IE59365B1

IE59365B1 - Antibacterial drugs for fish

Info

Publication number: IE59365B1
Application number: IE41587A
Authority: IE
Original assignee: Bayer Ag
Priority date: 1986-02-19
Filing date: 1987-02-18
Publication date: 1994-02-09
Also published as: IE870415L; CA1302274C; NO870494D0; ATE77551T1; NO870494L; DE3779939D1; DK174984B1; ES2041649T3; JPS62192321A; EP0238814A3; DK81787A; FI870657A; DK81787D0; EP0238814A2; EP0238814B1; FI870657A0; CN87100799A

Abstract

Antibacterial medicaments for fish contain 1-cyclopropyl-7-(1-piperazinyl)- 6-fluoro, 4-dihydro-4-4oxo-3- quinolinecarboxylic acid cpds. of formula (I) or their salts or hydrates; R1 = H, lower alkyl or lower hydroxyalkyl; R2 = H or lower alkyl. (I) are described in JA 71683/82 and 74667/83.

Description

The present invention relates to antibacterial medicaments for fish. In particular, the present invention relates to antibacterial medicaments which are suitable for the prevention, curing and treatment of infectious diseases in fish, which are caused by microorganisms or aquatic microorganisms, and which as active ingredient contain the quinoline derivatives, their salts or their hydrates of the general formula COOR.

Rj-N N (I) in which Rx indicates a hydrogen atom, a lower alkyl group or a lower hydroxyalkyl group and R2 indicates a hydrogen atom or a lower alkyl group, excepting l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(115 piperazinyl)quinolone-3-carboxylic acid (ciprofloxacin).

Recently, because of the problem of the 200-mile fishery zone and the cutback, caused by overfishing, in the fish stocks available for catching fish-breeding cultures have been operated to an increasingly large extent. In the wake of this trend, attempts have been directed at high-efficiency fish production. In particular in intensive fish cultures having a high population density, infectious diseases frequently occur in the fish, and if such diseases remain untreated, the damage occasionally amounts to complete destruction of the fish culture in the breeding establishment. Even if damage does not occur to this extent, the surviving fish are affected and have a considerably reduced commercial value. This type of problem occurs in many places, and there is a great need for its speedy and effective solution.

The majority of the infectious diseases of fish are caused by microorganisms or aquatic microorganisms, and to prevent or cure them until now, in practice a procedure has been used for oral administration to the fish in which antibacterial medicaments such as sulpha drugs, nitrofuran, synthesized penicillin, tetracycline, macrolide antibiotics, nalidixic acid, oxolinic acid, piromidic acid or chloramphenicol have been added to their feed or infected fish have been put for a certain period into water which contains antibiotics of this type dissolved therein, a so-called medicinal bath. However, the antibacterial agents known until now, such as are mentioned above, have the disadvantages that their antimicrobial spectra are narrow, their curative effect is weak, their safety margins (the differences between the effective dose and the toxic dose) are small, undesired side effects occur and their use is uneconomical, and as a result of this they are not very satisfactory.

It has been found that the quinoline derivatives, their salts and their hydrates of the above general formula (I) exhibit excellent preventative and curative effects in a broad way against various infectious diseases of fish caused by microorganisms and aquatic microorganisms, that they additionally are highly effective against resistant bacteria and against complications and that they have low toxicity, are safely and rapidly metabolised and are extremely highly suitable for preventative and curative antibacterial medicaments against infectious diseases of fish.

In the above formula (I), the lower alkyl struc30 tural units in the lower alkyl and lower hydroxyalkyl groups include straight-chain or branched-chain alkyl groups having up to 6 carbon atoms, preferably up to 4 carbon atoms, for example methyl, ethyl, n-propyl, isof propyl, n-butyl, sec-butyl, isobutyl, tert-butyl etc. ' 35 Preferred examples of Rx include the hydrogen atom, the methyl, the ethyl and the β-hydroxyethyl group. For R2, the hydrogen atom, the methyl and the ethyl group are likewise preferred.

Typical examples of the quinoline derivatives of the formula (I) utilisable as an effective ingredient in the antibacterial agents of the present invention include the following: methyl l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-piperazino-quinoline-3-carboxylate, ethyl l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-piperazino-quinoline-3-carboxylate, l-cyclopropyl-6-f luoro-1,4-dihydro-4-oxo-7- (4-methylpiperazino)-quinoline-3-carboxylic acid, ethyl 1-cyclopropy1-6-fluoro-1,4-dihydro-4-oxo-7-(4methylpiperazino, quinoline-3-carboxylate, l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-ethylpiperazino)-quinoline-3-carboxylic acid, ethyl l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(4ethylpiperazino, quinoline-3-carboxylate and l-cyclopropyl-6-f luoro-1,4-dihydro-4-oxo-7- (4-0-hydroxyethylpiperazino)-quinoline-3-carboxylic acid.

The quinoline derivatives of the formula (I) can be employed in the form of acid addition salts utilising the basicity of the piperazino group in the 7-position. Examples of acid addition salts of this type include salts with inorganic acids, such as hydrochlorides, hydrobromides, hydroiodides and sulphates and salts with organic acids such as acetates, citrates, benzenesulphonates and embonates (pamoates). If R2 in the quinoline derivatives of the formula (I) is a hydrogen atom, the carboxyl group in the 3-position can also be present in salt form. Salts of this type include alkali metal salts such as the sodium salts or potassium salts, alkaline earth metal salts such as the magnesium salts and calcium salts and also the ammonium salts, as well as physiologically tolerable salts and complexes of metals such as iron, cobalt, copper, manganese, zinc and aluminium.

In addition, the quinoline derivatives of the formula (I) or their salts can also be employed in the form of their hydrates.

Most of the quinoline derivatives of the formula (I) are compounds known per se, as are disclosed, for example, in JP Laid-Open Specifications 71683/82 and 74667/83, and can be prepared by means of the methods described in these Laid-Open Specifications.

For administration of the quinoline derivatives, their salts or their hydrates of the formula (I) [which are called active compounds of the formula I in the following] as antibacterial medicaments for fish these derivatives can, for oral administration, be mixed with the fish feed, or they can be dissolved in the water into which diseased fish are put and in which they are allowed to swim around (a method utilising a so-called medicinal bath).

In addition, the active compounds of the formula (I) can be processed to give suitable formulations for such administration forms as, for example, powders, granules or solutions as feed additives or soluble dispersions or solutions for medicinal baths. The pro20 cesses for the preparation of such formulations are similar to those which are normally used in practice in. the formulation of preventative or curative agents in the case of acute attack. According to general practice, one or more of various additives, for example extenders such as soya bean protein, lactose, brewer's yeast and limestone, diluents such as water, solubilisers such ae benzyl alcohol and n-butanol, thickeners such ae hydroxypropylmethylcellulose and pH regulators such as potassium hydroxide, sodium hydroxide, lactic acid, hydrochloric acid and acetic acid are mixed in a suitable manner with the active compound in order to prepare the suitable form of formulation. In the following, the typical forms are illustrated in detail.

I Formulation Example 1 (powder as a feed additive): Active compound of the formula (I) 1-10 parts by weight Soya bean protein 99-90 parts bv weight Total 100 parts by weight Soya bean protein is added to the active compound of the formula (I), and both components are homogeneously mixed with one another in a mixer.

Formulation Example 2 (solution as a feed additive or for a medicinal bath): Active compound of the formula (I) Potassium hydroxide Benzyl alcohol Hydroxypropylmethylcellulose 50 Purified water Total 0.5- 10 parts by weight 0.08-1.5 parts by weight 1.3 -1.4 parts by weight 0 -3.5 parts by weight remaining amount 100 parts by weight Potassium hydroxide is added to purified water, and the mixture is stirred until a homogeneous system is formed; the active compound of the formula (I), the benzyl alcohol and the hydroxypropylmethylcellulose 50 are added to this, and the mixture is stirred until it is homogeneous.

Formulation Example 3 (soluble powder for a medicinal bath): Active compound of the formula (I) 1-10 parts by weight (one which is water-soluble) Lactose 99-90 parts by weight Total 100 parts by weight Lactose is added to the active compound of the formula (I) and both components are mixed homogeneously with one another in a mixer.

When using the active compounds of the formula (I) as an antibacterial medicament for fish, the doses adminstered differ depending on the purpose of administration (prevention or cure of a disease) and on the type the strength and the extent of infection of the fish target group to be treated. Normally, however, a dose in the range from 5 to 1000 mg, preferably from 20 to 100 mg, per 1 kg body weight of the fish can be administered daily, either in one portion or in several partial amounts at various times. However, no particular clarification is needed that the abovementioned dose represents a rough standard which can be reduced or increased, depending on the age, body weight, disease state etc. of the fish target group. The period of adminstration is subject to no particular restrictions, but adequate effects can normally be achieved within a period of time of 1 to about 10 days.

The antibacterial medicaments made available by the present invention are widely effective against 2q various microorganisms or aquatic microorganisms which cause infectious diseases in fish. For example, the medicaments exhibit a potent antibacterial action against bacteria which belong to the orders Aeromonas, Edwardsiella, Pasteurella, Pseudomonas, Streptococcus and Vibrio, and as a result are extremely effective for the prevention, treatment and curing of infectious diseases in bred fresh water fish and sea fish such as young yellow-tails, yellow-tails, eels, ayus, trout, salmon, carp etc. and also in aquarium fish such as goldfish and ,n tropical fish.

Such outstanding activities of the antibacterial agents of the present invention are confirmed in vitro and in vivo with the aid of the following tests in which the following compounds were employed.

Compound A (prior art according to Art. 54(3)): Hydrochloride of 1-cyclopropy1-6-fluoro-1,4-dihydro-4oxo-7-piperazino-quinoline-3-carboxylic acid (decomposition point: 319-321eC).

Compound B (prior art according to Art. 54(3)): Monohydrate of the hydrochloride of l-cyclopropyl-6fluoro-1,4-dihydro-4-oxo-7-piperazino-quinoline-3-carboxylic acid.

Compound C: Hydrochloride of l-cyclopropyl-6-fluoro-1,4-dihydro-4oxo-7-(4-methylpiperazino)-quinoline-3-carboxylic acid (decomposition point: 345-347'C).

Compound D: l-Cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-ethylpiperazino)-quinoline-3-carboxylic acid.

Compound E Dihydrate of the hydrochloride of l-cyclopropyl-6-fluoro1,4-dihydro-4-oxo-7-(4-ethylpiperazino)-quinoline-3carboxylic acid.

Compound F: Hydrochloride of l-cyclopropyl-6-fluoro-1,4-dihydro-4oxo-7- (4-0-hydroxyethylpiperazino) -quinoline-3-carboxylic acid (decomposition point: 327-333*C).

Compound G: Embonate of l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7(4-ethylpiperazino)-quinoline-3-carboxylic acid.

Compound H: Ethyl l-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(4ethylpiperazino)-quinoline-3-carboxylate (decomposition point: 187-189*C).

Compound OA (control): 1-Ethyl-1,4-dihydro-6,7-methylenedioxy-4-oxo-3-quinolinecarboxylic acid.

Test Example 1 Antibacterial activity in vitro against pathogenic bacteria for fish Each of the test strains was cultured overnight, 5 and each culture broth (containing about 10® cells/ml) was inoculated into Mueller-Hinton agar (Difco), to which 1.0 to 2.0% sodium chloride had been added and which contained the test compound in the concentrations indicated in each case. The minimum concentration inhibiting growth (MIC) was determined for each compound after an incubation period of 20 h at 25-30°C. The results are indicated in Table 1 which follows: Table 1 Antibacterial activity in vitro against bacteria for fish (MIC; ^g/ml) Test Compound bacterium A B C D E F G pathogenic Central Η OA Pasteurella piscicida 0(8304 0.05 0.025 0.05 0.05 0.05 0.1 0.1 25.0 0.1 0(8309 <0.025 <0.0125 0.05 0.025 005 01 0.1 25 0 0.1 10 0(8312 0.05 0.025 0.05 0.05 0.05 01 0.05 12.5 0-1 0(8313 0.05 0.025 0-05 0.05 0.05 0.1 0.05 12.5 0-1 NC8319 <0.025 0,025 0.05 0.025 0.05 0.1 0.01 25-0 0-1 Vibrio anguillarum 15 NH8410 <0.025 0.025 <0.025 0-025 0.05 0.1 0.05 12.5 0-05 ΝΆ8340 <0.025 0.025 <0.025 0.025 0.05 0 1 0.05 25.0 0.05 ΝΆ8341 <0.025 0*025 <0.025 0*025 0.05 o.l 0.05 25.0 0-05 NA8346 <0.025 0.025 <0*025 0.025 0*05 0.1 005 12.5 005 MA8347 <0.025 0.025 <0.025 0.025 0*05 0.05 0.05 12.5 0-05 20 Aeraocnas hydrcphila KA8301 <0.025 <0.0125 <0.025 0.025 0.05 0.05 0.05 12.5 <0.0125 KA8414 <0*025 <0.0125 <0.025 <0.0125 <0.025 <0.025 0.05 25.0 <0.0125 KA8416 <0.025 <0.0125 <0.025 <0-0125 <0 025 <0-025 0.05 12.5 <0.0125 25 M 183 <0.025 <00125 <0 025 <0.0125 <0 025 <0.025 0.05 12.5 <0.0125 C 44 <0.025 <0*0125 <0*025 <0.0125 <0-025 <0.025 0.05 50.0 <0.0125 Test Example 2 Antibacterial activity of compound D in vitro against various pathogenic bacteria for fish Each of the test strains was cultured overnight, 5 and each culture broth (containing about 106 cells/ml) was inoculated into Mueller-Hinton agar (Difco), to which 1.0 to 2.0% sodium chloride had been added and which contained the test compound in the concentrations indicated in each case. The minimum concentration inhibiting growth (MIC) was determined for each compound after an incubation period of 20 h at 25-30®C. The results are indicated in Table 2 which follows: Table 2 Antibacterial activity of compound D in vitro against pathogenic bacteria for fish Test Number MIC: ug/ml bacterium of Compound D Oxolinic acid strains Aeromonas hydrophile 25 <0.0125-0.05 <0.0125-0.025 Aeromonas salmonicida 25 0.0125-0.1 0.05-3.2 Edwardsielie tarda 25 0.025-0.2 0.05-1.6 Pasteurella piscicida 25 <0.0125-0.05 0.025-0.1 Pseudomonas anguilliseptica 18 <0.0125-0.025 <0.0125-0.05 25 Streptococcus sp. Vibrio anguillarum 25 0.8 200-400 Origin: yellow-tail 25 0.05-0.1 0.025-0.05 Origin: ayu 25 0.025-0.4 0.05-25 Of the active compounds used in the above test examples, a preparation example for the compound H is given in the following as a reference.

Preparation Example 1 g of 96 per cent concentrated sulphuric acid were added dropwise to a suspension of 18 g of 1-cyclo35 propyl-7-(4-ethyl-1-piperazinyl)-6-fluoro-1,4-dihydro-4oxo-guinoline-3-carboxylic acid in 120 ml of ethanol. The mixture obtained was heated under reflux for 12 h, and after removal of the excess alcohol under reduced pressure the residue was dissolved in 200 ml of icewater. While cooling with ice, the pH of the system was brought to 12 to 14 by addition of a cold solution of 19.2 g of sodium hydroxide in 100 ml of water, and the e precipitate formed in the meantime was filtered with suction. The precipitate was then washed with water and dried at 100°C under reduced pressure. After recrystallisation thereof from toluene/light benzine, 10 g of the ethyl ester of l-cyclopropyl-7-(4-ethyl-l-piperazinyl) 10 6-f luoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid were obtained (52.5% of the theoretical amount), which melts at 187-189°C.

Claims

1. Patent Claims

1. Use of quinoline derivatives, their salts or their hydrates of the general formula (I) (I) 5 in which R 1 indicates a hydrogen atom, a lower alkyl group or a lower hydroxyalkyl group and R 2 indicates a hydrogen atom or a lower alkyl group excepting 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo10 7-(1-piperazinyl)quinoline-3-carboxylic acid (ciproflaxacin) for the preparation of antibacterial medicaments for fish.

2. Use according to Claim 1, characterised in that 1cyclopropyl-6-f luoro-1,4-dihydro-4-oxo-7-(4-ethyl15 piperazine) quinoline-3-carboxylic acid (enrofloxacin), its salts or hydrates is employed as the quinoline derivative of the formula I.

3. Use according to Claim 1, substantially as hereinbefore described.