NZ182323A - Crystalline diastereomeric forms of 1-ethoxycarbonyloxyethyl-6-(hexahydro-1h-azepinyl)-methyleneamino-penicillanate - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number 1 82323 1 8 232 3 •t Priority Qstejs): :7T?.........

Complete Specification Filed: PuDHCation Date: P.O. JoLirr.n', Ko: .l2fcp.

No.: Date: NEW ZEALAND PATENTS ACT, 19S3 COMPLETE SPECIFICATION "NEW 6-AMIDINOPENICILLANIC ACID DERIVATIVES' % £/We, LEO PHARMACEUTICAL PRODUCTS LTD. A/S (L0VENS KEMISKE FABRIK PRODUKTIONSAKTIESELSKAB), a company limited by shares, incorporated under the laws of Denmark, of DK-2750 Bailerup, Denmark, hereby declare the invention for whichXiC / we pray that a patent may be granted toxmc/os., and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to the crystalline diasterecmeric forms of the compounds of the following formula N-CH=N^? V"S\/CH3 r n u / :ch2-ch2 CH 1 2 ck2 / ch2-ch2 CH,, ft (. * coo-ij:h-ocooc2h5 ch^ and the crystalline hydrochlorides thereof.

Due to the asymmetric carbon atom present in the ester group as shown in the formula above by an asterisk the compound of the above formula exists in two different diastereomeric forms, in the following called A and B.

The compounds of the above formula have hitherto been described only as an amorphous product. This product together with other similar esters of different amidino-penicillanic acids are described in New Zealand Patent Specification No. 170033. In that specification the preparation of the amorphous product has been described and the product is according to Example 1 isolated as a "residue". The amorphous product contains a mixture of the diastereomeric forms. However, neither in the specification nor in the Example has any description of the separation of the mixture into the pure diastereomeric forms been given. > \ —• —- ~r-> }I Cs i • - tzzim 18 2323 More particularly, the present invention concerns the crystalline forms of the free bases A and B as well as their hydrochlorides, the preparation thereof and pharmaceutical compositions containing the compounds A and/or B either in the free form or as their hydrochlorides. The composition may. further contain other . active and inactive ingredients as mentioned more specifically below. .

The mixtures of the diastereomers are known to be valuable antibiotics. They are absorbed well after oral administration and after the absorption the ester group is easily hydrolysed by enzymes present in the organism, giving rise to the formation of the corresponding free aniidinopenicillanic acid, mecillinam,known from Dutoh " s-nt" $peci"f i o'v* Mo- I SSI.

I^IioHC? g>a'bon'b Nc"—70l6h 35 i—corresponding to British. Patont Wo. 1393590» Mecillinam is a potent antibiotic, especially valuable against gramnegative organisms, such as E.coli and Salmonella. Since the stability of compounds of this type is unsatisfactory for pharmaceutical purposes when they are amorphous, whereas in the crystalline state they show a high degree of stability it is of considerable importance for their practical utilization to obtain them in the crystalline state.

According,to one embodiment of the method of the present invention the compounds A and B are prepared as their hydrochlorides by adding one equivalent of hydrogen chloride in propanol-2 to an ethereal solution of the mixture of the free bases. The formed precipitate crystallize 1 8 2323 upon standing. On treatment of the crude crystals with acetone and recrystallization from methanol-ether or similar solvents the hydrochloride of the pure A form is obtained. When the mother liquor, now enriched in the B form as its hydrochloride, is taken to dryness and the residue is treated with a solvent pair, such as methanol-ether, propanol-2-diisopropylether etc., or combinations thereof, the B form crystallizes as its hydrochloride.

In a second embodiment of the method of the present invention, the hydrochlorides of the compounds A and B are prepared by dissolving the free base in ether, thereafter adding cold water and adjusting pH to 3*0 with N hydrochloric acid. The mixture of the amorphous hydrochlorides is obtained by freeze-drying of the aqueous phase. The crystalline hydrochloride of Comp. A is isolated by treatment of the amorphous mixture with acetone. The mother liquor, now enriched in Comp. B, is taken to dryness and treated with aqueous sodium hydrogen carbonate; the liberated base is purified on Sephadex and subsequently converted to the hydrochloride. Treatment of the hydrochloride with cold ethyl acetate gives the crystalline hydrochloride of C omp. B.

From the hydrochlorides the free bases A and B can be prepared by neutralizing an aqueous solution of the hydrochloride with a suitable base, such as sodium hydrogancarbonate. Upon standing, the free base of the A and B form, respectively, crystallizes and can be isolated in usual manner. - k - 1 8 23 2 The preparation of the starting material, i.e. the mixture of the free bases can be performed in known manner by one of the methods described in the above IN • ^PaCi/^lrATiorf V°/7eolh mentioned^ patent/arppliud. Liuu. DOB G3111J1. The method n<J-. I Q' used in the present case is described mare in detail in the following Example's.

It is also an object of the present invention to make pharmaceutical compositions adapted for use in the treatment of infectious diseases, and containing as the therapeutically active component the forms A and/or B or the hydrochlorides thereof mixed up with solid or liquid pharmaceutical carriers and auxiliary agents. Furthermore the composition can contain other therapeutically active ingredients with a view to combatting bacterial infections.

Among such other therapeutically active ingredients mention can particularly be made of the known orally active penicillins and cephalosporins as well as their orally active esters.

In the compositions, the proportion of therapeutically active material to carrier substance and auxiliary agent can vary between 1 $ and 99The compositions can either be worked up to pharmaceutical forms of presentation such as tablets, pills or dragees, or can be filled in medical containers such as capsules, or as far as suspensions are concerned filled into bottles. The total amount of active ingredients in the composition lies preferably in the range from 10$ to 90$ of the composition in form for oral administration. Pharmaceutical organic v8 232 3 or inorganic solid or liquid carriers suitable for oral administration can be used to make up the composition. Gelatine, lactose, starch, magnesium stearate, talc, vegetable and animal, fats and oils, gum,- polyalkyiene glycol, or other known carriers for medicaments are all suitable as carriers. Furthermore, the compositions may contain other pharmaceutically active components which can appropriately be administered together with the compounds of the invention in the treatment of infectious diseases, such as other suitable antibacterial! agents, such as sulphonam.ides, trimethoprime and the like. .

Another object of the invention resides in the selection of a dose of the compounds of the invention and a dosage unit which can be administered so that the desired activity is achieved without simultaneous secondary effects.

By the term "dosage unit" is meant a unitary, i.e. a single dose capable of being administered to a patient, and which may be readily handled and packed, remaining as a physically stable unit dose, comprising either the active mate"F±al as such or a mixture of it with a solid pharmaceutical carrier.

In preliminary clinical trials it has been found that the compounds of the invention as the sole active ingredient are conveniently administered in dosage units containing not less substance than from 0.025 g to 1 g and preferably from 0.05 g to 0.5 g.

Such dosage units are conveniently administered one to four times a day at appropriate intervals, always, 18 2323 however, in accordance with the orders from the medical practitioner and depending upon the condition of the patient. Accordingly, the daily dose will amount to from 0.025 S to k.O g of the compounds of the invention as the sole active ingredient and preferably from 0.2 g to 2 g per day.

Such a daily dose may be administered orally also in the form of an aqueous or oily suspension or solution; of the compound of the invention for which.purpose appropriately is employed a therapeutical composition as '.. i described above and containing from 10 mg to 50 mg of quch compound per ml of the fluid vehicle.

Xt is still another object of the invention to provide a therapeutical composition in dosage unit form which contains besides a compound of the invention one of the above mentioned antibiotically active substances resulting in a synergistic activity.

Suitable penicillins in such a synergistic mixture can be the known, natural, biosynthetic and semi-synthetic penicillins, and in particular penicillins for oral use such as, phenoxymethylpenicillin, ampicillin, amoxycillin, epicillin etc. and orally active cephalosporins such as cephalexin, cephradin etc., or easily hydrolizable esters thereof," such as pivampicillin, bacampicillin.and tal ampicillin1.

The .synergistic composition according to the invention can be worked up to any pharmaceutical forms of presentation such as tablets, pills, dragees, or suppositories, or the composition can'be filled into medical containers such as 1 8 232 3 capsules as far as suspensions are concerned, they may be filled into bottles, tubes, or similar containers.

In such synergistic compositions of the invention the compound of the present invention is present in an amount of from 20 to 80^ calculated on the basis of the total araounjt of antibiotically active components in the form of their free acids forming th^ synergistic mixture.

In the treatment of patients suffering from infectious diseases the synergistic compositions of the invention are conveniently administered in daily doses from 0.2 g to 4 g, corresponding to the amount of the compound of the invention plus the other antibiotic derivative in question calculated as free acids, but present as such or as salts or easily hydrolyzable esters thereof.

Appropriately, the daily dose is given in the form of dosage units, e.g. tablets, of which 1-2 tablets are given 2-k times a day.

Such dosage units can according to the invention contain from 0.1 g to 0.8 g in total of the compound of the invention and the other antibiotic derivative in question calculated as free acids, but present as such or as salts or easily hydrolyzable esters thereof.

It shall be understood, however, that the adequate doses and frequency of administration may vary, depending upon the condition of the patient and the character of the infection, and shall be determined by the medical practitioner. 18 232 Furthermore, according to the invention the dosage unit can appropriately be in the form of tablets, the inner core of which contains one or more of the active components with the necessary pharmaceutical auxiliary % agents, whereas the outer core contains the other active component(s) together with adequate auxiliary agents, or such double tablets are provided in which the halves contain their respective component(s) under conditions where no interaction between the components can occur.

The invention will now be illustrated by the following, non-limiting Examples. 182323 Example 1 A. 11-Ethoxycarbonyloxyethyl-benzylpenicilllnate.

A mixture of potassium benzylpenicillinate (38 g, 0.1 mple), 1-chlorodiethyl-carbonate (20 g, 0.13 mole), sodium hydrogencarbonate (l«5 g), potassium iodide (3 g) , water (lO ml) and acetone (250 ml) was refluXed for 16 hours with stirring. The solvent was removed under reduced pressure and the residue was treated with water (l50 ml) and ether (25,0 ml). After washing with water, the organic layer was dried and the solvent was removed in vacuo, light petroleum (300 ml) was added and the mixture was stirred for one hour. The solvent was decanted and the residual oil was dried in vacuo to give 1ethoxy-carbonyloxyethyl-benzylpenicillin— ate (32 g ) as a semicrystalline mass.

B. 1'-ethoxycarbonyloxyethyl-6-aminopenicillanate .

Phosphorous pentachloride (30.5 g, 0.15 mole) was dissolved in dry chloroform (245 ml-) by gentle heating (4o°C) After cooling to 20°C, quinoline (36 g, 0.28 mole) was added under stirring. The mixture was cooled to -15°C and a solution of 1'-ethoxycarbonyloxyethyl-benzylpenicillinate (4-5 g) , 0.1 mole)" in dry chloroform (50 ml) was added (10—15 min.) maintaining the temperature between -15°C( and 12°C. Stirring was continued for 10 min. whereafter ice-cold propanol-1 (87 ml) was added (20-25 min.) keeping the temperature 18232 at -15°C to -12°C. After stirring for 15 min. at this tem-perature^ice-cold 20°/ sodium chloride solution (170 ml) was added (4 rain.) keeping the temperature below -5°C.-The organic layer was separated and diluted with ether (500 ml) and subsequently extracted with 5 portions of ice-cold water (each 100 ml). The combined aqueous extracts were neutralised at 0°C with sodium hydrogen-carbonate after addition of ether (250 ml). The organic layer was separated,.washed with water, dried and concentrated in vacuo♦ Light petroleum (250 ml) was added and the mixture stirred for 30 min. The solvent was decanted and the residue dried in vacuo to give I'-ethoxy— carbonyloxyethyl-6-arainopenicillanate (22 g) as a viscous oil.

The product contained a small amount of quinoline (3) which could be removed by filtration on SephadexV LH 20 using a solvent mixture of chloroform - hexane (65:35).

C. 1'-e thoxyc arb ony1oxve thyl-6-(hexahydro-lH-azepin-yl)- methyleneaminopenicilianate "A solution of 11-ethoxycarbonyloxyethyl-6-amino-penicillanate (33 g, 0.1 mole) in ether (33° ml) was cooled to -25°C :and fcriethy-lamirte' (;1;5; 5 ml, 0.11 mole ) added under stirring. Dimethylsulphate complex of N-formylhexamethyleneimine (28 g, 0.11 mole) dissolved in chloroform (25 ml) was added (5 min.) and the mixture allowed to warm to 0C -at which temperature "the stirring 18 232 was continued for 1 hour. Water (200 ml) was added and the organic layer separated and washed with water, fresh water (400 ml) was added and pH adjusted to 3»5 with dilute phosphoric acid at 0°C. The aqueous phase was separated, washed with ether (100 ml) and neutralised with sodium hydrogencarbonate at 0°C..after^addition—of ether (200 ml). The organic phase was separated, washed with water, dried and the solvent removed in vacuo to give a mixture of the two diastereomeric 1'-ethoxycarbonyl- oxyethyl-6-(hexahydro-lH-azepin-l-yl)-methyleneaminopenicil- lanates as a viscous oil (27 g? + 172 (C = l, CHCl^))- D. The hydrochloride of Comp. A was prepared by adding an equivalent of HC1 in propanol-2 to an ethereal solution of the mixture of the free bases. The formed precipitate turned partly crystalline upon standing. The crystals were isolated -by treatment of the crude hydrochloride with acetone. Purification was achieved by recrystallization from methanol-ether. The mother liquor, now enriched in Comp. B, HC1, was taken to dryness and the residue treated with a solvent pair as methanol-ether, propanol-2-diiso-propylether etc. or combinations thereof, thus inducing the crystallization of Comp. B, HC1.

♦ The free bases, Comp. A and Comp. B, were prepared by neutralising an aqueous solution of the parent hydrochloride with a suitable base such as sodium hydrogen carbonate.

Upon standing^ the free bases crystallized and could be isolated by filtration. Both compounds exhibited ill-defined r -i20 ' melting points with decomposition; |_«J values (C=l CHC1 ) o ~ D 3 were +1^3 and +198 ,respectively. to fS ro 00 -spectra of diastereomers of 1 -ethoxycarbonyloxyethyl-6-(hexahydro-lH-azepin-yl) methyleneaminopenicillanate (I) CH I CH, xCH2 CH2. 2 • % H H S CH- \ I 1/ \ / 3 . N - CH==N —C. C < C. ru ; . / _T 1: i 3 CH„—CK, N =?C— C-0-CH-0-C-0-CH„-CH„ 2.2. I 3 I II 2 3 H 0 CH3 0 Solvent; CgO^, TMS ref., b scale ppm. r\ H 3 H H 6 H 0-CH2-CH3 0-CH2-CH3 H' -O-C-O 1 . CH3 - H O-C-O 1 C*3 S ,CH_ K CH„ / 2 CH, 1 <L CH2 ^H2 -ch2 -CH2^ -CH=N Comp, A 4,52 s ,33 d J=4,5 4,78 dd J =4.5 J=1 .3,84 q J =7 0,88 t ■ J=7 6, 83 q J =5 1,22 d J=5 1,52 s 1,58 s 1,1-1,8 m 2,4-3,6m 7,42 broad line Ccmp, B 4,54 s ,34 d J=4.5 4,78 dd J=4-.5 J=1 3,87 q J=7 0,90 t ■ J=7 6,90 q : J=5.5 • 1,18 d J= 5.5 1,48 broad s 1,1-1,8 m 2,4-3,6m 7,42 broad line Solvent CDC1„, Tt ,13 ref., 6 scale ppm. ' , ' HC1 Comp.A,HCl 4,45 s ,59 m (2H) 4,21 q J=7.S 1,30 t J=7.5 S, 75 q J=5,5 1,56 d J=5,5 1,57 s 1,70 s 1,5-2, 2 m 3,5-4, Om 7,83 ^road s 11,83 broad s ; Comp,B,HCl 4,48 s ,59 m (2H) 4, 23 q , : 1,30 t J=7 6,78 q J=5,5 1,57 d J=5,5 1,60 s 1.70 s 1,5-2,2 m 3,5-4,Om 7,84 oroad s 11,5 broad s 1 8 232 Example 2 Step d of Example 1 could also be performed in the following manner: The mixture of the two diastereomeric 11-ethoxycarbonyL oxyethyl-6-(hexahydro-lH-azepin-l-yl)-methyleneaminopeni-cillanates was dissolved in ether, cold water was added and pH adjusted to 3.0 with N hydrochloric acid. Freeze-drying of the aqueous phase gave the hydrochlorides as a colourless amorphous powder (29 g» [a]^ +183° (C=l, h^o)).

The amorphous mixture of the two diastereometic hydrochlorides was dissolved in cold acetone (100 ml) and crystallization was induced by scratching. After stirring for 2 hours at 0°C the crystals were filtered off (lO g) and recrystallized from methanol-ether to yield the pure hydrochloride of Comp. a as colourless crystals, mp 166°C (dec.), [oc]p° +168° (C = l, H20).

The acetone filtrate was rapidly taken to dryness in vacuo. The residue was dissolved in cold water and neutralized with (solid) sodium hydrogencarbonate. The liberated base was extracted with ether and purified by filtration on Sephadex LH 20 (solvent: chloroform-hexane (65:35))- After evaporation of the solvent, the residual base was converted into its hydrochloride as described above (12 g)., This hydrochloride, now enriched in Comp. B, was dissolved in ethyl acetate and crystallization and puri-cation were performed as described above to give the pure hydrochloride of Comp, B, mp 164°C (dec.) [o]^+195° (c= i, h2o).

-Ik - 18 232 Example 3 Preparation of tablets containing 1'-ethoxycarbonyl-oxyethyl-6-f(hexahydro-lH-azepin-l-yl)-methylenaamino] penicillanate hydrochloride, A-form. ■ Ingredients: 1 '-Ethoxycarbonyloxyethyl 6-[(hexahydro- lH-az epin-l-yl)-methyleneamino]-penicilla- . nate hydrochloride, A-form, m.p.: 160 C(dec) [a]D° +213° (c 1; CHC13) , ■ . 350 g Polyvinylpyrrolidone ..... 10 g Corn starch ■ 40 g Magnesium stearate ..... 4 g • The 1ethoxycarbonyloxyethyl ester ig screened through a sieve with 1.0 mm mesh openings. The powder is then wetted with a solution of polyvinylpyrrolidone in 150 ml of a solvent composed of 1 part of ethanol (96%) and 19 parts of acetone. The moist mass is passed through a sieve with 1.0 mm mesh openings and then dried at 30°C on trays Of other convenient drying equipment, for instance a "fluidized bed" drying cupboard.

...... When the solvent has evaporated, the granules are sifted through a sieve with 0.7 mm mesh openings, and are finally mixed with the corn starch and magnesium stearate.

The granulate is compressed into tablets of 0. 40 g weight using punches and dies of 12 mm diameter to yield . 1000 tablets each containing 0.35 g of the 11 -ethoxycarbonyl oxyethyl 6-[(hexah3rdro-lH-azepin-l-yl)-raethyleneamino}-peni cillanate hydrochloride, A-form. - - 15 - ' ■ ' _ 1 8 2323 Example k Capsules, each containing 0.150 g of 1'-ethoxycarbonyloxyethyl 6-[ (hexahydro-lH-azepin-l-yl)-methyle.neamino]-penicillanate hydrochloride, A-form and 0.175 g of 1'-ethoxycarbony 1 oxy.ethyl a-aminobenzylpenicillinate hydrochloride are prepared according to the following procedure: Ingredients: . . . 1'-ethoxycarbonyloxyethyl 6-[(hexa-hydro-lH-azepin-l-yl)-rnethyleneamino]- » penicillanate hydrochloride A-forra 150 g 1'-ethoxycarbonyloxyethyl a-aminobenzylpenicillinate hydrochloride 175 S Polyvinyl pyrrolidone 20 g Magnesium stearate k g 11-ethoxycarbonyloxyethyl 6-[(hexahydro—lH-azepin-l-yl)-methyleneamino]-penicillanate hydrochloride and 1'-ethoxycarbonyloxyethyl a-aminobenzylpenicillinate hydrochloride are mixed and passed through a 20 US Standard mesh sieve. After having been mixed again, the resulting powder is moistened with a solution of polyvinyl pyrrolidone in isopropanol (150 ml). The moistened mixture is granulated by passing it through a 20 US Standard mesh sieve and is afterwards dried by j0°C. For the drying operation, a conventional drying oven with trays, or other suitable. 1 8 23 2 drying apparatus, for instance functioning according to the fluidized bed principles, may be applied.

After drying, the granulate is passed through a 25 US> Standard mesh sieve and is finally mixed with the magnesium stearate.

The finished granulate is filled into hard gelatine-capsules No. 0, each capsule containing 0.3^9 g granulate, the above ingredients thereby corresponding to 1000 capsules. - - ; Example 5 For oral suspension the following formulation was prepared. 11-ethoxycarbonyloxyethyl 6-hexahydro-lH-azepin-1-(yl)-methyleneamino penicillanate A + B form (1:1) 8 g Sodium benzoate 0.5 g Sodium chloride 1 g Flavouring agents 5 S Aerosil ® 0.3 S Alkali salts of polysaccharide sulphates 2.0 g Sucrose ac* 100 g 182323

Claims (4)

WHAT WE CLAIM IS:

1. The crystalline diastereomeric form A of the hydrochloride of tlio compound of tlie following formula. I yC II,-CH X " v ?h2 N-cii^N^ I1 ? yen CH„ X "V X \( 3 2 cii2-ch2^ I CH3 N { J « v-coo-(J:H-OCOOC2H5 ch3 characterized in having a melting point of 166°C (dec.), an [a]^° of +168° (C=l, HgO), and an NMR-spectrum as shown in Table I.

2. The crystalline diastereomeric form B of the hydrochloride of the compound of the formula I of claim 1, characterized in having a molting point of 16'<°C (doc.), an q r* _ [«]p of +195 (C=l, ^2^^ an£* an NMR-spectrum as shown in Table I.

3. T^e crystalline diastereomeric form A of the compound of 2o formula I of claim 1, characterized in having an L«]q of +1'*3° (C = l, CHCl^) and em NMR-spectrum as shown in Table I."

4. The crystalline diastereomeric form B of the compound of r ~i 20 formula I of claim 1, characterized in having an j_ ac J^ of +1^8° (C = l, CHCl.^) and un NMR-spoctruin as shown in Table I. ^^P^TBTTOfflC^ DATED TrliS^rt- DAY OF 19f-<y 26 MAR 1984 A. J PARKS SON «_ res ^-s- RECEIVE AGENTS FOR THE APPLICANTS Saiw-~=r—18"- "1 "s