Microsphere injection filler and preparation method and reconstitution method thereof

Abstract

The present invention discloses a microsphere injection filler and a preparation method and a re-dissolution method thereof. The microsphere injection filler comprises a sodium alginate solution, an aliphatic polyester microsphere and an ion crosslinking agent solution, and the microsphere injection filler is in a gel state. The microsphere injection filler of the present invention comprises aliphatic polyester microspheres, a sodium alginate solution and an ion crosslinking agent solution, so that the microsphere injection filler is in a gel state, so that the aliphatic polyester microspheres are dispersed and fixed in the gel. When the microsphere injection filler of the present invention is used, it is only necessary to add an ion chelating agent solution before injection to convert the microsphere injection filler from a gel state to a fluid state before injection, so that the re-dissolution time of the microsphere injection filler is greatly shortened, and the aliphatic polyester microspheres are better dispersed after re-dissolution, and the sodium alginate can also show a filling effect immediately after injection.

Description

Technical Field

[0001] The present invention relates to the technical field of tissue filling materials, and in particular to a microsphere injection filler and a preparation method and a reconstitution method thereof. Background Art

[0002] Skin aging is a natural, complex and human process. In recent years, as people's anti-aging awareness has increased, injectable fillers have become an indispensable part of cosmetic medicine. Regenerative materials are materials that promote the regeneration of the body's own fibroblasts and collagen to achieve facial rejuvenation. Compared with traditional filling products with shorter validity periods, regenerative materials have attracted widespread attention due to their natural, gradual and long-lasting filling effects.

[0003] Aliphatic polyester microspheres are used as the main body of regenerative fillers because they can stimulate collagen proliferation, thereby achieving the effect of plumping up the face, reducing wrinkles, and filling depressions. However, aliphatic polyester microspheres usually need to be reconstituted with sterile water several hours before injection, which takes a long time to reconstitute. In addition, the reconstituted aliphatic polyester microspheres have poor dispersibility, and are prone to aggregation and deposition, which can lead to needle blockage during injection, increased injection pain, and even subcutaneous nodules after injection. At the same time, since sterile water can be quickly absorbed, the filling effect cannot be seen immediately after injection. Summary of the invention

[0004] Based on this, it is necessary to provide a microsphere injection filler that can solve the above problems.

[0005] In addition, it is also necessary to provide a method for preparing the above-mentioned microsphere injection filler.

[0006] In addition, it is also necessary to provide a method for re-dissolving the above-mentioned microsphere injection filler.

[0007] A microsphere injection filler comprises a sodium alginate solution, aliphatic polyester microspheres and an ion crosslinking agent solution, wherein the concentration of the sodium alginate solution is 5 g / L to 50 g / L, the concentration of the ion crosslinking agent solution is 0.5 wt% to 2 wt%, the ratio of the sodium alginate solution, the aliphatic polyester microspheres and the ion crosslinking agent solution is 2 mL: 0.05 g to 1 g: 50 μL to 500 μL, and the microsphere injection filler is in a gel state.

[0008] In one embodiment, the mass ratio of the solute of the sodium alginate solution, the aliphatic polyester microspheres and the solute of the ionic crosslinking agent solution is 10-100:50-1000:0.5-5.

[0009] In one embodiment, the material of the aliphatic polyester microspheres is selected from at least one of PCL, PLA, PLLA, PLGA, PHA, PLGA-PEG, PLA-PEG, PLLA-PEG, PCL-PEG, PLGA-PEG-PLGA, PLA-PEG-PLGA, PLLA-PEG-PLGA, PCL-PEG-PLGA, PLGA-PEG-PLA, PLA-PEG-PLA, PLLA-PEG-PLA, PCL-PEG-PLA, PLGA-PEG-PLLA, PLA-PEG-PLLA, PLLA-PEG-PLLA, PCL-PEG-PLLA, PLGA-PEG-PCL, PLA-PEG-PCL, PLLA-PEG-PCL and PCL-PEG-PCL.

[0010] In one embodiment, the solute of the ionic crosslinker solution is a soluble salt having a divalent cation.

[0011] In one embodiment, the solute of the ionic crosslinking agent solution is selected from at least one of calcium chloride, barium chloride, calcium sulfate and barium sulfate.

[0012] A method for preparing the above-mentioned microsphere injection filler comprises the following steps:

[0013] Providing aliphatic polyester microspheres, a sodium alginate solution with a concentration of 5 g / L to 50 g / L, and an ionic crosslinking agent solution with a concentration of 0.5 wt% to 2 wt%;

[0014] Dispersing the aliphatic polyester microspheres into the sodium alginate solution in a ratio of 0.05 g to 1 g: 2 mL, and mixing evenly to obtain an aliphatic polyester microsphere suspension;

[0015] The ionic crosslinking agent solution and the aliphatic polyester microsphere suspension are mixed evenly until the entire system is in a gel state to obtain the required microsphere injection filler, wherein the concentration of the ionic crosslinking agent solution is 0.5wt% to 2wt%, and the ratio of the sodium alginate solution to the ionic crosslinking agent solution is 2mL:50μL to 500μL.

[0016] In one embodiment, the preparation method of the sodium alginate solution is as follows: sodium alginate is dispersed in physiological saline, heated at 60° C. to 80° C. with stirring until dissolved, to obtain the sodium alginate solution.

[0017] A method for re-dissolving a microsphere injection filler comprises the following steps:

[0018] Providing the above-mentioned microsphere injection filler or the microsphere injection filler prepared by the above-mentioned method for preparing the microsphere injection filler;

[0019] The ion chelating agent solution and the microsphere injection filler are mixed evenly until the entire system changes from a gel state to a fluid state, the concentration of the ion chelating agent solution is 0.1wt% to 1wt%, and the ratio of the sodium alginate solution to the ion chelating agent solution is 2mL:0.2mL to 2mL.

[0020] In one embodiment, the mass ratio of the solute of the sodium alginate solution, the aliphatic polyester microspheres, the solute of the ionic crosslinking agent solution and the solute of the ionic chelating agent solution is 10-100:50-1000:0.5-5:2.5-25.

[0021] In one embodiment, the solute of the ionic crosslinking agent solution is selected from at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, tetrasodium ethylenediaminetetraacetic acid, and disodium nitrilotriacetate.

[0022] The microsphere injection filler of the present invention comprises aliphatic polyester microspheres, sodium alginate solution and ion crosslinking agent solution, so that the microsphere injection filler is in a gel state, thereby dispersing the aliphatic polyester microspheres in the gel.

[0023] When the microsphere injection filler of the present invention is used, it only needs to add an ion chelating agent solution before injection to transform the microsphere injection filler from a gel state to a fluid state before injection, thereby greatly shortening the re-dissolution time of the microsphere injection filler, and the aliphatic polyester microspheres after re-dissolution have better dispersibility, reducing the problems of needle blockage during injection, increased injection pain, and even subcutaneous nodules after injection caused by aggregation and deposition of aliphatic polyester microspheres, and at the same time, sodium alginate can show a filling effect immediately after injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] in:

[0026] Figure 1 The present invention is a flow chart of a method for preparing a microsphere injection filler according to one embodiment.

[0027] Figure 2 These are photos of the flow state and gel state of the microsphere injection filler obtained in Example 1. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The invention discloses a microsphere injection filler according to an embodiment of the invention, comprising a sodium alginate solution, aliphatic polyester microspheres and an ion crosslinking agent solution.

[0030] The concentration of the sodium alginate solution is 5g / L to 50g / L, the concentration of the ionic crosslinking agent solution is 0.5wt% to 2wt%, the ratio of the sodium alginate solution, the aliphatic polyester microspheres and the ionic crosslinking agent solution is 2mL: 0.05g to 1g: 50μL to 500μL, and the microsphere injection filler is in a gel state.

[0031] The microsphere injection filler of the present invention comprises aliphatic polyester microspheres, sodium alginate solution and ion crosslinking agent solution, so that the microsphere injection filler is in a gel state, thereby dispersing and fixing the aliphatic polyester microspheres in the gel.

[0032] When the microsphere injection filler of the present invention is used, it only needs to add an ion chelating agent solution before injection to transform the microsphere injection filler from a gel state to a fluid state before injection, thereby greatly shortening the re-dissolution time of the microsphere injection filler, and the aliphatic polyester microspheres after re-dissolution have better dispersibility, reducing the problems of needle blockage during injection, increased injection pain, and even subcutaneous nodules after injection caused by aggregation and deposition of aliphatic polyester microspheres, and at the same time, sodium alginate can show a filling effect immediately after injection.

[0033] Specifically, by adding an ionic crosslinker solution to make the microsphere injection filler in a gel state, the dispersibility of the aliphatic polyester microspheres can be better maintained, thereby making the aliphatic polyester microspheres more dispersible after re-dissolution, reducing problems such as needle blockage during injection, increased injection pain, and even subcutaneous nodules after injection caused by aggregation and deposition of aliphatic polyester microspheres.

[0034] When using this microsphere injection filler, it is only necessary to add an ion chelator solution before injection to transform the microsphere injection filler from a gel state to a fluid state before injection. This can effectively improve the re-dissolution efficiency and effect, and provide a new idea for the re-dissolution of aliphatic polyester microspheres.

[0035] In addition, sodium alginate has good biocompatibility, volume expansion efficiency and relatively slow metabolic behavior, which can effectively improve and prolong the immediate filling effect.

[0036] Generally speaking, the sodium alginate may be of different viscosities and different M / G ratios.

[0037] Preferably, in this embodiment, the mass ratio of the solute of the sodium alginate solution, the aliphatic polyester microspheres and the solute of the ionic crosslinking agent solution is 10-100:50-1000:0.5-5.

[0038] More preferably, the concentration of the sodium alginate solution is 20 g / L, the concentration of the ionic crosslinking agent solution is 1 wt %, and the ratio of the sodium alginate solution, the aliphatic polyester microspheres, and the ionic crosslinking agent solution is 2 mL: 0.05 g: 100 μL.

[0039] Preferably, in this embodiment, the material of the aliphatic polyester microspheres is selected from at least one of polycaprolactone (PCL), polylactic acid (PLA), poly L-lactide (PLLA), poly(lactideco-glycolide) (PLGA), polyhydroxyalkanoates (PHA), PLGA-PEG, PLA-PEG, PLLA-PEG, PCL-PEG, PLGA-PEG-PLGA, PLA-PEG-PLGA, PLLA-PEG-PLGA, PCL-PEG-PLGA, PLGA-PEG-PLA, PLA-PEG-PLA, PLLA-PEG-PLA, PCL-PEG-PLGA, PLGA-PEG-PLA, PLA-PEG-PLA, PLLA-PEG-PLA, PCL-PEG-PLA, PLGA-PEG-PLLA, PLA-PEG-PLLA, PLLA-PEG-PLLA, PCL-PEG-PLLA, PLGA-PEG-PCL, PLA-PEG-PCL, PLLA-PEG-PCL and PCL-PEG-PCL.

[0040] Aliphatic polyester microspheres can be prepared by emulsion solvent evaporation method, membrane emulsification method, spray drying method, microfluidics method, inkjet printing method or can be directly purchased.

[0041] Preferably, in this embodiment, the solvent of the sodium alginate solution is pure water, deionized water, physiological saline or PBS buffer, and the solvent of the ionic crosslinker solution is pure water, deionized water, physiological saline or PBS buffer.

[0042] Preferably, in this embodiment, the solute of the ionic crosslinking agent solution is a soluble salt having divalent cations.

[0043] Specifically, the solute of the ionic crosslinking agent solution is at least one selected from calcium chloride, barium chloride, calcium sulfate and barium sulfate.

[0044] Combination Figure 1 The present invention also discloses a method for preparing the microsphere injection filler according to an embodiment of the present invention, comprising the following steps:

[0045] S10, providing aliphatic polyester microspheres, a sodium alginate solution with a concentration of 5 g / L to 50 g / L, and an ionic crosslinking agent solution with a concentration of 0.5 wt % to 2 wt %.

[0046] In this embodiment, the preparation method of the sodium alginate solution is as follows: sodium alginate is dispersed in physiological saline, heated at 60° C. to 80° C. with stirring until dissolved, to obtain the sodium alginate solution.

[0047] Sodium alginate has good biocompatibility, volume expansion efficiency and relatively slow metabolic behavior, which can effectively improve and prolong the immediate filling effect.

[0048] S20, dispersing aliphatic polyester microspheres into sodium alginate solution in a ratio of 0.05 g to 1 g: 2 mL, and mixing evenly to obtain aliphatic polyester microsphere suspension.

[0049] Specifically, the aliphatic polyester microspheres can be uniformly dispersed in the sodium alginate solution by stirring / ultrasound.

[0050] By adding an ionic crosslinker solution to make the microsphere injection filler in a gel state, the dispersibility of the aliphatic polyester microspheres can be better maintained, thereby making the aliphatic polyester microspheres more dispersible after re-dissolution, reducing problems such as needle blockage during injection, increased injection pain, and even subcutaneous nodules after injection caused by aggregation and deposition of aliphatic polyester microspheres.

[0051] S30, uniformly mixing the ionic crosslinking agent solution and the aliphatic polyester microsphere suspension until the entire system is in a gel state, thereby obtaining the desired microsphere injection filler.

[0052] The concentration of the ionic crosslinking agent solution is 0.5 wt% to 2 wt%, and the ratio of the sodium alginate solution to the ionic crosslinking agent solution is 2 mL: 50 μL to 500 μL.

[0053] The microsphere injection filler prepared by the preparation method of the microsphere injection filler of the present invention comprises aliphatic polyester microspheres, sodium alginate solution and ion crosslinking agent solution, so that the microsphere injection filler is in a gel state, thereby fixing the aliphatic polyester microspheres in the gel.

[0054] The preparation method of the microsphere injection filler of the present invention is worthy of injection. When the microsphere injection filler is used, it only needs to add an ion chelating agent solution before injection to transform the microsphere injection filler from a gel state to a fluid state, thereby greatly shortening the re-dissolution time of the microsphere injection filler, and the aliphatic polyester microspheres after re-dissolution have better dispersibility, reducing the problems of needle blockage during injection, increased injection pain and even subcutaneous nodules after injection caused by aggregation and deposition of aliphatic polyester microspheres, and at the same time, sodium alginate can show the filling effect immediately after injection.

[0055] In addition, when using this microsphere injection filler, it is only necessary to add an ion chelator solution before injection to transform the microsphere injection filler from a gel state to a fluid state before injection. This can effectively improve the re-dissolution efficiency and effect, and provide a new idea for the re-dissolution of aliphatic polyester microspheres.

[0056] The present invention also discloses a method for re-dissolving the microsphere injection filler according to an embodiment of the present invention, comprising the following steps:

[0057] Providing the above-mentioned microsphere injection filler or the microsphere injection filler prepared by the above-mentioned method for preparing the microsphere injection filler;

[0058] The ion chelating agent solution and the microsphere injection filler are mixed evenly until the entire system changes from a gel state to a fluid state.

[0059] Generally speaking, the concentration of the ion chelating agent solution is 0.1 wt% to 1 wt%, and the ratio of the sodium alginate solution to the ion chelating agent solution is 2 mL: 0.2 mL to 2 mL.

[0060] Preferably, in this embodiment, the mass ratio of the solute of the sodium alginate solution, the aliphatic polyester microspheres, the solute of the ionic crosslinking agent solution and the solute of the ionic chelating agent solution is 10-100:50-1000:0.5-5:2.5-25.

[0061] Preferably, in this embodiment, the solute of the ionic crosslinking agent solution is selected from at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, tetrasodium ethylenediaminetetraacetic acid and disodium nitrilotriacetate.

[0062] Preferably, in this embodiment, the solvent of the ionic crosslinker solution is pure water, deionized water, physiological saline or PBS buffer.

[0063] When using this microsphere injection filler, it is only necessary to add an ion chelator solution before injection to transform the microsphere injection filler from a gel state to a fluid state before injection. This can effectively improve the re-dissolution efficiency and effect, and provide a new idea for the re-dissolution of aliphatic polyester microspheres.

[0064] The following are specific embodiments.

[0065] Example 1

[0066] Weigh 2 g of sodium alginate (sodium alginate M / G = 1:2, McLean, S875337-100 g), disperse it in 100 mL of physiological saline, heat and stir at 70° C. until dissolved, to obtain a sodium alginate solution.

[0067] 0.05 g of PCL microspheres were weighed and dispersed in 2 mL of sodium alginate solution, and the PCL microspheres were evenly dispersed by stirring to obtain a microsphere suspension. The PCL microspheres were prepared by a solvent evaporation method: a dichloromethane solution containing 5 wt% PCL was dispersed in a 2 wt% PVA solution, and the PCL microspheres were prepared by high-speed stirring for emulsification and low-speed stirring for solidification, and then washed and dried for use.

[0068] Add 100 μL of 1 wt% calcium chloride solution to the microsphere suspension until the entire system is gelled to a non-flowing state to obtain a microsphere injection filler ( Figure 2 b), sterilize and store for future use.

[0069] Add 1 mL of 0.5 wt% ethylenediaminetetraacetic acid saline solution to the obtained microsphere injection filler and shake until the whole system changes from a gel state to a fluid state ( Figure 2 a).

[0070] Combination Figure 2 ,Depend on Figure 2 a It can be seen that after the EDTA saline solution is added to the microsphere injection filler, the entire system changes from a gel state to a fluid state, and the PCL microspheres are evenly dispersed; Figure 2 b It can be seen that after cross-linking with the ionic cross-linking agent, the microsphere injection filler is converted into a gel state.

[0071] Example 2

[0072] Weigh 0.5 g of sodium alginate (sodium alginate M / G = 1:2, McLean, S875337-100 g), disperse it in 100 mL of physiological saline, heat and stir at 70° C. until dissolved, to obtain a sodium alginate solution.

[0073] 0.5 g of PCL microspheres were weighed and dispersed in 2 mL of sodium alginate solution, and the PCL microspheres were evenly dispersed by stirring to obtain a microsphere suspension. The PCL microspheres were prepared by a solvent evaporation method: a dichloromethane solution containing 5 wt% PCL was dispersed in a 2 wt% PVA solution, and the PCL microspheres were prepared by high-speed stirring for emulsification and low-speed stirring for solidification, and then washed and dried for use.

[0074] 50 μL of 2 wt % calcium chloride solution was added to the microsphere suspension until the entire system was gelled to a non-flowing state to obtain a microsphere injection filler, which was sterilized and stored for later use.

[0075] 2 mL of 0.1 wt% ethylenediaminetetraacetic acid saline solution was added to the obtained microsphere injection filler, and the mixture was shaken until the whole system changed from a gel state to a fluid state.

[0076] Example 3

[0077] Weigh 5 g of sodium alginate (sodium alginate M / G = 1:2, McLean, S875337-100 g), disperse it in 100 mL of normal saline, heat and stir at 70° C. until dissolved, to obtain a sodium alginate solution.

[0078] 1 g of PCL microspheres were weighed and dispersed in 2 mL of sodium alginate solution, and the PCL microspheres were evenly dispersed by stirring to obtain a microsphere suspension. The PCL microspheres were prepared by a solvent evaporation method: a dichloromethane solution containing 5 wt% PCL was dispersed in a 2 wt% PVA solution, and the PCL microspheres were prepared by high-speed stirring for emulsification and low-speed stirring for solidification, and then washed and dried for use.

[0079] 500 μL of 0.5 wt % calcium chloride solution was added to the microsphere suspension until the entire system was gelled to a non-flowing state to obtain a microsphere injection filler, which was sterilized and stored for later use.

[0080] 0.2 mL of 1 wt% ethylenediaminetetraacetic acid saline solution was added to the obtained microsphere injection filler, and the mixture was shaken until the whole system changed from a gel state to a fluid state.

[0081] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A microsphere injection filler, characterized in that: The invention comprises a sodium alginate solution, aliphatic polyester microspheres, an ion crosslinking agent solution and an ion chelating agent solution, wherein the concentration of the sodium alginate solution is 5 g / L-50 g / L, the concentration of the ion crosslinking agent solution is 0.5 wt%-2 wt%, and the ratio of the sodium alginate solution, the aliphatic polyester microspheres and the ion crosslinking agent solution is 2 mL: 0.05 g-1 g: 50 μL-500 μL; the sodium alginate solution, the aliphatic polyester microspheres and the ion crosslinking agent solution are mixed to form a gel filler, and the ion chelating agent solution is added before injection to convert the gel filler into a fluid state to form a microsphere injection filler.

2. The microsphere injection filler according to claim 1, characterized in that: The mass ratio of the solute of the sodium alginate solution, the aliphatic polyester microspheres and the solute of the ionic crosslinking agent solution is 10-100:50-1000:0.5-5.

3. The microsphere injection filler according to claim 1, characterized in that: The material of the aliphatic polyester microspheres is selected from at least one of PCL, PLA, PLLA, PLGA, PHA, PLGA-PEG, PLA-PEG, PLLA-PEG, PCL-PEG, PLGA-PEG-PLGA, PLA-PEG-PLGA, PLLA-PEG-PLGA, PCL-PEG-PLGA, PLGA-PEG-PLA, PLA-PEG-PLA, PLLA-PEG-PLA, PCL-PEG-PLA, PLGA-PEG-PLLA, PLA-PEG-PLLA, PLLA-PEG-PLLA, PCL-PEG-PLLA, PLGA-PEG-PCL, PLA-PEG-PCL, PLLA-PEG-PCL and PCL-PEG-PCL.

4. The microsphere injection filler according to claim 1, characterized in that: The solute of the ionic crosslinking agent solution is a soluble salt having divalent cations.

5. The microsphere injection filler according to claim 1, characterized in that: The solute of the ionic crosslinking agent solution is selected from at least one of calcium chloride and barium chloride.

6. A method for preparing the microsphere injection filler according to any one of claims 1 to 5, characterized in that: The steps include: Providing aliphatic polyester microspheres, sodium alginate solution and ionic crosslinking agent solution; Dispersing the aliphatic polyester microspheres into the sodium alginate solution and mixing them evenly to obtain an aliphatic polyester microsphere suspension; The ionic crosslinking agent solution and the aliphatic polyester microsphere suspension are mixed evenly until the whole system is in a gel state. The ionic chelating agent solution is added before injection to convert the gel filler into a fluid state to form a microsphere injection filler.

7. The method for preparing the microsphere injection filler according to claim 6, characterized in that: The preparation method of the sodium alginate solution is as follows: sodium alginate is dispersed in physiological saline, and heated and stirred at 60° C. to 80° C. until dissolved to obtain the sodium alginate solution.

8. A method for re-dissolving a microsphere injection filler, characterized in that: The steps include: Providing a microsphere injection filler as claimed in any one of claims 1 to 5 or a microsphere injection filler prepared by the preparation method of the microsphere injection filler as claimed in claim 6 or 7; The ion chelating agent solution and the gel filler are mixed evenly until the entire system changes from a gel state to a fluid state, the concentration of the ion chelating agent solution is 0.1wt%~1wt%, and the ratio of the sodium alginate solution to the ion chelating agent solution is 2mL:0.2mL~2mL.

9. The method for re-dissolving the microsphere injection filler according to claim 8, characterized in that: The mass ratio of the solute of the sodium alginate solution, the aliphatic polyester microspheres, the solute of the ion crosslinking agent solution and the solute of the ion chelating agent solution is 10-100:50-1000:0.5-5:2.5-25.

10. The method for re-dissolving the microsphere injection filler according to claim 8, characterized in that: The solute of the ion chelating agent solution is selected from at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, tetrasodium ethylenediaminetetraacetic acid and disodium nitrilotriacetate.

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