NZ212310A

NZ212310A - Pharmaceutical compositions containing(+)and(-)enantiomers of indacrinone and amiloride

Info

Publication number: NZ212310A
Application number: NZ212310A
Authority: NZ
Inventors: E H Blaine; E J Cragoe Jr; R F Hirschmann; J F Nancarrow; J A Tobert
Original assignee: Merck & Co Inc
Priority date: 1982-05-17
Filing date: 1982-05-17
Publication date: 1985-12-13

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £12310 2 123 1 Under the provisions of Regit*! latlon 23 (i) the ~ Specification has been ante-da£edi to - !9/s2_^ Priority Date{s): . • • Complete Specification Filed: Ctass: 1111 ■ 1 < • 1 • •• 11 * ^ D'EC,f9^5<" Publication Date: ... t > P.O. Journal, No: lai HO NEW ZEALAND PATENTS ACT, 1953 Divided from No. 200641 No.: Date: -wi .^7~Z COMPLETE SPECIFICATION INDACRINONE HAVING ENHANCED URICOSURIC PROPERTIES We, MERCK & CO., INC., a corporation duly organized and existing under the laws of the State of New Jersey, United States of America, of 126 East Lincoln Ave., Rahway, State of New Jersey, United States of America, > hereby declare the invention for which we pray that a patent may be granted to^f^us, and the method by which it is to be performed, to be particularly described in and by the following statement:- 2 123 - la_- TITLE OF THE INVENTION INDACRINONE HAVING ENHANCED URICOSURIC PROPERTIES 5 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is concerned with balancing the uricosuric and diuretic properties of indacrinone, a caceraic compound, through manipulation 10 of the proportion of its ( + ) and (-) enantiomers. There continues to be a great deal of interest in the discovery and development of diuretics which are also uricosuric, since nearly all currently available diuretics commonly lead to urate 15 retention, hyperuricemia, and, occasionally, attacks of gout. Hyperuricemia, in turn, may itself be a risk factor for the development of cardiovascular disease, carbohydrate intolerance, and urate-induced nephropathy. A large percentage of hypertensive 20 patients have hyperuricemia. For example, ticrvnafen, or tienilic acid, produces a prompt diuresis with an increased excretion of sodium and chloride, while at maximal drug effect, uric acid clearance increases about five-fold. This drug was approved for use as an antihypertensive agent in the United States in 1979, but it was later withdrawn when postmarketing surveillance revealed an unacceptably high incidence of hepatotoxicity. Uric acid transport by the renal tubules involves both readsorptive and secretory processes. There has been an interest in the mechanism of action of drugs that directly influence tubular transport systems for uric acid and thus alter the rate of uric acid excretion. Probenecid, for example, increases the urinary excretion of uric acid by inhibition of carrier-mediated reabsorption. Likewise, indacrinone or indacrynic acid, utilized in the present invention, inhibits urate reabsorption in the proximal tubule. The action of uricosuric agents is often seemingly contradictory, because of the complexity of the transport mechanisms involved. Thus, increase, decrease, or lack of effect on the excretion of uric acid is not only highly species dependent, but dosage dependent as well. Moreover, depending on the exact conditions, the combined effect of two uricosuric drugs may be either additive or antagonistic. The renal transport of uric acid in mammals* involves both secretion and reabsorption, but in man the process of reabsorption dominates so that the J * amount that is excreted is but a small fraction of 3 - that which is filtered. A variety of factors, including uricosuric drugs, can influence the relative importance of these bidirectional transport mechanisms in man. Also, as already indicated above, 5 uric acid is transported by carrier-mediated mechanisms and not by diffusion, and in man the site of transport is located in the proximal tubule, including both the convoluted and straight portions. 10 2. Brief Description of the Prior Art Indacrinone, as a racemic mixture, and as the (+) or (-) enantiomer, is described in U.S. Patent No. 4,096,267, which also refers generally to the possibility of combining different indanones 15 disclosed where greater diuretic activity and greater uricosuric activity are possessed by said indanones. However, nothing in this reference would suggest manipulation of the proportion of (+) and (-) enantiomers of indacrinone within critical limits, 20 for careful balancing of uricosuric and diuretic properties to give maximum therapeutic benefit, which has been accomplished with the present invention. The different pharmacodynamic effects of the (+) and (-) enantiomers of indacrinone, specifically 25 that the principal saluretic activity of indacrinone resides in the (-) enantiomer while uricosuric activity is present in both (-) and (+) enantiomers, are described by Irvin et al., Clin. Pharmacol. Ther., p. 260 (Feb. 1980); deSolms et al., J. Med. 30 Chem., Vol. 21, No. 5, pp. 437-443 (1978) ; and Woltersdorf et al. ACS Symposium Series No. 83 Diuretic Agents, pp. 219-220 (1978). However, none of these publications in any way suggest manipulation of the proportion of (+) and (-) enantiomers of indacrinone within critical limits so as to achieve the maximum therapeutic benefit from balanced uricosuric and diuretic properties, as is the case with the present invention. British Pat. No. 1,475,177 describes the combination of indacrinone racemic mixture, or the (-) enantiomer of indacrinone, with a potassium-sparing pyrazinoylguanidine diuretic, especially amiloride. However, this patent does not disclose or suggest a manipulated proportion of (+) and (-) enantiomers of indacrinone, or the combination of such a manipulated proportion with amiloride or other pyrazinoylguanidine diuretics. U.S. Patent No. 4,087,542 describes the diuretic (+) isomer and uricosuric (-) isomer of 6,7-dichloro-2, 3-d i hydro - 5- ( 2-thenoyl) benzof uran-2-carboxylic acid and teaches manipulating the ratio of these isomers to achieve a balance of diuretic and uricosuric properties. However, there is a total separation of diuretic and uricosuric activity between the two isomers, and the manipulation of these isomers would not be instructive as to even the possibility of manipulating the (+) and (-) enantiomers of indacrinone, a wholly different compound. Furthermore, at present there is not known to be any marketed or experimental drug in which a y ratio of enantiomers other than the synthetically occurring 50:50 is used. 2 123 1 - 5 - DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED 10 15 20 25 30 EMBODIMENTS Indacrinone, or indacrynic acid, is a potent, high ceiling diuretic which may be renamed as [6, 7-dichloro-2, 3-dihydro-2-methyl-l-oxo-2-phenyl-lH-inden-5-yl)oxy]acetic acid and may be represented by the following formulas: HOOCCH 0 HOOCCH S(+)-Indacrinone (I) R(-)-Indacrinone (I) The compound is a racemic mixture, and methods for its preparation are described in U.S. Patent No. 4,096,267. Methods for resolving the racemic mixture into its (+) and (-) enantiomers are described in said patent, as well as in deSolms et al., J. Med. Chem. , Vol. 21, No. 5, pp. 437-443 (1978) . As will be appreciated, diuretics are valuable therapeutic agents useful in the treatment of cardiovascular and renal diseases, for example in the managment of all types and grades of severity of congestive heart failure and in the treatment of mild, moderate, and severe forms of hypertension. As a result of the loss of water and electrolyte, dramatic improvement is noted in peripheral and > pulmonary edema, dyspnea, orthopnea, ascites and pleural effusion. Diuretics also provide effective therapy in various forms of renal edema, for example, edema associated with nephrosis and certain types of 2 12310 6 - nephritis. Their administration results in prompt excretion of retained fluid and electrolytes, especially sodium chloride. In addition to its potent diuretic and 5 saluretic properties, indacrinone also possesses important uricosuric properties as well. However, this uricosuric activity presents a complex picture, as will be apparent from the following. (1) Both enantiomers of indacrinone possess 10 uricosuric activity. However, the (-) enantiomer, which is 20 to 40 times more potent than the (+) enantiomer as a natriuretic agent, possesses uricosuric activity on an acute basis, that is, within the first few hours of administration, but on 15 a chronic basis, produces hyperuricemia. The uricosuric activity seen on an acute basis is considered to result from the increased flow of water through the renal tubule produced by the (-) enantiomer, together with somewhat decreased 20 reabsorption of urate produced by blockade of that reabsorption by the (-) enantiomer. However, as the acute phase passes and administration of the (-) enantiomer becomes chronic, a decrease in the extracellular fluid volume results which produces a 25 significantly enhanced rate of urate reabsorption. Thus, as the extracellular fluid volume becomes depleted, uricosuria ceases and urate reabsorption increases to the point that hyperuricemia results. Both the (-) and (+) enantiomers have > 30 significant intrinsic uricosuric activity; and it seems probable that they both act on the same site or sites in the proximal portion of the renal •= tubule which regulate urate reabsorption. When the (-) enantiomer is administered by itself, or when a racemic mixture of (-) and (+) enantioimers is administered, the final result, or net effect will be hyperuricemia, since the higher natriuretic potency of the (-) enantiomer overcomes the urate reabsorption inhibitory potency of both the (-) and (+) enantiomers through the mechanism of extracellular fluid depletion, as explained above. (2) Both enantiomers of indacrinone possess natriuretic properties. As already described above, the (-) enantiomer is significantly more potent as a natriuretic agent than the (+) enantiomer- However, the ( + ) enantiomer does have modest potency as a natriuretic agent, which again, further complicates the problem of manipulating the proportion of ( + ) and (-) enantiomers in order to achieve a balance of diuretic and uricosuric properties. (3) There is no practical way of reliably associating the degree of extracellular fluid volume depletion, which leads to hyperuricemia, with the extent of urate reabsorption inhibiton, which results in uricosuria. (4) The (+) enantiomer is considered to have a different site of action in the renal tubule from that of the (-) enantiomer, with correspondingly different therapeutic effects. (These sites of action and therapeutic effects are to be distinguished from the urate reabsorption regulation which occurs in the proximal renal tubule for both enantiomers, as already explained above.) The % natriuretic activity of the (-) enantiomer is ./ - 8 - considered to be effected in the ascending limb of Henle's loop portion of the renal tubule. The (+) enantiomer, on the other hand, probably expresses its therapeutic effects in a more distal portion of the 5 renal tubule. (5) Uricosuric activity is only desirable in the context of avoiding hyperuricemia and its consequences. Since there is no known advantage to a hypouricemic state, and since extensive uricosuria 10 has roccasionally cause urate precipitation in renal tubules, the goal of manipulating the proportion of ( + ) and (-) enantiomers must be to achieve, as nearly as possible, an isouricemic or slightly hypouricemic state, that is, administration of the indacrinone 15 final product should result in neither a rise nor a large fall in patient serum uric acid levels. As used in this context, the term "slightly hypouricemic" is intended to describe a decrease in serum or plasma uric acid levels of 20% or less from 20 the starting level for a particular patient, or from the mean starting level for a group of patients. The starting level may be a "normal" level of uric acid or it may be a "hyperuricemic" level. It is important to avoid hypouricemia of a greater extent 25 than that indicated, since it is thought that it can result in acute renal failure caused by tubular urate precipitation. Thus, use of ticrynafen can cause a decrease in plasma uric acid levels of as high as 40%, which is considered undesirably high. 30 it has been found that a composition of matter comprising, in coirJbination, 1 (a) the ( + ) enantiomer of indacrinone; and (b) the (-) enantiomer of indacrinone; wherein the weight ratio of (a) : (b) is from 4:1 to 9:1, that is, the ( + ) enantiomer is from 80% to 90% by weight of the total, and the (-) enantiomer is from 20% to 10% by weight of the total weight of indacrinone (hereinafter referred to as the "combination indacrinone enantiomer product"), is useful in the treatment of edema and hypertension which is also isouricemic or slightly hypouricemic. The preferred ratio of (a) : (b) is 4:1, that is, the (-r) enantiomer is 80% by weight and the (-) enantiomer is 20% by weight of the total weight of indacrinone. The combination indacrinone enantiomer product may be formulated into a pharmaceutical composition useful in the treatment of edema and hypertension which is also isouricemic or slightly hypouricemic, comprising a therapeutically effective amount of the combination indacrinone enantiomer product together with a non-toxic pharmaceutical carrier. 2 123 1 - 10 - The administration to a patient of a therapeutically effective amount of the combination indacrinone enantiomer product is useful where the conditions of edema and/or hypertension are present, and either or both of these are, or are not, also associated with a condition of hyperuricemia. The treatment will help eliminate such a hyperuricemic condition if it exists, or prevent it from occurring. The combination indacrinone enantiomer product can be administered to patients in a variety of therapeutic dosages and forms in conventional vehicles as, for example, by oral administration in the form of a tablet or gelatin capsule, or by intravenous injection. Also, the daily dosage of the product may be varied over the range of from 10:2.5 to 180:20 mg, ( + ) : (-) , once daily, preferably a daily dosage of from 40:10 or 45:5 to 90:10 mg. The dosage may be, for example, in the form of tablets containing 25, 50 or 100 mg of the active ingredient for the symptomatic adjustment of the dosage to the patient being treated. A suitable unit dosage form for the combination indacrinone enantiomer product can be prepared by mixing 50 mg of the enantiomer combination with 7 5 mg of pregelatinized starch, 75 mg of raicro-crystalline cellulose, and 2 mg of magnesium stearate and compressing the mixture into a tablet. Similarly, by employing more of the active ingredient and less - 11 - pregelatinized starch and microcrystalline cellulose, other dosage amounts can be put up in tablets. If desired, gelatin capsules and other unit dosage forms can be prepared to incorporate the combination indacrinone enantiomer product by conventional methods; or, said product can be made up as an injectable solution by methods well known to pharmacists- There are, however, two potential problems created by use of the combination indacrinone enantiomer product: kaliuresis and urate precipitation. It is a well-known characteristic of most potent natriuretic agents that they are also kaliuretic, that is, they cause the excretion of appreciable amounts of potassium ion. Excessive loss of potassium ion can result in hypokalemia, and this may lead to a decrease in total body potassium. Excessive potassium losses may lead to muscular weakness and a feeling of physical exhaustion, as well as other undesirable effects, such as cardiac arhythmias. Since excessive potassium losses may constitute an unfavorable consequence of using the combination indacrinone enantiomer product, it is preferred to combine said product with amiloride, a potassium-sparing diuretic. Concomitant use of amiloride will also serve to overcome a largely avoidable, though potentially more serious problem than the hypokalemia resulting /' from use of the combination indacrinone enantiomer product. That problem is urate or uric acid precipitation resulting from the higher concentrations of uric acid in the urine, produced, in turn, by the uricosuric activity of the combination indacrinone enantiomer product. When such urate precipitation does occur, it can lead to uric acid crystal deposits in the urinary tract, especially in the renal tubules and the formation of bladder and kidney stones. While this potential problem is largely avoided by careful balancing of the enantiomer ratio within critical limits, where the problem does occur, it is ameliorated by concomitant administration of amiloride, which increases urinary pH by producing a lesser degree of hydrogen ion secretion. The uric acid has less of a tendency to precipitate from the less acidic urine at a given concentration. Or, put another way, the uric acid is more soluble in alkaline urine. Amiloride, which may be named as 3,5-diamino-N-(amino-iminomethyl) -6-chloropyrazinecarboxamide , is coadministered with the combination indacrinone enantiomer product in a weight ratio range of from 5:1 to 20:1 of indacrinone enantiomer product:amiloride, provided that the total daily dosage of amiloride is from 1.25 to 10 mg. Accordingly, the present invention provides a composition of matter comprising, in combination: (a) the (+) enantiomer of indacrinone; and (b) the (-) enantiomer of indacrinone; wherein the weight ratio of (a):(b) is from 4:1 to 9:1, that is, the ( + ) enantiomer is from 80% to 90% by weight of the total, and the (-) enantiomer is from 20% to 10% by weight of the total weight of indacrinone; together with (c) amiloride; wherein the weight ratio of (a) + (b) : (c) is from 5zt to 20:1/ provided that the amount of amiloride is from 1.25 to 10 mg. The present invention also provides a pharmaceutical composition useful in the treatment of edema and hypertension which is also isouricemic or slightly hypouricemic, 2 1231 - 13 - comprising a therapeutically effective amount of, in combination, (a) the (+) enantiomer of indacrinone; and (b) the (-) enantiomer of indacrinone; wherein the weight ratio of (a) : (b) is from 4:1 to 9:1, that is, the (+) enantiomer is from 80% to 90% by weight of the total, and the (-) enantiomer is from 20% to 10% by weight of the total weight of indacrinone; together with (c) amiloride; wherein the weight ratio of (a) + (b):(c) is from 5:1 to 20:1, provided that the amount of amiloride is from 1.25 to 10 mg; together with a non-toxic pharmaceutical carrier. The preferred ratio of the combination indacrinone enantiomer product to amiloride is 10:1, and typical preferred products are 5 mg amiloride:40 mg (+):10 mg (-) indacrinone; and 5 mg amiloride:90 mg (+):10 mg (-) indacrinone. Coadministration of the amiloride preferably takes place by utilizing a pharmaceutical dosage in which the indacrinone enantiomer and amiloride active ingredients are admixed in the required ratios. 212310 - 14 - EXAMPLE 1 This example illustrates the effectiveness of the combination indacrinone enantiomer product in producing isouricemia or a slight hypourecemia, as measured by change in plasma uric acid levels, and as compared to the hvperuricemic effect of hydrochlorothiazide, and the unacceptably high hypouricemic effect of ticrynafen. The subjects for the study were fifty-nine healthy male volunteers with normal renal, hepatic, and cardiac function. Subjects with a serum uric acid of less than 4 mg/dl were excluded. The study was double-blind, multiclinic, balanced, incomplete block, divided into two 7-day treatment periods which were separated by a two week washout period. All subjects were randomly allocated to receive the following treatments: hydrochlorothiazide (HCTZ) 50 mg.; indacrinone (I) (+)/(-) ratios (mg/mg) of 0/10, 10/10, 20/10, 40/10, and 80/10; and ticrynafen (T) 250 mg. Medication was given once daily at 0900 hours for 7 consecutive days. There were no restrictions with regard to diet and activities; however, subjects were requested to refrain from strenuous exercise on Days 1 and 2 of each period. Blood samples were drawn on Day 1 at 1700 hours, on Days 0, 1 (first drug day), 5, and 7 at 0900 hours and 1700 hours, and on Days 2 and 8 aC .0900 hours. Plasma or serum was analyzed for uric acid by the 2123 - 15 - phosphotungstic acid method described by Caraway, W.T. in Amer. J. Clin. Pathol., 2_5:840-845 (1955). The results are shown in the following table of values: Mean Change From Baseline on Days 7-8 of Serum Uric Acid (mg/dl) Treatment Morning ' Evenina Hydrochlorothiazide 0.84 1.01 Indacrinone ( + )/(-) : 0/10 0. 84 0. 67 10/10 0.59 0.34 20/10 0. 50 0.17 40/10 -0.17 -0.34 80/10 -0.84 -1.18 Ticrynafen -2.52 -3.86 EXAMPLE 2 Tablets Containing 50 mg of the Combination Indacrinone Enantiomer Product per Tablet Per Tablet ( + ) [ 6,7-Dichloro-2 , 3-dihydro-2- 40 mg methyl-l-oxo-2-phenyl-lH-inden-5- yl)oxy]acetic acid (-) [ 6, 7-Dichloro-2, 3-dihydro-2- 10 nfg methyl-l-oxo-2-phenyl-lH-inden-5-yl)oxy]acetic acid Pregelatinized starch (Sta/Rx R 1500 - 75 mg Staley) Microcrystalline cellulose (Abicel R-FMC) 75 mg Magnesium stearate 2 mg• </div>

Claims

<div class="application article clearfix printTableText" id="claims"> The ( + ) and ( -) [6,7-dichloro-2,3-dihydro-2-methyl-l-oxo-2-phenyl-2H-inden-5-yl) oxy] acetic acid, pregelatinized starch, and microcrystalline cellulose are mixed well together; granulated with a 33% ethanol/water solution; dried; and milled. The magnesium stearate lubricant is then added and mixed in well, after which the mixture is compressed into a tablet. WHAT WE CLAIM IS:

1. A composition of matter comprising, in combination: (a) the ( + ) enantiomer of indacrinone; and (b) the (-) enantiomer of indacrinone; wherein the weight ratio of (a):(b) is from 4:1 to 9:1, that is, the (+) enantiomer is from 80% to 90% by weight of the total, and the (-) enantiomer is from 20% to 10% by weight of the total weight of indacrinone; together with (c) amiloride; wherein the weight ratio of (a) + (b):(c) is from 5:1 to 20:1, provided that the amount of amiloride is from 1.25 to 10 mg.

2. A pharmaceutical composition useful in the treatment of edema and hypertension which is also isouricemic or slightly hypouricemic, comprising a therapeutically effective amount of, in combination, (a) the (+) enantiomer of indacrinone; and (b) the (-) enantiomer of indacrinone; wherein the weight ratio of (a):(b) is from 4:1 to 9:1, that is, the (+) enantiomer is from 80% to 90% by weight of the total, and the (-) enantiomer is from 20% to 10% by weight of the total weight of indacrinone; together with (c) amiloride; wherein the weight ratio of (a) + (b):(c) is from 5:1 to i 20:1, provided that the amount of amiloride is from 1^-25 to 10 mg; together with a non-toxic pharmaceutical 1 carrier. - 18 - 123 1 o

3. A composition according to Claim 1 or Claim 2, wherein the weight ratio of (a):(b) is 4:1, that is, the ( + ) enantiomer is 80% by weight and the (-) enantiomer is 20% by weight of the total weight of indacrinone.

4. A composition according to any one of Claims 1 to 3, wherein the weight ratio of <a)+(b):(c) is 10:1. A . J. P ARK & SON PER ^^ AGENTS FCft THE APPLICANTS </div>