Compositions comprising cannabinoids

Abstract: There is provided a composition for the nasal delivery of a cannabinoid which comprises a cannabinoid in a biphasic delivery system or a cannabinoid in a microsphere delivery system.

Description: This invention relates to pharmaceutical compositions for nasal delivery of certain cannabinoids and pharmaceutically acceptable salts thereof. The present invention also relates to the delivery of cannabinoids across the nasal mucosa of animals, especially humans, for the treatment of conditions such as pain, nausea and to stimulate appetite. It is known that the active ingredients of cannabis, in the form of cannabinoids, can be useful in medical practice. The material delta-9-tetrahydrocannabinol (THC) is useful in the treatment of AIDS (J. Pain. Symptom Manage. 1995, 10, 89-97) when given orally. The drug is called Dronabinol and is formulated in sesame oil for oral delivery. The material is available commercially as the product Marinol® sold by Roxane in the USA. Dronabinol (9-delta THC or THC) exhibits complex effects on the central nervous system (CNS), including central sympathomimetic activity. Dronabinol has been shown to have a marked appetite stimulant effect and has been used in the treatment of AIDS-related anorexia. Dronabinol also demonstrates effects on mood, cognition, memory and perception. Furthermore, the drug has anti-emetic properties and is used for the control of nausea and vomiting associated with cancer chemotherapy. These effects appear to be dose related. After oral administration, Dronabinol has an onset of action of approximately 0.5 to 1 hour and a peak effect at 2 - 4 hours. The duration of action for psychoactive effects is 4 - 6 hours, but the appetite stimulant effect may continue for 24 hours or longer after administration. Dronabinol is almost completely absorbed (90-95%) after single oral doses. However, due to a combined effect of first pass hepatic metabolism and high lipid solubility only 10-20% of the administered dose reaches the systemic circulation. Studies on the use of THC in pain have been described in Pharm. J. 259, 104, 1997 and in Pharm. Sci. 3, 546, 1997. Nabilone, a synthetic cannabinoid has been reported to be an anti-emetic and anxiolytic, and also useful for treating pain of various etiologies such as multiple sclerosis (MS), peripheral neuropathy and spinal injuries (Lancet, 1995, 345, 579, Pharm. J. 259 , 104, 1997). It is also known that inhaling cannabis by smoking can lead to a more rapid onset of action than oral ingestion. A nasal formulation for the improved delivery of cannabinoids would be advantageous. Absorption of drugs from the nasal route tends to be rapid due to the large surface area available and the extensive blood supply. In addition, the drug is delivered directly to the systemic circulation and there is no loss due to "first pass" metabolism in the liver. The nasal route is known to provide advantages for the delivery of drugs, and for some drugs the pharmacokinetic profile following nasal administration is similar to that found after intravenous administration. However, THC is in the form of an oily liquid which is highly lipid soluble and only sparingly soluble in water. Hence, the person skilled in the art would consider it impossible to produce a simple nasal solution or other simple gel or suspension formulation that could produce sufficient nasal absorption and therapeutic plasma levels. The nasal administration of cannabinoids and their analogues has been described in US-4464378. It was suggested that the drugs would be administered as simple nasal sprays, ointments, gels or suspensions, though no examples of formulations produced with THC were described. As explained above, the person skilled in the art would not expect such simple formulations of THC to be successful due to the low water solubility. We have found surprisingly that cannabinoids and especially THC can be formulated successfully into a nasal product by using a biphasic delivery system and that such a biphasic delivery system provides improved nasal absorption and therapeutically relevant plasma levels. We have also found surprisingly that cannabinoids and especially THC can be delivered successfully via the nasal route by formulating into a microsphere system and particularly an albumin microsphere system. According to a first aspect of the present invention there is provided a composition for the nasal delivery of certain cannabinoids comprising a cannabinoid in a biphasic delivery system. The cannabinoids used are delta-8-tetrahydrocannabinol, delta-9-tetrahydrocannabinol, cannabidol, olivetol, cannabinol, cannabigerol, nabilone, delta-9-tetrahydro cannabinotic acid, and 3-dimethylnepty 11 carboxylic acid homologine 8, delta-8-tetrahydrocannabinol, (J. Med. Chem. 35, 3135, 1992) as well as the pharmaceutically acceptable salts. A suitable salt is THC-hemisuccinate. By a "biphasic delivery system" we are referring to a pharmaceutical composition comprising two phases of which one phase contains the dissolved, dispersed, solubilised or dissoluted drug and the other phase provides the carrier for the composition, for example the outer (surrounding) water phase in an emulsion system or the matrix of a microcapsule or microsphere system. By "improved nasal absorption" we mean more than 10%, preferably more than 20% and most preferably more than 30% bioavailability of the drug after nasal administration. By the term bioavailability, we mean the absorption of the drug as measured by the area under the plasma level versus time profile following nasal administration as compared to the same parameter when the drug is given by intravenous injection; the values for the area being corrected for the dose of the drug if necessary. Biphasic delivery systems may be in the form of emulsion systems, such as an oil-in-water (O/W) emulsion, aqueous systems containing a solubilising or dispersing agent or microsphere systems where the phase containing the drug can be encapsulated by or dispersed on the surface of the microspheres. An oil-in-water emulsion can be prepared using a combination of a pharmaceutically acceptable oil and emulsifier. The drug is dissolved in the oil phase which is then mixed with an aqueous phase typically containing a stabiliser under vigorous mixing, milling or homogenisation. Such emulsification methods are well described by Idson, Pharmaceutical Emulsions, Ch. 6, Pharmaceutical Dosage Forms, Disperse Systems. Vol.1. Ed. Lieberman et al. Dekker, New York, 1988. Preferred oils are vegetable oils such as soybean oil, olive oil, cotton seed oil, peanut oil, sesame oil and castor oil, with sesame oil and castor oil being preferred. Vitamin E (tocopherol) can also be used as the oil phase. This material is also an antioxidant and can help to stabilise the chosen cannabinoid which tend to be prone to oxidation. By the term Vitamin E (tocopherol) we include the α-, β-, γ- and δ- forms of tocopherol that differ by the number and position of methyl groups on the chromanol ring as well as the various isomers of these compounds. Pharmaceutically acceptable derivatives of tocopherol are also included, such as the esters of tocopherol, e.g. the linoleate, nicotinate, acetate or acid succinate ester. The United States Pharmacopoeia describes Vitamin E as a form of α-tocopherol. This includes d- or d, 1-α-tocopherol, d- or d, 1-α-tocopherol acetate and d- or d, 1-α-tocopherol succinate. The term Vitamin E is also used as a generic description for all tocopherol and tocotrienol derivatives that exhibit Vitamin E activity. Thus, the term tocopherols is synonymous with Vitamin E, but also for methyl tocols. A preferred Vitamin E composition for use in the emulsions of the present invention is α-tocopherol as described in the United States Pharmacopoeia, Volume 23, 1995 which is also known as all-rac-α-tocopherol. This material can be obtained from Roche Products Ltd., Heanor, UK. The chosen emulsifier will be one that confers good stability to the emulsion and is pharmaceutically acceptable. One preferred emulsifier is a block copolymer containing a polyoxyethylene block, i.e. a block made up of repeating ethylene oxide moieties. A suitable emulsifier of this type is Poloxamer, i.e. a polyoxyethylene-polyoxypropylene block copolymer, such as Poloxamer 188. See the Handbook of Pharmaceutical Excipients, p.352, 2nd Edn. Pharmaceutical Press, London, 1994, Eds, Wade and Weller. Another preferred emulsifier is a phospholipid emulsifier. This can be any pharmaceutically acceptable material derived from soybeans or eggs, e.g. soy or egg lecithins. Egg lecithins, such as the material provided by Lipoid (Germany) known as Lipoid E80, which contains both phosphatidylcholine and phosphatidyl ethanoline, are preferred, although other phospholipid materials could be used including phospholipid-polyethylene glycol (PEG) conjugates (PEGylated phospholipids) that have been described for use in liposome systems, e.g. by Litzinger et al, Biochem Biophys Acta, 1190 (1994) 99-107. The stability of the emulsion can be enhanced by the addition of a pharmaceutically acceptable co-emulsifier. Suitable co-emulsifiers include the fatty acids and salts thereof and bile acid and salts thereof. Suitable fatty acids are those having greater than 8 carbon atoms in their structure with oleic acid being a preferred material. A preferred bile acid is deoxycholic acid. Suitable salts are the pharmaceutically acceptable salts such as the alkali metal, e.g. Na and K, salts. These co-emulsifiers can be added at a concentration of 1% w/v, i.e. 1g of co-emulsifier per 100 mls, or less of the total emulsion. Bile salts and oleic acid are preferred co-emulsifiers. The quantity of oil in the emulsion can be from 5 to 50% on a v/v basis, preferably from 10 to 50% v/v and more preferably from 15 to 25% v/v. The drug is typically dissolved in the oil phase at a concentration of 0.1 to 20 % w/v, preferably from 1 to 10% w/v, i.e. from 0.1 to 20, preferably from 1 to 10 g of drug in 100 ml of oil. The emulsion formulation can be delivered to the nasal cavity using nasal spray devices known in the art such as those available from Pfeiffer and Valois. Such devices are familiar to the skilled artisan and can be single or multiple dosing systems. The preferred volume for nasal administration is 150 µl (per nostril) containing a dose of about 1 mg of THC. The biphasic delivery systems may also comprise a solubilising agent (solubilising phase) in an aqueous phase or in a solid phase. The solubilisation of the cannabinoid may be achieved by the use of a cyclodextrin or derivative thereof. Cyclodextrins are cyclic oligosaccharides which comprise glucopyranose units and cyclodextrins for use as pharmaceutical excipients have been described in detail by Thompson, Crit, Rev. Ther. Drug Carrier Sept. 14 1 (1997). Cyclodextrin and cyclodextrin derivatives which may be useful in the present invention include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodcxtrin, dimethyl-β-cyclodextrin, sulphobutylether cyclodextrin, 2,6-dimethyl 14-β cyclodextrin, 2, 3, 6- trimethyl 21-β cyclodextrin. The solubilising agent/cannabinoid formulation can be a simple aqueous product in which the drug is associated with the solubilising agent molecule, e.g. as a guest-host complex in which the drug (guest) is contained within a cavity in the solubilising agent molecule (host). Alternatively, the solubilising agent/cannabinoid formulation can be combined with the emulsion product described earlier when some of the drug can be present in the aqueous phase of the emulsion, solubilized in the solubilising agent, and a proportion of the drug can be present dissolved in the oil phase of the emulsion. Alternatively, a guest-host product between a solubilising agent and a cannabinoid can be freeze dried to produce a powder material and then mixed with a bioadhesive microsphere such as a bioadhesive swelling starch microsphere as described in PCT/GB88/00836. Other bioadhesive microspheres that may be used in the present compositions include those made from chitosan, polyvinyl pyrrolidone, alginate, polycarbophil, pectin, hyaluronic acid (and esters thereof), agar agarose, dextran, ovalbumin, collagen, casein. By bioadhesion we mean a material that can interact with mucus or a mucosal surface and thereby provide retention of a drug at a mucosal surface for a period of time longer than that found for a simple liquid or powder system. The concept of bioadhesion has been well discussed in books and reviews such as Bioadhesive Drug Delivery Systems, Ed. Lenaerts and Gurney, CRC Press, Bala Raton, 1990 and Bioadhesion possibilities and future trends. Ed. Gurney and Junginger, Wissenschaftliche, Verlagsgellschaft mbh, Stuttgard, 1990. Such a system will demonstrate good stability with high bioavailability when administered via the nasal route. The weight ratio of solubilising agent to cannabinoid is typically in the range of from 100:1 to 5:1, preferably in the range of from 50:1 to 10:1 and more preferably in the range of from 30:1 to 10:1. The weight ratio of solubilising agent/cannabinoid guest-host product to carrier, e.g. water or microspheres, can be varied but is typically in the range of from 1:100 to 1:5, preferably in the range of from 1:50 to 1:10 and particularly in the range of from 1:25 to 1:15. The systems containing a solubilising agent can also be mixed with a gelling system based on a polysaccharide such as gellan or pectin. These materials can be used to formulate a nasal liquid that can be sprayed into the nasal cavity but will then gel in the presence of endogenous cations. This gelling may prolong the contact time of the formulation in the nasal cavity either through bioadhesive interactions and/or the increase in viscosity. Pectin is a preferred material which can form gels in the presence of divalent cations such as calcium. Pectins with a low degree of esterification, i.e. less than 50%, for example, less than 35%, are suitable and these can be obtained from Copenhagen Pectin A/S as the commercial material known as Slendid Type 100 and Slendid Type 110. These pectins have been extracted from citrus peel and standardised by the addition of sucrose. The degree of esterification is less than 50% for both pectins and of the order of 10 % for type 100 and 35 % for type 110. Further suitable materials include GENU pectin types LM1912CS and Pomosin pectin types LM12CG and LM18CG. The concentration of pectin in the composition can be from 0.1 % to 10 % w/w, but is preferably from 0.5 to 5 % w/w on the total weight of the composition. The powdered product can be delivered nasally using an insufflator device of the type which is familiar to those skilled in the art. Such devices are manufactured by Teijin (Rhinocort™ insufflator), Bespak UK (nasal delivery device), Valois Monopoudre™, France. Doses of the drug, e.g. THC, in the range 0.25 to 40 mg per day can be administered, a preferred range is 0.5 to 30 mg per day and a more preferred range 1 to 20 mg per day. Example 1 An emulsion formulation of THC based on a vegetable oil THC is dissolved in sesame oil to give a concentration of 35 mg/ml. Water containing the dispersed emulsifying agent Lipoid E80 at 1.5% w/v (i.e. 1.5 g of Lipoid E80 per 100mls of water) is used as the continuous phase. The sesame oil-THC mixture is dispersed in the aqueous phase using a Silverson Mixer (Silverson Machine UN) in order to produce a course emulsion. The course emulsion is then passed through an APV. Lab 40 homogeniser to produce a fine emulsion of particles having an average size (i.e. diameter) of 250 nm as measured by Photon correlation spectroscopy. A small quantity, e.g. 1 % w/w on the total weight of the oil phase, of tocopherol can be added to the oil phase to provide a stabilizing function. The total oil content of the final emulsion is 20% w/v, i.e. the emulsion contains 20 g of oil per 100 mls thereof. The emulsion formulation of THC could be delivered to the nasal cavity using known nasal spray devices. The preferred volume for nasal administration is 150 µl (per nostril) containing a dose of about 1 mg of THC. Example 2 Castor oil emulsion formulation The formulation is produced as described in Example 1 except the sesame oil phase is exchanged with castor oil. The particle size of the emulsion will be about 280 nm as measured by photon correlation spectroscopy. Example 3 Vitamin E emulsion formulation The formulation is produced as described in Example 1 except the oil phase is exchanged with all-rac-α-tocopherol (no additional antioxidant is then required) and sodium deoxycholate co-emulsifier is added to the aqueous phase containing the Lipoid E80 at a concentration of 1 % w/v, i.e. 1 g of sodium deoxycholate per 100 mls of water. Example 4 200 mg of THC dissolved in 2 ml of ethanol was added to 6 ml of sesame oil. The oil/ethanol/THC solution was stirred in an open vessel for 2 hours at 50-60°C to evaporate the majority of the ethanol. Into 20 ml of 0.9% sodium chloride solution was dispersed 360 mg of egg yolk phospholipid (Lipoid E80) by warming to 40-50°C. The oil was added to the phospholipid dispersion and the two phases coarsely emulsified using an IKA laboratory homogeniser at 20,000 rpm for 2 minutes. This emulsion was then transferred to an APV Rannie Mini-Lab valve homogeniser and passed through twice at 500 bar to produce a milky off-white product. The final product contained 6.7 mg/ml THC. A nasal administration of 150 µl of the emulsion would provide 1 mg of THC. The present invention provides a composition for nasal delivery comprising a cannabinoid in a biphasic delivery system. The biphasic delivery system may be an oil-in-water emulsion. The oil phase in the emulsion system may be a vegetable oil, such as castor oil or tocopherol. The oil-in-water emulsion may contain an emulsifier, such as a phospholipid, or a block copolymer. The biphasic delivery system may comprise a solubilising agent for the cannabinoid. A cannabinoid suitable for use in the present invention is dronabinol. The present invention also provides the use of a cannabinoid in the manufacture of a composition as defined above for treating a patient in need of a cannabinoid. The present invention also provides the use of a cannabinoid in the manufacture of a composition as defined above for treating pain or nausea or to stimulate appetite. The present invention also provides the use of a composition as defined above for the manufacture of a medicament for treating a patient in need of a cannabinoid. The present invention also provides the use of a composition as defined above for the manufacture of a medicament for treating pain or nausea or to stimulate appetite. The present invention also provides the use of a cannabinoid in the manufacture of a composition as defined above for nasal delivery. The present invention also provides the use of a composition as defined above for the manufacture of a medicament for nasal delivery.

Claims: A composition for nasal delivery comprising a cannabinoid in a biphasic delivery system, wherein the biphasic delivery system is an oil-in-water emulsion and the cannabinoid is selected from delta-9-tetrahydrocannabinol, cannabidol, olivetol, cannabinol, cannabigerol, nabilone, delta-9-tetrahydrocannabinotic acid, 3-dimethylnepty 11 carboxylic acid homologine 8 and pharmaceutically acceptable salts thereof. A composition according to Claim 1, wherein the cannabinoid is delta-9-tetrahydrocannabinol (dronabinol). A composition according to Claim 1, wherein the oil phase in the emulsion system is a vegetable oil. A composition according Claim 3, wherein the oil phase in the emulsion system is castor oil or sesame oil. A composition according to Claim 3 or 4, wherein the oil phase additionally comprises tocopherol. A composition according to any one of Claims 1 to 5 comprising an emulsifier. A composition according to Claim 6, wherein the emulsifier is a phospholipid. A composition according to Claim 6, wherein the emulsifier is a block copolymer. A composition according to any one of Claims 1 to 8, further comprising a solubilising agent for the cannabinoid. A composition according to Claim 9, wherein the solubilising agent is a cyclodextrin or a derivative thereof. A composition according to Claim 9 or Claim 10, further comprising a polysaccharide gelling system. A composition according to Claim 11, wherein the polysaccharide is a pectin. A composition according to any one of Claims 1 to 12, wherein the quantity of oil in the emulsion is from 10 to 50% v/v. A composition according to any one of Claims 1 to 13, wherein drug is dissolved in the oil phase at a concentration of 1 to 10% w/v. The use of a cannabinoid selected from delta-9-tetrahydrocannabinol, cannabidol, olivetol, cannabinol, cannabigerol, nabilone, delta-9-tetrahydrocannabinotic acid, 3-dimethylnepty 11 carboxylic acid homologine 8, delta-8-tetrahydrocannabinol and pharmaceutically acceptable salts thereof in the manufacture of a composition for nasal delivery, which composition comprises a biphasic delivery system, wherein the biphasic delivery system is an oil-in-water emulsion. The use as according to Claim 15, wherein the use is for treating a patient in need of a cannabinoid. The use according to Claim 15, wherein the use is for treating pain or nausea or to stimulate appetite. The use according to any one of Claims 15 to 17, wherein the cannabinoid is delta-9-tetrahydrocannabinol (dronabinol). The use according to any one of Claims 15 to 18, wherein the oil phase in the emulsion system is a vegetable oil. The use according Claim 19, wherein the oil phase in the emulsion system is castor oil or sesame oil. The use according to Claim 19 or 20, wherein the oil phase additionally comprises tocopherol. The use according to any one of Claims 15 to 21 wherein the composition comprises an emulsifier. The use according to Claim 22, wherein the emulsifier is a phospholipid. The use according to Claim 22, wherein the emulsifier is a block copolymer. The use according to any one of Claims 15 to 24, wherein the composition further comprises a solubilising agent for the cannabinoid. The use according to Claim 25, wherein the solubilising agent is a cyclodextrin or a derivative thereof. The use according to Claim 25 or Claim 26, wherein the composition further comprises a polysaccharide gelling system. The use according to Claim 27, wherein the polysaccharide is a pectin. The use according to any one of Claims 15 to 28, wherein the quantity of oil in the emulsion is from 10 to 50% v/v. The use according to any one of Claims 15 to 29, wherein drug is dissolved in the oil phase at a concentration of 1 to 10% w/v.

Inventors: DAVIS STANLEY STEWART, WATTS PETER JAMES, DAVIS, STANLEY STEWART, WATTS, PETER JAMES, Watts, Peter James, c/o Archimedes Develop.Limited
Applicants: ARCHIMEDES DEV LTD, ARCHIMEDES DEVELOPMENT LIMITED
Application year: 1998
Main classification: A61K31
IPC codes: A61K31, A61K9