Composition capable of improving stability of bacteriophage lysin proteins

Abstract

The present invention relates to a composition for improving the stability of bacteriophage originated lysin proteins greatly even when the composition contains the bacteriophage originated lysin proteins at a high concentration. More precisely, the present invention relates to a method and a composition for improving significantly the stability of SAL-1 or LysK, the bacteriophage originated lysin protein, included at a high concentration in the composition.

Claims

1. A method for stabilizing SAL-1 or LysK in a composition in solution comprising adding divalent cations to the solution of SAL-1 represented by SEQ. ID. NO: 1 or LysK represented by SEQ. ID. NO: 2, and adding poloxamer to the solution.

2. The method for stabilizing SAL-1 or LysK according to claim 1, wherein the divalent cations are calcium ions or magnesium ions or a mixture thereof.

3. The method for stabilizing SAL-1 or LysK according to claim 1, wherein the concentration of the divalent cations is 0.1 mM to about 20 mM.

4. The method for stabilizing SAL-1 or LysK according to claim 1, wherein the concentration of the poloxamer is 0.01% (w/v) to about 2% (w/v).

5. The method for stabilizing SAL-1 or LysK according to claim 1, wherein the poloxamer is poloxamer 188.

6. An antibiotic composition comprising the bacteriophage lysin protein SAL-1 represented by SEQ. ID. NO: 1 or LysK represented by SEQ. ID. NO: 2, divalent cations as activity enhancers, and poloxamer as a stabilizer.

7. The antibiotic composition according to claim 6, wherein the divalent cations are calcium ions, magnesium ions, or a mixture thereof.

8. The antibiotic composition according to claim 6, wherein the concentration of the divalent cations is 0.1 mM to about 20 mM.

9. The antibiotic composition according to claim 6, wherein the concentration of the poloxamer is 0.01% (w/v) to about 2% (w/v).

10. The antibiotic composition according to claim 6, wherein the poloxamer is poloxamer 188.

11. The method for stabilizing SAL-1 or LysK according to claim 2, wherein the concentration of the divalent cations is 0.1 mM to about 20 mM.

12. The method for stabilizing SAL-1 or LysK according to claim 4, wherein the poloxamer is poloxamer 188.

13. The antibiotic composition according to claim 7, wherein the concentration of the divalent cations is 0.1 mM is about 20 mM.

14. The antibiotic composition according to claim 9, wherein the poloxamer is poloxamer 188.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The application of the preferred embodiments of the present invention is best understood with reference to the accompanying drawings, wherein:

(2) FIG. 1 is a diagram illustrating the outline of the purification process of SAL-1 used in this invention.

(3) FIG. 2 is a set of photographs illustrating the process of the stability test performed in this invention.

(4) FIG. 3 is a graph illustrating the result of the biological activity test performed in this invention. The horizontal axis presents the analysis time (min.) and the vertical axis presents OD.sub.600.

(5) FIG. 4 is a graph illustrating the summary of the result of size exclusion liquid chromatography performed in order to analyze the effect according to the concentration of poloxamer. The horizontal axis presents the poloxamer content % (w/v), and the vertical axis presents the ratio (%) of the peak area of SAL-1 after stirring to the peak area of SAL-1 before stirring.

(6) FIG. 5 is a graph illustrating the effect of the added magnesium ions or calcium ions to SAL-1 solution on the biological activity of SAL-1. The horizontal axis presents the analysis time (min.) and the vertical axis presents OD.sub.600. : calcium ions addition; : magnesium ions addition; : no addition.

(7) FIG. 6 illustrates the result of the stability test over the long-term storage of the SAL-1 solution prepared according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) As explained hereinbefore, the present invention provides a method and a composition characterized by containing poloxamer as a stabilizer to improve greatly the stability of the lysin protein in a solution comprising the bacteriophage lysin protein SAL-1 or LysK at a high concentration.

(9) Practical and presently preferred embodiments of the present invention are illustrative as shown in the following Examples, Experimental Examples and Manufacturing Examples.

(10) However, it will be appreciated that those skilled in the art, on consideration of this disclosure, may make modifications and improvements within the spirit and scope of the present invention.

Example 1

Investigation of a Surfactant Capable of Improving the Stability of a Solution Containing SAL-1

(11) The SAL-1 used in this invention was prepared according to the method described in Korean Patent No 10-075998, particularly purified and prepared according to the method illustrated in FIG. 1. The elution fraction of SAL-1 showing at least 95% purity was finally selected and concentrated until the concentration reached 20 mg/ml, resulting in SAL-1 solution. The concentrated SAL-1 solution was replaced with different buffers. The buffers herein were L-Histidine buffer (10 mM L-Histidine, 5% (w/v) Sorbitol, pH 6.0), Tris-buffer (10 mM Tris-HCl, 140 mM NaCl, pH 7.5), Acetate buffer (10 mM Sodium acetate, 5% (w/v) Sorbitol, pH 5.0), Phosphate buffer A (10 mM Sodium phosphate, 5% (w/v) Sorbitol, pH 6.0), Phosphate buffer B (10 mM Sodium phosphate, 140 mM NaCl, pH 6.0), and HEPES buffer (10 mM HEPES, pH 7.3). The SAL-1 solution replaced with each buffer was added with different surfactants. Then, the proper surfactant was investigated. Selection of the proper surfactant was performed by investigating the increase of the stability of SAL-1 and also by measuring the decrease of the biological activity of SAL-1 as well. That is, a surfactant that was capable of increasing the stability of SAL-1 in a solution without reducing the biological activity of SAL-1 was screened. In this investigation, every surfactant could not all be tested, so those considered to be applicable for a pharmaceutical composition were targeted, which were exemplified by Polyoxyethylene nonylphenyl ether, Polysorbate 20, Polysorbate 40, Polysorbate 60, Tyloxapol, Sorbitan Monostearate, and Polyethyleneglycol Monostearate.

(12) Stability test of the SAL-1 solution was performed as follows.

(13) {circle around (1)} adding a surfactant to SAL-1 solution (0.1%0.5%);

(14) {circle around (2)} stirring the mixture at room temperature for 1 hour;

(15) {circle around (3)} measuring turbidity at 600 nm using a spectrophotometer after stirring; and

(16) {circle around (4)} judging the improvement of stability when the turbidity was least increased, compared with that before stirring.

(17) Biological activity of SAL-1 was investigated as follows. Of course, those surfactants showing least stability improvement effect or none were eliminated from this investigation.

(18) {circle around (1)} adding a surfactant to SAL-1 solution (0.1% 0.5%);

(19) {circle around (2)} leaving the mixture at room temperature for 1 hour;

(20) {circle around (3)} preparing a bacteria suspension comprising Staphylococcus aureus at the concentration of 810.sup.8 cfu/ml by using 1PBS (8 g/L NaCl, 0.2 g/L KCl, 1.44 g/L Na.sub.2HPO.sub.4, 0.24 g/L KH.sub.2PO.sub.4, pH 7.0);

(21) {circle around (4)} adding the mixture of step {circle around (2)} to 1 ml of the bacteria suspension prepared in step {circle around (3)} to make the concentration of SAL-1 therein to be 1 g/ml (using the diluent of the mixture of step {circle around (2)});

(22) {circle around (5)} measuring OD.sub.600 over the time by using a spectrophotometer (when bacteriolysis occurred by SAL-1, OD.sub.600 was supposed to decrease over the time); and

(23) {circle around (6)} judging the biological activity of SAL-1 as high when OD.sub.600 was reduced greatly and fast over the time (judged by TOD.sub.50, which means the OD.sub.600 was reduced to half the first measured OD.sub.600).

(24) As a result, considering the stability of SAL-1 in a solution and the biological activity of SAL-1, poloxamer 188 was selected as the most appropriate surfactant that can improve the stability of SAL-1 in a solution with maintaining the biological activity of the same. Other surfactants were either weak in increasing the stability or reduced the biological activity of SAL-1. The stability test process according to the present invention is illustrated in FIG. 2. The biological activity test result is illustrated in FIG. 3. Buffer type did not affect the stability or the biological activity of SAL-1.

Example 2

Investigation of a Proper Concentration of Poloxamer

(25) A proper concentration of poloxamer was investigated in this example. The stability and the biological activity of SAL-1 in a solution was investigated by the same manner as described in Example 1. To investigate the stability more accurately, size exclusion high performance liquid chromatography was also performed as follows. BioSep-SEC-S2000 column (7.8 mm300 mm) was used as the analysis column. Buffer A (10 mM Tris-HCl, pH 7.5, 500 mM NaCl) was used as the analysis buffer. The flow rate after the addition of the sample was 1 ml/min. The volume of the sample added thereto was 50 l, and the detection was performed using UV detector at 280 nm.

(26) Following is the result of the investigation obtained by using a spectrophotometer when poloxamer was added at the concentrations of 0.10.5% (w/v). There was no significant difference over the concentration of poloxamer.

(27) TABLE-US-00001 TABLE 1 Poloxamer Content OD.sub.600 (%, w/v) Stirring Non-stirring 0 1.2893 0.0008 0.10 0.0148 0.0004 0.25 0.0195 0.0003 0.50 0.0126 0.0003

(28) The result of the size exclusion high performance liquid chromatography performed together is shown in FIG. 4. The result was consistent with that of the turbidity analysis using a spectrophotometer.

(29) Based on the above results, the proper concentration of poloxamer was determined as 0.1% (w/v) to expect the full effect of it.

Example 3

Investigation of the Effect of Poloxamer Addition to the Composition Comprising Additionally Calcium Ions or Magnesium Ions

(30) It was previously confirmed that the addition of calcium ions or magnesium ions was effective in increasing the biological activity of SAL-1, unlike the addition of other ions (FIG. 5). Unfortunately the stability of SAL-1 in a solution comprising calcium ions or magnesium ions was reduced even though the biological activity of SAL-1 was increased by the said ions. Based on the fact, the present inventors wanted to find out whether or not the addition of poloxamer to SAL-1 solution could be effective in improving the stability of SAL-1 in the presence of calcium ions or magnesium ions. The stability test was performed by the same manner as described in Example 1. Since the kind of buffer did not affect the result, L-Histidine buffer (10 mM L-Histidine, 5% (w/v) Sorbitol, pH 6.0) alone was used as the buffer in this example. Calcium ions or magnesium ions were in the form of chloride herein and the concentration thereof was 10 mM. The concentration of poloxamer was 0.1% (w/v) as determined in Example 2. The result is as follows.

(31) TABLE-US-00002 TABLE 2 Addition Calcium Magnesium OD.sub.600 after ions ions Poloxamer stirring x x x 0.200 x x 0.668 x x 1.093 x x 0.041 x 0.040 x 0.044

Example 4

Confirmation of the Effect of Poloxamer Addition in LysK Solution

(32) The effect of poloxamer addition in LysK solution was also investigated by the same manner as described in Example 3. The LysK used in this example was prepared by the same manner as used for the preparation of SAL-1. Considering that the difference over the buffer was minor in Example 1, L-histidine buffer or Tris buffer (10 mM Tris-HCl, pH 7.0) was used to replace LysK solution (20 mg/ml), to which poloxamer was added at the concentration of 0.1% (w/v). As a result, the addition of poloxamer resulted in the significant increase of the stability of LysK, in both cases of using the above two buffers (data not shown).

Example 5

Investigation of the Long-Term Storage Stability

(33) The stability that has been a target of the investigation in the above examples was the stability against external physical stimulus. In addition to the stability against physical stimulus, the storage stability is also very important for the industrial purpose. The SAL-1 solution prepared according to the present invention was kept in a refrigerator for 8 weeks, during which the stability of SAL-1 was investigated. Particularly, as shown in Example 2, size exclusion high performance liquid chromatography was performed for the stability analysis. The peak area presenting SAL-1 in the chromatography was analyzed to investigate the duration of SAL-1 peak over the time.

(34) In this example, the concentrations of SAL-1 in the SAL-1 solution were 1 mg/ml, 13 mg/ml, and 20 mg/ml. The purpose of using different concentration was to find out what concentration of SAL-1 would be appropriate for the best effect of the present invention. The sample analysis was specifically performed 4 weeks later, 6 weeks later, and 8 weeks later, respectively.

(35) As a result, as shown in FIG. 6, the peak area was maintained at least 93% (chromatography peak area), compared with the early peak, in every concentration tested herein after the storage in a refrigerator. In the meantime, the peak area was only maintained 60% at best in the absence of poloxamer (data not shown).

(36) The above results suggest that the composition of the present invention is effective in improving the stability of the lysin protein in the solution comprising the bacteriophage originated lysin protein as an active ingredient. In particular, the effect was high enough in a high concentration solution. The composition of the present invention has also been confirmed to be effective in the solution comprising particularly SAL-1 or LysK as an effective ingredient.

(37) Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing, other embodiments for carrying out the same purposes of the present invention. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended Claims.