such as irregular urination or diurea, particularly those associated with diabetes insipidus and nocturna1 enuresis.

DDAVP is currently available as an aqueous nasal spray composition which is administered by means of a metered spray pump. For instance, MINIRIN® nasal spray, Ferring AB, Sweden, contains 10 μg of desmopressin acetate per 100 μl, 0.5 % of chlorobutanol (w/v) as preservative, and sodium chloride. Intranasal administration of about 200 μl MINIRIN® spray, containing about 20 μg of desmopressin, provides an antidiuretic effect lasting in most adult patients for about 8 to 12 hours.

In a minority of cases a dose of up to 40 μg (400 μl) is required for similar effects.

For most nasally administered agents, the capacity of the human nasal cavity surface for holding aqueous solutions is limited. In most adults, this capacity is about 400 μl. For efficient systemic absorption of nasally administered therapeutics, the vehicle carrying the drug must remain in contact with the mucus-lined epithelium for a sufficient period of time.

400 μl volume is close to the maximum useful volume for known nasal spray compositions containing desmopressin. Nasal spray compositions having low concentrations of

DDAVP might allow coverage of a wider range of patients, such as including very young or elderly patients. However, even such dilute concentrations must be delivered in minute doses because of the potency of DDAVP. On the other hand, about 100 μl (containing a dose of 10 μg) of known solutions containing DDAVP is the lowest dose volume that can be conveniently reproduced by single actuations of the metered spray pump, and remain therapeutically effective.

Harris et al., J. Pharm. Sci. 11_ (1988) 337-339, conducting experiments based on healthy human volunteers, state that a given amount of desmopressin in larger volume, when given in a single dose, is absorbed substantially less effectively than the same amount in a smaller volume (see Fig. 1, Harris, ibid. ) . These findings are in full agreement with those of Anik et al., J. Pharm. Sci. 23 _. (1984) 684-685, who conducted similar tests on rhesus monkeys with nasally administered solutions containing the decapeptide nafarelin acetate. Both reports favor higher concentrations and discourage use of more dilute solutions.

The known results obtained with desmopressin are based on analysis of plasma levels of desmopressin and factor VIII:C. The release into plasma of factor VIII:C is known to be stimulated by high doses of desmopressin. The dosage administered intranasally in such experiments was approximately 300 μg, about ten times the average dose given to patients with urinary disorders.

Thus, there exists a problem in the art for achieving a balance between therapeutic needs and dosage related problems of DDAVP nasal compositions. There is a need in the art for precisely metered, easily administered, and consistently reproducible nasal delivery compositions containing DDAVP.

An object of the present invention is to provide a nasal spray composition containing desmopressin which allows effective delivery to a wider range of patients, including very young and elderly patients.

Another object is to provide an aqueous composition for nasal administration of between 2.5 and 7.5 μg of desmopressin per 100 μl, which allows consistent delivery of optimum therapeutic doses of the DDAVP.

Further objects include the provision of a sealed container for delivery of DDAVP nasal compositions, an assembly comprising the sealed container and a spray pump, and the use of the composition, the container, and the assembly in the management of urinary disorders.

It has now been surprisingly found that the known relationship between the concentration of desmopressin in the aqueous carrier for nasal spray administration, said concentration being a desmopressin concentration of at least 1 μg per 100 μl, and desmopressin uptake by the nasal mucosa, which relationship dissuades from using more dilute solutions, does not hold for substantially smaller desmopressin concentrations, such as concentrations ranging from 2.5 μg to 7.5 μg per 100 μl.

In accordance with the invention, there is disclosed an aqueous nasal spray composition containing between 2.5 and 7.5 μg of desmopressin per 100 μl, the preferred concentration being about 5 μg desmopressin per 100 μl aqueous composition. It has been unexpectedly found that these optimum ranges provide ideal nasal delivery conditions for optimal therapeutic effects for desmopressin.

A preferred embodiment of the composition according to the present invention comprises an osmotic pressure-

controlling agent, such as sodium chloride, and a preservative, such as chlorobutanol or a quaternary amine preservative such as benzalkonium chloride.

According to another embodiment, the composition additionally comprises a buffer, preferably a buffer comprising citrate and/or phosphate. The buffer used in the present compositions should maintain the pH from about 4 to about 6, preferably a pH of about 5.

It is especially preferred for the composition to comprise both benzalkonium chloride and the above-defined buffer, which makes the DDAVP nasal compositions of the present invention room-temperature stable, with shelf lives exceeding one year.

Additionally the composition according to the invention may contain absorption enhancers such as bile salts, monolauryl ethers of macrogols, phospholipids and fusidate derivatives.

It is preferred for the composition according to the invention to be administrable in a metered dose or multiples thereof, said metered dose comprising from 2.5 μg to 7.5 μg of desmopressin dissolved in from 50 μl to 150 μl of an aqueous carrier to provide a desmopressin concentration in said carrier ranging from 2.5 μg to 7.5 μg per 100 μl, for effecting a plasma profile essentially corresponding to that obtainable by single or multiple dose nasal administration of the same total amount of desmopressin dissolved in said carrier in substantially higher concentration.

It is also preferred for the composition according to the invention to be administrable in a metered dose or multiples thereof, said metered dose comprising from 2.5 μg to 7.5 μg of desmopressin dissolved in from 50 μl to

profile essentially equivalent, on a desmopressin unit dose weight basis, to a desmopressin plasma profile obtainable by nasal administration of a metered dose of desmopressin comprising substantially higher amounts of desmopressin in a corresponding smaller volume of aqueous carrier ranging from 50 μl to 150 μl.

Also disclosed is a sealed container filled with an aqueous desmopressin spray composition according to the invention and its use in connection with a spray pump. The container and the pump may be integrated as a unit and can also be made disposable. It is preferred for the pump to be a metered precompression spray pump. The pump is preferably designed for delivering a dose ranging from 2.5 to 7.5 μg desmopressin per actuation, with the optimum amount at about 5 μg.

The composition according to the invention is used for effective therapeutic management of various urinary disorders, such as diabetes insipidus, incontinence, and enuresis, particularly nocturnal enuresis.

FIGURE 1 graphically depicts therapeutical bioequivalence of known DDAVP nasal solutions and the DDAVP aqueous nasal compositions of the present invention.

The invention will now be explained in detail by reference to the following experimental examples.

EXAMPLE 1

Preparation of test solutions. Two desmopressin acetate nasal spray compositions (A and B) were prepared under aseptic conditions by dissolving the following components in 1 1 of Millipore®-filtered water:

composition A B

desmopressin acetate 100 mg 50 mg chlorobutanol* 5 g 5 g sodium chloride 9 g 9 g

* 1,1, l-trichloro-2-methylpropan-2-ol

pH was adjusted to 3.5 - 5.0 by addition of 2 N HCl. A denotes a currently known composition which was prepared for comparison, while B denotes the composition made according to the present invention.

EXAMPLE 2

Comparative testing. 24 healthy male volunteers were given 40 μg of desmopressin in the form of composition A from Example 1 (administration of a 4 x 100 μl = 400 μl dose) . After an interval of at least one week, the same test subjects were given desmopressin in the form of composition B (administration of a 8 x 100 μl = 800 μl dose) . Commercially available, metered-dose spray pumps manufactured by Erich Pfeiffer AG, Rudolfzell, Germany, set to the appropriate dosage volumes were used.

Blood was collected by venipuncture before administration (control) and at times 5, 15, 30, 45, 60, and 90 minutes, and 2, 4, 6, and 8 hours after administration. Plasma desmopressin was assayed by RIA as described by Harris, et al., J. Pharm. Sci. 77 (1988) 337-338 (for statistical treatment of data, see Harris ibid. , p. 338) .

The results are graphically depicted in Fig. 1, which shows plasma levels of desmopressin as a function of time. It is evident from Fig. 1 that composition (A) and the composition according to the present invention (B) are bioequivalent and therefore therapeutically equivalent. It

can also be seen that composition (B) has a substantially broader useful administration range.

EXAMPLE 3

Long shelf-life composition. A nasal spray composition according to the present invention having a shelf life of more than one year at room temperature was prepared by dissolving in 1000 ml of Millipore*'-filtered water: 50 mg of desmopressin acetate, 1.0 g of benzalkonium chloride, 6.3 g of sodium chloride, 1.56 g of citric acid, and 2.43 g of disodium hydrogen phosphate.

While the various embodiments of the present invention have been described herein, it is possible that one skilled in the art could modify the various reagents and reaction conditions and obtain similar results. Such modifications are contemplated as being within the scope of the present disclosure.