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Home , Amyl nitrite, Pentyl nitrite

|||||||| US00548961OA United States Patent 19 11 Patent Number: 5,489,610 Fung et al. 45) Date of Patent: 8 Feb. 6, 1996

54 SUSTAINED RELEASE ORGANIC 58 Field of Search ...... 514/506, 509, THERAPY 514/645, 740 75 Inventors: Ho-Leung Fung, Getzville; John A. 56) References Cited Bauer, Williamsville, both of N.Y. U.S. PATENT DOCUMENTS 73 Assignee: Research Foundation of the State 5,278,192 l/1994 Fung et al...... 514f645 University of New York, Albany, N.Y. OTHER PUBLICATIONS * Notice: The portion of the term of this patent Derwent Abstracts 78–35053A, "Medicaments for Treating disclaimed.subsequent to Jan. 11, 2011, has been Cardiardiogenic Shock”, Fribolinis is et al. (1978). Patent Abstracts of Japan, vol. 12, No. 467, Dec. 7, 1988, 21 Appl. No.: 199,280 "Tape Preparation'. 22, PCT Filed: Jun. 30, 1993 Primary Examiner-Frederick Krass Attorney, Agent, or Firm-Kirschstein et al. 86 PCT No.: PCT/US93/06235 (57) ABSTRACT S371 Date: Mar. 1, 1994 A method of treating a patient suffering from a condition S 102(e) Date: Mar. 1, 1994 requiring vasodilator therapy, comprising long term, con 87 PCT Pub. No.: WO94/01103 tinuous adminstration of an organic nitrite to the patient in a dosage form capable of delivering a sufficient therapeutic PCT Pub. Date:Jan. 20, 1994 amount of nitrite to the bloodstream of the patient thereby providing effective vasodilator therapy for at least 24 hours Related U.S. Application Data without the development of tolerance in the patient. The a method of the invention is useful in treating conditions such 63 Continuation-in-part of Ser. No. 908,224, Jul. 2, 1992, Pat. as , particularly chronic, stable angina pectoris, No. 5,278,192. ischemic diseases and congestive heart failure, and for (51l int. Cl...... A61K 31/13 controlling hypertension and/or impotence in male patients. 52 U.S. Cl...... 514/506; 514/509; 514/645; 514f740 14 Claims, 4 Drawing Sheets U.S. Patent Feb. 6, 1996 Sheet 1 of 4 5,489,610

OO

80 5R.LVEDP% 60 . 40

20; 2 4 6 8 O' "22 HOURS OF INFUSION FG.

OO 80 t LVEDP9, 60 OF INITIAL 40 20

O' 22 HOURS OF INFUSION FG.2 U.S. Patent Feb. 6, 1996 Sheet 2 of 4 5,489,610

20 OO

80 O LVEDP% sus

40 20 l O 2 4 6 8 O 22 HOURS OF INFUSION F. G. 3

OO 80 LVEDP, 60 % NITIAL 40 20 O O 5 O 5 20 25 HOURS OF INFUSION F. G. 4 U.S. Patent Feb. 6, 1996 Sheet 3 of 4 5,489,610

7 HEPTANE DINTRTE OO 8O LVEDP % NITIAL SO 40 20 O O 5 O 5 20 25 HOURS OF INFUSION F. G.5

CYCLOHEXYLMETHYL NITRITE

LVEDP, % NITIAL

O 5 O 5 20 25 HOURS OF INFUSION F. G. 6 U.S. Patent Feb. 6, 1996 Sheet 4 of 4 5,489,610 PHENYLETHY NITRITE OO 80 LVEDP, % NITAL 60 40 20

O 5 O 5 20 25 HOURS OF INFUSION F. G.7

3 CHLORO, 2.2 DIMETHYLPROPYL NITRITE OOH ------80 LVEDP % INITIAL 60 40 20

O 5 O 15 2O 25 HOURS OF INFUSION F. G. 8 5,489,610 1. 2 SUSTANED RELEASE ORGANIC NITRITE leaving the patient unprotected during the majority of the THERAPY "dose-off" period. Furthermore, a more frequent on/off dosing strategy (4 or 8 hour on/off cycles) was not successful CROSS-REFERENCE TO RELATED in avoiding tolerance development. At present no dosage APPLICATION regimen with has been developed that can achieve the dual objectives of avoidance of hemodynamic This application is a continuation-in-part of Application tolerance while continuously maintaining their beneficial Ser. No. 07/908,224, filed Jul. 2, 1992, now U.S. Pat. No. effects. 5,278,192. Additionally, headaches typically accompany treatment O with organic such as . Headaches may FIELD OF THE INVENTION be recurring with each daily dose, especially at higher doses. The present invention relates generally to therapy Aside from headaches, which may be severe and persistent, and, more particularly, to a method of vasodilator therapy for other adverse central nervous system (CNS) reactions treating ischemic diseases, angina pectoris, hypertension include apprehension, restlessness, weakness, vertigo, diz and/or congestive heart failure. 15 Ziness and faintness. BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION Congestive heart failure is a complex and heterogeneous The primary object of the present invention is to provide disease state associated with decreased cardiac performance 20 a new and improved method of vasodilator therapy, for and increased pulmonary and peripheral oedema. Conges example, in treating ischemic diseases, angina pectoris, tive heart failure results when the left, right or both ven congestive heart failure, impotence, and/or controlling tricles fail to pump sufficient blood to meet the body's needs. hypertension, substantially without development of hemo An estimated 4 million people currently in the United States dynamic tolerance in the patient. have congestive heart failure. While no single drug or drug 25 We have now discovered that tolerance associated with class has proven to be ideal in treating this disease, vasodi conventional vasodilator therapy (i.e., nitrovasodilators) can lator therapy constitutes a major approach in its clinical be avoided while providing effective long term, continuous management. treatment. More particularly, the present invention provides Organic , such as nitroglycerin, isosorbide a method for treating a patient suffering from a condition dinitrate, isosorbide-5-mononitrate, etc. are organic chemi 30 requiring vasodilator therapy, comprising the long term, cals that contain the ONO group. Nitrates are part of a continuous administration of an organic nitrite to the patient family of vasodilators called nitrovasodilators and have in a dosage form capable of delivering a sufficient amount of enjoyed extensive use in cardiovascular therapy; but other the nitrite to the bloodstream to provide effective vasodilator members of this class, e.g., nitroprusside, and therapy for at least 24 hours without development of toler organic are not organic nitrates. Nitrovasodilators 35 ance in the patient. The method of the invention is useful in such as and glyceryl trinitrate are useful treating conditions such as, for example, angina, particularly in treating congestive heart failure because they cause a chronic, stable angina pectoris, ischemic diseases and con prompt reduction in preload and/or afterload, and relieve the gestive heart failure, and for controlling hypertension and/or venous congestion often associated with this disease. impotence in male patients. Nitroglycerin, also referred to as trinitroglycerin or glyc 40 In connection with the method of the invention, any erin trinitrate, has also been used to treat angina pectoris for conventional drug delivery system for the dosage form can over 100 years. Nitroglycerin and other nitrovasodilators be employed. It is understood that the drug delivery system have been available for the treatment of angina pectoris and can take virtually as many different forms as there are congestive heart failure in a number of different dosage dosage forms available for delivery of nitrite to patients. For forms for some time. These include sublingual, oral and 45 example, drug delivery systems within the scope of the buccal tablets as well as capsules, topical creams and invention include sublingual, oral and buccal tablets as well ointments, patches, tapes, lingual sprays and intravenous as capsules, caplets, tablets, topical creams and ointments, Solutions. patches, tapes, lingual sprays and intravenous solutions. Transdermal nitroglycerin patches were introduced in 50 recent years in an effort to overcome some of the disadvan BRIEF DESCRIPTION OF THE DRAWINGS tages and inconveniences of other dosage forms. In particu FIG. 1 is a graph illustrating the effects of continuous lar, transdermal patches were formulated to provide intravenous infusion (10-15 g/min) of nitroglycerin to increased systemic bioavailability as well as constant deliv congestive heart failure rats. The pharmacologic effect mea ery of the drug over a 24 hour period or longer. Typically, the 55 patches are applied once daily, either in the morning or sured was the left ventricular end-diastolic pressure evening, and changed daily at approximately the same time, (LVEDP). and have become popular in the treatment of chronic, stable FIG. 2 is a graph illustrating the effects of continuous angina and congestive heart failure. intravenous infusion (3.13 or 5.0 l/hr) of to However, the positive effects of these patches are often 60 congestive heart failure rats. The pharmacologic effect mea short lived. For example, it has been shown that nitroglyc Sured was the LVEDP. erin produces rapid hemodynamic tolerance (within several FIG. 3 is a graph illustrating the effects of continuous hours) in congestive heart failure after continuous adminis intravenous infusion (3.13 pul/hr) of isoamyl nitrite to con tration either by intravenous or transdermal routes. Inter gestive heart failure rats. The pharmacologic effect mea mittent dosing with a regimen of 12 hours on/12 hours off 65 Sured was the LVEDP. can avoid development of tolerance but the effect of the FIG. 4 is a graph illustrating the effects of continuous previous dose is lost within 2 hours of , intravenous infusion (1.0 ul/hr) of 1,3-propane dinitrite to 5,489,610 3 4 congestive heart failure rats. The pharmacologic effect mea use of an intermittent dosing schedule with a nitrate free Sured was the LVEDP. interval of 10-12 hours (e.g., removal of a transdermal nitroglycerin system in the early evening and application of FIG. 5 is a graph illustrating the effects of continuous a new system the next morning, or other dosing regimens intravenous infusion (1.0 ul/hr) of 1,7-heptane dinitrite to that allow for a nitrate-free period). Additionally, the inter congestive heart failure rats. The pharmacologic effect mea mittent closing schedule leaves the patient exposed to the Sured was the LVEDP. potential risks of the condition during the "off" periods. FIG. 6 is a graph illustrating the effects of continuous Adverse reactions to nitrate therapy, regardless of form of intravenous infusion (3.13 ul/hr) of cyclohexylmethyl nitrite dosage, mainly involve the cardiovascular system. Head to congestive heart failure rats. The pharmacologic effect ache, the most frequent adverse effect, may be severe measured was the LVEDP. 10 (persistent or transient) and is perceived as a pulsating, FIG. 7 is a graph illustrating the effects of continuous throbbing sensation. Furthermore, postural may intravenous infusion (3.13 al/hr) of phenylethyl nitrite to occur in patients receiving nitrates which may cause dizzi congestive heart failure rats. The pharmacologic effect mea ness, weakness and other signs of cerebral ischemia. Some Sured was the LVEDP. 15 patients may have a marked sensitivity to the hypotensive FIG. 8 is a graph illustrating the effects of continuous effects of the nitrates and , , weakness, intravenous infusion (3.13 ul/hr) of 3-chloro-2,2-dimethyl restlessness, pallor, cold sweat, tachycardia, and propyl nitrite to congestive heart failure rats. The pharma cardiovascular collapse may occur with therapeutic doses. In cologic effect measured was the LVEDP. addition, in patients receiving transdermal delivery, periph 20 eral edema rash and/or dermatitis may occur. DETALED DESCRIPTION OF THE Turning to the various disease states which may be treated NVENTION by the novel method, in one embodiment of the invention, nitrite therapy can be used in treating chronic, stable angina The present invention provides a new vasodilator treat pectoris as well as unstable angina and silent ischemia. ment for long term, continuous therapy, without the devel Angina pectoris is a symptom of myocardial ischemia that is opment of any significant degree of tolerance in the patient 25 usually secondary to coronary heart disease. "Angina pec for at least one full day. More particularly, there is provided toris' as used herein, means a sense of discomfort arising in a method for long-term continuous administration of an the myocardium as a result of myocardial ischemia in the organic nitrite for treatment of a patient suffering from a absence of infarction. Angina usually implies severe chest condition such as, for example, chronic angina pectoris, pain or discomfort. Coronary heart disease is the leading controlling in hypertension and especially 30 cause of death and disability in the United States and angina hypertension associated with surgical anesthesia and cardio is the first clinical sign of this disease in about one-third of vascular procedures, ischemic diseases, congestive heart men and two-thirds of women. Patients who have a repro failure or pulmonary edema associated with acute myocar ducible pattern of angina that is associated with a certain dial infarction and/or impotence in male patients. The level of physical activity have chronic/stable angina. In organic nitrite can be administered in any known dosage 35 contrast, patients with unstable angina are experiencing new form by any conventional route of administration, for angina or a change in their angina pattern, frequency or example, lingually, sublingually, intrabuccally, orally, topi duration. cally, by inhalation or by IV infusion or other parenteral modalities. In another embodiment herein, nitrite therapy can be used 40 for treating hypertension. Hypertension as used herein, is a The only known clinical use of a nitrite for treating the cardiovascular disease characterized by elevation of blood above disease states is old, and includes the use of amyl pressure above arbitrary values considered "normal" for nitrite for the acute relief of angina pectoris, not for long people of similar racial and environmental background. term, continuous drug therapy. Clinical use of Hypertension affects the vasculature of all major organ has never been found useful on a chronic basis. It is 45 systems (e.g., heart, brain, kidneys), and myocardial infarc inconvenient, has a high incidence of adverse effects, has an tion and congestive heart failure (CHF) account for the unpleasant odor and is highly volatile. majority of deaths secondary to hypertension (i.e., hyper For a better understanding of the present invention, it is tension is a major etiologic factor in development of CHF). first necessary to look at the tolerance problems associated The morbidity and mortality that is associated with hyper with conventional nitrate therapy, the particular disease 50 tension, increases linearly with higher systolic and diastolic states to be treated and the biochemical mechanisms of blood pressures. The vast majority (e.g., about 85-90%) of organic nitrates and nitrites. Turning first to nitrate therapy, individuals with hypertension have essential or primary tolerance to the individual nitrates as well as cross-tolerance hypertension which has no established cause. Hypertension may occur with repeated, prolonged use. is currently treated using thiazide diuretics, calcium channel Tolerance to the vascular and antianginal effects of the 55 blockers, beta blockers or angiotensin converting has been shown in clinical studies, by experience from inhibitors, sometimes combined with non-drug interven occupational exposure, and in isolated in vitro tissue experi tions. ments. Such tolerance is a principal factor limiting the In still another embodiment of the invention, nitrite efficacy of long-term nitrate therapy. Tolerance to nitrates therapy can be used for treating congestive heart failure appears to be associated with sustained plasma drug con 60 (CHF). CHF results when the left, right or both ventricles centrations and frequent administration, i.e. continuous fail to pump sufficient blood to meet the body's needs. therapy. Rapid development of tolerance has occurred with Increased cardiac workload and impaired myocardial con oral, IV, and topical nitrate therapy (i.e., transdermal systems tractility are important factors which contribute to the devel or nitroglycerin ointment). Tolerance to the pharmacologic opment of CHF. There are four major determinants which effects is generally minor with intermittent use of sublingual 65 contribute to the left ventricular workload: preload, after nitrates. Furthermore, some evidence suggests that the load, contractility and heart rate. Preload is the term to development of tolerance can be prevented or minimized by describe forces acting on the venous side of the circulation 5,489,610 S 6 to affect myocardial wall tension. As venous return (i.e., unresponsive to the body's mechanisms and other traditional blood flowing into the heart) increases, the volume of blood therapy, however, the problems associated with hemody in the left ventricle increases. This increased volume raises namic tolerance, as previously mentioned, and other adverse the pressure within the ventricle (left ventricle end-diastolic side effects render this therapy inadequate. pressure (LVEDP) which in turn increases the "stretch' or 5 Organic nitrites which can be used in the present inven wall tension of the ventricle. An elevated preload will tion include any organic nitrite , i.e., any ester of nitrous aggravate congestive heart failure. Afterload is the tension acid and an organic , provided that the starting developed in the ventricular wall as contraction (systole) alcohol is not toxic and does not interfere with or counteract occurs. Afterload is regulated by the resistance or impedance the vasodilating effect of the nitrite. Such organic nitrites can against which the ventricle must pump during its ejection 10 include, for example, straight or branched chain and is chiefly determined by arterial blood pressure. Con- nitrites, arylalkyl nitrites, cycloalkyl nitrites, haloalkyl or tractility describes the inherent ability of the myocardium halocycloalkyl nitrites and heterocyclic nitrites, as well as () to develop force and/or shorten indepen- di- and trinitrite analogs of the foregoing. The di- and dent of preload or afterload. trinitrite esters may be produced by reacting When the heart begins to fail, the body activates several 15 with the appropriate diols or triols or by forming partial complex compensatory mechanisms in an attempt to main- esters of polyols such as pentaerythritol. Preferred nitrites tain cardiac output and oxygenation of vital organs. These containing alkyl groups are those in which the alkyl is include cardiac (ventricular) dilation, cardiac hypertrophy, C1-Co increased sympathetic tone and sodium and water retention. Illustrative examples of organic nitrites which may be Nitrate vasodilator therapy has been used to manage CHF useful in the method of the invention are shown below.

CH3 CHNO isobutyl nitrite cis- ONO CH3 CHNO, isoamyl nitrite cis-r ONO oNo1 Nu-1N ONO CHNO 1,3-propane dinitrite

ONo1N1 S-1N1N ONO CH4N2O4. 1,7-heptane dinitrite

CH-N-> CH CHNO2 3-hexyl nitrite ONO CHY-1N1,N1,N- ONO CH7NO2 octyl nitrite

CH ONO CH3NO2 4-methyl-2- cis- CH3 CH CH1NO2 4-methyl-1-pentyl nitrite cus-N- ONO ONO CH5NO2 2-heptyl nitrite cir-N- CH ONO CH7NO. 3-octyl nitrite car-N- CH ONO CH3NO2 2-methyl-2-pentyl nitrite

CH ~-'s CHCH3 CH CHNO 5-methyl-2-hexyl nitrite cus-N- ONO CH CH ONO CH7NO2 6-methyl-2-heptyl nitrite cis-N- CH3 5,489,610

-continued cyclohexylmethyl nitrite Cr ONO CHNO CHNO 2-phenylethyl nitrite

C O N O CHCNO 3-chloro-2,2-dimethylpropyl nitrite H3 CH3 ONO CH tert-amyl nitrite CH

ONO CH 3 CH5NO2 2-methyl-2-hexyl nitrite CH C H3 DrS-N- 3 CH1N1 N-1). ONO CH1NO2 hexyl nitrite oNon-r ONO CHN2O4. 2-methyl-1,3-propane dinitrite CH

ONO ONO CHONO 2,2-dimethyl-1,3-propane dinitrite 3. CH3H CH 2-methyl-2-propyl-1,3-propane dinitrite

ONO ONO

ONO ONO CH5NO glyceryl trinitrite ONO

R CHNO glycery mononitrite rs-sR 1-nitrite: REONO; RER"EOH or 2-nitrite: RER"-cCH; R'cCNO HO CHNO isosorbide 5-mononitrite H O

ONO CHNOs isoidide 5-mononitrite

ONO CH3NOs isomannide 5-mononitrite

ONO CHOH CHNOs pentaerythrityl mononitrite HOCH2 -- CHONO CH2OH 5,489,610 10 -continued CH2OH pentaerythrityl dinitrite HOCH2 -- CHONO CHONO CHONO pentaerythrityl trinitrite HOCH2 -- CHONO CHONO CHONO pentaerythrityl tetranitrite ONOCH -- CHONO CHONO

In accordance with the present invention, the dosage of 15 upward until angina is effectively controlled or adverse nitrite is preferably a daily dosage amount adequate to effects preclude further increases. In the treatment of con provide the necessary protection or relief to the patient from gestive heart failure (CHF), an initial dose of about 1.5 congestive heart failure, angina pectoris and/or hypertension inches of 2% nitrite ointment (approximately 22.5 mg) can symptoms. It is understood that the absolute amount will be used and gradually increased in 0.5 to 1-inch increments vary with the patient, the particular nitrite employed, and the 20 up to a dosage of 4 inches every 4-6 hours. Again, the dosage form to be administered. Also, these parameters will dosage should be titrated upward until symptoms of CHF are affect the delivery rates or fluxes employed in the drug controlled. delivery system utilized. For purpose of example only, In accordance with another embodiment of the invention, various dosage forms are described hereinafter ill detail. 25 the treatment is accomplished by an oral delivery system, the However, it is apparent that the dosages will vary based on particular dosage form being selected from capsules, caplets, the above parameters. tablets and similar pharmaceutically acceptable oral dosage In accordance with one embodiment of the invention, forms. When an oral dosage form is employed, the unit dose when a transdermal nitrite patch is employed, it is preferably will be selected to deliver to the patient from about 2.5 to applied at the same time each day to areas of clean, dry, 30 about 300 mg/day of nitrite, preferably from about 5 to about hairless skin of the upper arm or body. Skin areas with 160 mg/day, preferably, the entire daily unit dosage will be irritation, extensive scarring or calluses should be avoided, provided in one or two sustained release capsules, caplets or and application sites should be rotated to avoid potential tablets designed to provide the desired drug delivery profile skin irritation. The usual initial adult dosage is 1 transdermal patch applied every 24 hours. The total nitrite delivered from as described herein. Alternatively, combinations of different a single patch (unit dosage) will be in the range of from 35 oral delivery dosage forms and strengths can be employed to about 1 to about 100 mg/day, preferably from about 2 to achieve the desired drug delivery profile. about 60 mg/day, and more preferably from about 5 to about In accordance with still another embodiment of the inven 30 mg/day for the typical patient. It is understood theft tion, treatment of chronic, angina pectoris can be accom transdermal nitrite drug delivery can be effected either plished by sublingual and/or buccal dosages. For long-term through application of a gel or ointment (described herein 40 treatment, nitrite extended-release buccal (transmucosal) after) to the skin or through the use of various commercially tablets can be placed on the oral mucosa between the lip and available transdermal delivery systems. gum above the upper incisors or between the cheek and gum. A number of different transdermal products which can The tablet should be allowed to dissolve undisturbed. The employ the organic nitrite in accordance with the invention initial dosage is preferably about 1 mg 3 times daily given are described by Curtis Black, "Transdermal Drug Deliv 45 every 5 hours during waking hours and dosage should be ery”, Pharmacist, Nov. 1982, pp. 49-75, which disclosure is titrated upward incrementally until angina is effectually hereby incorporated by reference. Additionally, exemplary controlled. Preferably, for long-term treatment of angina patents relating to delivery systems include U.S. Pat. Nos. pectoris, about 1.0 to 9.0 mg. of nitrite as an extended 4,191,015; 3,742,951, 4,191,015; 3,742,951 and 4,262,003 release formulation can be administered orally about every which disclose using a permeation enhancer to control 8 or 12 hours. delivery rates, which disclosures are hereby incorporated by 50 reference. In accordance with still another embodiment of the inven The nitrite can also be applied topically as an ointment. tion, treatment of congestive heart failure can be accom The ointment is spread on any non-hairy skin area (usually plished by IV administration of nitrite. When administered the chest or back) in a thin, uniform layer without massaging by IV, the nitrite should be diluted with a suitable stabilizer or rubbing and using applicator paper typically supplied by 55 before administration. The preferred dosage range for IV the manufacturer. To protect clothing, plastic wrap held in administration is about 5ug/minute to about 500 ug/minute. place by an elastic bandage, tape or the like can be used to It is recommended that IV administration begin with an cover the ointment. The amount of nitrite reaching the: initial low dosage, with the dosage to be titrated upward by circulation varies directly with the size of the area of increments of 5 or 10 g/minute until the appropriate blood application and the amount of ointment applied. The oint 60 pressure response is obtained and/or chest pain decreases. ment is typically spread over an area approximately equiva The type of IV administration set used, polyvinyl chloride lent to 3.5 by 2.25 inches or greater (6 by 6 inches). A (PVC) or non-PVC, should be considered in dosage estima suggested initial dosage is 0.5 inch, squeezed from the tube, tions. of the 2% ointment (approximately 7.5 mg) every 8 hours. The following examples are presented to further illustrate When the dose to be applied is in multiples of whole inches, 65 the method of the present invention and organic nitrite unit-dose preparations that provide the equivalent of 1 inch compounds which can be effectively used in practicing the of the 2% ointment can be used. Dosages should be titrated method. 5,489,610 11 12 EXAMPLE I units ml ) length of polyethylene tubing (PE-50, Clay-Adams, Parsippany, N.J.) with a slightly tapered tip Synthesis of Organic Nitrites and no bevel was inserted and advanced to the left ventricle, Certain organic nitrites and dinitrites useful in the present approximately 2 mm past the aortic valve. The tapered tip method of treatment were synthesized using an adaptation of 5 was intended to minimize valvular damage during insertion. the method of Bevillard and Choucroum, Bull. Soc. Chim. Proper placement of the catheter was assured by monitoring France, 337, 1957, whereby esterification of an alcohol or pressure waveforms detected by a Statham P231D pressure diol with nitrous acid produces a mononitrite or dinitrite transducer (Gould, Cleveland, Ohio) and displayed on a eSter. Narco Biosystems Physiograph (Narco Biosystems, Hous 10 A volume of 100 ml of distilled water was shaken with ton, Tex.). The catheter was firmly secured and brought 100 ml of the parent alcohol in a separatory funnel at room through a subcutaneous tunnel to the dorsal cervical region. temperature (23 C.). The water layer, now saturated with The neck incision was then closed using a purse string the alcohol, was separated and an aliquot of 40 ml was Sulture. mixed with 4 grams of powder . A volume of To allow detachment of the transducer from the rat, so as 0.5 ml of 4N HCl was added to the mixture dropwise over 5 to facilitate repeated haemodynamic measurements and 3–5 minutes with constant stirring at 23°C., followed by the instrument recalibration over many hours, a fluid filled addition of 2 ml concentrated HSO (also dropwise over 20 needle hub/PRN adapter (Deseret Medical, Sandy, Utah) minutes). The mixture was stirred for 1 hour, and the nitrite assembly was devised. This adapter was attached to the formed separated as a layer on top of the aqueous mixture. PE-50 catheter and securely sutured to the back of the neck. This layer was separated at the end of the reaction, dried 20 This system was similar in design and function to a marketed over MgSO, further purified by distillation if necessary, and product developed for similar purposes by Vascular Assess Port, Norfolk Medical Products, Skokie, Ill. Left ventricular stored at -20° C. pressures were easily measured by penetrating the rubber The existence of a nitrite product was indicated by the septum of the PRN adapter assembly with a needle tipped presence of a characteristic "fingerprint' in the ultraviolet 25 length of PE-50 (fluid filled) which was connected to the absorbance spectrum between 300-400 mm. Gas chromato transducer. No dampening of these pressure tracings graphic analysis indicated the presence of only one peak in occurred provided air bubbles were carefully avoided. Trac the products. Identity of the specific nitrite was confirmed by ings using the needle hub/PRN adapter assembly were elemental analysis. identical to the initial tracings made using a continuous 30 length of tubing of comparable length (35-40 cm). Prior to EXAMPLE II recording ventricular pressures, the physiograph was prop Rat Mode of Congestive Heart Failure erly calibrated using an identical needle hub/PRN adapter system and a pressure manometer placed at the approximate Congestive heart failure was produced in rats secondary height of the animals head. to ligation of the left coronary artery, similar to the technique 35 Determinations of left ventricular and diastolic and peak of Selye et al., "Simple Techniques for the Surgical Occlu systolic pressures were carried out by calculating the mean sion of Coronary Vessels in the Rat', Angiology, 1960, Vol. of at least 30 consecutive tracings. Baseline haemodynamic II, pp. 398-407, which disclosure is hereby incorporated by measurements were made at least 3 hours after termination reference. Male Sprague-Dawley rats (300-325 grams) were of halothane according to Flaim, et al., "Multiple Simulta anaesthetized with a combination of Innovar (0.3 ml kg 40 neous Determinations of Haemodynamics and Flow Distri intramuscularly, Pitman-Moore, Washington Crossing, N.J.) bution in Conscious Rat', J. Pharmacol. Meth., 1984, Vol. II, and (2.0 mg kg intramuscularly), then orally pp. 1-39, which disclosure is hereby incorporated by refer intubated and maintained by a Harvard rodent ventilator ence, and their average values were calculated from at least (Harvard Apparatus, South Natick, Mass.). A left thorac 3 sets of tracings recorded over 30 minutes. This technique otomy was made at the fifth intercostal space, and the 45 of left heart catheterization provided continuous measure pericardium was gently torn. The left coronary artery was ment of stable left ventricular pressures typically for 1 day then ligated by an intramural suture (6-0 silk) placed just and often for as long as 2-3 days. Failure of the catheter below the left atrium, approximately 3 mm from the: origin. system, when it occurred, was most commonly due to Vessel occlusion was ascertained by the paling of the fouling of the tip within the left ventricle. ventricle distal to the suture. The lungs were then hyperin 50 flated and the ribs closed by three interrupted sutures. The entire thoracotomy region was then swabbed with antibac EXAMPLE IV terial ointment, and the muscle and skin layers were closed using an uninterrupted purse string suture. These animals Nitroglycerin Infusion were then allowed to recover for at least 6 weeks, producing 55 a fully healed myocardial infarct. Complete occlusion of the Prior to left ventricular catheterisation, a polyethylene left coronary artery in surviving rats typically produced a catheter (PE-50) was placed in the left femoral vein of the transmural infarct at the apex and anterior free wall of the rat and tunneled subcutaneously to the base of the neck. left ventricle. Overall mortality of this procedure was Nitroglycerin (NTG) solution 1.0 mg/ml, Schwarz Pharma approximately 40% during the 6-8 week recovery. 60 GmbH, Germany, was infused via this catheter using a Harvard infusion pump at a flow rate of 10-15 ug/min. Glass EXAMPLE II syringes were used for NTG infusion to avoid drug absorp tion. Rats with congestive failure (as previously described) Instrumentation were infused with NTG continuously for a period of 10 Rats were anaesthetized with halothane 1.5-2.0% in oxy 65 hours. Left ventricular pressures were measured in con gen and maintained via a Harvard rodent ventilator. The scious, unrestrained rats periodically throughout the infusion right cartoid artery was isolated. A fluid filled (saline with 10 experiment. 5,489,610 13 14 With reference to FIG. 1, the effects of continuous, long ance development within the first 24 hours as was seen after term infusion of NTG in congestive heart failure rats are just about 2 hours for infusion with nitroglycerin (FIG. 1). shown. Pressure tracings were detected using high fidelity microtransducer and recorded by a Gould physiograph. The EXAMPLE VIII-XII results show that intravenous infusion caused initial reduc 5 tion in left ventricular end-diastolic pressure, but this effect Infusion was carried out as described in Example IV is not maintained during continuous infusion for 10 hours, except that the rats with congestive heart failure were indicating the development of tolerance. Data is expressed infused with the nitrites listed below. The infusion rate was as meant (SEM), n= 10-15. 1.0 ui/hr for Examples VIII and IX and 3.13 ul/hr for 10 Examples X, XI and XII. The results of each infusion are EXAMPLE V reflected in the respective figures indicated: Isobutyl Nitrite Infusion Example Nitrite Results Shown In VIII 1,3-propane FIG. 4 Infusion was carried out as described in Example IV 15 dinitrite except that the rats with congestive heart failure were IX 1,7-heptane F.G. 5 infused with isobutyl nitrite (ISBN), instead of nitroglycerin, dinitrite continuously for a period of 24 hours. Left ventricular X cyclohexylmethyl F.G. 6 nitrite pressures were measured in conscious, unrestrained rats XI Phenylethyl nitrite FIG. 7 periodically throughout the infusion experiment. XII 3-chloro-2,2-dimethyl- FIG. 8 With reference to FIG. 2, the effects of continuous, long propyl nitrite term infusion of ISBN to congestive heart failure rats; are shown. Intravenous infusion (3.13 or 5.0 ui/hr) caused rapid In each instance the initial rapid reductions in LVEDP initial reductions in left ventricular end-diastolic pressure, were substantially maintained even after 24 hours of con and these initial effects were maintained throughout the 25 tinuous infusion. infusion period, most significantly, even after 24 hours of continuous infusion. These results demonstrate that ISBN EXAMPLE XIII can be a useful and novel vasodilator, without tolerance development within the first 24 hours as was seen after just Effect of Nitrite Therapy on the Central Nervous about 2 hours for infusion with nitroglycerin (FIG. 1). 30 System

EXAMPLE VI It was observed that during nitrite therapy there was a lack of apparent effects on the central nervous system of the rats. Transdermal Administration During nitroglycerin infusion, the rats invariably became 35 lethargic and they would not eat, drink or move about in A 2% ointment of isobutyl nitrite (ISBN) in petrolatum their cages. These behaviors, which disappeared rapidly was prepared. Approximately 500 mg of the ointment was after the drug was withdrawn, likely are reflective of the then applied to the shaved abdomen of an anesthetized rat. known side-effects of nitroglycerin, i.e., the occurrence of Arterial blood pressure and heart rate was measured in the headache in patients. When rats with heart failure were rat before and during ointment application. It was observed 40 infused with nitrites, at doses which produced comparable that ointment application caused a reduction in blood pres hemodynamic effects as nitroglycerin, the rats appeared sure after 35 minutes of ointment application. The average normal and carried out their routine activities. These obser blood pressure over 30 minutes prior to ointment treatment vations suggest that nitrites may not cause the undesirable was 108/83 mmHg. At 35-40 minutes after application, effects on the central nervous system that are produced by blood pressure was 93/68 mmHg. These results suggest that 45 nitroglycerin and other nitrates. ISBN is capable of being absorbed transdermally at con It should be understood that the Examples described centrations significant to produce a vasodilator effect and herein are for purposes of illustration only and not limita they are consistent with the high lipophilicity of ISBN. tion, and that various modifications and/or changes that may suggest themselves to one skilled in the art are intended to EXAMPLE VII 50 be included within the spirit of this application and the scope of the appended claims. Isoamyl Nitrite Infusion We claim: 1. A method of vasodilator therapy for treating a patient Infusion was carried out as described in Example IV, suffering from a condition requiring such therapy, compris except that the rats with congestive heart failure were 55 ing the long-term, continuous administration of an organic infused with isoamyl nitrite, instead of nitroglycerin, con nitrite to the patient in a dosage form capable of delivering tinuously for a period of 24 hours. Left ventricular pressures a sufficient therapeutic amount of said nitrite to the blood were measured in conscious, unrestrained rats periodically stream of the patient, thereby providing effective vasodilator throughout the infusion experiment. therapy for at least 24 hours without development of toler With reference to FIG. 3, the effects of continuous, long 60 ance in the patient, said nitrite being selected from the group term infusion of isoamyl nitrite to congestive heart failure consisting of 1,3-propane dinitrite, 1,7-heptane dinitrite, rats are shown. Intravenous infusion (3.13 ul/hr) caused cyclohexylmethyl nitrite, 2-phenylethyl nitrite, 3-chloro-2,2 rapid initial reductions in left ventricular end-diastolic pres dimethylpropyl nitrite, tert-amyl nitrite, 2-methyl-2-hexyl sure, and these initial effects were maintained throughout the nitrite, hexyl nitrite, 2-methyl-1,3-propane dinitrite, 2,2, infusion period, most significantly, even after 24 hours of 65 dimethyl-1,3-propane dinitrite, 2-methyl-2-propyl-1,3-pro continuous infusion. These results demonstrate that isoamyl pane dinitrite, 3-hexyl nitrite, octyl nitrite, 4-methyl-2- nitrite can be a useful and novel vasodilator, without toler pentyl nitrite, 4-methyl- 1 -pentyl nitrite, 2-heptyl nitrite, 5,489,610 15 16 3-octyl nitrite, 2-methyl- 2-pentyl nitrite, 5-methyl-2-hexyl 9. The method of claim 8, wherein the dosage of nitrite nitrite, 6-methyl-2-heptyl nitrite, glyceryl dinitrite, glyceryl administered to the patient from said patch is between 5 and mononitrite, isosorbide 5-mononitrite, isoidide 5-mononi trite, isomannide 5-mononitrite, pentaerythrityl mononitrite, 100 mg/day. pentaerythrityl dinitrite, pentaerythrityl trinitrite and pen 10. The method of claim 1, wherein said nitrite is selected taerythrity tetranitrite. from the group consisting of 1,3-propane dinitrite, 1,7- 2. The method of claim 1, wherein said dosage form is a heptane dinitrite, cyclohexylmethyl nitrite, 2-phenylethyl transdermal delivery system. 3. The method of claim 2, wherein said transdermal nitrite and 3-chloro-2,2 dimethylpropyl nitrite. delivery system is selected from the group consisting of a 10 11. The method of claim 1, wherein said condition is patch, tape, ointment and topical cream. selected from the group consisting of angina pectoris, con 4. The method of claim 1, wherein said dosage form is an gestive heart failure, hypertension, ischemic disease, impo intravenous infusion. 5. The method of claim 1, wherein said nitrite is admin tence and unstable angina. istered by a route selected from the group consisting of 5 12. The method of claim 11, wherein said condition is Sublingual, oral and buccal. angina pectoris. 6. The method of claim 5, wherein said dosage form is a 13. The method of claim 1, wherein said condition is tablet, capsule or caplet. congestive heart failure. 7. The method of claim 3, wherein said transdermal system is a patch. 20 14. The method of claim 1, wherein said dosage is 8. The method of claim 7, wherein the dosage of nitrite delivered to the patient at a constant rate. administered to the patient from said patch is at least 2 mg/day. ck k k k