Claims for Patent: 6,299,900

Summary for Patent: 6,299,900

Title:	Dermal penetration enhancers and drug delivery systems involving same
Abstract:	A transdermal drug delivery system which comprises at least one physiologically active agent or prodrug thereof and at least one dermal penetration enhancer; characterized in that the dermal penetration enhancer is a safe skin-tolerant ester sunscreen. A non-occlusive, percutaneous or transdermal drug delivery system which comprises: (i) an effective amount of at least one physiologically active agent or prodrug thereof; (ii) at least one non-volatile dermal penetration enhancer; and (iii) at least one volatile liquid; characterised in that the dermal penetration enhancer is adapted to transport the physiologically active agent across a dermal surface or mucosal membrane of an animal, including a human, when the volatile liquid evaporates, to form a reservoir or depot of a mixture comprising the penetration enhancer and the physiologically active agent or prodrug within said surface or membrane; and the dermal penetration enhancer is of low toxicity to, and is tolerated by, the dermal surface or mucosal membrane of the animal.
Inventor(s):	Reed; Barry Leonard (Strathmore, AU), Morgan; Timothy Matthias (Parkville, AU), Finnin; Barrie Charles (Glen Iris, AU)
Assignee:	Monash University (Victoria, AU)
Application Number:	09/125,436
Patent Claims:	1. A transdermal drug delivery system which comprises: a therapeutically effective amount of at least one physiologically active agent; and at least one dermal penetration enhancer present in an amount of from 10 to 10,000 wt % based on the weight of the active agent; wherein the dermal penetration enhancer is at least one of a safe skin-tolerant ester sunscreen of formula (I): ##STR2## wherein R.sup.3 is hydrogen, lower alkyl, lower alkoxy, halide, hydroxy or NR.sup.3 R.sup.4 ; R.sup.2 is a C.sub.8 to C.sub.18 alkyl, R.sup.3 and R.sup.4 are each independently hydrogen, lower alkyl or R.sup.3 and R.sup.4 together with the nitrogen atom to which they are attached form a 5- or 6-membered heterocyclic ring; n is 0 or 1, and q is 1 or 2, wherein when n is 0 and R.sup.1 is NR.sup.3 R.sup.4, then NR.sup.3 R.sup.4 is para-substituted. 2. A drug delivery system according to claim 1, wherein said ester is a C.sub.8 to C.sub.18 alkyl para-aminobenzoate, C.sub.8 to C.sub.18 alkyl dimethyl-para-aminobenzoate, C.sub.8 to C.sub.18 alkyl cinnamate, C.sub.8 to C.sub.18 alkyl methoxycinnamate or C.sub.8 to C.sub.18 alkyl salicylate. 3. A drug delivery system according to claim 2, wherein said ester is octyl dimethyl-para-aminobenzoate, octyl para-methoxycinnamate or octyl salicylate. 4. A drug delivery system according to claim 1, further comprising a pharmaceutical compounding agent, co-solvent, surfactant, emulsifier, antioxidant, preservative, stabiliser, diluent or a mixture of two or more of said components. 5. A transdermal drug delivery system as claimed in claim 1, further comprising at least one volatile liquid. 6. A drug delivery system according to claim 1, wherein the drug delivery system is not supersaturated with respect to the physiologically active agent. 7. A transdermal drug delivery system according to claim 1 that further comprises at least one volatile liquid present in an amount to act as a vehicle for the active agent and penetration enhancer. 8. A method for administering at least one systemic or locally acting physiologically active agent or prodrug thereof to an animal which comprises applying an effective amount of the physiologically active agent in the form of a drug delivery system according to claim 1 to a dermal surface or mucosal membrane of said animal. 9. A method according to claim 8, wherein the animal is a human. 10. A method according to claim 8, wherein the drug delivery system is applied by an aerosol or spray comprising a shroud adapted to keep an actuator nozzle of the apparatus at a pre-determined height above the site of application. 11. A method for the treatment or prophylaxis of a disease or condition in an animal which comprises administering to a dermal surface or mucosal membrane of said animal in need of such treatment a therapeutically effective amount of the drug delivery system according to claim 1 to a dermal surface or mucosal membrane of said animal. 12. A method according to claim 11, wherein the disease or condition requires male hormone replacement in testosterone deficient hypogonadal men, female hormone replacement therapy for postmenopausal women, androgen replacement therapy for females lacking libido, male contraception or female contraception. 13. A method according to claim 11, wherein the disease or condition is soft tissue injury, narcotic withdrawal, severe post-operative pain, motion sickness, oestrogen dependent breast cancer, prostatic enlargement and/or prostatic cancer, alopecia and acne, anxiety disorders, male impotence, Raynauds syndrome and varicose veins, sleep disorders, jetlag, herpes virus infections, deep vein thrombosis, migraine, high blood pressure, malaria, diagnosis of cystic fibrosis, asthma or nocturnal asthma. 14. A non-occlusive, percutaneous or transdermal drug delivery system which comprises: (i) a therapeutically effective amount of at least one physiologically active agent; (ii) at least one dermal penetration enhancer, which is a safe skin-tolerant ester sunscreen, and is present in an amount of from 10 to 10,000 wt % based on the weight of the active agent; (iii) at least one volatile liquid present in an amount to act as a vehicle for the active agent and penetration enhancer; wherein: the dermal penetration enhancer (A) is adapted to transport the physiologically active agent across a dermal surface or mucosal membrane of an animal, when the volatile liquid evaporates, to form a reservoir or depot of a mixture comprising the penetration enhancer and the physiologically active agent within said surface or membrane, and (B) is of low toxicity to, and is tolerated by, the dermal surface or mucosal membrane of the animal; and, after application of the system to an area of the dermal surface, the area becomes touch-dry within 3 minutes of application. 15. A drug delivery system according to claim 14, wherein the dermal surface becomes touch-dry within one minute of application. 16. A drug delivery system according to claim 14, wherein said ester is of formula (I): ##STR3## wherein R.sup.1 is hydrogen, lower alkyl, lower alkoxy, halide, hydroxy or NR.sup.3 R.sup.4 ; R.sup.2 is a long chain alkyl; R.sup.3 and R.sup.4 are each independently hydrogen, lower alkyl or R.sup.3 and R.sup.4 together with the nitrogen atom to which they are attached form a 5- or 6-membered heterocyclic ring; n is 0 or 1; and q is 1 or 2. 17. A drug delivery system according to claim 14, wherein said ester is a long chain alkyl para-aminobenzoate, long chain alkyl dimethyl-para-aminobenzoate, long chain alkyl cinnamate, long chain alkyl methoxycinnamate or long chain alkyl salicylate. 18. A drug delivery system according to claim 17, wherein said ester is octyl dimethyl-para-aminobenzoate, octyl para-methoxycinnamate or octyl salicylate. 19. A drug delivery system according to claim 15, wherein the volatile liquid is ethanol or isopropanol. 20. A drug delivery system according to claim 15, wherein the physiologically active agent is a steroid, hormone derivative, non-steroidal anti-inflammatory drug, opioid analgesic, antinauseant, antioestrogen, aromatase inhibitor, 5-alpha reductase inhibitor, anxiolytic, prostaglandin, anti-viral drug, anti-migraine compound, antihypertensive agent, anti-malarial compound, bronchodilator anti-depressant, anti-alzheimer's agent, neuroleptic and antipsychotic agent, anti-parkinson's agent, antiandrogen or anorectic agent. 21. A drug delivery system according to claim 15, wherein the physiologically active agent is testosterone, oestradiol, ethinyloestradiol, progesterone, norethisterone acetate, ibuprofen, ketoprofen, flurbiprofen, naproxen, diclofenac, fentanyl, buprenorphine, scopolamine, prochlorperazine, metochlopramide, ondansetron, tamoxifen, epitiostanol, exemestane, 4-hydroxy-androstenedione and its derivatives, finasteride, turosteride, LY191704, MK-306, alprazolam, alprostadil, prostacylcin and its derivatives, melatonin, n-docosanol, tromantadine, lipophilic pro-drugs of acyclovir, low molecular weight heparin, enoxaparin, sumatriptan, amlodipine, nitrendipine, primaquine, minoxidil, minoxidil pro-drugs, pilocarpine, salbutamol, terbutaline, salmeterol, ibogaine, bupropian, rolipram, tacrine, fluphenazine, haloperidol, N-0923, cyproterone acetate or mazindol. 22. A drug delivery system according to claim 14, wherein the system is applied to the dermal surface by an aerosol, as a spray. 23. A drug delivery system according to claim 22, wherein the aerosol is a fixed or variable metered dose aerosol. 24. A drug delivery system according to any one of claim 15, further comprising a pharmaceutical compounding agent, co-solvent, surfactant, emulsifier, antioxidant, preservative, stabiliser, diluent or a mixture of two or more of said components. 25. A transdermal drug delivery system according to claim 14, wherein the physiologically active agent or prodrug thereof, the dermal penetration enhancer, and the volatile liquid are a single phase.