Claims
- 1. (1R,5S,6S)-6-[R-1-hydroxyethyl]-1-methyl-2-[1,2-diiminomethyl)-4-pyrazolidinyl]-thio-carbapenem-3-carboxylic acid.
- 2. The chemical compound formed by the reaction of (1R,5S,6S)-2-[pyrazolidinyl]thio-6-[R-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylic acid with ethyl formimidate hydrochloride prior to cyclization, said chemical compound being capable of in situ cyclization whereby upon said cyclization there is produced the compound (1R,5S,6S)-2-[(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazolium-6-yl]thio-6-[R-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 62-89016 |
Apr 1987 |
JPX |
|
INFORMATION DISCLOSURE STATEMENT
This application is a divisional of Ser. No. 357,350, filed May 26, 1989, now U.S. Pat. No. 4,925,935, dated May 15, 1990, which is in turn a division of Ser. No. 130,121, filed Dec. 8, 1987, now U.S. Pat. No. 4,866,171, dated Sept. 12, 1989. A related application is Ser. No. 357,349, filed May 26, 1989, now U.S. Pat. No. 4,925,836, dated May 15, 1990.
Prior art cited under 37 CFR .sctn.1.97:
European Application (I) (AB) discloses a broad group of compounds, but never specifically any compound with a structure that is suggestive of the group 5H-pyrazolo[1,2-a]triazolinium-6-yl. Pyridinium compounds are a focal point of the exemplified disclosure, including (5S,6S)-2-[2-(2,3-cyclohexeno-1-pyridinium)ethylthio]-6-[(R)-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate (page 63, lines 1-3). European Application (I) (AB) also includes a disclosure of a list of 97 ring groups at Example 35 (pages 139-145), which disclosed 97 heterocyclic rings, including the ring forming the group (5H-pyrazolo[1,2-a]triazolinium-6-yl) (page 140, line 10, left hand entry); if that variable is plugged into the formula at page 139, line 10, this would create the (1R,5S,6S)-2-[(5H-pyrazolo[1,2-a]triazolinium-6-yl)]thio-6-[(R)-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate. In order to make the compound most relevant to the instant invention according to the generic teaching of the published patent application, it would be necessary to use a starting material 6-mercapto-5H-pyrazolo[1,2-a]triazolinium halide. However, a method for making 6-mercapto-5H-pyrazolo[1,2-a]triazolinium halide is not described in that application, nor is a method for making it described in the literature. The 2-(2,3-cyclohexeno-1-pyridinium)ethylthio group which is remote, as it is based upon the pyridinium group which is not suggestive of the instant (5H-pyrazolo[1,2-a]triazolinium-6-yl) group.
Kim (AA) and European APplication II (AC) are cumulative.
In accordance with a first aspect of the invention there is provided (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[(1,2-diiminomethyl)-4-pyrazolidinyl]-thio-carbapenem-3-carboxylic acid.
In accordance with a second aspect of the invention there is provided (1R,5S,6S)-2-[(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazolium-6-yl]thio-6-[R-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate. This compound also may be in the form of the corresponding acid or pharmaceutically acceptable salt, in which case there is included an anionic group balancing the traizolinium positive charge. As such an anionic group may be mentioned, for example, the chloride, acatate or carbonate. As the salt may be mentioned the alkali metal salts, for example, sodium.
In accordance with a third aspect of the invention, there is provided a method for the preparation of (1R,5S,6S)-2-[(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazolium-6-yl)]thio-6-[R-1 -hydroxyethyl]-1-methyl-carbapenem-3-carboxylate, which comprises contacting (1R,5S,6S)-2-[4-pyrazolidinyl]thio-6-[(R)-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylic acid with ethyl formimidate hydrohalide under conditions to introduce iminomethyl substitution at each of the free hydrogen positions of the nitrogen atoms of the pyrazolidinyl nucleus, which would be expected to yield the compound (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[1,2-diiminomethyl)-4-pyrazolidinyl]thio-carbapenem-3-carboxylic acid, and recovering the in situ formed (1R,5S,6S)-2-[(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazolium-6yl)]thio-6-[R-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate. Surprisingly, the (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[(1,2-diiminomethyl)-4-pyrazolidinyl]thio-carbapenem-3-carboxylic acid is not recovered. The compound is produced in a transitory state, and is converted in situ into the (1R,5S,6S)-2-[(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4 ]triazolium-6yl)]thio-6-[R-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate. In a preferred embodiment of this aspect of the invention, the ethyl formimidate hydrohalide is the hydrochloride or hydrobromide, and still more preferably is the hydrochloride. Preferably, the reaction is conducted in the presence of a buffer, which in one embodiment is a phosphate. The pH is generally from about 5 to about 9, and more preferably 6 to about 7.5, and the temperature is generally from about -15.degree. C. to about 30.degree. C., and preferably from about -5.degree. C. to about +10.degree. C.
As used herein, and unless otherwise specified, the compound "I" refers to both the compound (1R,5S,6S)-2-[(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazolium-6yl)]thio-6-[R-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylate, as well as the acid or pharmaceutically acceptable salt of such compound which includes an anionic group balancing the traizolinium positive charge. The compound (I) manifest high antibacterial activity, a strong action of inhibiting .beta.-lactamase as well as improved resistance to kidney dehydropeptidase. The carbapenem compound (I) may be prepared by reacting a compound identified as the compound (II): ##STR1## wherein R.sup.1 is a carboxyl protecting group, and R.sup.0 is an acyl group.
Immediately after the reaction of the compound (V) with the alkyl formimidate, a compound (1R,5S,6S)-6-[R-1-hydroxyethyl]-1-methyl-2-[(1,2-diiminomethyl)-4-pyrazolidinyl]-thio-carbapenem-3-carboxylic acid is formed, which exists briefly before there is conversion to the final product (I). Under the conditions of the present synthesis, the intermediate compound (1R,5S,6S)-6-[R-1-hydroxyethyl]-1-methyl-2-](1,2-diiminomethyl)-4-pyrazolidinyl]thio-carbapenem-3-carboxylic acid is not recovered but exists only as a transitory intermediate.
The carbapenem compound represented by the formula (II) to be employed as a starting compound in the process described above is known per se and may be prepared in such a manner as disclosed, for example, in Japanese Patent Publication (Laid-Open) No. 123,985/1981 or, more preferably, in accordance with the spatially selective method as indicated in Reaction Scheme A below and proposed by the present inventors (as disclosed, for example, in Japanese Patent Application No. 315,444/1986). ##STR5## wherein R.sup.3 is hydrogen atom or a lower alkyl group; Z is tertiary-butyldimethylsilyl group; and R.sup.2 and
In the specification of the present application, the term "lower" stands for a group or a compound affixed with this term as having the number of carbon atoms ranging from 1 to 7, preferably from 1 to 4.
The term "lower alkyl" referred to herein stands for a straight-chained or branched-chain hydrocarbon group having preferably from 1 to 6 carbon atoms and may include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert.-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl or the like.
The term "carboxyl protecting group" referred to herein stands for any group capable of protecting the carboxyl group of the compound involved without adversely affecting any other substituents and the reactions that follow any may include, for example, an ester residue such as a lower alkyl ester residue including, for example, methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-, iso-, sec- or tert.-butyl ester, n-hexyl ester or the like; an aralkyl ester residue including, for example, benzyl ester, p-nitrobenzyl ester, o-nitrobenzyl ester, p-methoxylbenzyl ester or the like; and a lower aliphatic acyloxymethyl ester residue including, for example, acetoxymethyl ester, propionyloxymethyl ester, n- or iso-butyryloxymethyl ester, pivaloyloxymethyl ester or the like.
The term "acyl group" referred to herein stands for, in a narrower sense, a moiety obtainable by removing the hydroxyl group from the carboxyl group of an organic carboxylic acid as well as, in a broader sense, any acyl group derived from an organic sulfonic acid or an organic phosphoric acid. Such an acyl group may include, for example, a lower alkanoyl group such as acetyl, propionyl, butyryl or the like; a (halo)lower alkyl sulfonyl group such as methanesulfonyl, trifluoromethanesulfonyl or the like; a substituted or unsubstituted arylsulfonyl group such as benzenesulfonyl, p-nitrobenzenesulfonyl, p-bromobenzenesulfonyl, toluenesulfonyl, 2,4,6-triisopropylbenzenesulfonyl or the like; and diphenylphosphoryl.
The term "amino protecting group" referred to herein stands for groups usually employed in peptide chemistry, for example, phthaloyl, benzyloxycarbonyl, tert-butoxycarbonyl, p-nitrobenzyloxycarbonyl or the like.
Each of the steps of the Reaction Scheme A above for preparing the compounds represented by the formula (II) in a highly spatial selectivity will be described below more in detail.
The step (a) involves the reaction of the N-propionyl-1,3-thiazoline-2-thione derivative of the formula (VII) with a tin(II)triflate in the presence of a base to give an enolate and then the reaction of the resulting enolate with the compound of the formula (VI) to give the azetidin-2-one derivative of the formula (VIII).
The enolization reaction of the N-propionyl-1,3-thiazoline-2-thione derivative of the formula (VII) with the tin(II)-triflate may be carried out usually in a solvent inert in the reaction, such as an ether, i.e., diethyl ether, tetrahydrofuran or the like; a hydrocarbon, i.e., toluene, xylene, cyclohexane or the like; a halogenated hydrocarbon, i.e., dichloromethane, chloroform or the like. Preferably tetrahydrofuran can be used.
Reaction temperatures are not limited to a particular range of temperatures and may vary in a wide range with starting materials to be used or the like. Usually the reaction temperatures may be in a range of relatively low temperatures as low as from approximately -100.degree. C. to about room temperature, preferably from approximately from "78.degree. C. to approximately 0.degree. C.
A quantity of the tin(II) triflate with respect to the compound of the formula (VII) is not critical and may range usually from approximately 1 mole to approximately 2 moles, preferably from 1 to 1.5 moles, of the tin(II) triflate per mole of the compound of the formula (VI).
The enolization reaction above is carried out usually in the presence of the base including, for example, a tertiary amine such as triethylamine, diisopropylethyl amine, 1,4-diazebicyclo[2,2,2]octane, N-methylmorpholine, N-ethylpiperidine, pyridine or the like. N-Ethylpiperidine is employed advantageously. The base may be used at a rate ranging generally from approximately 1.0 to approximately 3 mole equivalents, preferably from 1.0 to 2 molar equivalents, per mole of the compound of the formula (VII).
The enolization reaction as described above may be completed generally in approximately 5 minutes to approximately 4 hours, thus leading to the formation of the enolate.
After completion of the enolization reaction, the resulting enolate may be used as it is for further reaction with the compound of the formula (VI).
The resulting enolate is then subjected to the alkylation reaction with the compound of the formula (VI). The alkylation reaction may be conducted at temperatures in the range generally from approximately -100.degree. C. to about room temperature, preferably from approximately from -78.degree. C. to approximately -10.degree. C. A quantity of the compound of the formula (VII) is not critical and may vary conveniently in a range generally from approximately 0.5 mole to approximately 5 moles, preferably from 0.5 to 2 moles, per mole of the compound of the formula (VII) used for the enolization.
The alkylation reaction may be carried out under such conditions as have been described above generally for approximately 5 minutes to approximately 5 hours, preferably for 5 minutes to approximately 2 hours.
The enolization and alkylation reactions may be carried out preferably in an inert atmosphere such as in the atmosphere of nitrogen gas or argon gas.
The reaction product obtained by the above reaction is then treated with water. For instance, after completion of the reaction, a phosphate buffer with approximately pH 7 is added, and a mixture is then stirred to be followed by filtration of undissolved materials. After filtration, the compound of the formula (VIII) is separated and purified in conventional manner, such as by means of extraction, recrystallization, chromatography and so on.
The step (b) is a step by which the compound of the formula (IX) may be prepared by reacting the azetidin-2-one derivative of the formula (VIII) obtained by the step (a) above with a magnesium malonate represented by the general formula: (R.sup.3 OOCCH.sub.2 CO.sub.2).sub.2 Mg in the presence of imidazole.
The reaction is carried out preferably in an inert organic solvent such as, for example, an ether solvent, i.e., ether, tetrahydrofuran, dioxane or the like; a hydrocarbon solvent, i.e., toluene, xylene cyclohexane or the like; a halogenated hydrocarbon solvent, i.e., dichloromethane, chloroform or the like; acetonitrile and so on. Particularly acetonitrile may be employed conveniently.
Reaction temperatures are not limited strictly to a particular range and may vary in a wide range with starting materials to be used or the like. They may range generally from approximately 0.degree. C. to approximately 100.degree. C. preferably around room temperature.
A quantity of the magnesium malonate with respect to the compound of the formula (VIII) may be about an equimolar amount, and the reaction may be completed in approximately 50 hours, preferably in approximately 20 hours.
The magnesium malonate to be used may include, for example, p-nitrobenzylmagnesium malonate, benzylmagnesium malonate, methylmagnesium malonate and so on. Among them, p-nitrobenzylmagnesium malonate is preferably used.
The step (c) is a step to eliminate a hydroxyl protecting group Z from the compound of the formula (IX) obtained by the step (b) above. The tertiary-butyldimethylsilyl group as the hydroxyl protecting group Z may be eliminated by subjecting the compound of the formula (IX) to acidic hydrolysis in a solvent such as methanol, ethanol, tetrahydrofuran, dioxane or the like in the presence of an acid such as a mineral acid, i.e., hydrochloric acid, sulfuric acid or an organic acid, i.e., acetic acid at temperatures ranging from 0.degree. C. to 100.degree. C. for reaction periods ranging from 0.5 to 18 hours.
The above step may yield the compound represented by the formula (X) in a quantitative amount.
The step (d) is a step by which the diazo compound of the formula (XI) may be prepared by treating the compound of the formula (X) obtainable by the above step (c) with an azide compound in the presence of a base in such an inert organic sovent as have been enumerated for the step (b) above.
The azide compound to be used in the step (d) may including, for example, p-carboxylbenzenesulfonyl azide, toluenesulfonyl azide, methanesulfonyl azide, dodecylbenzenesulfonyl azide or the like. The base to be used therein may include, for example, triethylamine, pyridine, diethylamine or the like.
The reaction may be carried out, for instance, by adding p-toluenesulfonyl azide in acetonitrile preferably in the presence of triethylamine to 0.degree. C. to 100.degree. C., preferably at room temperature for 1 to 50 hours. This reaction produces the diazo compound represented by the formula (XI) with high yield.
The step (e) is a step by which the diazo compound of the formula (XI) obtained by the step (d) above may be cyclized to give the compound of the formula (XII). This step may be carried out preferably in an inert solvent such as benzene, toluene, tetrahydrofuran, cyclohexane, ethyl acetate, dichloromethane or the like, preferably in toluene, at temperatures ranging from 25.degree. C. to 110.degree. C. for 1 to 5 hours in the presence of a metal catalyst such as a metal carboxylate compound including, for example, bis(acetylacetonato)Cu(II), CuSo.sub.4, copper powder, Rh.sub.2 (OCOCH.sub.3).sub.4, rhodium octanoate, Pb(OCOCH.sub.3).sub.4 or the like. As an alternative procedure, the above cyclization step may be carried out by subjecting the compound of the formula (XI) irradiation from a light source through a Pyrex filter (its wavelength being larger than 300 nm) in a solvent such as benzene, diethyl ether or the like at 0.degree. C. to 250.degree. C. for 0.5 to 2 hours.
The step (f) produces the compound of the formula (II) by reacting the compound of the formula (XII) obtainable by the step (c) with a reactive derivative of an acid represented by the formula: RaOH. The reactive acid derivative may include, for example, an acid anhydride such as acetic acid anhydride, methanesulfonic acid anhydride, p-toluenesulfonic acid anhydride, p-nitrobenzenesulfonic acid anhydride, 2,4,6-triisopropylbenzenesulfonic acid anhydride, trifluoromethanesulfonic acid anhydride or the like or an acid halide such as an acid chloride, i.e., acetyl chloride, propionyl chloride, diphenylphosphoric chloride, toluenesulfonyl chloride, p-bromobenezenesulfonyl chloride or the like. Diphenylphosphoric chloride (R.sup.0 =diphenylphosphoryl group) is particularly preferred.
The reaction of the compound of the formula (XIII) with the reactive acid derivative may be carried out, for example, in a manner similar to a conventional acylation reaction in an inert solvent such as methylene chloride, acetonitrile, dimethylformamide or the like, conveniently in the presence of a base such as diisopropylethyl amine, triethylamine, 4-dimethylaminopyridine or the like at temperatures ranging from -20.degree. C. to 40.degree. C. for approximately 30 minutes to approximately 4 hours.
The reaction consisting of a series of the steps as have been described above provides the compound represented by the formula (II) with a highly spatial selectively and with such a spatial arrangement that the methyl group at the 1-position of the carbapenem skeleton is arranged in the R configuration, the sustituent at the 5-position thereof is in the R configuration, and the substituent and the hydroxymethyl group each at the 6-position thereof are in the S and R configurations, respectively.
The compound represented by the formula (II) is then reacted with a mercapto reagent represented by the formula (III) to give the compound represented by the formula (IV).
The reaction of the compound of the formula (II) with the mercapto reagent of the formula (III) may be carried out, for instance, by reacting the compound of the formula (II) with the mercapto reagent of the formula (III) in an excess amount ranging from about equimolar amount to approximately 1.5 molar amount in an appropriate solvent such as tetrahydrofuran, dichloromethane, dioxane, dimethylformamide, dimethylsulfoxide, acetonitrile, hexamethylene phosphoramide or the like, preferably in the presence of a base such as sodium hydrogen carbonate, potassium carbonate, triethylamine, diisopropylethyl amine or the like at a temperature range from approximately -40.degree. C. to approximately 25.degree. C. for approximately 30 minutes to approximately 24 hours.
The reaction described above provides the carbapenem compound represented by the formulated (IV) in which the carboxyl group at the 3-position thereof is protected by the carboxyl protecting group R.sup.2 and the substituent at 2-position thereof is protected by the amino protecting group R.sup.0. The removal of the protecting groups R.sup.2 and R.sup.0 may be made by a per se known reaction for removing a protective group, such as solvolysis or hydrogenolysis. In a typical reaction, the compound represented by the formula (IV) may be treated, for instance, in a mixture of solvents such as tetrahydrofuran-water, tetrahydrofuran-ethanol-water, dioxane-water, dioxane-ethanol-water, n-butanol-water or the like containing morpholino-propane sulfonic acid-sodium hydroxide buffer solution (pH 7), a phosphate buffer solution (pH 7), dipotassium phosphate, sodium bicarbonate or the like, using hydrogen under 1 to 4 atmospheric pressures, in the presence of a catalyst for hydrogenation such as platinum oxide, palladium-activated carbon or palladium hydroxide-activated carbon at temperatures ranging from approximately 0.degree. C. to approximately 5020 C. for approximately 0.25to approximately 4 hours.
In accordance with the above steps, (1R, 5S, 6S)-2-[4-pyrazolidinyl]thio-6-[(R)-1-hydroxyethyl]-1-methyl-carbapenem-3-carboxylic acid represented by the formula (V) is produced. Then, this compound of the formula (V) is converted to the present carbapenem compound of the formula (I) by reacting with alkyl imidoformate. The reaction with the compound of the formula (V) with alkyl imidoformate may be conducted by dissolving the compound of the formula (V) in a week basic medium, for instance, in the basic medium (pH 8.5) consisting of a phosphate buffer(pH 7.5) and 1N-sodium hydroxide solution and causing a ethyl formimidate on the resulting solution.
The mercapto reagent of the formula (III) to be employed in the process described above may be prepared in a manner as indicated in Reaction Scheme B blow. ##STR6## wherein R.sup.b has the same mean as above:
4-Hydroxyprazoline of the formula (XIII) prepared by the reaction between hydrazine hydrate and epihalohydrin is treated with the acylation reagent of the formula R.sup.b X to give the compound of the formula (XIII). Then, the resulting compound of the formula (XIV) is converted to the compound of the formula (XV) by methansulfonylation, and the compound of the formula (XV) is reacted with the compound of the formula R.sup.c SH such as thiolacetic acid to obtain the compound of the formula (XVI). Finally, the resulting compound of the formula (XVI) is converted to the objective mercapto reagent of the formula (III) by reacting with alkali metal alkoxide such as sodium methoxide, sodium ethoxide or the like.
The compound of the present invention represented by the formula (I) may be converted to a pharmaceutically acceptable salt thereof by usually manner. Such a salt may be, for example, an alkali metal salt such as sodium, potassium salt thereof; an amino acid salt such as arginine, ornithine, lysine salt thereof; and an ammonium slat such as diethanolammonium, triethanolammonium salt thereof, but the sodium or potassium salt thereof may be more preferable, described above.
The objection compounds of the formula (I) in accordance with the present invention represented by (1R, 5S, 6S)-2-(5H-H-pyrazolo[1,2-a]triazolinium-6-yl)thio-6-[(R)-1-hydroxylethyl]-1-methyl-carbapenem -3-carboxylic acids are novel compounds that are not disclosed specifically in the above-mentioned publication and that are extremely stable against dehydropeptidase (DHP) known as a kidney enzyme and superior in antibacterial activities. The remarkably high antibacterial activities and stability against the kidney DHP of the compound of the formula (I) according to the present invention have been determined by biological tests as well be described below.
The antibacterial activities were tested by an agar plate dilution method in accordance with the standard method of the Japanese Chemotherapy Society (Chemotherapy, Vol. 29, 76-79 (1981)).
A Mueller-Hinton (MH) agar liquid medium of a test microorganism was cultured overnight at 37.degree. C. and the resultant culture medium was diluted with a buffered saline gelatin (BSG) solution to contain approximately 108 cells of the test microorganims per milliliter, and then the diluted solution was inoculated with a microplanter at the rate of approximately 5 microliters on a MH agar medium containing a test compound. This medium was then incubated at 37.degree. C. for 18 hours. The minimum inhibitory concentration (MIC) is determined as a minimum concentration in which no test microorganism could grow. It is noted here that the test organisms used were all standard strains.
Table 1 shows the test results. It is to be noted here that the test compound used therein was the compound (15) obtained in Example No. 6. As control compounds were used ones clinically employed widely, vis., cefazolin (CEZ) as a cephalosporin compound, and imipenem as a carbapenem compound.
From the foregoing results, it is apparent that the carbapenem compound according to the present invention has superior antibacterial activities.
The antibacterial activities against clinically isolated .beta.-lactamase producing strains have been tested by the agar plate dilution method in accordance with the standard method of The Japanese Chemotherapy Society (Chemotherapy, Vol. 29, 76-79 (1981)). A solution of a cephalosporinase producing strain stored by Episome Research Institute, which was prepared by incubating the strain in a sensitivity test broth (STB; product of Nissui K.K.) for 18 hours, was diluted with a fresh STB solution to contain 105 cells per milliliter and the diluted solution was then inoculated as spots with a microplanter on a sensitivity disk agar-N (SDA; product of Nissui K.K.) containing a test compound. The disk agar was then incubated for 18 to 20 hours. A minimum inhibitory concentration was determined as a minimum concentration in which the test microorganism had no longer grown after a 18 to 20 hour incubation.
Table 2 shows the test results. It is to be noted here that the test compound used therein was the compound (15) obtained in Example No. 6. As control compounds were used ceftazidime (CAS) as a cephalosporin compound, and imipenem as a carbapenem compound, both being recognized as having remarkably high antibacterial activities against the test strains and being widely employed clinically.
It has been found from the above results that the carbapenem compound according to the present invention had the antibacterial activities P. aeruginosa and P. cepacia belonging to Pseudomonadaceae as high as imipenem and particularly higher than CAZ having anti-Pseudomonas activities.
It has been further found that the carbapenem compound according thereto had the activities against enteric bacteria excluding the genus Proteus as high as imipenem and superior to CAZ.
(1) Strains of Test Organisms:
Fifty-four strains of P. aeruginosa demonstrating a resistance against the following agents in such concentrations as having been indicated between the following parentheses were employed for sensitivity tests against clinical isolates. It is noted here that the 54 strains have been chosen because there have been the strains in duplicate with the agents.______________________________________Ceftazidime (CAZ) (25 to 100 .mu.g/ml) 21 strainsCefsulodine (CFS) (25 to >100 .mu.g/ml) 23 strainsPiperacilin (PIPC) (25 to >100 .mu.g/ml) 15 strainsGentamycin (GM) (25 to >100 .mu.g/ml) 21 strainsAmikacin (AMK) (25 to >100 .mu.g/ml) 26 strainsOfloxacin (OFLX) (25 to >100 .mu.g/ml) 4 strains______________________________________
(2) Test Procedures:
The test procedures were based on the agar plate dilution method in accordance with the standard method of the Japanese Chemotherapy Society. A minimum inhibitory concentration (MIC) was determined in substantially the same manner as the test procedures II above using the 54 strains of P. aeruginosa having an anti-Pseudomonas resistance.
(3) Results:
The compound (15) obtained in Example 6, on the one hand, was found to demonstrate the antibacterial activities to inhibit the growth of approximately 98% of the test microorganisms in a concentration of 6.25 .mu.g/ml and all the test microorganisms in a concentration of 12.5 .mu.g/ml.
The imipenem, on the other hand, was found to inhibit the growth of approximately 98% of the test microorganisms in a concentration of 6.25 .mu.g/ml and all the test microorganism in a concentration of 12.5 .mu.g/ml.
(1) Stains of the Test Organisms:
Twenty-stains of C. freundii demonstrating a resistance again st the following agent as same manner described above Test 1.
(2) Test Procedures:
The tests were carried out in the same manner as described above Test 1.
(3) Results:
The compound (15) obtained in Example 6 was found to demonstrate the antibacterial activities to inhibit the growth of approximately 98% of the test microorganisms in a concentration of 0.78 .mu.g/ml and all the test microorganisms in a concentration of 1.56 .mu.g/ml.
The imipenem, on the other hand, was found to inhibit the growth of approximately 90% of the test microorganisms in a concentration of 0.78 .mu.g/ml and all the test microorganisms in a concentration of 1.56 .mu.g/ml.
From the above results, it has been found apparent that the compound according to the present invention is superior in the antibacterial activities to imipenem.
(1) Swine Kidney Dehydropeptidase-I (DHP-I):
The swine kidney (8 kg) was homogenized and an enzyme protein was allowed to precipitate. After a connective lipid was removed with acetone, the resultant material was made soluble by treatment with butanol and purified in the order by the ammonium sulfate fraction method, thereby producing DPH-I enzyme from a 75% ammonium sulfate fraction.
The DHP-I enzyme was then adjusted to give an enzyme concentration of 25 mg/10 ml (phosphate buffer, pH 7.1), and divided into 1 ml portions. The portions were frozen and stored at -40.degree. C. or less until use.
(2) Test Compound:
As a test compound was used the compound (15) obtained in Example 6 that follows.
The test compounds was adjusted in situ to give the concentration of 117 .mu.M with a 50 mM sodium phosphate buffer solution (pH=7.1).
As control compounds were employed glycyl dehydrophenylalanine (Gl-dh-Ph) and imipenem, and they were adjusted in situ each to give the concentration of 177 .mu.M with the same sodium phosphate buffer solution.
(1) Measurement for Hydrolysis Activity against DHP-I Enzyme Substrate by Late Assay:
To 1.2 ml of a 50 mM sodium phosphate buffer solution (substrate) containing 177 .mu.M of each of Gh-dh-Ph and imipenem as the control compounds was added 0.2 ml of the DHP-I enzyme solution (25 mg/10 ml) prepared above in the final substrate concentration of 100 .mu.M. The solution was then incubated at 3720 C. for 10 minutes. An initial velocity of hydrolysis of the substrate was measured from a decrease in absorbency at a particular .lambda.max of each of the substrates.
A blank test was conducted in substantially the same manner as above by adding 0.2 ml of the sodium phosphate buffer solution (pH 7.1) to 1.2 ml of the above substrate.
(2) Measurement for Stability of Test Compounds against DHP-I by High Performance Liquid Chromatography Method (HPLC):
The test compound according to the present invention and the control compounds have been treated in substantially the same manner as (1) above. The incubation, however, was conducted at 37.degree. C. for 4.5 hours or for 24 hours. A degree of the hydrolysis of the compounds each after the test periods of time was measured by the HPLC method.
The initial velocity of hydrolysis of each of the substrates against DHP-I by the late assay was found as follows:______________________________________Gl-dh-Ph 17.4 .mu.M/minuteImipenem 0.56 .mu.M/minute______________________________________
Table 3 below shows measurement results on stability of the compound according to the present invention and imipenem against DHP-I.
From the stability test results against DHP-I, it is found apparent that the carbapenem compound according to the present invention was stabler by approximately twenty-eight times than that of imipenem.
Toxicological studies have been carried out using a group of 10 male mice of CrjCD(SD) type weighing from 20 to 23 grams. A solution containing the carbapenem compound (15) of the present invention obtained by Example 6 was administered subcutaneously to the mice and subjected to observations for one week.
The results have revealed that a group of the mice to which the carbapenem compound (14) of the present invention had been administered in the amount of 500 mg/kg were alive without any abnormal observations.
As have been described above, the carbapenem compounds according to the present invention demonstrate a wider scope of antibacterial spectra compared to conventional cephalosporin compounds and remarkable antibacterial activities comparative to imipenem as well as an overwhelmingly higher resistance against DHP compared to imipenem. The carbapenem compounds according to the present invention further possess superior antibacterial activities against clinically isolated strains and present favorable effects on infection preventive tests on mice against various organisms.
Therefore, the carbapenem compounds of the formula (I) according to the present invention permit a signal administration without a combination with any other compounds and without a risk of any side effect that might be caused to arise in combination with a DHP inhibitor, unlike imipenem that was led for the first time to a practically useful antibacterial agent in combination with cilastatin acting as a DHP inhibitor. The carbapenem compounds are accordingly extremely useful as antibacterial agents for therapy and prevention of infectious diseases from various pathogenic organisms.
The carbapenem compound of the formula (I) according to the present invention may be administered as an antibacterial agent to the human being and other mammarian animals in the form of a pharmaceutically acceptable composition containing an antibacterially effective amount thereof. A quantity of administration may vary in a wide range with agents of patients, weights, patient conditions, forms or routes of administration, patient's diagnoses or the like and may be orally, parenterally or topically administered, usually, to adult patients once or in several installments per day in a standard daily dose range from approximately 200 to approximately 3,000 mg.
The pharmaceutically acceptable composition of the carbapenem compound of the formula (I) according to the present invention may cantain an inorganic or organic, solid or liquid carrier or diluent, which is conventionally used for preparations of medicines, particularly antibiotic preparations, such as an excipient, e.g., starch, lactose, white sugar, crystalline cellulose, calcium hydrogen phosphate or the like; a binder, e.g., acacia, hydroxypropyl cellulose, alginic acid, gelatin, polyvinyl pyrolidone or the like; a lubricant, e.g., stearic acid, magnesium stearate, calcium stearate, talc, hydrogenated plant oil or the like; a disintegrator, e.g., modified starch, calcium carboxylmethyl cellulose, low substituted hydroxypropyl cellulose or the like; or a dissolution aid, e.g., a non-ionic surface active agent, an anionic surface active agent or the like, and may be prepared into forms suitable for oral, parenteral or topical administration. The formulations for oral administration may include solid preparations such as tablets, coatings, capsules, troches, powders, fine powders, granules, dry syrups or the like or liquid preparations such as syrups or the like; the formulations for parenteral administration may include, for example, injectable solutions, drip-feed solutions, depositories or the like; and the formulations for topical administration may include, for example, ointments, tinctures, creams, gels or the like. These formulations may be formed by procedures known per se to those skilled in the art in the field of pharmaceutical formulations.
The carbapenem compounds of the formula (I) according to the present invention are suitably administered in the form of parenteral formulations, particularly in the form of injectable solutions.
The production of the carbapenem compounds of the formula (I) according to the present invention will be described more in detail by way of working examples.
In the following description, the following symbols are used to have the particular meanings:
US Referenced Citations (4)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 168707 |
Jan 1986 |
EPX |
| 170073 |
Feb 1986 |
EPX |
Divisions (2)
|
Number |
Date |
Country |
| Parent |
357350 |
May 1989 |
|
| Parent |
130121 |
Dec 1987 |
|
Patent Grant
4990613
