FORMULATIONS CONTAINING TRIAZINONES AND IRON WITH A LOW AMOUNT OF FREE IRON IONS

Abstract

Formulations containing triazinones, selected from toltrazuril, ponazuril and diclazuril, a polynuclear iron(III) polysaccharide complex compound which are suitable for the simultaneous control of coccidiosis and anaemic states in animals and which exhibit a low amount of free iron ions even after storage, while the formulations comprises Ca.sup.2+ and Na.sup.+ in a molar ratio of Ca.sup.2+:Na.sup.+ from ≥0 to ≤3. In one embodiment the triazinone is toltrazuril and the polynuclear iron(III) polysaccharide complex compound is iron(III) dextran glucoheptonate.

Claims

1. A formulation comprising a triazinone selected from the list consisting of toltrazuril, ponazuril and diclazuril, a polynuclear iron(III)polysaccharide complex compound, and a molar ratio of Ca.sup.2+ to Na.sup.+ from ≥0 to ≤3, with the exception of sodium propionate and/or sodium benzoate being the sole source of Na.sup.+ in the formulation when the molar ratio of Ca.sup.2+ to Na.sup.+ is 0.

2. A formulation according to claim 1, with the further exception of those formulations being selected from the list consisting of a. a formulation, consisting of 3.5% toltrazuril, 17.8% of iron (as Gleptoferron), 0.1% of sorbitan monooleate, 10% diethylene glycol monoethyl ether, 1% of sodium chloride, and Water ad 100%, b. a formulation, consisting of 3.5% toltrazuril, 19.3% of iron (as Gleptoferron), 0.3% of Propylene Glycol Monolaurate, 0.1% of copolymer Polyoxyl 35-hydrogenated castor oil, 1% Sodium Chloride, and Water ad 100%, c. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 0.1% Sodium Docusate, 0.1% silicone emulsion, l.5% sodium chloride, and Water ad 100%, d. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 0.1% Sodium Docusate, 5% diethylene glycol monoeethyl ether, 0.1% silicone emulsion, 1% sodium chloride, and Water ad 100%, e. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 0.6% Phenole, 0.2% Sodium Docusate, 0.1% simethicone emulsion USP 30%, 0.5% colloidal silicone dioxide, 1% povidone, 0.5% sodium chloride, and Water ad 100%, f. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 0.6% Phenole, 0.2% Sodium Docusate, 0.1% simethicone emulsion USP 30%, 0.5% colloidal silicone dioxide, 1% povidone, 1% sodium chloride, and Water ad 100%, g. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 0.6% Phenole, 0.1% Sodium Docusate, 0.1% simethicone emulsion USP 30%, 0.5% colloidal silicone dioxide, 1% povidone, 1% sodium chloride, and Water ad 100%, h. a formulation, consisting of 2.9% toltrazuril, 18.8% of iron (as Gleptoferron), 0.6% Phenole, 0.1% Sodium Docusate, 0.1% simethicone emulsion USP 30%, 0.5% colloidal silicone dioxide, 1% povidone, 1% sodium chloride, and Water ad 100%, i. a formulation, consisting of 2.9% toltrazuril, 18.8% of iron (as Gleptoferron), 0.3% of sorbitan monooleate, 0.1% of copolymer 15 Polyoxyl 35 -hydrogenated castor oil, 1.5% of sodium chloride and water, j. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 0.3% of sorbitan monooleate, 0.1% of copolymer Polyoxyl 35-hydrogenated castor oil, 1.5% of sodium chloride and water, and k. a formulation, consisting of 4.2% toltrazuril, 13.5% of iron (as Gleptoferron), 1% of sodium chloride, 1% of polyvinylpyrrolidone, 0.6% of phenol, 0.5% of colloidal silicon dioxide, 0.1% of sodium docusate, 0.1% of simethicon emulsion and water.

3. The formulation according to claim 1, wherein the formulation has a molar ratio of Ca.sup.2+ to Na.sup.+ from >0 to ≤3.

4. The formulation according to claim 1, wherein Ca.sup.2+ and Na.sup.+ are present as their respective chloride salts.

5. The formulation according to claim 4, wherein the total content of CaCl.sub.2 and NaCl is from ≥0.1% (m/V) to ≥3% (m/V).

6. The formulation according to claim 1, wherein active iron in the form of the polynuclear iron(III) polysaccharide complex compound is present from ≥10% (m/V) to ≤30% (m/V).

7. The formulation according to claim 1, wherein the triazinone is toltrazuril and the polynuclear iron(III) polysaccharide complex compound is iron(III)dextran glucoheptonate.

8. The formulation according to claim 1, wherein the formulation also comprises at least one non-ionic surfactant.

9. A method of simultaneous treatment of a coccidial infection and an iron deficiency, comprising administering to a mammal in need thereof a formulation according to claim 1.

10. The method according to claim 9, wherein the formulation is administered by parenteral application.

11. The method according to claim 9, wherein the formulation is administered by injection.

12. The method according to claim 9, wherein the mammal is a piglet in the period from birth to 10 days after birth.

13. A method of imparting a content of dissolved free iron of ≤3500 ppm in a formulation comprising a triazinone selected from the list consisting of toltrazuril, ponazuril and diclazuril, and a polynuclear iron(III) polysaccharide complex compound, after storage at a temperature of ≥20° C. to ≤40° C. for at least 6 months, the method comprising providing in the formulation Ca.sup.2+ and Na.sup.+ in a molar ratio of Ca.sup.2+ to Na.sup.+ from ≥0 to ≤3.

Description

EXAMPLES

[0167] Analytical Methods Applied

[0168] In general, many methods are known to those skilled in the art to determine the amount of free iron in the formulations according to the present invention and the present invention is not bound to or depending on any particular method. More specifically, it's shown in the subsequent set of experiments, that a formulation comprising a certain ratio of CaCl.sub.2:NaCl is beneficial in terms of stabilizing the complexed iron therein and that this is independent from the analytical methods applied to determine the free iron content in any of the formulations.

[0169] It is also understood that the content of free iron measured in absolute numbers may differ from method to method, as the methods vary in their ability to detect different species of labile iron (i.e. iron that is not yet freely dissolved but still partially complexed in a defective polysaccharide complex compound). The effect of minimizing the content of free iron according to the present invention, is however not relying on these differences, as any of the methods would—regardless of absolute value measured—always measure a decrease of free iron as a function of the molar ratio of Ca.sup.2+ to Na.sup.+, which is the relevant finding of this invention.

[0170] Polarography:

[0171] In case polarography is used to detect the amount of free iron in the formulations, the below described method is applied throughout the Examples of this invention.

[0172] A “Metrohm VA 797 Computrace” with mercury multi-mode electrode (MME), platinum auxiliary electrode and reference electrode “Ag/AgCl/KCl (3 mol/l)” was used as a polarograph.

[0173] The polarograph was equipped with an automatic dosing unit (Dosino 800) and a sampler (863 Compact VA Autosampler) The voltammetric process is performed in DPP mode using a dropping mercury electrode. Freely available iron ions are detected electrochemically on the mercury with Triethanolamine in an alkaline medium. A quantitative evaluation is performed using the standard addition process.

[0174] Any samples were prepared by transferring approximately 1 mL of a freshly shaken sample to a 10 mL volumetric flask on an analytical balance and the actual weight of the sample is recorded. The flask is filled to the calibrating mark with ultrapure water and shaken vigorously.

[0175] To produce a calibration solution and amount of FeCl.sub.3, corresponding to approximately 100 mg of iron (accurate to 0.1 mg) is measured into a 100 mL volumetric flask, dissolved with ultrapure water, and approximately 1 mL of concentrated hydrochloric acid is added and filled to the calibrating mark with ultrapure water. To result in a nominal concentration of 1 g/L

[0176] To produce the supporting electrolyte, 4.48 g triethanolamine and 0.56 g potassium hydroxide is dissolved in 100 mL ultrapure water.

[0177] The actual polarography was thereafter conducted after having added 10 mL of the supporting electrolyte to the sample and then starting the hereinafter measurement protocol.

[0178] At first, a blank value measurement is taken. Thereafter, 1 mL sample solution is added. The measurement signal of the sample solution had to be within the verified linear range of the equipment. If the first readout was beyond the verified linear range, the sample quantity was reduced (e.g. from 1 mL to100 μL) until the readout was well within the verified linear range.

[0179] Thereafter 100 μL of calibration solution was added twice. On the basis of the current (nA) readout of sample and current (nA) readout of the calibration solution (taken twice) the free iron content is computed from the peak heights using a linear regression mode, using the below equation:

[00001]$W\left(\mathrm{Fe}\right)=\frac{m\left(s\right)I\left(p\right)}{m\left(p\right)I\left(s\right)}\left[\frac{\mathrm{.Math.g}}{g}\right]$

[0180] With W(Fe) being the content of free iron in a given sample [mg/kg], m(s) being the mass of iron [μg] in the calibration solution, I(p) being the current (nA) measured for the sample, I(s) being the current (nA) measured for the calibration solution and m(p) being the mass (g) of the sample measured.

[0181] Dialysis

[0182] In case dialysis is used to detect the amount of free iron in the formulations, the below described method is applied throughout the Examples of this invention. Dialysis—actually being rather purification than a measurement method—is hereinafter taken synonymously for the two step application of dialysis and subsequent inductively coupled plasma atomic optical emission spectrometry (ICP-OES) of the dialyzed samples.

[0183] The sample formulation is therefore placed in a dialysis tube to have the free iron diffusing into the water acceptor phase around the dialysis tube to thereafter quantitatively analyze the free iron in the acceptor phase by ICP-OES using a Varian Vista Pro device.

[0184] In any of the measurements taken hereinafter, a 6.3 mm ( 8/32 inch) dialysis tube with 12000-14000 Dalton pore size was used (e.g. Medicell Int. Ltd. Dialysis tubing Visking Code DTV12000.01.000; or Roth Dialysis tube Visking, Cellulose type 8/32 inch, thickness 0.05 mm, width 10 mm). From said dialysis tube about 30 cm are taken and closed with a knot on one end, which then is widened by pressurized air.

[0185] A bottle containing a representative sample of the formulation to be analyzed is shaken carefully to potentially re-suspend and homogenize and using a syringe about 3 mL of the sample are withdrawn therefrom and filled into the dialysis tube. The tube is carefully placed into a 30 mL test tube which is filled with 20 mL of deionized water, while the open end of the dialysis tube is fixed at the test tube with a screw cap. The time allowed for dialysis is about 24 h at a temperature of about 22° C.

[0186] Thereafter the dialysis tube is carefully removed and an aliquot of the acceptor phase water is taken and made subject to ICP-OES.

[0187] The aliquot volume varied depending on the content of free iron and optimum detection conditions of the ICP-OES device (i.e. either the aliquot amount is reduced or increased, if the free iron content is not well within the reliable range of measurement of the device). Accordingly, further dilution of the sample was sometimes necessary.

[0188] Photometry

[0189] In case photometry is used to detect the amount of free iron in the formulations, the below described method is applied throughout the Examples of this invention.

[0190] In general this analytical method is described well in Ph. Eur.2.2.25, clarifying that it relies on a color reaction of free iron with Bathophenantroline and subsequent spectrophotometric detection

[0191] To generate a calibration standard, eight volumes of the iron standard solution (10 μg/mL Fe.sup.3+ as Fe(NO.sub.3).sub.3 in equal steps from 1 to 8 mL) were each added up to 10 mL with purified deionized water.

[0192] To these solutions, 5 mL hydroxylamin hydrochlorid solution (10% M/V), 10.0 mL bathophenantroline solution (0.0332% M/V) and 5.0 mL sodium acetate solution (10% M/V) were added and stored for later use.

[0193] 0.8 to 1.0 g of either sample formulation or calibration solution were each added into a 250 mL flask and diluted with purified deionized water ad 250 mL. From those an aliquot of 10 mL is transferred into a separate flask. In case of a sample, again 5 mL hydroxylamin hydrochlorid solution, 10.0 mL bathophenantroline solution and 5.0 mL sodium acetate solution were added (just as described above in the context of the calibration standard) and the solutions was mixed.

[0194] The mixture (with either the sample or the calibration solution) was stored for 30 min at room temperature.

[0195] Next, the mixture is extracted twice with trichloromethane in a separatory funnel, while the two resulting trichloromethane phases are thereafter combined into a 50 mL calibration flask and the volume completed ad 50 mL with 2-propanol.

[0196] The solution is filled into a cuvette and the adsorption is measured against 2-propanol as reference standard at 533 nm with a calibrated standard spectrophotometer of any type.

[0197] Method for Preparing the Formulations of the Susequent Examples

[0198] Any formulations described and exemplified in the context of the present invention may be prepared with any method which is appropriate for a person skilled in the art.

[0199] Still, the formulations according to the subsequent examples were prepared according to the general process hereinafter, outlined by means of one specific example of a formulation having 2.72% MN toltrazuril, 18.2% MN active iron, 0.5% MN phenol and any desired amount of any surfactants.

[0200] A 15% M/M pre-suspension of Toltrazuril in the iron (III) dextran glucoheptonate (Gleptoferron) colloidal solution was produced first. In a second step, the suspended toltrazuril in the crude suspension concentrate was micronized by wet bead milling. In a third step, the obtained suspension concentrate was diluted with calculated amounts of iron (III) dextran glucoheptonate (Gleptoferron) colloidal solution, surfactant(s) and preservative (phenol) stock solutions, and water to add up to the desired final concentration. The salts were also added during this third step.

[0201] The respective surfactants and preservatives were always added by means of adding a higher concentrated stock solution of the respective preservative and/or surfactants, while—in the context of the subsequent examples—the stock solutions were a 50% M/M Tween 20 stock solution, a 25% M/M Tween 80 stock solution, 5% M/M Docusate Sodium stock solution for the surfactants and a 5% M/M Phenol stock solution for the preservative.

[0202] The above referred to 15% M/M toltrazuril pre-suspension is prepared by filling a suitable amount of iron (III) dextran glucoheptonate (Gleptoferron) colloidal solution into a beaker and adding necessary amounts of surfactant to obtain 0.6% M/M Tween 20, 0.3% M/M Tween 80 and 0.15% M/M Docusate sodium. In this first step, Tween 80 and Tween 20 are added as 100% substance.

[0203] The solution is stirred with a dissolver disc. Then, under continuous stirring, the calculated amount of Toltrazuril is added to obtain a 15% M/M dispersion. The dispersion is stirred with the dissolver disc for 10 minutes and subsequently homogenized with an ultra-turrax at 9500rpm for another 10 minutes to produce a homogenous pre-suspension.

[0204] In the above referred to second step of micronization by wet bead milling, the milling chamber of the bead mill (Dyno-Mill KDL , Willy A Bachhofen AG, 300 mL milling chamber volume) is filled with ZrO2/Y-millig beads (0.6-0.8 mm diameter; 75% chamber fill grade). The pre-suspension is stirred with a paddle-stirrer and then conveyed through the bead mill by the use of a peristaltic pump at a flow rate of 30-40 g/min. The milled suspension is discharged in a second beaker. The milling process is usually repeated two to three times to obtain the desired fine particle size of the toltrazuril.

[0205] The thereby obtained suspension concentrate is taken as stock-suspension and starting point of the third step mentioned above. For a 1000 mL final suspension, 181.3 g of the concentrate are weighed into a 2000 mL beaker. The amounts of iron (III) dextran glucoheptonate, phenol stock solution, surfactant stock solutions and q.s. water to be added are calculated to obtain a final suspension containing 2.72% M/V toltrazuril, 18.2% M/V active iron, 0.5% M/V phenol and the desired surfactant concentrations.

[0206] The amounts of salt and surfactant solutions are calculated to obtain the % M/V percentages given in the respective examples. Under continuous stirring with a paddle stirrer, the suspension concentrate becomes diluted with the calculated amount of the iron (III) dextran glucoheptonate (Gleptoferron) colloidal solution. Next, the calculated amounts of NaCl and CaCl.sub.2 are added and dissolved. Then the calculated amounts of the surfactant stock solutions and the phenol stock solution are added with a pipette. The suspension is then quantitatively transferred into a 1000 mL volumetric flask and filled up to 1000 mL with deionized water.

Example 1

[0207] Formulations containing 3.64% MN toltrazuril, 18.2% MN active iron (added in the form of Gleptoferron 20% MN iron), 0.5% MN phenol, 0.09% MN nonionic surfactant polysorbate 80 (Ph.Eur. name; also termed Tween™ 80 as trade name or polyoxiethylene sorbitan monostearate as the chemical name), 0.14% M/V nonionic surfactant polysorbate 20 (Ph. Eur.name; also termed Tween™ 20 as trade name or polyoxiethylene sorbitan monolaurate as the chemical name), and mixtures of sodium chloride and calcium chloride according to Table 1 were prepared.

[0208] The samples were analyzed by polarography for the content of free iron after the periods and at conditions of storage as stated in Table 1.

TABLE-US-00001 TABLE 1 Formulations of Example 1 and free iron content measured as a function of salt ratio Iron Iron (3 Iron (3 Iron (6 Iron (6 Iron (9 Iron (9 (10 d at months months months months months months [% M/V] or 25° C.) at 30° C.) at 40° C.) at 30° C.) at 40° C.) at 30° C.) at 40° C.) Salt or ratio ratio [g/100 mL] [g/100 mL] [g/100 mL] [g/100 mL] [g/100 mL] [g/100 mL] [g/100 mL] a CaCl.sub.2 0.3 0.0465 0.065 0.117 0.087 0.164 0.086 0.162 NaCl 0.9 n(CaCl.sub.2/NaCl) 0.175 b CaCl.sub.2 1 NaCl 3 n(CaCl.sub.2/NaCl) 0.175 c CaCl.sub.2 0.5 0.044 0.059 0.108 0.075 0.153 0.082 0.159 NaCl 2 n(CaCl.sub.2/NaCl) 0.132

[0209] From the above data, it can be seen that the content of free iron is less at a lower molar ratio of CaCl.sub.2:NaCl. The effect is more pronounced if more harsh (higher temperature) storage conditions.

[0210] For the formulations a and b of example 1, both having the identical molar ratio of CaCl.sub.2:NaCl the respective average is displayed. The measured amount of free iron after 10 days did not deviate significantly. For example the deviation between a and b after 10 days at 25° C. was 0.001 g/100 mL.

Example 2

[0211] To investigate if the effect of molar ratio of CaCl.sub.2:NaCl is irrespective of the respective amounts of surfactant and whether the particle size of toltrazuril in the formulation has an effect on the stabilization of iron complexes by the molar ratio of CaCl.sub.2:NaCl, a comprehensive series of different formulations containing different ratios of CaCl.sub.2:NaCl and particle sizes of toltrazuril [D(v, 95)] has been undertaken

[0212] All of the formulations of this experimental series contain 18.2% M/V of iron (as iron (III) dextran glucoheptonate (Gleptoferron, CAS No. 57680-55-4) colloidal solution); 2.72% MN of suspended toltrazuril and 0.5% MN of phenol as preservative. Respective details of the toltrazuril particle sizes and individual concentrations of salts and surfactants are specified in Table 2.

[0213] In this example, the method for detection of the free iron was dialysis.

[0214] Plotting the iron content measured over the ratio of CaCl.sub.2:NaCl for each storage time and measurement method, and applying a linear fit to it, consistently shows a lowered free iron content at lower ratio of CaCl.sub.2:NaCl, translating into a prove of the individual protective effect of a suitable ratio of CaCl.sub.2:NaCl to the complexed iron pursuant to the present invention.

[0215] An exemplary graphical representation is given in FIG. 1 for the free iron content pursuant to Table 3 plotted over the molar ratio of CaCl.sub.2:NaCl after 12 months of storage (with multiple time ratios being represented by average free iron content of the multiple measurements and ending with ratios of ≤1 to allow better graphical representation).

TABLE-US-00002 TABLE 2 Formulations of Example 2 Docusate Tween 20 Tween 80 Sodium NaCl CaCl.sub.2 D(v,95) # [% (M/V)] [% (M/V)] [% (M/V)] [% (M/V)] [% (M/V)] [μm] 1 0.200 0.100 0.050 0.400 0.400 4.5 2 0.200 0.100 0.050 0.400 0.400 4.3 3 0.200 0.100 0.050 0.400 0.400 5.6 4 0.288 0.076 0.073 0.645 0.332 5.4 5 0.088 0.308 0.063 0.607 0.369 5.5 7 0.000 0.500 0.067 0.947 0.184 5.7 8 0.000 0.43 0.015 0.166 1.028 4.7 9 0.038 0.063 0.038 0.522 0.000 5.0 10 0.316 0.000 0.028 0.741 0.240 5.7 11 0.161 0.199 0.095 0.331 0.069 5.6 12 0.400 0.000 0.091 0.478 0.295 4.9 13 0.450 0.011 0.010 0.405 0.000 5.7 14 0.113 0.000 0.075 0.112 0.888 5.5 16 0.345 0.100 0.024 0.256 0.859 5.7 18 0.258 0.242 0.085 0.683 0.517 5.3 19 0.013 0.088 0.070 1.000 0.000 5.1 20 0.050 0.050 0.042 0.566 0.027 5.0 21 0.000 0.329 0.000 0.800 0.119 5.1 23 0.125 0.375 0.078 0.075 0.627 5.2 24 0.000 0.399 0.03 0.441 0.152 5.3 26 0.250 0.000 0.100 1.095 0.000 4.8 27 0.376 0.018 0.047 0.202 0.798 5.2 28 0.500 0.000 0.033 1.200 0.000 5.3 29 0.113 0.000 0.075 0.113 0.888 5.6 30 0.000 0.500 0.067 0.947 0.184 5.0

TABLE-US-00003 TABLE 3 Measured free iron content of samples measured by dialysis after different times of storage at 30° C. Iron [ppm] Iron [ppm] Iron [ppm] No n(CaCl.sub.2/NaCl) 2.5 Mo 6 Mo 12 Mo 1 0.526 400 840 1251 2 0.526 380 790 1165 3 0.526 420 780 1090 4 0.271 430 780 1100 5 0.320 430 780 1000 7 0.102 330 750 1000 8 3.260 380 900 1300 9 0.000 280 690 1100 10 0.170 280 730 1050 11 0.109 290 620 1030 12 0.325 310 690 1050 13 0.000 290 710 910 14 4.153 350 820 1400 16 1.763 440 780 1100 18 0.398 370 680 1100 19 0.000 330 620 870 20 0.025 370 690 990 21 0.078 350 690 1000 23 4.376 340 — 1200 24 0.181 320 — 1100 26 0.000 290 — 810 27 2.076 350 — 1100 28 0.000 270 — 880 29 4.151 310 — 1100 30 0.102 240 — 1000

Example 3

[0216] To further investigate the influence of molar ratio of CaCl.sub.2:NaCl in view of its dependency on the presence of an ionic surfactant a third series of formulations, mostly identical to Example 2, but not comprising docusate sodium was prepared and stored and analyzed accordingly.

TABLE-US-00004 TABLE 4 Formulations of Example 3 Tween 20 Tween 80 NaCl CaCl.sub.2 D(v,95) No [% (M/V)] [% (M/V)] [% (M/V)] [% (M/V)] [μm] 1 0.200% 0.100% 0.350% 0.350% 4.8 2 0.200% 0.100% 0.350% 0.350% 5.1 3 0.200% 0.100% 0.350% 0.350% 4.4 4 0.317% 0.128% 0.816% 0.142% 4.8 5 0.077% 0.265% 0.009% 0.409% 5.4 6 0.388% 0.005% 0.084% 0.792% 4.8 7 0.171% 0.249% 0.965% 0.032% 4.6 8 0.332% 0.024% 0.540% 0.459% 4.5 9 0.219% 0.045% 0.772% 0.012% 4.3 10 0.251% 0.195% 0.044% 0.723% 4.5 11 0.422% 0.004% 0.431% 0.381% 4.3 12 0.113% 0.084% 0.928% 0.071% 4.4 13 0.449% 0.001% 0.855% 0.104% 4.5 14 0.186% 0.003% 0.000% 1.000% 4.5 15 0.093% 0.188% 0.520% 0.121% 4.3 16 0.235% 0.015% 0.581% 0.335% 4.4 17 0.155% 0.000% 0.352% 0.270% 4.2 18 0.096% 0.055% 0.324% 0.324% 3.8 19 0.089% 0.069% 0.296% 0.653% 4.0 20 0.000% 0.214% 0.133% 0.864% 4.1 21 0.440% 0.010% 0.891% 0.054% 4.6 22 0.064% 0.228% 0.404% 0.087% 4.1 23 0.291% 0.119% 0.217% 0.185% 4.8 24 0.050% 0.137% 0.638% 0.356% 3.9 25 0.210% 0.034% 0.064% 0.581% 4.6 26 0.132% 0.282% 0.458% 0.541% 4.2 27 0.342% 0.108% 0.193% 0.292% 4.3 28 0.178% 0.163% 0.169% 0.231% 4.1

[0217] Dialysis and polarography were used to detect free iron. Results after 6 months at 30° C. are shown in Table 5. Results after 18 months at 30° C. are shown in Table 6

TABLE-US-00005 TABLE 5 Measured free iron content of samples measured by dialysis after 6 months at 30° C. No n(CaCl.sub.2/NaCl) Iron [ppm] 1 0.53 700 2 0.53 670 3 0.53 690 4 0.09 580 5 23.37 710 6 4.98 730 7 0.02 590 8 0.45 700 9 0.01 600 10 8.57 750 11 0.47 670 12 0.04 580 13 0.06 660 14 n.a. — 15 0.12 690 16 0.30 700 17 0.40 670 18 0.53 650 19 1.16 700 20 3.41 720 21 0.03 580 22 0.11 670 23 0.45 750 24 0.29 660 25 4.78 760 26 0.62 780 27 0.80 810 28 0.72 810

TABLE-US-00006 TABLE 6 Measured free iron content of samples measured by polarography after 18 months at 30° C. No n(CaCl.sub.2/NaCl) Iron [ppm]C 1 0.53 2076 2 0.53 2018 3 0.53 1970 7 0.02 1886 13 0.06 1853 17 0.40 1880 20 3.41 2980 21 0.03 1897 26 0.62 1958 28 0.72 2131

[0218] The effect molar ratio of CaCl.sub.2:NaCl is visualized in FIG. 2 based on the data of Table 6, clarifying that if a low free iron content (e.g. below 2500 ppm) of the formulation is intended to be achieved even after prolonged storage, a corresponding low molar ratio of CaCl.sub.2:NaCl must be ensured.

Example 4

[0219] The foregoing examples demonstrated the effect of a low molar ratio of CaCl.sub.2:NaCl against release of free iron ions or small complex fragments from the polynuclear iron(III) polysaccharide complex upon storage over time and at higher temperatures. Consequently, the protective effect should be at maximum if the ratio approaches 0 as it is the case when no or very small amounts of Ca.sup.2+ ions are present, e.g. from impurities.

[0220] To verify on an otherwise identical formulation basis, specific suspensions of other than content of Ca.sup.2+ and Na.sup.+ ions (NaCl or CaCl.sub.2) identical composition were prepared and checked for the respective stability of iron therein (see Table 7 & Table 9). Therefore suspensions containing only NaCl and only CaCl.sub.2 were prepared, stored at 40° C. for a couple of months and analyzed for the content of free iron in course of an Example 4a.

[0221] Within another arm of this setup and to verify that the effect is not restricted and/or related to any other agent in a formulation but truly relates to a ratio while both ions (Ca2+ and Na+) are present (see Table 8 & Table 10) solutions containing only NaCl and only CaCl.sub.2 together with an iron (III) dextran glucoheptonate were prepared, stored at 40° C. for a couple of months and analyzed for the content of free iron (Example 4b).

[0222] In both arms (4a and 4b) analysis was done via the dialysis method, as indicated below.

[0223] The full compositions of the respective formulations are outlined in Table 7 and Table 8, while the remainder to 100% [M/V] is water.

TABLE-US-00007 TABLE 7 Formulations of Example 4a that contain no NaCl or CaCl.sub.2 in suspension Iron (III) as Gleptoferron Toltrazuril complex Tween 80 Tween 20 Phenol NaCl CaCl.sub.2 No % [M/V] % [M/V] % [M/V] % [M/V] % [M/V] [% M/V)] [% M/V)] 1 1.82 18.2 0.07 0.13 0.5 0.9 0 2 1.82 18.2 0.07 0.13 0.5 0 0.9 3 1.82 18.2 0.07 0.13 0.5 0.55 0 4 1.82 18.2 0.07 0.13 0.5 0.9 0 5 1.82 18.2 0.07 0.13 0.5 2.0 0 6 1.82 18.2 0.07 0.13 0.5 0 0.55 7 1.82 18.2 0.07 0.13 0.5 0 0.9 8 1.82 18.2 0.07 0.13 0.5 0 2.0

TABLE-US-00008 TABLE 8 Formulations of Example 4b that contain no NaCl or CaCl.sub.2 and only Iron(III) complex in solution Iron (III) as Gleptoferron No complex % [M/V] NaCl [% M/V)] CaCl.sub.2 [% M/V)] 9 18.2 0 0 10 18.2 0.55 0 11 18.2 0.9 0 12 18.2 2.0 0 13 18.2 0 0.54 14 18.2 0 0.86 15 18.2 0 2.0

TABLE-US-00009 TABLE 9 Free iron content of respective samples measured by dialysis (storage at 40° C.) taken from Example 4a Iron [ppm] Iron [ppm] Iron [ppm] Iron [ppm] Iron [ppm] Iron [ppm] No Start 1 Month 2 Month 3 Months 5 Months 6 Months 1 97 760 1300 2 130 960 1500 3 92 680 1000 1500 4 54 600 990 1400 5 44 540 890 1300 6 96 780 1100 1600 7 88 800 1200 1600 8 80 750 1200 1600

TABLE-US-00010 TABLE 10 Free iron content of respective samples measured by dialysis (storage at 40° C.) taken from Example 4b Iron [ppm] Iron [ppm] Iron [ppm] Iron [ppm] No Start 1 Month 3 Months 6 Months 9 110 720 1200 1500 10 72 650 1100 1300 11 64 570 930 1300 12 68 520 810 1200 13 95 710 1100 1500 14 94 680 1200 1600 15 67 670 1100 1600

[0224] Taking the above data from Table 8 and Table 10 and plotting the increase of free iron (e.g. after 6 months) individually over sodium- and calcium chloride content, one can see that neither sodium nor calcium individually reduce the formation of free iron. Those data evidence, that the molar ratio of CaCl2:NaCl is decisive, as actually both negatively influence the free iron amounts with increasing concentration thereof (FIG. 3 & FIG. 4).