LV12889B - Kristālisks ceftiofūrs brīvas skābes formā - Google Patents

Description

Description

INTRODUCTION [0001] This invention relates to a novel crystalline form of ceftiofur free acid, a process for preparing this crystalline form, and a sustained-release pharmaceutical composition containing this crystalline form.

BACKGROUND OFTHE INVENTION ro [0002] Many cephalosporin compounds, derivatives thereof, and processes for their preparation, are knovvn. For example, the follovving are knovvn: amorphous cefuroxime axetil, its crystalline sodium salt, its naphthyridine derivative and its sesquihydrate (U.S. Patents 4,820,833; 4,298,732; 4,442,101); crystalline sodium cephemcarboxylate (U.S. Patent 4,692,519); crystallinecephem heptahydrate (U.S. Patent 4,555,404); crystalline cephalosporin di-ortri-hydrate (U.S. Patents 4,812,561; 5,017,380; 4,933,443); cefadroxil monohydrate (U.S. Patent 4,898,938); anhydrous crystal15 lineceftazidime and its pentahydrate (U.S. Patents 4,624,948; 4,616,080; EP 0278 656); sodium amoxicillin pyrrolidone solvate (U.S. Patent 4,318,852); cefazolin sodium monohydrate (U.S. Patent 4,104,470); crystalline o-formylcefamandole (U.S. Patent 4,006,138); salts of 3-acetoxymethyl-7-(iminoacetamido)-cephalosporanic acid derivatives, vvhich may be either crystalline or amorphous (U.S. Patent 5,103,012); crystalline monohydrate of 7-[D-a-amino-a-(p-hydroxyphenyl)acetamido]-3-methyl-3-cephem-4-carboxylic acid (U.S. Patent 4,504,657); crystalline hydrochloride salt of syn-7-[[(2-amino-4-thiazolyl)(methoxyimino)acetyl] amino]-3-methyl-3-cephem-4-carboxylic acid (U.S. Patent 4,400,503); crystaliine cephem acid addition salts (Canadian Patent Application 2,018,794); crystalline (pivaloyloxy) methyl 7p-[2-(2-amino-4-thiazolyl)acetamido]-3-[[[1-[2-(dimethylamino)ethyl]-1H-tetrazol-5-yl]thio]methyl]-3-cephem4-carboxylate (Chemical Abstracts 97:38761q (1982)); crystalline cephalexin (Chemical Abstracts 84:184895j (1976); crystalline cephalexin monohydrate (U.S. Patent 3,531,481); crystalline 7-(D-2-naphthylglycylamido)-3-methyl-3-ce25 phem-4-carboxylic acid tetrahydrate (U.S. Patent 4,474,780); the preparation of a specific crystalline cephalosporin compound by stirring and the addition of methanol and butylacetate (Chemical Abstracts 110:212490z (1989)); a method for producing pure crystaliine antibiotics products, such as penicillin and cephalosporin, by treating vvith ethanol in one ortvvo steps (U.S. Patent 4,912,211).

[0003] From the large number of patents and literature references that is available on cephalosporin compounds, it appears that the occurrence of an anhydrous or nonsolvated, non-salt, crystalline form of a cephalosporin compound is rare. Most such crystalline forms tend to be salts, hydrates, solvates or other derivatives thereof, [0004] The cephalosporin antibiotic 7-[2-(2-amino-1,3-thiazol4-yl)-2-methoxyimino)acetamido]-3-[(fur-2-ylcarbonyl) thiomethyl]-3-cephem-4-carboxylic acid (also named 7-[2-(2-amino-4-thiazolyl)-2-methoxyimino)-acetamido]-3-[2(furanylcarbonylthiomethyl)-8-oxo-5-thia-1 -azabicyclo[4.2.0]oct-2-ene-1 -carboxylic acid) of the formula I in the Formu35 ia Chart belovv, its alkali mētai, alkaline earth mētai and amine salts of the carboxylic acid group, and easiiy hydrolyzabie ester groups thereof are described and claimed in U.S. Patent No. 4,464,367 (Labeeuvv et al.). This cephalosporin free acid compound is novv knovvn by the generic name ceftiofur.'' See also Merck lndex, Eleventh Edition, 1948 (1989). [0005] Ceftiofur Sodium is currently marketed by The Upjohn Company as NAXCEL® or EXCENEL® Sterile Solution to treat bovine respiratory disease (BRD). This product is administered intra-muscularly (IM) over a three to five day period using daily doses.

[0006] The free acid and cationic mētai and amine salt and ester forms of this cephalosporin antibiotic are somevvhat unstable chemically and are obtained as amorphous compounds vvhich are difficult to purify, and are less desirable to work vvith in manufacturing pharmaceutical formulations containing them. This amorphous free acid and salts are difficult solids to isolate and handle in pharmaceutical manufacturing plants, vvhich those in the pharmaceutical art vvould prefer to avoid.

[0007] Hovvever, it is not predictable how to make a specific crystalline form of a particular active drug compound. More specifically, it is not predictable how to make an anhydrous or nonsolvated, non-salt, crystalline form of a cephalosporin.

INFORMATION DISCLOSURE [0008] U.S. Patent 4,464,367 (Labeeuvv et al.), as discussed above, discloses the preparation of the amorphous form of the ceftiofur free acid in Example 1 (b).

[0009] U.S. Patent 4,937,330 (Sacks et al.) discloses the preparation of the ceftiofur sodium salt by neutralizing the hydrochloride salt vvith a basie resin. The amorphous free acid is disclosed as an intermediate in this process.

[0010] U.S. Patent 4,902,683 (Amin etal.) discloses and claims the hydrobromide and hydrochloride salts of ceftiofur, the crystalline form of the hydrochloride salt, processes for their preparation, and pharmaceutical compositions containing them for veterinary use. U.S. Patent 5,079,007 (Putnam) discloses controlled-release antibiotic implants con2 taining crystalline ceftiofur hydrochloride and amorphous ceftiofur sodium salt.

[0011] U.S. Patent 4,877,782 (Cazers et al.) discloses zinc ceftiofur comp!exes vvhich are useful as antibiotics especially in veterinary medicine. U.S. Patent 5,143,137 (Cazers et al.) discloses disulfide derivatives of ceftiofur, vvhich are useful as antibacterial aģents especially in veterinary medicine.

[0012] U.S. Patents 4,912,212 (Ochiai et al.) and 4,973,684 (Ochiai et al.) disclose cephem compounds having a residue of a nucleophilic compound at the 3-position.

[0013] U.S. Patent 5,013,713 (Mitchell) discloses methods for the prolonged release of biologically active somatotropins.

[0014] U.S. Patent 4,521,431 (Crookes) discloses a novel crystal form of ranitidine, designated Form 2, vvhich has favorable filtration and drying characteristics over crystal Form 1.

[0015] Hoover, Dispensing of Medication, 8^th Ed., Mack Pub. Co. (1976); and J.R. Robinson Ed., Sustained and Controlled Release Drug Delivery Systems, Marcel Dekker, (1978), disclose the technique for prolonging the release of a drug into the body by decreasing the solubility (by one or more techniques) of the drug, vvhich decreases the dissolution rāte if the drug is provided in a suspension.

[0016] V.H. Guerrini, et. al., Pharmacokinetic evaluation of a slow-release cefotaxime suspension in the dog and sheep, Am. J. Vet. Res., vol. 47, no. 9, (1986) discuss the concept of sustained release formulations. Guerrini et al. discloses that the subcutaneous (sc) administration of cefotaxime in an oil suspension in dogs and sheep provides satisfactory and more prolonged plasma concentrations (C_p) than did aqueous preparation given intramuscular (im) (sheep only) or given sc (sheep and dogs).

[0017] WO-A-8 706 231 discloses crystalline anhydrous anoxycillin. EP-A-0 122 585 dicloses crystalline anhydrous ceftazidin. DE-A-1 207 933 discloses crystalline anhydrous D-a-aminobenzylpenicillin.

SUMMARY OFTHE INVENTION [0018] The present invention particularly provides:

a crystalline compound of the formula I vvhich is 7-[2-(2-amino-1,3-thiazol-4-yl)-2-methoxyimino)acetamido]-3-( (fur-2-ylcarbonyl)thiomethyl]-3-cephem-4-carboxylic acid, i.e. crystalline ceftiofur free acid; ceftiofur free acid in vvhich at least forty percent (40%) of the compound is crystalline; a pharmaceutical composition vvhich comprises a crystalline compound of the formula I; and a process for preparing a crystalline free acid of the formula I which comprises combining a solution of ceftiofur free acid or hydrochloride in acetone or tetrahydrofuran (THF), vvith vvater, is at a temperature of betvveen 40’C and 60’C.

[0019] Throughout this document, the follovving terms have the indicated meanings:

[0020] By sustained-release is meant a formulation in vvhich the drug becomes biologically available to the patient at a measured rāte over a prolonged period.

[0021 ] By pharmaceutically acceptable carrier or excipient is meant any carrier or excipient that is commonly used in pharmaceutical compositions and are vvell knovvn and readily prepared by one of ordinary skill in the art. Such carrier or excipient may be a solid or Iiquid and contain one or more suspending, dispersing, stabilizing, emulsifying, buffering, thickening, svveetening, flavoring, coloring or preservative aģents.

[0022] Solubility is a direct consequence of a solid's strueture and the intermolecular forces holding the solid together and is defined as the amount of drug vvhich exists in solution vvhen equiiibrium is achieved betvveen solution and solid State material.

[0023] Dissolution rāte is the kinetic translation of solubility for a vvell stirred system under sink conditions.

[0024] “ln-vivo release is the biological consequence of the dissolution rāte of a compound vvhich is characterized by time to maximum concentration and the maximum concentration in the biological fluid of interest.

[0025] Hygroscopity is the ab i lity of a compound to piek up moisture from or y ie Id moisture to the atmosphere vvith changes in relative humidity.

[0026] This invention provides a crystalline form of 7-[2-(2-amino-1,3-thiazol-4-yl)-2-methoxyimino)acetamido]-3-[ (fur-2-ylcarbonyl)thiomethyl]-3-cephem-4-carboxylic acid (also named 7-[2-(2-amino-4-thiazolyl)-2-methoxyimino)acetamido]-3-[2-(furanylcarbonyl thiomethyl)-8-oxo-5-thia-1 -azabicyclo[4.2.0]oct-2-ene-1 -carboxylic acid), also knovvn as ceftiofur, of formula I in the Formula Chart. The crystalline form of the present invention is more precisely described as a non-salt, crystalline form of ceftiofur that is anhydrous or nonsolvated.

[0027] As indicated above, the cephalosporin antibiotic can be named by either of tvvo different nomenclature systems. Some prefer the more formai CHEMICAL ABSTRACTS system whereby the compound is named as a derivative of a bicyclo ring system. Some prefer the simpler cephem ring system nomenclature.

[0028] Crystaliine organic compounds consist of a large number of atoms vvhich are arranged in a periodic array in three-dimensional space. The structural periodicity normally manifests distinct physical properties, such as sharp, explicit spectral features by most spectroscopic probes (e.g., X-ray diffraction, infrared and solid state NMR). X-ray diffraction (XRD) is acknovvledged to be one of the most sensitive methods to determine the crystallinity of solids. Crystals yield explicit diffraction maxima vvhich arise at specific angles consistent vvith the lattice interplanar spacings, as pre5 dicted by Bragg's lavv.

[0029] On the contrary, amorphous materiāls do not possess long-range order. They often retain additional volume betvveen molecules, as in the liquid state. Amorphous solids normally unveil a featureless XRD pattern vvith broad, diffuse halos because of the absence of the long range order of repeating crystal lattice.

[0030] Crystalline materiāls are preferred in most pharmaceutical applications. Crystaliine forms are thermodynamio ically more stable than amorphous forms of the same substance. This thermodynamic stability is reflected in the lovver solubility and improved physical stability of the crystalline form. The regular packing of the molecules in the crystalline solid denies the incorporation of Chemical impurities. Hence crystalline materiāls generaily possess higher Chemical purity than their amorphous counterparts. The packing in the crystalline solid constrains the molecules to vvell defined lattice positions and reduces the molecular mobitity that is the prerequisite for Chemical reactions. Hence, crystalline is solids, vvith very fevv notable exceptions, are chemically more stable than amorphous solids of the same molecular composition.

[0031] The crystallineceftiofurfree acid ofthe present invention has a distinct fourier transform infrared (FTIR)spectrum and a distinct povvder X-ray diffraction (XRD) profilē. By either means, the material is readily differentiated from other ceftiofur-containing solids, including crystalline ceftiofur hydrochloride salt, amorphous ceftiofur sodium salt, amorphous ceftiofur free acid, and amorphous ceftiofur zinc salt. The identity of the material as ceftiofur has been confirmed chromatographically and spectroscopically. The crystallinity of the material is confirmed by the presence of an XRD pattern. The XRD observations are corroborated by the observation of birefringence vvith polarized light microscopy. Birefringence is an accepted U.S. Pharmacopeia method of determining crystallinity. (U.S. Pharmacopeia and National Formulary, Vol. 22, page 1577, (1989)). The material exists as the unassociated free acid of ceftiofur, verified by the absence of chloride (present in the ceftiofur hydrochloride starting material).

[0032] Representative FTIR and XRD patterns ofthe crystailineceftiofurfree acid of the present invention are shovvn in Figurēs 2, 4 and 5 belovv and of the amorphous ceftiofur free acid, prepared as described in Example 1 (b) of U.S. Patent 4,464,367, are shovvn in Figurēs 1 and 3 belovv. As vvould be apparent to one of ordinary skill in this art, the compound of Figurē 3 is in the amorphous form because of the broad, nondistinctive peaks in its XRD spectrum. Figurē oo 1, vvhich is the FTIR spectrum for this compound, is consistent vvith this interpretation of Figurē 3. The compound of Figurēs 4 and 5 is in the crystailine form because of the sharp, distinctive peaks in its XRD spectra. Figurē 2, vvhich is the FTIR spectrum for this compound, is consistent vvith this interpretation of Figurēs 4 and 5. Table I lists the characteristic diffraction peaks for the crystalline ceftiofur free acid of the present invention.

[0033] Furthermore, the crystalline ceftiofur free acid of the present invention, vvhich contains an amino group and a carboxylic acid group, can also be vvritten as a Zvvitterion (or dipolar ion) as shovvn in formula IA of the Formula Chart belovv. Many of its physical and Chemical properties, are consistent vvith the Zvvitterion structure. It is a nonvolatile, crystalline solid vvhich melts vvith decomposition at high temperatures; and it is insoluble in non-polar solvents, but is sparingiy soluble in vvater. One of the most sensitive and convenient analytical methods used to identify the Zvvitterion structure of a free amino acid is the infrared spectroscopy (IR). For example, asymmetric and symmetric stretching modes of the NH₃ ⁺ ion are assigned at about 3250 and 2600-2400 cm¹, respectively, vvhile the carboxylate COO' ion stretching vibration locates at about 1565 cm·¹. It is noteworthy that the C=O stretching mode of a normai carboxylic acid (not an amino acid) appears at about the 1750-1700 cm·¹ spectral range. The IR of crystalline ceftiofur free acid of the present invention at solid phase (see Figurē 2 belovv) is totally consistent vvith the Zvvitterion structure of formula IA.

[0034] The crystalline ceftiofur free acid of the present invention has advantageous physical-chemical properties. It has lovver solubility in aqueous solvents than its crystalline hydrochloride salt starting material. The lovver solubility is beiieved to contribute to its slovv dissolution rāte and its sustained release properties in-vivo, as discussed further in the Examples belovv. Also, both its hygroscopicity and stability (in bulk and formulations) are superior to other ceftiofur salts, such as the crystalline hydrochloride salt and the amorphous free acid. Additionally, the crystalline free acid is so considerably more stable, has improved Processing characteristics, and can be dried more easily due to its increased stability at elevated temperatures. All of these properties are very useful vvhen formulating a pharmaceutical product from the crystalline free acid.

[0035] A comparison of these physical-chemical properties of the crystalline ceftiofur free acid of the present invention, of the amorphous ceftiofur free acid, prepared as described in Example 1 (b) of U.S. Patent 4,464,367, and of the crystalline ceftiofur hydrochloride salt is summarized in Table il belovv. From this table, it is apparentthat the measurable properties of the crystalline free acid of the present invention are distinctly different from and superior to those of the amorphous free acid and the crystalline hydrochloride salt. Also, from this table, it is apparent that vvhile the physicalchemical properties of a compound may be expected to improve as a consequence of going from an amorphous form to a crystalline form, the favorable characteristics of crystalline ceftiofur free acid relative to crystalline ceftiofur hydrochloride salt vvere unpredictable and unanticipated. Surprisingiy and unexpectedly, the crystalline free acid of the present invention is anhydrous, vvhereas thecrystalline hydrochloride salt exists as eitherthe hemihydrate orthe monohydrate, or as a mixture of the tvvo, at normai ambient relative humidity. The anhydrous nature of the free acid lends itself to improved formulation characteristics. Also, as further demonstrated in the Examples belovv, crystalline free acid has sustained release properties in vivo vvhile the crystalline hydrochloride does not have useful sustained release properties.

[0036] Another propertyof these ceftiofur compounds, vvhich is compared in Table II, is their thermal stability (differential scanning calorimetry (DSC) decomposition temperature). (The decomposition temperatures given belovv and in Table II are approximate and are the result of a single reading from typical lots of these compounds.) Ceftiofur is thermally unstable in the solid-state at high temperatures. Liquefaction is accompanied by decomposition. Underthese circumstances, it is more useful to compare decomposition temperatures than melting temperatures, because the sample decomposes before the melting process is complete. DSC is a convenient technique for monitoring the heat evolved during sample decomposition. The peak decomposition temperatures and the onset of decomposition can be extracted from the profilē of heat flovv as a funetion of temperature.

[0037] Decomposition of ceftiofur free acid and ceftiofur hydrochloride salt is exothermic and occurs in tvvo stages. The first stage of decomposition occurs at lovver temperatures and is largely complete before the second stage begins. The first stage of decomposition producēs an exothermic peak in the DSC at a temperature that depends on the solid phase. The onset for this peak is typically measured as an intersection of the baseline and the peak upslope. Since the onset provides a good estimate of the temperature vvhere decomposition begins, it reflects the thermal stability of the solid phase.

[0038] Underthetypical DSC scan conditions of5’C/minute, the onset temperature for atypical sample of amorphous ceftiofur free acid vvas about 144°C. The broad decomposition exotherm had a peak temperature of about 177°C. Under the same conditions, the onset temperature for a typical sample of crystalline ceftiofur free acid vvas about 212’C, and the peak temperature vvas about 222°C. The increased onset temperature for the crystalline ceftiofur free acid reflects a large enhancement in the thermal stability of the crystalline phase as a consequence of the regular paeking of molecules in the crystalline lattice.

[0039] As noted above, ceftiofur hydrochloride salt is another crystalline solid containing the ceftiofur molecule. At the DSC scan rāte of 5°C/minute, the onset temperature for thermal decomposition in a typical sample of ceftiofur hydrochloride salt vvas 187°C, and the peak temperature vvas 192°C. Surprisingly and unexpectedly, the crystalline ceftiofur free acid has better thermal stability, as measured by DSC, than the crystalline hydrochloride salt.

[0040] Thus, as discussed above, it is not predictable vvhat properties acrystalline compound vvill have. Furthermore, and as exemplified belovv, it is not predictable how to prepare the crystalline form of any given compound.

[0041 ] Typically to achieve the crystalline form of an organic compound, the compound is placed in an organic solvent in vvhich it is minimally soluble at room temperature, and then heated to obtain a solution of the compound. The solution is cooled dovvn and during this cooling period, the compound vvill crystallize out.

[0042] The preparation of crystalline ceftiofur hydrochloride is considered to involve a typical crystallization. Several methods for the preparation of ceftiofur hydrochloride are described in U.S. Patent 4,902,683. In one readily used method, once the hydrochloride salt is obtained by adding hydrochloric acid to a vvater/acetone solution of ceftiofur, the resulting solution is cooled slowly to obtain crystalline ceftiofur hydrochloride.

[0043] Hovvever, the preparation of crystalline ceftiofur free acid of the present invention provides a surprising and unique approach to the preparation of a crystalline compound. In the process of the present invention, heat is necessary to inducē crystallization of ceftiofur free acid. For example, in one readily used method of the present invention, a tetrahydrofuransolutionofceftiofurfree acid is added to hot vvater vvith stirring. Initially, theceftiofurfree acid precipitates out as an amorphous solid; hovvever, continued stirring and heating of the solution results in the formation of crystailine ceftiofur free acid, vvhich is a single polymorph.

[0044] Such a method for inducing the crystallization of a compound is not typical. In fact, vvhen a chemist places an organic compound in an organic, vvater-miscible solvent, and dilutes tiffs solution vvith vvater to cause precipitation (commonly termed vvater knockout), one vvould most commonly expect to obtain an amorphous, not a crystalline, compound.

[0045] More specifically, the crystalline form of ceftiofur free acid of the present invention is prepared by combining the crystalline ceftiofur hydrochioride of formula II, prepared as described in U.S. Patent 4,902,683, which is hereby incorporated by reference herein, vvith any of several different organic/aqueous Solutions, including 1:1 Solutions of vvater vvith a vvater miscible solvent, such as acetone, acetonitrile, methanol, tetrahydrofuran (THF) or isopropanol, or a 3:7 solution of vvater vvith a vvater miscible solvent, such as ethanol. The use of the polyvinylpyridine resin to neutralize the hydrochloride salt of ceftiofur is further described in U.S. Patent 4,937,330 (Sacks et al.), vvhich is hereby incorporated by reference herein.

[0046] The preferred procedure for the preparation of crystalline ceftiofur free acid begins vvith crystalline ceftiofur hydrochloride, vvhich is treated vvith polyvinylpyridine resin in atetrahydrofuran-watermixtureto remove the hydrochloride from ceftiofur. After filtration of this mixture to remove the polyvinylpyridine resin, the filtrate is added slowly to vvater, vvhich is preferred, or the vvater is added to the filtrate. The vvater must be at a temperature of betvveen 40°C and 60°C. Most preferably, the vvater is at approximately 50’C. The ratio of vvater to filtrate is in the range of 10:1 to

2:1. Preferably, the ratio of vvaterto filtrate is approximately 3:1. This mixture is then stirred for a time period of betvveen thirty (30) minūtes and twenty-four (24) hours. Preferably, it is stirred for a time period of betvveen thirty (30) minūtes and four (4) hours. More preferably, it is stirred for approximately tvvo (2) hours. Most preferably, it is stirred for betvveen thirty (30) minūtes and one (1) hour. Finally, the mixture is filtered, preferably immediately, and dried by procedures vvell knovvn to one of ordinary skill in the art to obtain the crystalline free acid of the present invention. Example 3 belovv is the most preferred process for the preparation of the crystalline free acid of the present invention.

[0047] By modifying the above described procedure, (e.g., length of heating and stirring) compositions of ceftiofur free acid, containing varying percentages of crystalline free acid, may be obtained. For example, longer periods of heating and stirring typically result in compositions containing more crystalline free acid. Compositions containing at least forty percent (40%) or fifty percent (50%) of the crystalline free acid are preferred, vvith compositions containing at least seventy percent (70%) being most preferred.

[0048] The crystalline ceftiofur free acid of the present invention is useful as the active antibiotic drug compound in pharmaceutical dosage forms for treating valuable mammalian animals and humāns to treat bacterial infections in that valuable animal or human. Presently it is contemplated that this compound will be especially useful as a veterinary antibiotic drug to treat valuable animals such as cattle, svvine, horses, sheep, goats, dogs and cats to fight the effects of bacterial infections caused by susceptible organisms, such as Pasturella hemolitica, Pasturella multiocida, Salmonella typhimurium, Salmonella choleraeasuis, Actinbacillus plearopneumoniae, Streptococcus suis, Haemophilus somnus, E. coli, Staphylococcus aureus and the like, some of vvhich are commonly associated vvith diseases in animals, such as bovine respiratory disease and svvine respiratory disease.

[0049] The term dosage unit form as used in this specification refers to physically discrete units suitable as unitary dosages for mammalian subjects, each unit containing as the essential active ingredient a predetermined quantity of the crystalline ceftiofur free acid of this invention vvith the required pharmaceutical means vvhich adapt said ingredient for systemic administration. The specification for the novel dosage unit forms of this invention are dictated by and directly dependent on the physical characteristics of the essential active ingredient and the particular effect to be achieved in vievv of the limitations inherent in the art of compounding such an essential active material for beneficial effects in humāns and animals as disclosed in detail in this specification. Examples of suitable dosage unit forms in accordance vvith this invention are liquid preparations in suitable liquid vehicles for intramuscular, intramammary and intravenous administration, suppositories and sterile dry preparations forthe extemporaneous preparation (mixing just prior to administration) of sterile injectable preparations in a suitable liquid vehicle or for administration as a solid implant. Suitable solid diluents or carriers for the solid pharmaceutical dosage unit forms are selected from the group consisting of lipids, carbohydrates, proteins and mineral solids, for example, starch, sucrose, lactose, kaolin, dicalcium phosphate, gelatin, acacia, corn syrup, com starch, talc and the like. Liquid preparations are prepared in vvater or aqueous vehicles vvhich advantageously contain suspending aģents, for example, methylcellulose, alginates, tragacanth, pectin, kelgin, carragenan, acacia, polyvinylpyrrolidone, polyvinyl alcohol, and the like, to increase the viscosity of the composition. Additionally for injectable forms, the formulation must be sterile and may be fluid to the extent that easy syringeability exists or may be solid for implants. Such preparations must be stable under the conditions of manufacture and storage, and ordinarily contain in addition to the principal solvent or suspending liquid, preservatives in the nature of bacteriostatic and fungistatic aģents, for example, parabens, chlorobutanol, benzyl alcohol, benzoic acid, phenol, thimerosal, and the like to preserve the composition against microorganisms. In many cases, it is preferable to include osmotically active aģents, for example, sugars or sodium chloride in isotonic concentrations. Carriers and vehicles include vegetable oils, dimethylacetamide, dimethylformamaide, ethyI lactate, ethyI carbonate, isopropyl myristate, ethanol, polyols, for example, glycerol, propylene glycol, liquid polyethylene glycol, and the like. Any solid preparations for subsequent extemporaneous preparation of sterile injectable preparations are sterilized, by exposure to heat, cobalt 60 irradiation, or by exposure to a sterilizing gas, for example, ethylene oxide. The aforesaid carriers, vehicles, diluents, surfactants, excipients, preservatives, isotonic aģents and the like constitute the pharmaceutical so means vvhich adapt the preparations for systemic administration.

[0050] The various pharmaceutical dosage forms exemplified in U.S. Patent 4,902,683 (Amin et al.), especially columns 9-16, and the antibiotic implants disclosed in U.S. Patent No. 5,079,007 (Putnam), are also hereby incorporated by reference herein.

[0051] Due to the lovver solubility of the crystalline ceftiofur free acid, its rāte of dissolution is slovver. As a result the absorption rāte is less, and thus various controlled release or sustained-release formulation(s) can also be prepared using it. A controlled release or sustained-release formulation can be more conveniently given once per treatment as opposed to being given daily vvith other formulations. For example, Ceftiofur Sodium, vvhich is currently marketed as NAXCEL® or EXCENEL® Sterile Solution, is administered IM in daily doses over a three to five day period.

[0052] Using the criteria for sustained release as the time vvhich plasma concentrations remain above some minimum concentration (t_{>0 2}), a comparison of various derivatives of ceftiofur can be made. In aqueous formulations, an inverse rank order correlation is seen (as expected from solubility data) betvveen the aqueous solubility at neutral pH and the time above the selected minimum concentration for the ceftiofur salts (sodium < crystalline hydrochloride < crystalline free acid < zinc). In oil formulations, an unexpected order of duration is seen (sodium < crystalline hydrochloride < zinc < crystalline free acid), vvith the crystalline free acid being the longest. This difference is of practical and statistical significance. Since the crystalline hydrochloride had much greater solubility than the crystalline free acid, this data shovvs the sustained-release property of the crystalline free acid, especially in oil formulations, vvhich is further exemplified in Examples 5 and 6 belovv.

[0053] The preparation of such oil formulations is vvell knovvn to one of ordinary skill in the formulation art. Conventional oil formulations and methods for their preparation are set forth in U.S. Patent 5,013,713 (Mitchell), vvhich is hereby incorporated by reference herein, specifically, column 6, lines 17-59; column 7, lines 22-37; column 7, line 48, through column 8, line 4; and column 9, line 59, through column 10, line 23. Preferred oils include corn oil, peanut oil, sesame oil, olive oil, paim oil, safflovver oil, soybean oil, cottonseed oil, rapeseed oil, sunflovver oil and mixtures thereof. Most preferred is cottonseed oil.

[0054] As mentioned above, the compositions of the present invention are useful for parenteral administration, e.g., by injection intraperitoneally or, more preferably, subcutaneously or intramuscularly. Also as mentioned above, the duration of sustained-release is that period of time during vvhich the active drug is delivered at the rāte required for the desired biological effect, typically indicated by the concentration of the drug in the mammal’s circuiating blood stream. [0055] The pharmaceutical dosage unit forms of the crystalline ceftiofur free acid (active ingredient) of the present invention are prepared in accordance vvith the preceding general description to provide to the mammai undergoing treatment from about 1.1 to 6 mg/kg of the active ingredient per dosage unit form. The preferred dosage is about 2 to 6 mg/kg of the active ingredient, vvith about 4.4 mg/kg being the most preferred dosage, especially for bovine or svvine respiratory disease. Variations in the above dosages of crystalline ceftiofur free acid for the specific mammai and/or disease being treated vvould be readily knovvn and apparent to one of ordinary skill in the art of veterinary medicine. [0056] Furthermore, the amount of the active ingredient provided in the pharmaceutical dosage unit forms is that amount sufficient to obtain the antibiotic effects vvithin the aforesaid effective non-toxic dosage ranges. For example, the injectable formulations of the crystalline ceftiofur free acid of the present invention, as described above, preferably have a concentration of active ingredient of from about twenty (20) to tvvo hundred (200) mg/ml in order to provide to the mammai being treated the appropriate dosage of the active ingredient, as described above.

DETAILED DESCRIPTION OF THE INVENTION [0057] The invention is further illustrated by the follovving detailed examples. FTIR Experimental Conditions:

A. The infrared spectrum ofthe sample of Example 1 vvas collected using a Matsan Galaxy 5020 FTIR spectrometer. The sample vvas prepared as a 1% potassium bromide (KBr) peliet for data acquisition. Important instrumental parameters are listed belovv:

Resolution Sensitivity Infrared Range cm’¹ 1

4000-600 cm-¹

The infrared spectrum of Figurē 1 belovv vvas collected using this procedure. The resulting FTIR spectrum of this sample is consistent vvith the determination that it vvas amorphous.

B. The infrared spectrum ofthe sample of Example 2 vvas collected using a Digilab FTS-40 FTIR spectrometer. The sample vvas prepared as mineral oil dispersion for data acquisition. Important instrumental parameters are listed belovv:

Resolution Coadded Scan Apodization Detector Sensitivity Infrared Range cm'¹ 16

Boxcar Function MCT-B 1

4000-600 cm’¹ [0058] The infrared spectrum of Figurē 2 belovv vvas collected using this procedure. The resulting FTIR spectrum of this sample is consistent vvith the determination that it vvas crystalline.

XRD Experimental Conditions:

[0059]

Α. A Rigaku DMAX-A X-ray diffractometer vvas used for the acquisition of povvder XRD pattern for the sample of Example 2. The instrument uses the copper radiation vvith a nickel filter (CuKa, 1.5406 A). Major instrumental īo parameters are set as follovvs: 40 KV voltage, 30 mA povver, beam aperture of 1⁰ and detector aperture (receiving slit) of 0.30 mm. Ali patterns vvere scanned over the spectral range of 3-40° tvvo-theta angles vvith a scan rāte of

1.5° tvvo-theta/min (step size of 0.05° and counting time at 2 second/step). Each XRD scan produced an ASCII file vvhich vvas then converted (vvith a Galactic's SpectraCalc softvvare) to a binary format for data analysis and output. The sample vvas ground to fine povvders and packed into an aluminum tray.

TheXRD pattern of Figurē 4 and Table 1 belovv vvere collected using this procedure. The resulting XRD pattern of this sample indicated that it vvas crystalline.

Β. A Siemens D-500 diffractometer vvas used for acquisition of the povvder XRD patterns for samples of Examples 1 and 2. The instrument uses the copper radiation vvith a nickel filter (CuKa). Other parameters vvere set as follovvs: 40 KV voltage, 30 mA povver, beam aperture of 0.3°, detector aperture of 0.05°, and a continuous scan rāte of 2’ tvvo-theta/min. The chart rāte of strip chart recorder vvas set at 1.0’ tvvo-theta/cm. The spectral range is 3-40° tvvotheta. The sample vvas ground to fine povvders, if necessary, and then packed into sample tray.

[0060] The XRD patterns of Figurēs 3 and 5 belovv vvere collected using this procedure. The sample for Figurē 3 vvas a hand-ground, tan povvder. Its resulting XRD pattern indicated that it vvas amorphous. The sample for Figurē 5 vvas a tan povvder. Its resulting XRD pattern indicated that it vvas crystalline.

EXAMPLE 1 Preparation of Amorphous Ceftiofur Free Acid [0061] Using the procedure described in Example 1(b) of U.S. Patent 4,464,367 (Labeeuvvetal.) (assigned to Sanofi,

Paris, France), the ceftiofur free acid vvas obtained as follovvs:

[0062] A mixture of 50 g of tritylated ceftiofur, 83 ml of formic acid, and 83 ml of vvater is heated to 53’C to 58°C and stirred at this temperature for 30 minūtes. This slurry is filtered and the solids vvashed vvith 83 ml of 70/30 formic acid/ vvater. The filtrate is diluted vvith 334 ml of ethanol and concentrated dovvn to an oil under vacuum. This material is dried under vacuum for 60 hours. The resulting foam is slurried vvith 167 ml of ethanol. This slurry is filtered and vvashed vvith diethyl ether. The solids are dissolved in 835 ml of acetone and 1567 ml of ethanol. This solution is concentrated under vacuum to a volume of 167 ml. This slurry is cooled to 25°C and filtered. The solids are vvashed tvvice vvith ethanol and tvvice vvith ether. These solids are dried at room temperature to give about 15.1 g of amorphous ceftiofur free acid.

Physical characteristics are as follovvs:

FTIR spectrum: Figurē 1 belovv.

XRD: Figurē 3 belovv.

[0063] The FTIR and XRD spectra indicate that the title product is amorphous (noncrystalline).

EXAMPLE 2 Preparation of Crystalline Ceftiofur Free Acid [0064] A slurry of 75.12 g of ceftiofur hydrochloride in 375 ml of tetrahydrofuran and 37.5 ml of vvater is stirred at room temperature for 1 hour. To this slurry is added 37.5 g of polyvinylpyridine resin and 225 ml of tetrahydrofuran.

The resulting mixture is stirred at room temperature for 30 minūtes and then filtered. The resin is vvashed vvith 150 ml of tetrahydrofuran. The filtrate is heated to >45°C and diluted vvith 1075 ml of 50°C vvater. To this cloudy solution is added 2.25 g of crystalline ceftiofur free acid and the resulting mixture is stirred for about 10 minūtes. This slurry is then diluted further by the slow addition of 905 ml of vvater vvhile maintaining the temperature at >45°C. The resulting slurry is stirred at 50-55°C for thirty (30) minūtes to one (1) hour and is gradually cooled to 19°C and filtered. The solids are vvashed with vvater and dried vvith nitrogen to give about 65 g of crystalline ceftiofur free acid (vvhich is approximately 94.5% crystalline).

[0065] Physical characteristics are as follovvs:

FTIR spectrum: Figurē 2 below.

XRD: Figurēs 4 and 5 belovv.

[0066] The FTIR and XRD spectra indicate the title product is crystalline. Table I belovv lists the characteristics diffraction peaks for the crystalline ceftiofur free acid of the present invention. EXAMPLE 3 Preparation of Crystalline Ceftiofur Free Acid [0067] Ceftiofur hydrochloride (17.1 g) is slurried for at least one hour at room temperature vvith 70 ml of tetrahydrofuran and 5.1 ml of vvater. To this slurry are added 8.6 g of PVP resin follovved by 60 mi of tetrahydrofuran. After stirring for 45 minūtes this slurry is filtered. The PVP resin is vvashed vvith tvvo 31 ml portions of tetrahydrofuran. The filtrate is then added slowly over a period of about one hour to 515 ml of vvater at 45-55’C. This slurry is stirred at 45-55’C for 30 minūtes and filtered immediately at the end of the addition. The solids are vvashed vvith 70 ml of vvater and dried at 50’C to give 13.5 g of crystalline ceftiofur free acid. EXAMPLE 4 Sustained-Release Oil Formulation [0068] An example of a sustained-release formulation, containing the crystalline ceftiofur free acid of the present invention, vvhich is prepared by procedures readily knovvn to one of ordinary skill in the formulation art, has the follovving ingredients:

Ceftiofur Free Acid (Crystalline) Lecithin (Phospholipon 90-H) Sorbitan Mono-oleate (Span 80) Cottonseed Oil

100 mg activity per milliliter 0.5 mg per milliliter 1.5 mg per milliliter q.s.

EXAMPLE 5 Piasma Disposition of Sustained-Release Aqueous Suspensions of Ceftiofur Crystalline Free Acid in Cattle [0069] Sixteen Holstein calves vvere administered ceftiofur crystalline free acid in an aqueous suspension (100 mg/ mL) by the intramuscular (IM) or subcutaneous (SC) route of administration as a single dose of 1.1 mg ceftiofur activity/ kg in a crossover study (each calf got each treatment), vvith a tvvo-vveek vvashout betvveen doses. Blood samples vvere obtained serially for 120 hours for analysis of ceftiofur and metabolites (measured as desfuroylceftiofur acetamide by HPLC). The primary decision variable vvas the time ceftiofur metabolite concentrations remained above 0.2 μς/ηηί (t_{>0 2}), vvith secondary decision variables being relative area under the concentration-time curve (AUC) of the treatments and injection site irritancy assessed antemortem by visual and manual inspection of the injection sites over time. Both t^ 2 and AUC vvere calculated using both the predictive pharmacokinetic equation method and the direct graphical method of trapezoids (AUC) and log linear interpolation (t_{>0 2}).

[0070] The t_{>0 2} for ceftiofur crystailine free acid aqueous suspension vvas 26.98 h after IM and 30.43 h after SC administration (P = 0.257).

EXAMPLE 6 Piasma Disposition of Sustained-Release Oil Suspensions of Ceftiofur Crystalline Free Acid in Cattle: Comparison to Aqueous Solution of Ceftiofur Sodium [0071] Sixteen Holstein calves vvere administered ceftiofur crystalline free acid in an oil suspension (100 mg/mL) or ceftiofur sodium (NAXCEL® Sterile Povvder) as an aqueous solution (50 mg/mL) subcutaneously (SC) in a crossover study (each calf received each treatment), vvith a two-week vvashout period betvveen doses (2.2 mg ceftiofur activity/ kg body vveight). Blood samples vvere obtained serially for 120 hours after drug administration for analysis of ceftiofur and metabolites (measured as desfuroylceftiofur acetamide by HPLC). The primary decision variable vvas the time ceftiofur metabolite concentrations remained above 0.2 pg/mL (t_{>0 2}), vvith secondary decision variables being relative area under the concentration-time curve (AUC) of the treatments and injection site irritancy assessed antemortem by visual and manual inspection of the injection site over time. Both t_{>0 2} and AUC vvere calculated using both the predictive pharmacokinetic equation method and the direct graphical method of trapezoids (AUC) and log-iinear interpolation (L0.2)· [0072] The oil suspension of ceftiofur crystalline free acid vvas equally bioavaiiable vvith the aqueous solution of ceftiofur sodium vvhen both vvere administered subcutaneously (P>0.05). When compared to the t_{>0 2} for ceftiofur sodium (45.50 h), the t_>02 for ceftiofur crystalline free acid (121.58 h) vvas significantly longer (P<0.0001). The termiņai phase half-life (corresponding to the absorption phase in this flip-flop pharmacokinetic modei) of the crystalline free acid in oil vvas also longer.

EXAMPLE 7 In Vitro Dissolution of Ceftiofur Oil Suspension Formulations [0073] 100 mg samples of crystaliine ceftiofur free acid, amorphous ceftiofur free acid (prepared as described in Example 1) and crystalline ceftiofur hydrochloride, vvhich vvere ali prepared as oil formulations as described in Example

4 above, vvere loaded into teflon dissolution celis and sealed vvith a constant surface area dialysis membrane. The loaded celis vvere placed in a Standard dissolution apparatus containing 500 ml of pH 7 aqueous dissolution media vvhich vvas stirred by a 50 RPM rotating paddle.

[0074] The results obtained are shovvn belovv in Figurē 6 belovv. (In Figurē 6 ali formulations are 100 mg/ml. One Standard deviation is shovvn. The sample designated lovv crystallinity vvas approximately 32.7% crystalline by XRD; io the sample designated high crystallinity vvas approximately 74.7% crystalline by XRD.) The formulations containing the crystalline ceftiofur hydrochloride and the amorphous ceftiofur free acid shovv very fast release from the formulation into the dissolution media. The formulations of crystalline ceftiofur free acid, especially the highly crystalline sample, shovvs a significantly reduced release of drug into the aqueous dissolution compartment.

EXAMPLE 8 Plasma Disposition of Ceftiofur Free Acid Oil Suspensions Administered Subcutaneously in Cattle [0075] Cattle vvere administered a single subcutaneous dose (4.4 mg/kg body vveight) of crystalline ceftiofur free acid and amorphous ceftiofur free acid (both prepared and then formulated as described above in Examples 1,3 and 4). The concentration of plasma ceftiofur and desfuroylceftiofur related metabolites vvere determined over time for 120 hours. The primary decision criteria (that most related to efficacy) vvas considered to be the time that the ceftiofur metabolite concentrations remained above 0.2 mcg/ml (t_{>0 2})· Less important parameters calculated included area under the concentration-time curve (AUC) for each treatment and time to maximum concentrations (t^).

[0076] The results are shovvn graphically in Figurē 7 belovv by plotting plasma concentration of desfuroylceftiofur acetamide (DCA) versus time using average data for 6 animals/treatment. Both t^ ₂ and AUC vvere calculated using the predictive pharmacokinetic equation method and the direct graphical method of trapezoids (AUC) and log-linear interpolation (t_{>0 2}) The ¹>0.2 for crystalline ceftiofur free acid vvas 101 hours after dosing vvhereas the amorphous ceftiofur free acid gavē a value of 41 hours. Additionally, the AUCs comparison shovvs that the crystalline ceftiofur free acid has a value more than tvvice that of the amorphous ceftiofur free acid previously claimed (183 mcg hr/ml versus 70 mcg hr/ml). This is especially important in light of the tvvo forms obtaining statistically equivalent peak concentrations (9.1 mcg/ml for the amorphous ceftiofur free acid versus 7.3 mcg/ml for the crystailine ceftiofur free acid). By the secondary measure of sustained release, time to peak concentration (t_max), the crystalline form shovvs delayed release as compared to the amorphous form of ceftiofur free acid (8 hours versus 2 hours).

EXAMPLE 9 Plasma Disposition of Crystalline Ceftiofur in Oil Suspensions : Comparison of Crystalline Ceftiofur

Hydrochloride and Crystalline Ceftiofur Free Acid [0077] In separate but simiiarly designed studies conducted in the same laboratory, crystalline ceftiofur free acid (CFA) and crystalline ceftiofur hydrochloride (HCl) suspensions vvere administered subcutaneously to cattle at a dose of 2.2 mg/kg body vveight. In each experiment, plasma samples vvere obtained for up to 120 hours after drug admin40 istration for determination of ceftiofur and its metabolites. The results are shovvn graphically in Figurē 8 belovv by plotting plasma concentration (on a logarithmic scaie) versus time using average data for 16 animals/treatment. The primary decision criteria (that most related to efficacy) vvas considered to be the time that the ceftiofur metabolite concentrations remained above 0.2 mcg/ml (t_>02). Less important parameters measures included area under the concentration-time curve (AUC) for each treatment and time to peak and peak concentrations.

[0078] The AUC values vvere comparable for the tvvo crystal forms (103.3 for the crystalline hydrochloride and 121.3 for the crystalline free acid). Hovvever, the parameter, t_{>0 2}, used to describe sustained release effect vvas significantly greater for the free acid crystai form (121.6 hours versus 38.5 hours). Like the amorphous material cited in Example 8, the crystalline hydrochloride shovved faster release vvhen compared to the crystalline free acid by the criteria t_max (2 hours for the hydrochloride versus 8 hours for the crystalline).

BRIEF DESCRIPTION OF DRAVVINGS

Figurē 1 [0079] FTIR Spectrum of Amorphous Ceftiofur Free Acid

Figurē 2 [0080] FTIR Spectrum of Crystalline Ceftiofur Free Acid

Figurē 3 [0081] XRD Diffraction Pattern of Amorphous Ceftiofur Free Acid

Figurē 4 [0082] XRD Diffraction Pattern of Crystalline Ceftiofur Free Acid

Figurē 5 [0083] XRD Diffraction Pattern of Crystalline Ceftiofur Free Acid

Figurē 6 [0084] Ceftiofur Oil Suspension Dissolution Comparison

Figurē 7 [0085] Plasma Disposition Profilē of Ceftiofur Free Acid: Amorphous vs. Crystalline

Figurē 8 [0086] Ceftiofur in Plasma: Ceftiofur HCl vs. Ceftiofur CFA

Figurē 9 [0087] Ceftiofur Dissolution Rāte Comparison

FORMULA CHART

II

och₃

Formula I

Formula IA

Formula Π

TABLE I

CHARACTERISTIC XRD DIFFRACTION PEAKS OF CRYSTALLINE CEFTIOFUR FREE ACID
Two-Theta Angie” (degree)	d-Spacing (Angstrom)	Relative lntensity#, ~(arbitrary)
38.45*	2.339	65
38.20	2.354	25
36.85	2.437	13
35.35	2.537	25
32.35	2.765	26
28.30	3.151	31
27.80	3.206	28
27.15	3.282	40
25.65	3.470	95
25.25	3.524	68
24.45	3.638	53
23.50	3.783	40
21.60	4.111	60
21.40	4.149	48
19.85	4.469	70
18.15	4.884	56
15.30	5.786	100
14.50	6.104	37
10.55	8.379	35
8.60	10.273	29

*: diffraction peak of the Aluminum sample tray :±0.10·

The relative intensity for each peak is determined by ratioing its intensity to Ihat of the strongest peak at 15.3 ’ angie as 100. °° The peaks that are reported in this table are those having a relative intensity greater than 10.

TABLE II

COMPARISON OF PROPERTIES OF CRYSTALLINE CEFTIOFUR FREE ACID, AMORPHOUS CEFTIOFUR FREE ACID, AND CRYSTALLINE CEFTIOFUR HYDROCHLORIDE
Properties	Crystalline Free Acid	Amorphous Free Acid	Crystalline Hydrochloride Salt
Thermal Stability (DSC decomposition temperature)	peak = 222°C	peak =177°C	peak= 192°C
Solubility - pH7	= 8 mg/mL	= 100 mg/mL	= 100 mgmL
Dissolution Rāte*	Slovv	Fast	Fast
In Vivo Release	Prolonged	Fast	Fast
Purity	High	Lovv	High

*Shown graphically in Figurē 9 below.

TABLE II (continued)

COMPARISON OF PROPERTIES OF CRYSTALLINE CEFTIOFUR FREE ACID, AMORPHOUS CEFTIOFUR FREE ACID, AND CRYSTALLINE CEFTIOFUR HYDROCHLORIDE
Properties	Crystalline Free Acid	Amorphous Free Acid	Crystalline Hydrochloride Salt
Stability in Aqueous Formulations (>90% initial potency)	Stable for 6 months	Unstable in 6 vveeks	Unstable in 6 vveeks
Hygroscopity	Lovv	High	Moderate
Processing	Micronizes easier	Difficult to micronize	Micronizes easier

Claims

Claims (20)

IZGUDROJUMA FORMULA

1. Savienojums, kas ir kristāliska ceftiofūra brīva skābe.

2 tēta leņķis** (grādi) Starpplakņu attālums (angstrēmi) Relatīvā intensitāte*, °° (pieņemtas vienības) 38,20 2,354 25 36,85 2,437 13 35,35 2,537 25 32,35 2,765 26 28,30 3,151 31 27,80 3,206 28 27,15 3,282 40 25,65 3,470 95 25,25 3,524 68 24,45 3,638 53 23,50 3,783 40 21,60 4,111 60 21,40 4,149 48 19,85 4,469 70 18,15 4,884 56 15,30 5,786 100 14,50 6,104 37 10,55 8,379 35 8,60 10,273 29

**: ±0,10° *: Katras smailes relatīvā intensitāte ir noteikta kā tās intensitātes attiecība pret 10 lielākās smailes 15,3° leņķī intensitāti, kas ir 100.

oo; Smailes, kas ietvertas šajā tabulā, ir tās, kuru relatīvā intensitāte ir lielāka par 10.

2. Savienojums saskaņā ar 1. punktu, kas uzrāda pamatā sekojošas pulvera rentgenstaru difrakcijas īpašības:

3. Savienojums, kas ir ceftiofura brīva skābe, pie kam 40% savienojuma ir kristāliskā veidā.

4. Savienojums saskaņā ar 3. punktu, pie kam vismaz 50% savienojuma

5 apmēram 50° C.

5. Savienojums saskaņā ar 3. punktu, pie kam vismaz 70% savienojuma ir kristāliskā veidā.

īo

5 ir kristāliskā veidā.

6. Farmaceitiska kompozīcija, kas satur savienojumu saskaņā ar jebkuru no iepriekšējiem punktiem un farmaceitiski pieņemamu nesēju vai palīgvielu.

7. Kompozīcija saskaņā ar 6. punktu, kas ir ilgstošas izdalīšanās

8. Kompozīcija saskaņā ar 6. punktu vai 7. punktu, kas satur 20 līdz 200 mg/ml savienojuma.

20

9. Kompozīcija saskaņā ar jebkuru no 6. punkta līdz 8. punktam, kas ir piemērota, lai to ievadītu ar subkutānām vai intramuskulārām injekcijām.

10. Kompozīcija saskaņā ar jebkuru no 6. punkta līdz 9. punktam, kas ir

25 bezūdens kompozīcija.

11. Kompozīcija saskaņā ar 10. punktu, pie kam nesējs vai palīgviela ir ella.

30

12. Kompozīcija saskaņā ar 11. punktu, pie kam eļļa ir izvēlēta no kukurūzas eļļas, zemesriekstu eļļas, sēžama eļļas, olīveļļas, palmu eļļas, saflora eļļas, sojas pupu eļļas, kokvilnas sēklu eļļas, rapšu sēklu eļļas, saulespuķu eļļas un to maisījumiem.

35

13. Kristāliskas ceftiofūra brīvas skābes iegūšanas paņēmiens, kas ietver ceftiofura brīvas skābes vai hidrohlorīda šķīduma acetonā vai tetrahidrofurāna (THF) kombinēšanu ar ūdeni 40°C līdz 60° G temperatūrā.

14. Paņēmiens saskaņā ar 13. punktu, pie kam ūdens temperatūra ir

15. Process saskaņā ar 13. punktu vai 14. punktu, pie kam šķīdums ir THF.

w

15 kompozīcija.

16. Process saskaņā ar 15. punktu, pie kam ūdens attiecība pret THF šķīdumu ir 10:1 līdz 2:1.

17. Process saskaņā ar 16. punktu, pie kam ūdens attiecība pret THF šķīdumu ir apmēram 3:1.

18. Paņēmiens saskaņā ar jebkuru no 13. punkta līdz 17. punktam, kas papildus ietver kombinācijas maisīšanu laika periodā starp 30 minūtēm un 24 stundām.

20

19. Paņēmiens saskaņā ar 18. punktu, pie kam laika periods ir starp 30 minūtēm un 4 stundām.

20. Paņēmiens saskaņā ar 18. punktu, pie kam laika periods ir starp 30 minūtēm un 1 stundu.